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The objectives were to evaluate the effects of standardized ileal digestible (SID) His:Lys ratio above the current NRC requirement on growth performance, intestinal health, and mobilization of His-containing proteins, including hemoglobin, carnosine, and trypsinogen, in nursery pigs from 7 to 11 kg body weight (BW). Forty pigs (26 d of age; initial BW of 7.1 ± 0.5 kg) were allotted to 5 dietary treatments based on a randomized complete block design with sex and initial BW as blocks. Dietary treatments were supplemented with varying SID His to Lys ratios of 26%, 32%, 38%, 43%, and 49% and fed to pigs for 14 d (SID Lys = 1.22%). Feed intake and BW were recorded at d 0, 7, and 14 to measure growth performance. Blood samples were collected on d 12. Pigs were euthanized on d 14 to collect pancreas, longissimus dorsi muscles, mid-jejunum, and jejunal mucosa. Data were analyzed using the Proc Mixed of SAS. Growth performance was not affected, whereas varying SID His to Lys ratio affected hemoglobin (P  < 0.05, max: 12 g/dL at 36%), immunoglobulin A (IgA, P  < 0.05, min: 1.25 μg/mg at 35%) in jejunal mucosa, villus height (P  = 0.065, max: 536 μm at 40%) in jejunum, trypsinogen (P  = 0.083, max: 242 pg/mg at 41%) in pancreas, and carnosine (P  = 0.051, max: 4.7 ng/mg at 38%) in muscles. Varying SID His to Lys ratios linearly increased (P  < 0.05, from 1.95 to 2.80 nmol/mg) protein carbonyl in muscles and decreased (P  < 0.05, from 29.1% to 26.9%) enterocyte proliferation. In conclusion, SID His to Lys ratio between 35% and 41% in diets fed to nursery pigs at 7 to 11 kg enhanced intestinal health and maximized concentrations of His-containing proteins, indicating that His-containing proteins are effective response criteria when determining His requirement. [ABSTRACT FROM AUTHOR]

The objective was to determine the effects of injectable vitamin E (VE) before or after transit on feedlot cattle receiving performance, health, and blood parameters. Angus × Simmental steers (n = 196; body weight [ BW ] = 163 ± 29 kg) were utilized in a randomized complete block design. Steers were blocked by BW and randomly assigned to 1 of 3 treatments: intramuscular injections of saline pre- and post-transit (CON), intramuscular injections of VE (2,000 mg d-α-tocopherol) pre-transit and saline post-transit (PRE), or intramuscular injections of saline pre-transit and VE (2,000 mg d-α-tocopherol) post-transit (POST). Pre-transit injections were administered on day 0, and steers were transported on day 7 for approximately 4 h (348 km). After arrival, steers were fed a common corn silage-based diet in GrowSafe bunks. Final BW tended to be greater (P = 0.08) for CON steers compared with POST steers while PRE steers were intermediate. From days 7 to 63, treatment affected average daily gain (ADG) with PRE and CON steers exhibiting (P = 0.04) greater ADG compared with POST steers. Dry matter intake (DMI), water intake, and gain to feed from days 7 to 63 were not affected (P ≥ 0.17) by treatment. Day 0 serum α-tocopherol concentrations were considered marginal (2.3 ± 0.2 mg/l). A treatment × day interaction (P < 0.01) was observed for serum α-tocopherol concentrations. Serum α-tocopherol concentrations were greatest for PRE steers on day 7 (prior to and post-transit), but greater for POST steers on dys 10 and 14. Plasma ferric-reducing antioxidant potential concentrations increased (P = 0.04) for POST steers compared with CON steers and PRE steers being intermediate. Plasma non-esterified fatty acids (NEFA) concentrations exhibited a treatment × day interaction (P = 0.04) with CON and POST steers being 16% and 14% greater than PRE steers on day 14, respectively. On day 21, NEFA concentrations were greatest for POST steers compared with PRE steers and CON steers being intermediate. There was no main effect (P ≥ 0.14) of treatment on the number of bovine respiratory disease morbidity treatments. Hair cortisol concentrations were decreased (P < 0.01) 14 days after transit for PRE and POST steers compared with CON steers. Overall, injectable VE administered before or after transit increased serum tocopherol concentrations while reducing stress, but did not improve the growth performance of beef steers during the receiving phase. [ABSTRACT FROM AUTHOR]

Genomic testing is a commercially available tool that has the potential to be beneficial in selecting cattle for retained ownership, as well as making management and marketing decisions after finishing. The objectives of this study were to determine if commercially available genomic tests are predictive of differences in finishing performance of steers from sires selected based on divergent growth and milk EPDs. The commercial genomic testing of milk and average daily gain (ADG) scores used in the current experiment were based on Neogen Igenity Beef test results. Two trials were conducted at the OSU Willard Sparks Beef Research Center in Stillwater, Oklahoma. These experiments used two sets of steers from the OSU Range Cow Research Center (400 ± 13 kg, n = 154) from a spring calving cowherd (South Range Unit) and a fall calving cowherd (North Range Unit) of primarily Angus ancestry. Following preconditioning and a wheat pasture stocker program (South Range) or dry lot growing period (North Range), steers were allocated into pens (n = 5 animals/pen) by Igenity ADG Score: low growth (LG) had scores ranging from 1 to 4, medium growth (MG) had scores from 5 to 6, and high (HG) had scores from 7 to 10. Steers were blocked by initial BW and fed a step-up diet for 30 d before being switched to a finishing ration diet (8% prairie hay, 20% Sweet Bran, 62% dry-rolled corn, 5% liquid supplement, and 5% dry supplement [DM basis]). Cattle were fed ractopamine hydrochloride for 30 d before slaughter. The heavy block was on feed for an average of 136 d, while the light block was on feed for an average of 160 d. Data were analyzed as a randomized complete block design using the mixed procedure of SAS (SAS Inst. Inc., Cary NC) with pen as the experimental unit and finishing pen within block as the random statement. During the feeding period, HG steers gained more rapidly than MG or LG steers, with ADG of 2.08, 1.94, and 1.90 kg/d, respectively (P = 0.04). Because gains were greater, BW at slaughter for the HG steers was greater than MG and LG, averaging 690, 669, and 660 kg, respectively (P = 0.04) and hot carcass weights were greater for HG than MG and LG, averaging 438, 426 and 418 kg, respectively (P = 0.02). There were no other differences (P > 0.19) in carcass characteristics among steers. These data suggests that the genomic testing is accurate predictor of performance and can be used by producers can make better marketing decisions in selecting cattle for the retained. Genomic testing could be very beneficial for producers looking to minimize risk and maximize performance in their herd. [ABSTRACT FROM AUTHOR]

The rumen simulation technique (RUSITEC) was used to investigate the effect of ergot alkaloids (EA) and a mycotoxin deactivating product (Biomin AA; MDP) on nutrient digestion, ruminal fermentation parameters, total gas, methane, and microbial nitrogen production. Ruminal fermentation vessels received a feedlot finishing diet of 90:10 concentrate:barley silage (DM basis). Using a randomized complete block design, treatments were assigned (n = 4 vessels/treatment) within two RUSITEC apparatuses in a 2 × 2 factorial arrangement. Treatments included: (1) control (CON) diet (no EA and no MDP); (2) CON diet + 1 g/d MDP; (3) CON diet + 20 mg/kg EA; and (4) CON diet + 20 mg/kg EA + 1 g/d MDP. The study was conducted over 14 d with 7 d of adaptation and 7 d of sample collection. Data were analyzed in SAS using PROC MIXED including fixed effects of EA, MDP, and the EA×MDP interaction. Random effects included RUSITEC apparatus and cow rumen inoculum (n = 4). Ergot alkaloids decreased dry matter (DMD) (P = 0.01; 87.9 vs. 87.2%) and organic matter disappearance (OMD) (P = 0.02; 88.8 vs. 88.4%). Inclusion of MDP increased OMD (P = 0.01; 88.3 vs. 88.9%). Neutral detergent fiber disappearance (NDFD) was improved with MDP; however, an EA×MDP interaction was observed with MDP increasing (P < 0.001) NDFD more with EA diet compared to CON. Acetate proportion decreased (P = 0.01) and isovalerate increased (P = 0.03) with EA. Consequently, acetate:propionate was reduced (P = 0.03) with EA. Inclusion of MDP increased total volatile fatty acid (VFA) production (P < 0.001), and proportions of acetate (P = 0.03) and propionate (P = 0.03), and decreased valerate (P < 0.001), isovalerate (P = 0.04), and caproate (P = 0.002). Treatments did not affect (P ≥ 0.17) ammonia, total gas, or methane production (mg/d or mg/g of organic matter fermented). The inclusion of MDP reduced (P < 0.001) microbial nitrogen (MN) production in the effluent and increased (P = 0.01) feed particle-bound MN. Consequently, total MN decreased (P = 0.001) with MDP. In all treatments, the dominant microbial phyla were Firmicutes, Bacteroidota, and Proteobacteria, and the major microbial genus was Prevotella. Inclusion of MDP further increased the abundance of Bacteroidota (P = 0.04) as it increased both Prevotella (P = 0.04) and Prevotellaceae_UCG-003 (P = 0.001). In conclusion, EA reduced OMD and acetate production due to impaired rumen function, these responses were successfully reversed by the addition of MDP. [ABSTRACT FROM AUTHOR]

Our objectives were to compare the antifungal activity of 5 lignosulfonates, and 2 chitosans against fungi isolated from spoiled hay, and assess the effects of an optimized lignosulfonate, chitosan, and propionic acid (PRP) on high-moisture alfalfa hay. In experiment 1, we determined the minimum inhibitory concentration and minimum fungicidal concentration of 4 sodium lignosulfonates, 1 magnesium lignosulfonate, 2 chitosans, and PRP (positive control) against Aspergillus amoenus , Mucor circinelloides , Penicillium solitum , and Debaromyces hansenii at pH 4 and 6. Among sodium lignosulfonates, the one from Sappi Ltd. (NaSP) was the most antifungal at pH 4. However, chitosans had the strongest fungicidal activity with the exception of M. circinelloides at both pH 4 and 6. PRP had more antifungal effects than NaSP and was only better than chitosans for M. circinelloides. In experiment 2, we evaluated the effects of 3 additives (ADV): optimized NaSP (NaSP-O, UMaine), naïve chitosan (ChNv, Sigma–Aldrich), and PRP on high-moisture alfalfa hay. The experimental design was a randomized complete block design replicated 5 times. Treatment design was the factorial combination of 3 ADV× 5 doses (0, 0.25, 0.5, 1, and 2% w/w fresh basis). Additives were added to 35 g of sterile alfalfa hay (71.5 ± 0.23% DM), inoculated with a mixture of previously isolated spoilage fungi (5.8 log cfu/fresh g), and aerobically incubated in vitro for 23 d (25°C). After incubation, DM losses were reduced by doses as low as 0.25% for both NaSP-O and PRP (⁠ x ¯ = 1.61) vs. untreated hay (24.0%), partially due to the decrease of mold and yeast counts as their doses increased. Also, hay NH3-N was lower in NaSP-O and PRP, with doses as low as 0.25%, relative to untreated hay (⁠ x ¯ = 1.13 vs. 7.80% of N, respectively). Both NaSP-O and PRP increased digestible DM recovery (⁠ x ¯ = 69.7) and total volatile fatty acids (⁠ x ¯ = 94.3), with doses as low as 0.25%, compared with untreated hay (52.7% and 83.8 mM, respectively). However, ChNv did not decrease mold nor yeast counts (⁠ x ¯ = 6.59 and x ¯ = 6.16 log cfu/fresh g, respectively) and did not prevent DM losses relative to untreated hay. Overall, when using an alfalfa hay substrate in vitro, NaSP-O was able to prevent fungal spoilage to a similar extent to PRP. Thus, further studies are warranted to develop NaSP-O as a hay preservative under field conditions. [ABSTRACT FROM AUTHOR]

A study evaluated the effects of adding multi-enzyme mixture to diets deficient in net energy (NE), standardized ileal digestible (SID) amino acids (AA), standardized total tract digestible (STTD) P, and Ca on growth performance, bone mineralization, nutrient digestibility, and fecal microbial composition of grow-finish pigs. A total of 300 pigs (initial body weight [BW] = 29.2 kg) were housed by sex and BW in 45 pens of 7 or 6 pigs and fed 5 diets in a randomized complete block design. Diets were positive control (PC), and negative control 1 (NC1) or negative control 2 (NC2) without or with multi-enzyme mixture. The multi-enzyme mixture supplied at least 1,800, 1,244, 6,600, and 1,000 units of xylanase, β -glucanase, arabinofuranosidase, and phytase per kilogram of diet, respectively. The PC was adequate in all nutrients. The NC1 diet had lower content NE, SID AA, STTD P, and Ca than PC diet by about 7%, 7%, 32%, and 13%, respectively. The NC2 diet had lower NE, SID AA, STTD P, and Ca than PC diet by 7%, 7%, 50%, and 22%, respectively. The diets were fed in four phases based on BW: Phase 1: 29–45 kg, Phase 2: 45–70 kg, Phase 3: 70–90 kg, and Phase 4: 90–120 kg. Nutrient digestibility, bone mineralization, and fecal microbial composition were determined at the end of Phase 1. Pigs fed PC diet had greater (P < 0.05) overall G:F than those fed NC1 diet or NC2 diet. Multi-enzyme mixture increased (P < 0.05) overall G:F, but the G:F of the multi-enzyme mixture-supplemented diets did not reach (P < 0.05) that of PC diet. Multi-enzyme mixture tended to increase (P = 0.08) femur breaking strength. Multi-enzyme mixture increased (P < 0.05) the ATTD of GE for the NC2 diet, but unaffected the ATTD of GE for the NC1 diet. Multi-enzyme mixture decreased (P < 0.05) the relative abundance of the Cyanobacteria and increased (P < 0.05) relative abundance of Butyricicoccus in feces. Thus, the NE, SID AA, STTD P, and Ca could be lowered by about 7%, 7%, 49%, and 22%, respectively, in multi-enzyme mixture-supplemented diets without negative effects on bone mineralization of grow-finish pigs. However, multi-enzyme mixture supplementation may not fully restore G:F of the grow-finish pigs fed diets that have lower NE and SID AA contents than recommended by 7%. Since an increase in content of Butyricicoccus in intestine is associated with improved gut health, addition of the multi-enzyme mixture in diets for pigs can additionally improve their gut health. [ABSTRACT FROM AUTHOR]

This experiment was conducted at the Marvin Klemme Research Station near Bessie, OK in the summers of 2021 and 2022 to test the effects of increased supplementation rates with extruded DDGS cubes on animal performance and supplemental efficiency of steers grazing mixed grass prairie in Western Oklahoma. Steers (n = 133 BW = 247 ± 24 kg and n = 96 BW = 264 ± 16 kg) in 2021 and 2022, respectively, were allocated to 3 supplementation treatments; 1) Negative Control (NC), ad lib free choice mineral only, 2) Low Supplement (LS), 0.91 kg of supplemental DDGS cubes animal-1·d-1, and 3) Medium Supplement (MS), 1.81 kg of supplemental DDGS cubes/animal/d. Pastures were stocked at 2.02 ha/steer in 2021 but the stocking density in 2022 was decreased to 2.83 ha/steer due to drought causing poor range condition and limited forage biomass availability. Data were analyzed as a randomized complete block design using PROC MIXED in SAS 9.4. In 2021, early season ADG of LS and MS were 0.43 and 0.58 ± 0.033 kg greater (P < 0.0001) than NC, respectively. Late season ADG was increased by 0.21 and 0.29 ± 0.033 kg (P < 0.0001) by LS and MS, respectively. Overall, ADG was 0.34 and 0.46 ± 0.29 kg greater (P < 0.0001) than NC for LS and MS, respectively. Supplemental efficiency in the early summer was 0.16 ± 0.03 kg of added gain/kg of supplement greater (P < 0.0001) for LS than MS. Late season efficiency was 0.07 ± 0.02 greater (P < 0.0001) for LS than MS. Season long supplemental efficiency was 0.12 ± 0.02 greater (P < 0.0001) for LS than MS. Gain per hectare was greatest for MS, 30.5 and 8.0 ± 1.92 kg greater (P = 0.0003) than NC and LS, respectively. In 2022, early season ADG was increased by 0.2 ± 0.054 kg (P = 0.0003) for both LS and MS. Late season ADG was 0.27 and 0.52 ± 0.043 kg greater (P < 0.0001) than NC for LS and MS, respectively, while overall ADG was 0.24 and 0.37 ± 0.04 kg greater (P < 0.0001) for LS and MS, respectively. Early season supplemental efficiency was 0.11 ± 0.04 greater (P = 0.005) for LS than MS, late season efficiency did not differ (P = 0.89). Overall efficiency was 0.05 ± 0.03 greater (P = 0.05) for LS than MS. Gain per hectare of MS was 17.8 and 6.5 ± 1.92 kg greater (P = 0.001) than NC and LS, respectively. These data suggest that increased supplementation rates with extruded DDGS cube is a viable option to increase performance of steers grazing mixed grass prairie, especially when forage quality is deficient in nutritive value or availability, but, in most cases the efficiency of the supplement decreases. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of a specialty energy source, which comprises of 28% fat and 55% corn-syrup solids (Solu-E; International Ingredient Corporation, Fenton, MO) on growth performance and fecal microbiota population of nursery pigs. Two hundred and eighty-eight (initial body weight = 5.91 kg) mixed gender pigs were assigned to 4 dietary treatments in a randomized complete block design with body weight as a blocking factor. There were 12 replicate pens per treatment with 6 pigs per pen. Experimental diets were fed in the first 2 phases (d 0 to 21) in pellet form followed by a common phase 3 (d 21 to 42) diet in mash form. Four levels of Solu-E (0%, 4%, 8%, and 12%) were used to formulate 4 dietary treatments for phase 1 (d 0 to 7) and phase 2 (d 7 to 21) at the expense of poultry fat and corn to be isocaloric. There was no difference in average daily feed intake among four treatments during this experiment (Table 1). Average daily gain (ADG) in phase 1 linearly increased (P < 0.05) with increasing inclusion level of Solu-E in experimental diets (from 0.092 to 0.113 kg/d). Pigs fed diets with 8% Solu-E had greater (P < 0.05) ADG and feed efficiency compared with 4% and 12% Solu-E in phase 2, but no difference from 0% Solu-E. Pigs fed diets with 8% Solu-E had greater (P < 0.05) ADG and feed efficiency compared with 0%, 4%, and 12% Solu-E from d 0 to 21, which is consistent with the heavier (P < 0.05) body weight after 21 days of feeding 8% Solu-E diets than other diets. Realtime PCR assay for Enterotoxigenic Escherichia coli, Clostridium perfringens, Salmonella spp., and Lawsonia intracellularis were performed on pooled fecal samples from each treatment collected on d 7. The effect of Solu-E on fecal microbiota was not observed in this study as the PCR assay results were negative for all four treatments. In summary, 8% Solu-E can be used as an excellent energy source to enhance growth performance in the first three weeks of nursery. [ABSTRACT FROM AUTHOR]

An experiment was conducted to test the hypothesis that there are no differences among sources of sunflower co-products on the apparent total tract digestibility (ATTD) of P and Ca and on the standardized total tract digestibility (STTD) of P regardless of where the ingredients were produced. Six sources of sunflower meal (SFM) were obtained from the U.S. (2 sources), Ukraine (2 sources), Hungary, and Italy. A source of sunflower expellers (SFE) from the U.S. was also used. Seven diets were formulated by mixing each source of sunflower co-product with cornstarch; therefore, the sunflower co-product was the only source of P in these diets. Seven additional diets that were similar to the previous seven diets with the exception that 300 units per kg of microbial phytase were added were also formulated. A total of 112 barrows (initial body weight = 17.95 kg ± 1.37 kg) were allotted to the 14 diets using 4 blocks, 2 pigs per diet in each block, and a total of 8 replicate pigs per diet. Pigs were placed in individual metabolism crates to allow for the total collection of fecal materials for 4 days after 7 days of adaptation to the diets. Diets and dried fecal samples were analyzed for dry matter, Ca, and P. Data for Ca and P digestibility were analyzed in a randomized complete block design in a 7 × 2 factorial arrangement using the PROC MIXED function in SAS. Results indicated that diets containing phytase had greater (P < 0.01) ATTD of Ca and P and greater (P < 0.01) STTD of P than diets without phytase (Table 1). Digestibility of P was also greater in one of the sources of SFM from Ukraine compared with the other sources except for the SFM from Hungary (Table 2). Pigs fed the diet containing one of the sources of SFM from the U.S. had greater (P < 0.05) ATTD of Ca compared with pigs fed diets containing the other source of SFM from the U.S. or one of the Ukraine SFM sources. In conclusion, some variability in the ATTD and STTD of P and the ATTD Ca was observed among SFM of different origins, but the ATTD and STTD of P and ATTD of Ca in SFM and SFE were greater if microbial phytase was used. [ABSTRACT FROM AUTHOR]

Previous studies evaluating 15 mg/kg narasin have shown improvements in BW, ADG, G:F, and HCW and carcass yield when fed for an extended period of time (>60 days). However, a detailed evaluation of feeding duration of narasin has not been completed. This study evaluated the effect of narasin feeding duration on growth performance and carcass characteristics of growing-finishing pigs. The study was carried out over a fixed time of 112 days using 1,644 pigs in a randomized complete block design. Narasin was included at 15 mg/kg in the last two, three, or four growing-finishing dietary phases, which resulted in narasin being fed for the last 68, 94, or 112 days of study and compared with a negative control diet. Pigs were fed diets that met or exceeded nutrient recommendations of growing-finishing pigs (NRC, 2012). Pigs were offered ad libitum access to feed and water throughout the study and weighed every 28 days and at every marketing event. Feed additions and feed remaining in the feeder at the time of pig weighing were recorded. Pigs were sent for harvest to a commercial slaughter facility in three marketing groups: Group 1 - 20% of pigs marketed on day 84 of study, Group 2 - 20% of pigs marketed on day 98 of study, and Group 3 - remaining 60% of pigs marketed on day 112 of study. Standard carcass grading measurements were collected for each pig and summarized by pen for data analysis. There were limited statistical differences (P > 0.05) between treatments for growth or carcass measures, likely due to the limited number of replicates (n = 16) in this research facility. Nonetheless, there were numerical improvements from feeding narasin. Final live BW (+0.3, +0.4, +1.5 kg, respectively) and ADG (+0.1, +0.4, and +1.3%, respectively; Table 1) numerically increased with increased feeding duration of narasin. Overall G:F was relatively unaffected by feeding duration. Hot carcass weight increased with increased narasin feeding duration (+0.2, +1.1, +1.9 kg, respectively), resulting in increased carcass yield with increased feeding duration (-0.2, +0.1, +0.4 percentage units, respectively). Collectively, carcass ADG and carcass G:F trended toward improvement with increased feeding duration. Results of this study confirm previously observed improvements in growth performance from extended feeding of narasin compared with controls, suggesting that a greater response to narasin is observed with longer feeding durations. [ABSTRACT FROM AUTHOR]

Previous studies evaluating 15 mg/kg of narasin have shown improvements in BW, ADG, and G:F. However, FDA approved labeling for narasin indicates improved G:F with increased inclusion levels (20 to 30 mg/kg), which may provide greater economic return with higher feed costs. Some commercial systems have shown improvements in ADG and G:F when feeding 20 or 30 mg/kg narasin compared with 15 mg/kg. As such, two studies were conducted to evaluate 30 mg/kg of narasin on growth performance and carcass characteristics of growing-finishing pigs. Studies were carried out using a randomized complete block design with three narasin levels: 0, 15, or 30 mg/kg. Study 1 (2,545 pigs) was carried out from 42.6 ± 1.3 kg to 132.9 ± 3.6 kg. Study 2 (1,235 pigs) was carried out over a fixed time of 112 days from 39.1 ± 3.0 kg to 139.8 ± 3.5 kg. All pigs were fed diets that met or exceeded nutrient recommendations of growing-finishing pigs (NRC, 2012). Pigs were offered ad libitum access to feed and water throughout the study and weighed every 28 days and at every marketing event. Feed additions and feed remaining in the feeder at the time of pig weighing was recorded. Due to relatively low carcass recovery at the harvest facility, carcass data for Study 1 are not presented. Feeding 30 mg/kg of narasin did not improve (P > 0.05) growth or carcass performance compared with feeding 15 mg/kg narasin (Table 1). Compared with controls, feeding 15 mg/kg narasin increased final body weight (1.3 kg and 1.5 kg for Study 1 and 2, respectively), increased hot carcass weight (1.9 kg - Study 2), and improved carcass yield (0.4 percentage units), although differences were not always statistically different (P > 0.05). Overall G:F was improved 1.5% (P < 0.05) in Study 1, but not different (P > 0.05) than controls in Study 2. Results of this study confirm improvements in growth performance and carcass characteristics from feeding 15 mg/kg narasin to growing-finishing pigs. The outcomes of feeding 30 mg/kg of narasin were unexpected based on field outcomes and warrant further research. [ABSTRACT FROM AUTHOR]

The objective of this research was to determine the influence manger space restriction had on program fed feedlot heifers during the growing phase. Charolais × Angus heifers [initial body weight (BW) = 329 ± 22.1 kg] were used in a 109-d backgrounding phase study. Heifers were received from a ranch in western South Dakota approximately 60 days before study initiation. Initial processing (53 days before study initiation) included individual BW measurement, application of a unique identification tag, vaccination against viral respiratory pathogens (Bovi-Shield Gold 5, Zoetis, Parsippany, NJ) and clostridial species (Ultrabac/Somubac 7, Zoetis), and administration of doramectin pour-on (Dectomax, Zoetis) for control of internal and external parasites. All heifers were administered 36 mg of zeranol (Ralgro, Merck Animal Health, Madison, NJ) at study initiation. Upon study initiation, heifers were assigned to 1 of 10 pens (n = 5 pens/treatment with 10 heifers/pen) in a randomized complete block design (blocked by location). Each pen was randomly assigned to 1 of 2 treatments: 20.3 cm (8IN) or 40.6 cm (16IN) of linear bunk space/heifer. Heifers were individually weighed on days 1, 14, 35, 63, 84 and 109. Heifers were programmed to gain 1.36 kg daily based on predictive equations for a medium frame steer calf set forth by the California Net Energy System. To calculate predictive values, a final BW of 575 kg was assumed to be the mature BW of the heifers and tabular net energy values of 2.05 NEm and 1.36 NEg from d 1 to 22, 2.00 NEm and 1.35 NEg from d 23 to 82, and 1.97 NEm and 1.32 NEg from d 83 to 109 were used, because of ingredient inventory changes. Data were analyzed using the GLIMMIX procedure of SAS 9.4 with manger space allocation as the fixed effect and block as the random effect. No differences (P > 0.35) were observed between 8IN or 16IN heifers for initial BW, final BW, average daily gain, dry matter intake, feed efficiency, variation in daily BW gain (within pen standard deviation) or applied energetic measures. No differences (P > 0.50) were observed between treatments for morbidity. Although not statistically analyzed, 8IN heifers appeared to have looser stools during the first two weeks compared with the 16IN heifers. These data suggest restricting manger space allocation from 40.6 cm to 20.3 cm did not negatively influence gain efficiency or the efficiency of dietary net energy utilization in heifers programmed fed a concentratebased diet to gain 1.36 kg daily. The use of tabular net energy values and required net energy of maintenance and retained energy equations are an effective means to program cattle to a desired daily rate of gain during the growing phase. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of the weaning strategy (WS; early, at 130 ± 21 d vs normal, at 187 ± 20 d) and backgrounding length (BGL; short vs long) on growth performance, carcass characteristics, and relative mRNA expression in the longissimus muscle (LM) of beef steers. Angus × SimAngus-crossbred steers [n = 120; body weight (BW) = 130 ± 11.2 kg] were used in randomized complete block design. Steer calves were blocked by age and BW and randomly assigned to 1 of 4 treatments (2×2 factorial arrangement). Treatments consisted of early or normal weaned steers with either a short or a long BGL. Early weaned steers were ad libitum-fed a grain-based diet for 49 d until nursing calves were normally weaned. Subsequently, steers were ad libitum-fed a hay-based diet for 214 d or a concentrates-based diet for 95 d, for the long or the short BGL, respectively. Steers were finished on a high grain diet until harvested at a common 12th rib fat thickness. Longissimus muscle biopsies were performed on days 1, 57, 112, 168, 255. Data were analyzed using PROC MIXED in SAS. Early weaned steers were heavier (P < 0.01; Table 1) at the beginning of the backgrounding and finishing period. When the finishing phase began, steers with a long BGL were heavier (P < 0.01; Table 1) than steers with a short BGL. There was a WS × BGL interaction (P = 0.01; Table 1) for final BW, where normal weaned steers with a long BGL were the heaviest among treatments. In the finishing phase, steers with a long BGL had greater DMI and ADG, but lower G:F (P < 0.01; Table 1) than steers with a short BGL. There was WS × BGL interaction (P = 0.03; Table 1) for days on feed (DOF) in the finishing phase, where early weaned steers with a short BGL required less days on DOF to reach harvesting target than the remaining treatments. No interactions or treatment effects (P = 0.11; Table 2) were detected for marbling score (MS). For the mRNA expression of ZFP423, a WS × d interaction was detected (P < 0.01; Figure 1). Day×WS interaction (P < 0.01) was observed for ZFP423 mRNA expression, early weaned steers showed a greater expression at d 112 and a decreased expression at d 255. For DLK1, a BGL×d interaction occurred (P < 0.01; Figure 2). In d 57 steers with a short BGL presented a greater DLK1 mRNA expression than steers with long BGL, whereas in d 255, this was inverted. Overall, data from this experiment does not support the implementation of different WS and BGL as a method to improve the MS of beef carcasses. [ABSTRACT FROM AUTHOR]

This study was to investigate the effects of supplementing encapsulated butyrate additives in nursery phase 1 and 2 diets with and without pharmacological levels of ZnO on growth performance of nursery pigs. Pigs (n = 720; ~21 d of age, 5.72 kg of BW) were assigned to 6 treatments (n = 12, 10 pigs/pen, mixed sex) in a randomized complete block design with initial BW as a block and fed for 42 days in 3 phases (d 0-9, d 10-21, and d 22-42, respectively). Treatments were: 1) Control, basal diet with 3,000 ppm of Zn in phase 1, 1,500 ppm of Zn in phase 2 and 125 ppm of Zn in phase 3 (i.e., pharmacological levels); 2) Control with GBM Performant (encapsulated butyrate additive with 63% butyric acid) at 0.475 kg/MT in phase 1 and 2 diets; 3) Control with GBM Performant at 0.75 kg/MT in phase 1 and 2 diets; 4) basal diet with GBM Performant at 0.475 kg/MT in phase 1 and 2 diets without pharmacological levels of ZnO; (5) basal diet with GBM Performant at 0.75 kg/MT in phase 1 and 2 diets without pharmacological levels of ZnO; (6) Control with Product A (encapsulated butyrate additive with 40% butyric acid) at 0.48 kg/MT, which provided equivalate dietary butyrate content as treatments 2 and 4. All phase 1 and phase 2 diets were added with antibiotics. Diets contained nutrients meeting or exceeding NRC requirements. Growth performance was measured for each phase. Data were analyzed using SAS v9.4 with pen serving as the experimental unit and differences considered significant at P = 0.05. During phase 1, all GBM Performant treatments had greater (P < 0.01) ADG than Control or Product A treatment. The GBM Performant treatments also had greater ADFI (P = 0.04) and Gain:Feed (P = 0.07) than Product A treatment with Control being intermediate. Throughout the trial, GBM Performant treatment without pharmacological levels of ZnO showed greater ADG (P < 0.01) and ADFI (P < 0.01) than GBM Performant treatment with pharmacological levels of ZnO and the Control, whereas the Product A treatment showed the least ADG and ADFI. The GBM Performant treatment without pharmacological levels of ZnO tended to have greater overall Gain:Feed (P = 0.08) than other treatment groups. There was no significant difference on overall performance from the two supplementing dosage levels of GBM Performant. In conclusion, under the current trial condition, GBM Performant supplementation in phase 1 and 2 diets improved growth performance of nursery pigs than Control group without butyrate. When removing ZnO, GBM Performant treatment showed more benefits on performance compared with pigs supplemented with GBM Performant and pharmacological level of ZnO. [ABSTRACT FROM AUTHOR]

Weaning pigs is often concurrent with transportation-induced stress which can impair growth performance, feed efficiency, and immune resilience, contributing to reduced welfare and increased production losses. The objective of this experiment was to mitigate the adverse effects of early life transport stress on subsequent immune challenges by providing supplemental tryptophan (Trp) during the nursery period. A total of 384 pigs were transported for 8 h at weaning and used in a randomized complete block design with a 2x2 factorial arrangement of immune challenge (Vaccine challenged vs. Unvaccinated) and dietary treatment (Supplemented Trp vs. Non-supplemented Trp). Pigs were fed standard nursery diets, in four phases, over 35-d with pigs receiving 1X or 2X the NRC (2012) recommended Trp concentration. There were 12 pens/treatment with 8 pigs/pen (5 barrows and 3 gilts). Individual BW and pen feed intakes were determined weekly. One-half the pigs on each dietary treatment were subjected to a 3-wk vaccine challenge consisting of Mycoplasma (Respisure-One), Influenza (Flusure XP), and Ileitis (Porcilis) vaccines administered in week 2, 3, and 4 post-weaning, respectively. Data were analyzed as a RCB using GLM procedure in SAS 9.4 with fixed effects of dietary treatment and immune challenge, the interactions, and random effect of replicate. Beginning on d 7 and continuing throughout the nursery period, pigs fed diets containing 2X NRC (2012) Trp were heavier (P < 0.05) than pigs fed diets containing 1X Trp. Heavier BW were the result of an overall improvement in ADG for 2X Trp fed pigs (P < 0.006). There was a tendency (P < 0.08) for an interaction of dietary Trp concentration and vaccine challenge on overall ADFI, with added Trp increasing ADFI in pigs not undergoing a vaccine challenge but having no effect in vaccine challenged pigs. During week 4 post-weaning, G:F was less (P < 0.04) for vaccinated pigs compared with unvaccinated pigs. An interaction between dietary Trp and immune challenge was observed in week 5 postchallenge for G:F (P=0.0372) with G:F being reduced in vaccinated pigs fed 1X Trp, but not in vaccinated pigs fed 2X Trp; indicating that supplemental Trp may have added value in immune challenged pigs. Overall, increasing dietary Trp in nursery diets to 2X the NRC (2012) recommendation improves ADG in nursery pigs and maintains feed efficiency during a vaccine-induced immune challenge. [ABSTRACT FROM AUTHOR]

Recently, there has been interest in including triticale (X Triticosecale Wittmack) within forage programs in the southwest USA. Our objectives were to evaluate in vitro disappearance kinetics of neutral detergent fiber (NDF) and dry matter (DM) for cultivars identified during 2019 as positively or negatively deviant from typical cultivars, based specifically on regressions of 48-h in vitro disappearance of NDF on growth stage (GRST). All NDF analyses included the use of heat-stable α-amylase and sodium sulfite, as well as correction for residual ash (as NDF om). Seven triticale cultivars were established on December 18, 2019 at the University of Arizona Maricopa Agricultural Center, located near Maricopa, AZ. Forage plots were arranged in a randomized complete block design with three complete blocks (replications), and then harvested on seven dates the following late-winter and spring (February 26, March 17, April 1, April 14, April 28, May 12, and May 26). Based on a linear model, GRST was highly variable among cultivars on March 17 (44 ± 10.6), April 1 (57 ± 12.1), April 14 (67 ± 8.9), and April 28 (79 ± 7.2) compared with other harvest dates (SD ≤ 1.7). For concentrations of as NDF om , all cultivars exhibited linear (P  ≤ 0.042) and quadratic (P  < 0.001) polynomial contrasts in response to harvest date, and all cultivars except Merlin Max (P  ≥ 0.063) exhibited at least one additional cubic or quartic effect (P  ≤ 0.015). A contributing factor to the unique response by Merlin Max was the numerically greater maximum canopy height (145 ± 9.8 cm) compared with the mean of all cultivars (107 ± 17.7 cm), which also was associated with greater percentages of stem, as well as reduced percentages of DM partitioned within the grain head. Regressions of as NDF om disappearance after 30- or 48-h incubations on GRST indicated this was an effective independent variable (R 2 ≥ 0.927), and responses were most often linear in nature. Generally, relationships for DM disappearance were quadratic, ostensibly due to the complicating effect of grain fill, but GRST was again an effective predictor variable with R 2 statistics ≥ 0.852 for 12 of 14 combinations of cultivar and incubation time. Predicted percentages of digestible DM attributed to as NDF om disappearance were ≥50.3% through the fully flowered stage of growth, but digestible contributions from nonfiber components following the onset of grain fill profoundly affected overall DM digestibility among cultivars harvested at later GRST. [ABSTRACT FROM AUTHOR]

Creating ensiled forage on a laboratory-scale is a tedious and cumbersome process. One must ensure an anaerobic environment for the success of the fermentation while also striving to replicate field-scale conditions. The objective of this experiment was to determine the effect of laboratory-scale silo type on nutritive value and fermentation profiles of grass-legume silage. This experiment was conducted as a generalized complete block design. There was one treatment factor (silo type) with 11 levels: field-scale baleage control (CON), miniature wrapped baleage (MINI), large fermentation bucket (6GAL), small fermentation bucket (2GAL), miniature silo (PVC), pint-sized Mason-type jar with "BurpLid" (BURP), pint-sized Mason-type jar with Ball-brand fermentation lid (BALL), pint-sized Mason-type jar with an airlock lid (LOCK), single-layered vacuum-sealed bag using a chamber-style sealer (CHMB), double-layered vacuum-sealed bag using a chamber-style sealer (HCHMB), single-layered vacuum-sealed bag using a suction-style sealer (FOOD), or double-layered vacuum-sealed bag using a suction-style sealer (HFOOD). Harvest served as the random blocking factor. Forage was harvested from a single alfalfa-bermudagrass pastures at the Wiregrass Research and Extension Center in Headland, AL. Forage was cut 24 h before collection and allowed to sun-cure. After allocation to treatment, samples were allowed to ferment for 56 d. Following fermentation, samples were assayed for NDF, ADF, ADL, CP, pH, mold, and yeast. Dunnett's test revealed a difference (P < 0.05) from CON for NDF, ADF, and pH. Samples from PVC had 26% greater NDF and 45% greater ADF than CON (58 and 37%, respectively). Samples from BALL were 3 units greater and samples from LOCK were 2 units greater in pH than CON (4.8). When comparing alternative treatments exclusive of CON, there were differences (P ≤ 0.01) in NDF, ADF, ADL, pH, and mold counts among treatments. Results are interpreted to mean that BALL and LOCK are not effective representatives of field-scale silage production due to lack of pH drop, while PVC alters the fiber profiles. All other methods showed promise as prospects for laboratory silage procedures. [ABSTRACT FROM AUTHOR]

Though much effort has been made to characterize the in vivo (IV) and in situ (IS) dry matter digestibility (DMD) of southeastern forages, there is a lack of information identifying methods that best represent the in vivo digestibility of these forages. Thus, the objective of our study was to compare IV and IS methods to determine which technique best represents the in vivo DMD of four bermudagrass (Cynodon dactylon [L.] Pers.) cul-tivars. In an IV experiment, ruminally fistulated heifers (n = 4) were randomly assigned to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection) in a Latin square design. On d 28 of each period, rumen fluid was collected 4 h post-feeding for an accompanying IV experiment using a completely randomized design with a 4 x 2 factorial treatment structure. Factors in the IV experiment included bermudagrass cultivar (COS, RUS, T44, and T85) and digestibility method (Tilley and Terry [TT] or Goering and Van Soest [GVS]). On d 31 of in vivo periods 3 and 5, an accompanying IS experiment was conducted as a randomized complete block design with three treatment factors (in vivo diet [previous described], bermudagrass cultivar [previously described], and incubation timepoint [0, 0.25, 0.50, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24, 48, 72, 96, 120, 144, and 168 h]). Correlations were computed between in vivo DM disappearance and each of the IV (TT and GVS) and IS (24, 48, and 72 h) methods. Regressions were calculated for each of the individual IV and IS measurements, and a stepwise regression was used to determine the predictive value of linear combinations of the measurements. None of the IV or IS DMD values were correlated with in vivo DMD (P ≥ 0.18). Individual IV and IS DMD values did not yield significant models through linear regression (P ≥ 0.18), though the best model (based on AIC) was TT IVDMD (r² = 0.09; P = 0.26). Stepwise regression revealed that there was no linear combination of IV or IS DMD that improved prediction beyond single predictor models. While both IV and IS experiments remain viable tools to screen forages and make relative comparisons, results from this experiment are interpreted to mean that neither of these methods is suitable for prediction of in vivo performance. [ABSTRACT FROM AUTHOR]

Five ruminally cannulated steers (body weight = 390 ± 7.86 kg) were used in two experiments to evaluate the effects of flake density and starch retrogradation on in situ ruminal degradation of steam-flaked corn. In experiment 1, sifted flakes with flake densities of 257, 296, 335, 373, and 412 g/L (enzymatic starch availabilities: 87%, 76%, 66%, 43%, and 49%, respectively) were evaluated in a randomized complete block design experiment. In experiment 2, the experimental design was a randomized complete block design with a 3 × 2 factorial arrangement of treatments. Three steam-flaked corn fractions corresponding to different particle sizes were used: flakes + fines (not sifted; >4 and <4 mm), sifted flakes (>4 mm), and sifted fines (<4 mm). Particle size fractions were stored for 3 d at either 23 °C or 55 °C (starch availabilities averaged across particle sizes: 53.3% and 25.5%, respectively) in heat-sealed foil bags. Samples were ruminally incubated for 0, 3, 6, 12, 24, 48, 72, or 96 h. Degradation data were modeled to obtain the rate and extent of degradation and passage rate was set to 6% per hour. In experiment 1, the rate of degradation decreased linearly (P < 0.01) and in situ ruminal dry matter (DM) degradability decreased linearly (P < 0.01) from 78.9% to 57.3% as flake density increased from 257 to 412 g/L. In experiment 2, storage of steam-flaked corn samples at 55 °C for 3 d decreased (P < 0.01) the rate of degradation by 37.6% across all particle sizes. Storing samples at 55 °C for 3 d decreased (P < 0.01) in situ ruminal DM degradability of flakes + fines, sifted flakes, and sifted fines by 20.9%, 22.6%, and 14.7%, respectively. Using data from experiment 1 and 2, enzymatic starch availability of sifted flakes was positively correlated (R 2 = 0.97; P < 0.01) with in situ ruminal DM degradability. The results demonstrate that decreased starch availability resulting from either starch retrogradation or increased flake density is associated with decreased ruminal digestibility. Decreases in starch availability and in situ ruminal degradability may indicate that increasing flake density or starch retrogradation could potentially alter the site of digestion in cattle. Using prediction equations, decreases in ruminal starch digestibility of steam-flaked corn caused by increasing flake density or increasing starch retrogradation could increase energetic efficiency, depending on the rate of passage and if small intestinal starch digestibility is maintained. [ABSTRACT FROM AUTHOR]

Phytogenic feed additives (PFA) have been shown to provide anti-inflammatory, anti-microbial and antioxidant properties across many species including livestock and can positively influence animal performance. The objective of this study was to evaluate the effects of feeding a PFA to growing and finishing beef steers on growth performance, feed efficiency, carcass traits, and liver abscesses. Forty-five crossbred steers (initial BW; 272 ± 20.5 kg) were housed in individual pens and used in a randomized complete block design including a 110-d growing period followed by a 120-d finishing period. The steers were blocked by BW and randomly allocated to 1 of 3 treatments: control (CON) basal diet without PFA or monensin; basal diet with a phytogenic feed additive (PFA; 500 mg· animal-1·/day-1) or basal diet with monensin (MON; 300 mg/head/d). The growing diet consisted of 60% silage and 40% concentrate, while the finishing diet consisted of 10% silage and 90% of concentrate (DM basis). In the growing period, dry matter intake (DMI) did not differ; whereas, final BW (415 vs. 403 kg; P = 0.10) and average daily gain (1.31 vs. 1.20 kg/d; P = 0.12) was numerically greater with PFA than CON, respectively, with no difference from MON. Feed efficiency (gain:feed) in the growing period was greater (P = 0.04) with MON (173 g/kg) than PFA (161 g/kg) and CON (156 g/kg). In the finishing period, growth performance, feed efficiency, carcass traits did not differ among treatments; whereas, DMI was numerically less (P = 0.11) with PFA (10.2 kg/d) than CON (10.8 kg/d), but there was no difference between PFA and MON (9.8 kg/d). The percentage of abscessed livers did not differ between PFA and CON, but the proportion of abscessed livers tended (P = 0.09) to be greater with MON compared with PFA and CON, without difference in severely abscessed livers among treatments. These results indicate that feed efficiency of growing steers was not improved by PFA to the level with MON. However, supplementation of PFA or MON resulted in similar finishing performance and feed efficiency. [ABSTRACT FROM AUTHOR]

This objective was to evaluate the effects of insufficient (WET) or ample (CUR) curing on red clover silage (29.4 and 45.3% DM, respectively) and hay (65.1 and 89.1% DM, respectively) ruminal degradation. The red clover field was divided into 5 blocks and each block was divided into 2 plots and then assigned randomly to silage and hay. Hay was packed into minibales (~500 fresh g; ~232 kg DM/m³) and silage into mini-silos (19.5 L; ~214 kg DM/m³). Measurements were taken once storage processes had stabilized for hay and silage (50 and 78 d, respectively). Samples were ground to pass 4-mm screen and weighed (5 g DM) into 10 x 20 cm ANKOM R1020 in situ bags. Bags were hooked to a rope, placed in the ventral sac of the rumen of 2 dairy cows for 0, 3, 6, 12, 24, 48, 72, and 96 h. All bags were removed simultaneously, washed, dried, and weighed. This procedure was conducted separately for each block. Data were analyzed as a randomized complete block design (5 blocks) with a 2 (curing extents) x 2 (storage methods) factorial. Differences were declared at P = 0.05. Discrete lag times were higher for WET than CUR (0.23 vs. 0 ± 0.08 h, respectively). The potentially degradable fraction was greater in hay than in silage (50.2 vs. 45.1 ± 1.32% of DM, respectively). Moreover, WET had a greater potentially degradable fraction than CUR (49.6 vs. 45.7 ± 1.32% of DM, respectively). The degradation rate was less in hay than silage (5 vs. 8 ± 0.4%/h, respectively). The WET treatment had a decreased degradation rate than CUR (5 vs. 7, respectively). The undegradable fraction was not different between WET and CUR hay (x2 = 23.3 ± 1.13% of DM). In contrast, WET silage had a decreased undegradable fraction than CUR silage (17.1 vs. 20, respectively). In conclusion, haymaking increased the potentially degradable fraction relative to ensiling but reduced the rate of digestion. For both storage methods, curing reduced the potentially degradable fraction but increased the rate of digestion. [ABSTRACT FROM AUTHOR]

Buffers are an essential component in various biochemical and biophysical assays, enabling the control of pH shifts in the environment. The Tilley and Terry (1963) and Goering Van Soest (1970) methods dominate in vitro forage digestibility research with equally viable results. However, the methods utilize distinct buffer solutions to control the in vitro environment. Given this divergence, it is of interest whether differences in estimates are a factor of the methodology, or the buffer solutions employed in the method. The objective of this study was to determine the effects of in vitro DM digestibility (IVDMD) methodology and buffer solution on digestibility estimates of four bermudagrass cultivars. We conducted our experiment as a randomized complete block design with a 2 × 2 × 4 factorial treatment structure. Approximately 1,000 mL of rumen content (solid and liquid fractions) were collected from two ruminally fistulated heifers in each of two periods (blocks). The samples were separated into two 500-mL aliquots; the first aliquot was subjected to the procedures of Tilley and Terry (1963), and the second aliquot was subjected to the Goering and Van Soest (1970) procedure. Duplicate samples of four bermudagrass cultivars (Coastal, Russell, Tifton 44, Tifton 85) were placed in 125-mL Erlenmeyer flasks and incubated according to the assigned in vitro method. One-half of the samples in each method received the methodologically prescribed buffer solution, and the other one-half in each method received the opposite buffer. There was no effect of in vitro method (P = 0.78), buffer solution (P = 0.53), or bermudagrass cultivar (P = 0.46), or their interactions (P = 0.23) on IVDMD estimates in this experiment. Results are interpreted to mean that buffer type is not pivotal to methodological success, and both methods will yield similar estimates of digestibility. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of 5 and 10 d low feed intake (LF) on the ruminant gastrointestinal tract (GIT). Twelve rams and nine wethers were used in a randomized complete block design where they were blocked by castration status and BW. After 5 d of ad libitum feeding, lambs were either exposed to 0 (CON; 100% DMI; n = 7), 5 (LF5; 30% DMI; n = 7), or 10 d (LF10; 30% DMI; n = 7) of LF. At the end of the study, lambs were euthanized, the GIT was removed to determine the digesta and tissue weights by region and the weights of the liver, spleen, and kidneys were recorded. There were no castration × treatment interactions (P = 0.32). Initial (P = 0.97) and final (P = 0.19) BW did not differ by treatment. The weight of the reticulo-ruminal tissue tended to be less (P = 0.06) for LF10 than CON, with LF5 being intermediate but not different. Ruminal digesta weight was not affected (P = 0.98). Omasal tissue weight did not differ among treatments (P = 0.24), but digesta weight tended (P = 0.07) to be greater for CON compared with LF10 and LF5. Abomasal tissue weight was reduced for LF10 (P = 0.04), with LF5 being intermediate but not different. Abomasal digesta weight was less for LF5 and LF10 than CON (P = 0.04). The weight of the duodenum tended (P = 0.08) to be greater for CON than LF10 and LF5, but digesta weight was not affected (P = 0.16). For the jejunum, tissue and digesta weight tended (P = 0.07) to be greater for CON than LF10, with LF5 being intermediate. The weight of the ileum tended to be the greatest for CON, intermediate for LF5, and the least for LF10 (P = 0.10), but digesta weight was not affected (P = 0.81). Cecal tissue weight was not affected by treatment (P = 0.89); whereas digesta weight was the greatest (P = 0.03) for LF10, the least for CON, and intermediate but not different for LF5. In contrast, colonic tissue weight was less for LF10 relative to LF5 and CON (P = 0.01) and digesta weight tended (P = 0.05) to be greater for CON than LF5 and LF10. Liver weight was reduced (P < 0.01) for both LF5 and LF10 relative to CON, but kidney and spleen weights were not affected (P = 0.33). This study indicates that exposing ruminants to LF rapidly reduces the weights for regions of the GIT and liver. These changes likely implicate a reduced absorptive capacity of the GIT and a lesser metabolic capacity of the liver. [ABSTRACT FROM AUTHOR]

Use of growth promoting implants in beef heifers in Southwestern rangelands has been reported to improve growth, however, the effect on ovarian parameters is unknown. Therefore, the objective of this study was to investigate the influence of level of supplementation when heifers were administered a second Synovex-C implant at weaning on ovarian parameters. At two months of age all heifers (n = 17) were administered a Synovex-C implant. At weaning (8-months old), heifers were stratified by body weight and antral follicle counts and assigned to receive one of two levels of supplementation (High or Low) and Implant (No Implant or Implant). Heifers assigned to Implant were administered a second Synovex-C implant at weaning, thereby creating four treatment groups: High Implant (n = 4), High No Implant (n = 4), Low Implant (n = 5), and Low No Implant (n = 4). Heifers were utilized in a complete randomized block design with a 2x2 factorial. Heifers were individually fed supplement three times a week for 26 weeks with refusals being weighed after each feeding to determine intake. For the first 4 weeks of the study, High and Low heifers were offered 4.54 kg/h/d and 2.72 kg/h/d, respectively, of 20% CP cube. After acclimation High and Low heifers were offered 2.95 kg/h/d and 1.59 kg/h/d, respectively, of 32% CP cube for the remainder of the study. At the end of the supplementation period heifers underwent bilateral ovariectomies. Weight, height, and length of each ovary was recorded. Surface antral follicles were counted on both ovaries and recorded. Height and length of the largest preovulatory follicle was recorded and follicular fluid was collected for analysis of estradiol and progesterone concentrations. Ovarian and follicular measurements were analyzed using MIXED procedures in SAS. Ovarian weight (P = 0.16), ovarian length (P = 0.46), or ovarian height (P = 0.32) were not influenced by implant, supplement level, or their interaction. There was no difference among total surface antral follicle count between implant (No Implant: 34.2 ± 4.3 vs Implant: 40.0 ± 4.6), supplement level (High: 32.75 ± 4.6 vs Low: 41.43 ± 4.3), and their interaction (P = 0.19). Preovulatory follicle diameter was not impacted by implant (No Implant: 10.82 ± 1.27 mm vs Implant: 9.42 ± 1.27 mm), supplement level (High: 10.48 ± 1.27 mm vs Low: 9.77 ± 1.27 mm), or their interaction (P = 0.45). Implant, supplement level, or their interaction did not influence progesterone (P = 0.43), estradiol (P = 0.42), or the estradiol:progesterone ratio (P = 0.41) in follicular fluid. In conclusion, administration of a second Synovex-C implant at weaning did not impact ovarian parameters or the composition of follicular fluid. USDA is an equal opportunity provider and employer. [ABSTRACT FROM AUTHOR]

This study evaluated starch dilution with different sources of fiber from terminal implant to harvest on feedlot cattle performance, rumen buffering characteristics, and carcass outcomes. Steers (n = 416) were allocated to 48 pens in a randomized complete block design and assigned to 1 of 4 dietary treatments. Treatments were steam-flaked corn-based diets: CON; 7.5% corn stalks fed for the entire feeding period or CON followed by CS; 14.8% corn stalks, WD; 9.5% wet distillers grains with solubles and 7.5% corn stalks, or NR; 19.0% wet distillers grains with solubles and 0.0% corn stalks fed from terminal implant to harvest. Steers were transitioned to CS, WD, and NR over 6 d using a two-ration system. Within each pen, 2 steers received an indwelling rumen pH bolus and a 3-axis accelerometer ear-tag to quantify rumination. Treatment differences were considered statistically significant when P < 0.10. Dry matter (DM) and metabolizable energy (ME) intake were greatest for cattle consuming CS, intermediate for WD and CON, and least for NR (P < 0.01). The average daily gain (ADG) did not differ among treatments (P = 0.18); however, feed efficiency (G:F) was least for NR, intermediate for WD, and greatest for CS and CON (P = 0.10). Steers consuming CS had more (P = 0.08) 12th rib fat than NR, WD, or CON, but no other differences (P = 0.24) in carcass characteristics were observed. A treatment × day interaction (P < 0.01) was observed for daily rumination time and ruminal pH. Results suggest that increasing the concentration of corn stalks in the diet post-terminal implant increased DM and ME intake and rumination; replacing corn stalks with wet distillers grains with solubles improved G:F and reduced rumination with minimal impacts on ruminal pH. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of insufficient (WET) or ample (CUR) curing on red clover silage (29.4 and 45.3% DM, respectively) and hay (65.1 and 89.1% DM, respectively) in vitro fermentation measures. Measurements were taken at the start of storage (STRT), after 14 d (MicA), and once storage processes had stabilized for hay and silage (50 and 78 d, respectively; LATE). The red clover field was divided into 5 blocks and each block was divided into 2 plots and then assigned randomly to silage and hay (storage methods). Hay was packed into mini-bales (~500 fresh g; ~232 kg DM/m3) and silage into mini-silos (19.5 L; ~214 kg DM/m3). Samples at each storage stage were analyzed for in vitro gas production (48 h). Gas kinetics were recorded using the Ankom RF Gas Production System. Data were analyzed as a randomized complete block design (5 blocks) with a 2 (curing extents) x 2 (storage methods) x 3 (storage phases) factorial. Differences were declared at P = 0.05. The data was analyzed using the GLIMMIX procedure of SAS 9.4. At STRT, the Asymptotic maximal gas production (M) and fermentation rate (k) were not different between CUR and WET hay (x2 = 240.5 ± 7.33 mL/g incubated DM and x2 = 13.2 ± 0.56% of gas production/h, respectively). However, at MicA, CUR hay had a greater M and k than WET hay (232.7 vs. 192.6 and 13.9 vs. 9.33, respectively). The same was observed at LATE (237.6 vs. 197.6 and 13 vs. 8.36, respectively). At STRT, the CUR and WET silage was not different for M and k (x2 = 233.4 ± 7.33 mL/g incubated DM and x2 = 14.06 ± 0.56% of gas production/h, respectively). A similar trend was observed at MicA (x2 = 220 and 13.6, respectively) and LATE (x2 = 219.7 and 14.7). In conclusion, ample curing of red clover hay preserves the fermentation kinetics relative to insufficient curing, especially after 14 d of storage. In the case of red clover silage, the fermentation kinetics was not affected by the curing extent across the storage period. [ABSTRACT FROM AUTHOR]

The objective of this project was to examine the effectiveness of feeding a kaolin and yeast-based feed additive on the performance of feedlot cattle. Seventy-five steers (initial BW; 545 ± 42.4 kg) were blocked by BW and randomly allocated into 25 blocks of 3 steers (n = 25 per treatment) in a randomized complete block design with 3 treatments including control, low (10 g/day) and high (15 g/day) kaolin and yeast-based feed additive (FA) supplementation. The steers were fed a finishing diet consisting of 7% corn silage, 1% straw, and 92% corn-based concentrate (DM basis). The duration of the feeding period was 120 days. Supplementation of high grain finishing diet with FA did not affect feed intake (average, 12.4 kg/d), final BW (average, 768 kg), averaged daily gain (average, 1.77 kg/d), carcass traits, and abscessed livers. However, increasing the feeding of FA (0, 10, 15 g/d) to finishing steers linearly (P = 0.05) improved feed efficiency from 0.139 to 0.143 and 0.148 kg gain/kg feed and linearly (P = 0.06) improved net energy for maintenance from 2.05 to 2.10 and 2.15 Mcal/kg and net energy for growth from1.39 to 1.43 and 1.47 Mcal/kg, respectively. Fecal IgA concentration linearly (P = 0.06) increased from 15.0 to 22.7 and 30.1 μg/g with increasing FA addition, suggesting an improvement in nutrient absorption, and potentially better gut health. The increasing addition of FA also linearly (P = 0.03) increased plasma lipopolysaccharide binding protein (LBP) concentration from 46.3 to 56.2 and 64.7 μg/mL but decreased blood total antioxidants from 0.282 to 0.251 and 0.204 mM. These results suggest that the addition of FA may support gut health. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of myristic acid on intestinal health and growth performance of nursery pigs. Thirty-six newly weaned pigs (6.6 ± 0.4 kg BW) were assigned to 3 treatments (n = 12) in a randomized complete block design with initial BW and sex as blocks. Pigs were fed for 35 d in 3 phases (10, 10, and 15 d respectively). Treatments were 1) NC: basal diet; 2) PC: NC + 0.25% bacitracin methylene disalicylate (antibiotic; bacitracin: 276 g/t feed) in all phases; and 3) MA: NC + myristic acid at 0.075% in phases 1 and 2 and 0.045% in phase 3. Diets contained nutrients meeting the requirement. Growth performance and fecal score were measured for each phase. Pigs were euthanized to collect jejunal mucosa, jejunal tissues, and ileal digesta. Data were analyzed using preplanned contrasts (NC vs. PC and NC vs. MA) in the Proc MIXED procedure of SAS. Compared with the NC, the PC improved (P < 0.05) ADG in phase 1 (43 to 101 g/d) and ADFI in phase 2 (458 to 578 g/d), whereas the MA improved (P < 0.05) ADG (541 to 668 g/d) and ADFI (801 to 996 g/d) in phase 3. Overall, the PC tended to improve ADG (353 to 419 g/d; P = 0.063), and ADFI (515 to 606 g/d; P = 0.051), whereas the MA improved (P < 0.05) ADG (353 to 431 g/d) and ADFI (515 to 623 g/d) compared with the NC group. The PC decreased (P < 0.05) fecal score (3.17 to 3.03) in phase 2 compared with the NC. The PC tended to decrease IL8 (P = 0.053; 0.53 to 0.37 ng/mg of protein) and protein carbonyl (P = 0.075; 2.65 to 1.66 nmol/mg of protein) in jejunal mucosa compared with the NC. The PC increased (P < 0.05) the villus height to crypt depth ratio (2.61 to 3.02) compared with that of NC. The MA tended to decrease IgG (P = 0.051; 2.44 to 1.67 μg/mg of protein) and IL8 (P = 0.090; 0.53 to 0.39 ng/mg of protein) in jejunal mucosa compared with that of the NC. The MA tended to increase relative abundance of Bacteroidetes (P = 0.075; 3.8 to 13.9) at phylum level, Prevotellaceae (P = 0.073; 3.7 to 13.8) at family level, and Prevotella (P = 0.085; 4.2 to 15.4) at genus level compared with the NC. In this study, it was shown that both bacitracin and myristic supplementation could improve the intestinal health and growth performance of nursery pigs. Effects of bacitracin on intestinal health and growth performance was rather immediate whereas the effects of myristic acid were obtained after a 3-week feeding. [ABSTRACT FROM AUTHOR]

Our objective was to assess the effects of insufficient (WET) or ample (CUR) curing on the phytoestrogen concentrations of red clover silage (29.4 and 45.3% DM) and hay (65.1 and 89.1, respectively). Measurements were taken at the start of storage (STRT), after 14 d (MicA), and once storage processes had stabilized for hay and silage (50 and 78 d, respectively; LATE). Hay was packed into mini-bales (~500 fresh g; ~232 kg DM/m³) and silage into minisilos (19.5 L; ~214 kg DM/m³). Data were analyzed as a randomized complete block design (5 blocks) with a 2 (curing extents) x 2 (storage methods) x 3 (storage phases) factorial. Differences were declared at P ≤ 0.05. The concentration of formononetin was greater in silage vs. hay at STRT (4,624 vs. 2,893 ± 175 mg/kg of DM, respectively), MicA (5,383 vs. 2,110), and LATE (5,666 vs. 2,569). Also, more formononetin was found in WET vs. CUR silage (5,841 vs. 4,608.1± 154 mg/kg of DM, respectively). However, no differences were observed between WET vs. CUR hay (x2 = 2,524). At STRT, biochanin A was greater in silage vs. hay (3,105 vs. 2,012 ± 139 mg/kg of DM, respectively). A similar trend was observed at MicA (3,233 vs. 1,057), and LATE (3,295 vs. 1,228). In addition, more biochanin A was observed in WET vs. CUR silage (3,793 vs. 2,628.9 ± 127 mg/kg of DM, respectively). The opposite was observed in WET vs. CUR hay (1,219.5 vs. 1,644.9). The genistein concentration was greater in silage vs. hay at STRT (149 vs. 120 ± 8.36 mg/kg of DM, respectively), MicA (246 vs. 62.6), and LATE (264 vs. 72.9). Also, the concentration of genistein was greater in WET vs. CUR silage (236 vs. 202.3 ± 7.21 mg/kg of DM, respectively) but the opposite was observed in WET vs. CUR hay (72.8 vs. 97.3). In the case of daidzein, hay had a greater concentration of this phytoestrogen than silage (12.8 vs. 6.67 ± 0.43 mg/kg of DM, respectively). In conclusion, red clover silage maintains greater concentrations of formononetin, biochanin A, and genistein than hay during curing period and across the storage phase. Also, adequate curing is more beneficial for silage than hay in terms of decreasing the phytoestrogen concentrations. [ABSTRACT FROM AUTHOR]

Supplemental feed may be provided to cattle in grazing systems to increase ADG, but can be labor intensive. This study evaluated the performance of steers grazing smooth bromegrass pastures supplemented dried distillers grains plus solubles (DDGS) either daily or three times per week. Crossbred steers (n = 144, initial BW 317 ± 1.25 kg) were used in a randomized complete block design with 3 treatments allocated randomly to 24 paddocks in one of 6 blocks. Treatments consisted of: 1) steers supplemented daily with 0.8% of BW (DM-basis) of DDGS, 2) steers supplemented three times a week with 1.86% of BW (DM-basis) of DDGS, and 3) steers that received no supplementation (control). All steers were implanted with 40 mg trenbolone acetate and 8 mg estradiol (Rev-G; Merck Animal Health, De Soto, KS) implants. Paddocks were divided equally into three strips and rotationally grazed. Put-and-take steers were utilized to match stocking rate with forage growth. Each treatment group rotated through three 0.81-hectare strips per pasture. Pre-graze and post-graze biomass was measured at ground level from each paddock at each rotation. Pre-graze biomass samples were used to determine forage availability. Grazing was initiated in early May with cattle removed from pastures in August, for a total of 97 grazing days. Data were analyzed with MIXED procedure of SAS with paddock as experimental unit and treatment and block as fixed effects. Treatment means of ADG and ending BW differed (P < 0.01) among treatments. The control calves gained 0.85 kg/d. The supplemented treatments significantly increased (P < 0.01) ADG compared with the control, with daily supplementation gaining 1.25 kg/d and 3x gaining 1.11 kg/d. The ADG was decreased (P < 0.01) with 3x a week compared with daily supplementation. The differences in ADG resulted in similar differences in final live BW. The control had a finial live BW of 398 kg and final live BW of both supplemented treatments was significantly increased (P < 0.01) when compared with the control treatment. Final live BW of 3x supplemented steers (423 kg) was decreased (P < 0.01) when compared with daily supplemented steers (436 kg). For steers grazing smooth bromegrass pastures, daily supplementation of DDGS resulted in greater gains and therefore greater final BW when compared with three times a week supplementation and the non-supplemented control. [ABSTRACT FROM AUTHOR]

At weaning it is increasingly common to feed low crude protein (CP) and low standardized ileal digestible (SID) lysine (LYS) diets for improved health outcomes. This nutrient restriction often leads to decreased growth. Compensatory growth in this discussion is a period of enhanced growth that occurs after a period of nutrient restriction. This experiment was conducted to determine if compensatory growth occurs after one or two-weeks restriction of SID LYS at weaning. For the experiment, pigs (n = 252; ~23.5 days of age, 7.24 ± 1.02 kg BW, 8 reps/treatmentt, 5 or 6 pigs/pen) were randomly allotted to one of six treatments in a randomized complete block design with a 2 x 3 factorial arrangement of treatments. Treatment main effects were SID LYS/CP (0.07 or 0.065) or duration of SID LYS restriction (1.2% SID LYS for 0, 1, or 2 weeks). When not restricted, pigs were fed a diet with 1.5% SID LYS. After the first 14 days, all pigs consumed a common diet for 24 days with 1.35% SID LYS. Body weight, feed disappearance, visual fecal scores, and visual piglet scores were measured. Visual fecal scores (1 = normal to 4 = watery) and visual pig appearance scores (1 = pale and hairy to 4 = normal color and well-rounded muscle) were assessed on ordered likert scales to determine the probabilities of observing a more normal stool quality and a worse visual appearance, respectively. Performance data were analyzed as a general linear model. Stool quality and visual appearance were analyzed as a generalized linear mixed model. Pairwise comparisons with Tukey adjustment were used for treatment LSmean separation. No effect of SID LYS/CP or interaction of SID LYS/CP and SID LYS program was detected. Results for the main effect of SID LYS program is presented in Table 1. Restricting SID LYS for the first week resulted in decreased ADG and gain:feed (P < 0.05; Table 1). This same effect was observed in week 2. However, those pigs that moved from 1.2% SID LYS in week 1 to 1.5% SID LYS in week 2 had the similar ADG and gain:feed during week 2 as the pigs that consumed 1.5% SID LYS for both weeks. Pigs that had two weeks of SID LYS restriction had lower body weight at d 38 (P< 0.05), whereas pigs with one week of SID LYS restriction had similar body weight at d 38 to unrestricted LYS fed pigs. In addition to performance, unrestricted LYS decreased stool quality (P<0.05) but improved the visual appearance of pigs (P < 0.10) at d 14 and d 38. In conclusion, pigs can have compensatory growth when SID LYS is restricted from 1.5% to 1.2% for one week, but not two weeks. [ABSTRACT FROM AUTHOR]

Two studies were conducted to estimate the SID Thr:Lys requirement for growth and feed efficiency of PIC 337×1050 pigs from approximately 12- to 70-kg. In Exp. 1, 987 pigs [initial body weight (BW) = 11.8±0.32 kg] were used from 12- to 24-kg. In Exp. 2,875 pigs (initial BW = 43.4±0.58 kg] were used from 43- to 70-kg. Pens of pigs were blocked by BW and randomly allotted to dietary treatments in randomized complete block designs, with 21 to 27 pigs per pen with 8 and 7 replications per treatment (Exp. 1 and 2, respectively). Pens were provided 1 of 5 dietary treatments with increasing SID Thr:Lys ratios at 53, 58, 62, 65, and 68% in each experiment. Two corn-soybean meal-based diets containing 53 and 68% Thr:Lys ratios were blended to achieve target SID Thr:Lys treatment levels in each experiment. In Exp. 1 (12- to 24-kg), ADG and final BW increased (linear, P = 0.006) while ADFI, G:F, Thr intake/d, and Thr intake/kg of gain increased (quadratic, P = 0.001) as Thr:Lys ratio increased (Table). Additionally, Lys intake/d increased (quadratic, P < 0.001) while Lys intake/kg of gain decreased (quadratic, P < 0.001) with increasing Thr:Lys ratio. In Exp. 2 (43- to 70-kg), ADG, G:F, final BW, Thr intake/d and Thr intake/kg of gain also increased (linear, P = 0.036) as dietary Thr:Lys increased. Moreover, Lys intake/kg of gain decreased (linear, P = 0.023) with increasing Thr:Lys. A quadratic polynomial (QP) model predicted a requirement at levels greater than 68% SID Thr:Lys for ADG from 12- to 24-kg, while a QP model suggested that maximum G:F was achieved at 61.8% SID Thr:Lys (Exp. 1). From 43- to 70-kg, QP models suggested maximum ADG and G:F were achieved at levels greater than 68% SID Thr:Lys (Exp. 2). However, similar fitting BLL models predicted no further improvement to G:F and ADG beyond 65 and 67% SID Thr:Lys, respectively. In summary, these results suggest the optimal SID Thr:Lys for 12- to 24-kg pigs is 61.8% for feed efficiency and greater than 68% for ADG. From 43- to 70-kg, the requirement was predicted at or above 65 and 67% SID Thr:Lys for G:F and ADG, respectively. [ABSTRACT FROM AUTHOR]

The study aimed to quantify the effect of increasing the feeding level during late gestation on reproductive performance, body weight (BW) and body condition (BC) at pre- and post-farrowing and at weaning in gilts. A total of 815 PIC Camborough X54 gilts were individually weighed at day 90 of gestation and assigned to two feeding levels in a randomized complete block design. Gilts received either 2.3 kg/d [4.95 Mcal/d of net energy (NE) and 11.5 g/d of standard ileal digestible lysine (SID Lys); CONTROL] or 3.1 kg/d (6.67 Mcal/d of NE and 15.5 g/d of SID Lys; BUMP) from 90 d until farrowing. Gilts were housed in group pens during gestation and feed was provided using a feed box setting. Feed contained 2.15 Mcal/kg of NE and 5 g/kg of SID Lys. Caliper information was individually collected at day 90 of gestation to assess BC. Caliper and BW measurements were collected pre-farrowing and at weaning and their difference was calculated. Additionally, post-farrowing 48 h BW was predicted using the following equation: Gilt 48h postfarrow BW = -20.81 + (0.98 × pre-farrow BW). Total born (TB), born alive (BA), stillborn (SB), and mummified (MM) were collected for each gilt at farrowing, and their percentage per litter was calculated and used for analysis. Data were analyzed using a general linear model considering gilt as the experimental unit. The model included treatment as fixed effect and gilt as random effect. Caliper or BW at 90 days of gestation were considered as covariable for BW and BC analysis, respectively. Alpha for determination of significance was 0.05 and trend were identified at 0.10. BUMP gilts were 7.5 and 7.4 kg heavier than CONTROL gilts at pre- and post-farrowing, respectively (P < 0.001; Table 1). The BW at weaning did not differ between treatments (P = 0.32); however, BUMP gilts lost 6.3 kg BW more than CONTROL gilts (P < 0.001; Table 1) during the lactation period. Regarding BC, caliper at pre-farrow was 0.3 units greater for BUMP gilts compared with CONTROL gilts (P < 0.001; Table 1). No differences were observed in caliper loss during the lactation period and at weaning between treatments (P > 0.05; Table 1). The BUMP gilts tended to have 0.5 more TB compared with CONTROL gilts (P = 0.054; Table 1). Nevertheless, TB is related to the early gestation period and embryo survivability. No differences were observed in BA, SB and MM between treatments (P > 0.05; Table 1). In summary, increasing the feeding level by 0.9 kg/d in late gestation resulted in increased gilt weight and caliper at pre-farrow, and greater weight loss during the lactation period. Although reproductive performance traits were not altered by treatments, these will be followed in subsequent parities. [ABSTRACT FROM AUTHOR]

This study was conducted to estimate the SID Trp:Lys requirement for growth and feed efficiency of PIC 337 × 1050 pigs from approximately 46- to 73-kg. A total of 840 pigs [initial body weight (BW) = 45.9 ± 0.95 kg] were used in a 28-d growth performance study. Pens of pigs were blocked by BW and randomly allotted to dietary treatments with 22 to 27 pigs per pen and 7 replications per treatment in a randomized complete block design. Pens were provided 1 of 5 dietary treatments with increasing SID Trp:Lys ratios at 15, 17.5, 19, 21, and 23%. Two corn-soybean meal-based diets with 30% DDGS containing 15 and 23% Trp:Lys ratios were blended to achieve dietary targets for SID Trp:Lys. Average daily gain, ADFI, G:F, Trp Intake/kg of gain, and final BW increased (quadratic, P = 0.008) with increasing Trp:Lys ratio, while Trp intake/d increased linearly (P < 0.001; Table). Additionally, Lys intake/d increased (quadratic, P = 0.009) while Lys intake/kg of gain decreased (quadratic, P = 0.008). A broken-line linear model predicted no further improvement to ADG beyond 19.5% SID Trp:Lys for 46- to 73-kg pigs. Meanwhile, a broken-line linear model suggested no further improvement to G:F beyond 19.3% SID Trp:Lys, while a similar fitting quadratic polynomial model suggested that maximum G:F was achieved at 21.3% SID Trp:Lys. In summary, these results suggest that the optimal SID Trp:Lys level for 46- to 73-kg pigs is 19.5% for ADG and 19.3 to 21.3% for feed efficiency. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate growth performance and economic return of PIC 800 × Camborough pigs fed increasing SID Lys from approximately 12- to 136-kg. Pens of pigs were blocked by body weight (BW) and randomly assigned to 1 of 5 dietary treatments in a randomized complete block design with 26 pigs per pen and 16 pens per treatment. Pens were provided 1 of 5 dietary treatments with increasing SID Lys at 85, 93, 100, 107, and 115% of current (2021) PIC recommendations within 6 dietary phases as follows: phase 1 (1.09, 1.19, 1.28, 1.36, and 1.47%), phase 2 (0.97, 1.06, 1.14, 1.22, and 1.32%), phase 3 (0.87, 0.95, 1.02, 1.09, and 1.17%), phase 4 (0.75, 0.82, 0.88, 0.94, and 1.01%), phase 5 (0.66, 0.72, 0.77, 0.82, and 0.89%), and phase 6 (0.59, 0.64, 0.69, 0.74, and 0.79%). Two corn-soybean meal-based diets containing low and high Lys were blended to achieve target SID Lys levels for each treatment diet within phase. Overall (d 0 to 143), increasing SID Lys improved (linear, P = 0.007) ADG and G:F, but did not impact ADFI (P > 0.10; Table). A tendency (linear, P = 0.067) for heavier hot carcass weights (HCW) was observed in pigs fed increasing SID Lys. However, there was no evidence for differences (P > 0.10) in carcass yield, backfat depth, loin depth, or carcass lean percentage across treatments. The linear (LM) model served as the best fit for both growth and economic parameters. The LM model predicted maximum ADG and G:F at levels greater than 115% of PIC's current recommendations. However, for income over feed cost (IOFC), the LM model predicted maximum profitability at or below 85% of the current Lys recommendations of PIC. In conclusion, the optimal SID Lys level for PIC 800 × Camborough pigs from 12- to 136-kg differed upon response criteria, with growth performance maximized at levels at or above 115% of the recommendation for SID Lys by PIC; however, maximal economic returns were observed at or below 85% of PIC's current SID Lys recommendations. [ABSTRACT FROM AUTHOR]

A total of 1,125 pigs (31.4 kg BW) of DNA genetics were used in a 109-d experiment to evaluate the effect of SID Lys feeding curve of pigs from 31.4 to 133.3 kg BW. Forty-five pens of mixed sex pigs were used. Pens were blocked by location within the barn with barrow and gilt numbers in pens kept consistent within block. Pens were allotted to one of five dietary treatments in a randomized complete block design with 9 replicate pens per treatment. Dietary SID lysine concentrations were evaluated on a curve (corresponding to 90, 95, 100, 105, and 110% of the DNA Genetics SID lysine recommendations) using a 6-phase feeding program throughout the experimental period. The 100% curve concentrations used were 1.16% for phase 1 (31.4 - 47.5 kg), 1.02% for phase 2 (47.5 - 64.4 kg), 0.92% for phase 3 (64.4 - 81.8 kg), 0.79% for phase 4 (81.8 - 98.9 kg), 0.72% for phase 5 (98.9 - 117.1 kg), and 0.65% for phase 6 (117.1 - 133.3 kg). Diets were corn-soybean meal-DDGS-based and formulated for equal NE concentrations across treatment within diet phase. Data were analyzed using a general linear model. Orthogonal contrasts with coefficients for equally spaced treatments were used to analyze for linear and quadratic effects. A linear (P < 0.05) increase was observed for BW, average daily gain, and G:F as SID lysine level in the diet increased. There was a linear increase observed (P < 0.05) for lysine intake (g/d and g per lb. gain) as SID lysine level of the diet increased. While no difference (P > 0.10) was observed for NE intake, caloric efficiency improved linearly (P < 0.05) as lysine level in the diet increased. Furthermore, return over feed cost improved linearly (P < 0.05) as dietary SID lysine level increased. There was no effect of SID lysine level fed on mortality and morbidity. A linear response (P < 0.05) for hot carcass weight and loin depth was observed as SID lysine level increased. Additionally, a quadratic response was observed (P < 0.05) for fat depth and percent lean as SID lysine level increased. These data indicate the SID lysine level that optimized growth and carcass measurements for DNA pigs ranging from 31.4 to 133.3 kg to be above the 105% curve, corresponding to 1.22, 1.071, 0.966, 0.83, 0.756, and 0.683 for diet phases 1 through 6, respectively. [ABSTRACT FROM AUTHOR]

A management strategy to improve growth performance at weaning is segregation of pigs in the nursery period by body weight (BW; Light, Medium, and Heavy) in an attempt to increase productive performance and decrease within pen variation in BW. However, the result of current studies indicated that this practice may not be as effective as not sorting pigs. The objective was to determine the effect on productive performance and coefficient of variation (CV) within four categories of BW: Normal (without segregation), Light, Medium, and Heavy. A total of 24 Experimental Units, (EU; 50% barrows and 50% gilts) in an Incomplete Randomized Block Design with four treatments (Trt) and six replicates per Trt. Pen was the EU and block was the weaning group. Treatments were four; Normal (without segregation; 6.35 kg BW); Light (4.45 kg BW); Medium (5.89 kg BW); and Heavy (7.15 kg BW). Pigs were weighed individually on d 21 (at the beginning of the experiment), 70, 119, 135 and 146 of life. Growth data were analyzed using PROC MEANS and GLM of SAS. Results indicated that at the beginning of the experiment (for design) BW and the CV were different (P < 0.05). From weaning to d 70 Medium and Normal categories had similar BW (29.79 vs. 30.57 kg; P > 0.05), respectively. Light and Heavy pigs remained unchanged in their weight categories. Interestingly, the CV at d 70 was 3.46 percentage points greater in all the groups of pigs that were regrouped by weight, in fact, the only group that reduced the CV at d 70 was the Normal (it was decreased by 3.26 percentage points). Average daily gain at day 70 was less (P < 0.05) for Light (0.62 kg/d) compared with any of the other treatments (0.69 kg/d, average of the rest of the treatments). Average daily feed intake was less for Light (0.940 kg/d) followed by Medium and Normal (1.00 and 1.04 kg per day, respectively) and the Heavy which had the greatest intake (1.08 kg/d). No differences were found in removed animals and mortality (P > 0.05). However, the total number of animals treated parenterally was greater in the Light and Medium (16.75 vs. 12.80, respectively; P < 0.05) than the Heavy and Normal (7.83 and 7.00, respectively, P < 0.05). At the end of the experiment the BW of the pigs was different between treatments (P < 0.05) being the Light group pigs the least heavy (120.62 kg), followed by the Medium (128.02 kg) and Normal (131.31 kg) the treatment Heavy was the heaviest with 133.04 kg. These results suggest that segregation in nursery by BW has a negative effect on the CV. [ABSTRACT FROM AUTHOR]

The objective of these experiments was to determine if the importance of pellet quality was dependent on pig weight ranges. Therefore, a total of 350 grow-finish pigs (line 600 × 241; DNA) were used in 3 separate experiments. Each experiment was conducted as a randomized complete block design. Pigs were weighed before the onset of each experiment and split into 7 blocks based on average body weight, resulting in 7 replications per treatment. For Exp. 1, 2, and 3, pigs were fed treatments for 20 days from 43 to 68 kg, 21 days from 81 to 107 kg, and 20 days from 118 to 144 kg, respectively. Pelleted diets for Exp. 1, 2, and 3 were steam conditioned at approximately 83, 77, and 67°C, respectively and subsequently pelleted with a 30-horsepower pellet mill (1012-2 HD Master Model, California Pellet Mill, Crawfordsville, IN). For Exp. 1 and 2 diets were pelleted with a 4.8 × 31.8 mm (L:D 6.7) die while a 4.8 × 57.2 mm (L:D 12) die was used for Exp. 3. Treatments consisted of a mash diet and pellets with fines inclusion rates of 9-16, 41-47, 60-68, and 84-91%. For Exp.1, pigs fed pellets with 12.5% fines had improved (P < 0.05) G:F when compared with those fed the mash diet. Pig ADFI increased (linear, P = 0.006) as percent fines at the feeder increased. Pig G:F decreased (linear, P = 0.002) as percent fines increased at the feeder. For Exp. 2, pigs fed pellets with 15.5% fines had improved (P < 0.05) G:F compared with those fed the mash diet. Pig ADFI increased (linear, P = 0.016) when fed pellets with increasing percent fines at the feeder. Pig G:F decreased (linear, P = < 0.001) as fines percentage increased at the feeder. For Exp. 3, pigs fed pellets with 9.6 and 41.8% fines had increased (P < 0.05) G:F when compared with those fed mash diets. Pig G:F decreased (linear, P = 0.005) as pellet fines percentage increased at the feeder. In conclusion, feeding pigs 12.5, 15.5, and 9.6% fines in Exp. 1, 2, and 3 improved G:F by 3.9, 5.4, and 9.1%, respectively, compared with pigs fed mashed diets. Increasing the percent fines from 12.5 to 90.4%, 15.5 to 86.0%, and 9.6 to 83.6% reduced G:F of pigs by 5.7, 7.7, and 5.6% for Exp. 1, 2, and 3, respectively. [ABSTRACT FROM AUTHOR]

The Association of American Feed Control Officials (AAFCO) is gathering information about the safety and efficacy of hemp and its derivatives as potential animal feedstuffs. Yearling rough-stock bulls (n = 38) were used in a randomized complete block design to evaluate the effects of hempseed meal (HSM) as a concentrate ingredient on growth, dry matter intake (DMI), and efficiency. Bulls were blocked by body weight (BW), grouped into 10 pens (n = 3 or 4 bulls/pen), and randomly assigned to hempseed meal (HSM) or a control supplement treatment (CON; 72.5% cottonseed meal, 14.5% soy hulls, and 13% fat). Ingredients for CON were used because they were common commercial commodities and were formulated to match the macronutrients of HSM. Treatments were top-dressed at 10% of the diet, while 90% was fed as a mixed ration [50% bermudagrass hay, 40% textured commercial feed (10% CP)]. Feed delivery, treatment delivery, and orts were recorded daily. Diet samples were dried and used to calculate dry matter intake (DMI). Blood for urea-N (SUN; VetScan Chemistry Analyzer) and BW were obtained on days 0, 21, 42, and 63. Efficiency was evaluated for each period using DMI and average daily gain (ADG). Data were analyzed using the GLIMMIX procedure in SAS 9.4. Results were considered significant at P < 0.05, and tendencies were discussed at 0.05 > P > 0.10. No treatment×time interaction occurred for BW (P = 0.999), ADG (P = 0.563), interim DMI (P = 0.672), feed efficiency (P = 0.254), or SUN (P = 0.170). Treatment did not affect BW (320.4 and 324.69 ± 121.57 kg for CON and HSM, respectively, P = 0.996), but BW increased over time (261.13 ± 74.71 and 322.5 ± 121.57 kg, initial and final BW, respectively, P = 0.001). No treatment effect on ADG occurred (0.73 and 0.84 ± 0.13 kg for CON and HSM, respectively, P = 0.680). However, ADG decreased over time (1.0 ± 0.29, 1.19 ± 0.21 and 0.79 ± 0.13 kg, d0-21, d21-42, and d42-63, respectively, P = 0.005). Daily DMI resulted in a treatment×time interaction, where HSM often consumed more DM than CON (P < 0.01). Interim DMI increased over time (7.44 ± 1.25, 7.84 ± 0.98, and 8.18 ± 0.82 kg, d0-21, d21-42, and d42-63, respectively, P = 0.0073), but when combined with ADG to determine feed efficiency, the main effects were not different (P = 0.17). Over time, SUN increased (4.91, 10.52, 11.66 and 12.72 ± 0.35 mg/dL for days 0, 21, 42 and 63, respectively, P < 0.001), and HSM had greater SUN than CON (10.46 and 9.45 ± 0.30 mg/dL for HSM and CON, respectively, P = 0.0426). These data suggest that bulls fed HSM at 10% diet DM perform similarly to bulls fed the same nutrient profile of standard commercial feed ingredients, indicating comparable nutrient availability between the treatments. Conversely, increased DMI and SUN in the HSM bulls suggest a difference in nitrogen metabolism between the treatments that warrants further investigation. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of supplementing dry live yeast (LY ; Saccharomyces cerevisiae) on in vitro gas production (IVGP) fermentation dynamics, pH, and CH4 concentration at 48 h, and in situ rumen parameters and digestibility of DM (DMD) and NDF (NDFD) of growing cattle during 3 feeding phases: grower (GRW) for 17 d (38% steamed-flaked corn; SFC), transition (TRANS) for 15 d (55.5% SFC: 1.2 Mcal/kg NEg), and finisher (FIN) for 13 d (73% SFC: 1.23 Mcal/kg NEg). Twenty British-crossbred, ruminally cannulated steers (183 kg ± 44 kg) 6 mo of age were blocked by weight into 5 pens containing Calan gate feeders and received a control (CON) diet (17.2% CP, 35.8% NDF, 86.7% DM) without LY on days −12 to 0. After that, animals were randomly assigned to treatments (TRT), 5 animals per TRT: CON or LY at inclusion rates of 5 g/d (LY1), 10 g/d (LY2), or 15 g/d (LY3) top dressed every morning at 0800 for 45 d. The DMD and NDFD were assessed during 7 separate collection days using in situ nylon bags containing 5 g of GRW, TRANS, or FIN diets, incubated at 1200 for 48 h. Protozoa counts (PC) were determined during 5 collection periods. Data were analyzed as a repeated measure within a randomized complete block design, assuming a random effect of the pen. For GRW, TRT altered the total gas production of the nonfiber carbohydrate (NFC ; P = 0.045) and the fractional rate of degradation (kd) of the fiber carbohydrate (FC) pool (P = 0.001) in a cubic pattern (P ≤ 0.05): LY2 had the most gas production and fastest kd. TRT also influenced DMD (P = 0.035) and NDFD (P = 0.012) with LY2 providing the greatest digestibility. For TRANS, TRT tended to affect the NFC kd (P = 0.078) and influenced pH (P = 0.04) and DMD (P < 0.001) in which LY2 yielded the fastest kd, highest pH, and greatest DMD. For FIN, there was an effect of TRT on total gas production (P < 0.001) and kd (P = 0.004) of the NFC pool, FC kd (P = 0.012), in vitro CH4 concentration (P < 0.001), PC (P < 0.001), DMD (P = 0.039), and NDFD (P = 0.008). LY1 had the highest PC and provided the greatest DMD and NDFD. LY2 had the fastest kd of both the NFC and FC pools and had the least CH4 concentration. LY3 had the greatest NFC gas production. No specific dose–response pattern was observed, but 10 g/d provided the most beneficial result for all diets. We concluded that supplementation with LY affected IVGP as well as ruminal parameters and digestibilities. [ABSTRACT FROM AUTHOR]

The energy values of solvent-extracted canola meal (SECM) and expeller-derived canola meal (EDCM) for broiler chickens and growing pigs were determined in 2 experiments using the regression method. Corn–soybean meal reference diet (RF) and 4 test diets were prepared. The test diets consisted of SECM or EDCM that partly replaced the energy sources in the RF at 100 or 200 g/kg, respectively. The ratios of all energy ingredients were kept similar across all experimental diets. In Exp. 1, a total of 300 birds were fed standard broiler starter diet from days 0 to 19 posthatching. On day 19, 240 birds (776 ± 79.3 g initial BW) were assigned into 5 experimental diets in a randomized complex block design with BW as a blocking factor. Excreta were collected from days 23 to 25 and ileal digesta were collected after birds were euthanized by CO2 asphyxiation on day 26. In Exp. 2, 40 barrows (28.4 ± 1.6 kg initial BW) were allotted to 5 experimental diets according to the randomized complete block design with BW as a blocking factor. After 5-d adaption period, the feces and urine samples were collected for 5 d by total collection method. The ileal digestible energy (IDE), apparent ME (AME), and nitrogen-corrected apparent ME (AME n ) in Exp. 1 and the DE, AME, and AMEn in Exp. 2 for experimental diets and canola meals were determined. In Exp. 1, the inclusion of canola meals to RF linearly decreased the IDE, AME, and AMEn for birds fed SECM diets (P < 0.01) and the AME and AMEn for birds fed EDCM diets (P < 0.01). Furthermore, quadratic effects were also found in the IDE, AME, and AMEn by the inclusion of EDCM to RF (P < 0.05). The IDE were 2,194 and 3,514 kcal/kg DM for SECM and EDCM in broiler chickens, respectively. The respective ME and MEn values were 1,919 and 1,695 kcal/kg DM for SECM and 3,134 and 2,937 kcal/kg DM for EDCM. In Exp. 2, the SECM or EDCM addition to RF linearly decreased the AME and AMEn for pigs (P < 0.01). The DE content was also decreased linearly with the increasing level of SECM (P < 0.01). The DE, ME, and MEn of SECM for pigs were 3,109, 2,891, and 2,655 kcal/kg DM, respectively. The EDCM contained 3,850 kcal of DE, 3,581 kcal of ME, and 3,491 kcal of MEn/kg DM for pigs. In conclusion, the energy values of EDCM are greater than those of SECM for broiler chickens and pigs, and pigs utilize more of the GE in SECM and EDCM than broiler chickens. [ABSTRACT FROM AUTHOR]

Dormant forage at weaning in Southwestern rangelands may not be nutritionally sufficient to support growth potential of calves administered a growth promoting implant. Therefore, the objective of this study was to investigate the influence of level of supplementation when heifers were administered a Synovex-C implant at weaning on growth and antral follicle counts (AFC). At weaning (8 months old), heifers (n = 17) were stratified by bodyweights (BW) and AFC and assigned to receive one of two levels of supplement (High or Low) and implant (Implant and No Implant; all heifers received a Synovex C implant at 2 months old). Heifers assigned to the Implant group received a second Synovex-C implant at weaning, thus creating four treatment groups: High Implant (n = 4), High No Implant (n = 4), Low Implant (n = 5), and Low No Implant (n = 4). Heifers were utilized in a complete randomized block design with a 2 x 2 factorial. Heifers were individually fed supplement three times a week for 26 weeks with refusals being weighed after each feeding to determine intake. During the receiving phase High and Low heifers were offered 1.94 kg/h/d and 1.17 kg/h/d, respectively, of 20% CP cube for the first 4 weeks of the study. After acclimation High and Low heifers were offered 1.26 kg/h/d and 0.68 kg/h/d, respectively, of 32% CP cube for the remainder of the study. Biweekly BW and monthly body condition scores (BCS) were recorded. Prior to the start of the project and 45 d before the breeding season, AFC were conducted via transrectal ultrasonography. Average daily gain (ADG), BW, and BCS were analyzed as repeated measures in SAS (PROC MIXED). Antral follicle counts were analyzed using MIXED procedures in SAS. Implant, supplement level, implant × supplement level, and implant × supplement level × week did not impact BW or BCS (P ≥ 0.22). Week (P < 0.0001), implant × week (P < 0.0004), and supplement level × week (P < 0.0001) impacted BW. Week (P < 0.0001), implant × week (P = 0.008), and supplement level × week (P = 0.0005) influenced ADG. Implant heifers tended to have increased ADG (P < 0.09) and High Implant heifers tended to have increased ADG compared to the other implant x supplement level treatments (P ≤ 0.09). Body condition score was significantly different across weeks (P < 0.0001). There was no difference between week (P = 0.64) on AFC. Implant (P > 0.22), supplement level (P > 0.43), and implant x supplement level (P > 0.80) did not influence AFC. In conclusion, administration of a second Synovex-C implant at weaning did not impact AFC and feeding implanted heifers at a higher supplementation level tended to improve ADG. [ABSTRACT FROM AUTHOR]

Camborough PIC sows (n = 291) were fed 1 of 5 dietary treatments to evaluate the standardized ileal digestible (SID) Thr:Lys requirement during lactation. Sows were blocked by parity (1, 2, and 3+) and randomly allotted to 1 of 5 SID Thr:Lys ratios (52, 60, 68, 76, and 84). SID Lys was formulated to 1.03% and SID methionine and cystine (M + C):Lys was 55%. Sows were allowed 5.45 kg feed/day starting on the day of farrowing. All other nutrients met or exceeded the NRC (2012) requirements. Sows were allowed ad libitum access to water, and piglets were cross-fostered within treatment within 24 h of birth. Data collected during the study included sow prefarrow BW, sow weaning weight, starting litter weight, weaning litter weight, piglet mortality, weaning-to-estrus interval, and subsequent total born piglets. Data were analyzed as a randomized complete block design using PROC MIXED with sow as the experimental unit and treatment and parity as fixed effects. Requirement estimation models evaluated were quadratic polynomial, broken-line linear, and broken-line quadratic (BLQ) using PROC NLMIXED. Models that differed in their Bayesian information criterion (BIC) values by at least 2 points were considered to have meaningful differences in their data fit. The best-fit model was based on the best BIC value. As the SID Thr:Lys ratio increased, there was a quadratic response on ADFI (4.73, 4.57, 4.67, 4.55, and 4.60 kg/d; P = 0.001) and percent of sow BW loss (−6.4, −7.89, −7.35, −6.19, and −5.81; P = 0.004). In addition, there was a trend for weaning-to-estrus interval to be affected by the ratio (5.4, 4.4, 4.6, 4.5, and 4.8; P = 0.07). Daily litter gain was also quadratically improved as the SID Thr:Lys ratio increased (2.67, 2.67, 2.78, 2.77, and 2.68 kg/d; P -value = 0.001). For daily litter gain, the BLQ model was determined to be the best fit with an estimated SID Thr:Lys requirement of 65%. In conclusion, the optimal SID Thr:Lys ratio for litter growth was 65. [ABSTRACT FROM AUTHOR]

An experiment was conducted with 430 sows to evaluate the ideal standardized ileal digestible (SID) Val:Lys on sow and litter performance during an 18.6-d lactation period. The SID Val:Lys ratios measured were based on the previously published literature and then values above and below reported values. Sows were randomly allotted within parity block (parity 1, parity 2, and parity 3+) to one of five corn–soybean meal-based lactation diets formulated to contain different levels of SID Val:Lys (0.50, 0.62, 0.75, 0.88, and 1.00, respectively). All diets were formulated to be isocaloric (3.35 ME Mcal/kg) with 0.95% SID Lys and contained vitamins and minerals that exceeded recommendations (NRC, 2012). Experimental diets were given to sows from 112 d of pregnancy throughout the 23-d lactation period. Litters were standardized within 48 h after farrowing. Sows were fed with the Howema computerized feeding system that mixed the high and low diets to create the intermediate diets, weighed the feed for each sow and then delivered the feed to each individual feeding hopper to record daily sow feed intake during lactation. Data were analyzed as a randomized complete block design using the PROC MIXED procedure of SAS with sow as the experimental unit and treatment as a fixed effect and parity as the random effect. Results were considered significant at P ≤ 0.05 and considered a trend at P > 0.05 and P ≤ 0.10. Sow ADFI was not significantly different (5.2, 5.2, 5.2, 5.0, and 5.4 ± 0.15 kg/d, respectively). On average, sows consumed ~45 g of SID Lys per day. Sow wean to estrus (5.2, 4.7, 5.3, 5.5, and 4.5 ± 0.32 d, respectively) was not different as the Val:Lys ratio changed. Increasing the Val:Lys ratio resulted in no differences (2.66, 2.64, 2.76, 2.61, and 2.62 ± 0.08 kg; P > 0.10) in average daily litter gain. There were no differences in sow weight loss or subsequent total born across the dietary treatments. Overall, increasing levels of SID Val:Lys did not change sow reproductive performance or piglet growth rate. [ABSTRACT FROM AUTHOR]

In Phase 1 (days 0 to 56) of a two-phase experiment, 81 steers (initial BW = 189 ± 22 kg) were arranged in a generalized randomized block design, allocated to nine pens (nine steers per pen) and assigned to one of three dietary treatments. Treatments consisted of different inclusion rates of Fermenten (FER) in a backgrounding diet fed ad libitum, and were as follows: 0% (CON), 2%, or s FER in the diet DM. Steer was considered the experimental unit, and individual DMI was measured using the GrowSafe system. In Phase 2 (days 57 to 112), treatments were discontinued and steers were relocated to a paddock with free access to a common basal diet, to assess potential residual effects of FER. Effect of treatment was measured on performance, concentration of serum urea nitrogen (SUN), NEFA and glucose, and apparent total tract digestibility of nutrients. On day 56, steers fed 4% FER had lesser (P = 0.01) BW than 2% FER steers. Steers fed CON also tended (P = 0.08) to have greater BW than 4% FER steers. ADG was not different (P = 0.96) between CON and 2% FER steers, whereas steers in the 4% FER treatment had lesser (P ≤ 0.01) ADG than CON and 2% FER. Steers in the 4% FER treatment had lesser (P = 0.04) DMI than CON, and were less feed efficient (P ≤ 0.04) than 2% FER and CON steers. However, DMI as a percentage of the BW did not differ (P = 0.07) across treatments. A treatment effect was observed for final BW on day 112 (P = 0.05), where 4% FER tended (P = 0.07) to have lesser BW than CON. In Phase 2, ADG was not different (P = 0.18) among treatments. However, overall ADG (days 0 to 112) was lesser (P = 0.02) for steers fed 4% FER when compared with CON. There was no difference (P ≥ 0.12) in longissimus muscle area gain or 12th rib fat depth gain. There was a treatment × day interaction for serum concentrations of glucose (P < 0.001), NEFA (P < 0.001), and SUN (P < 0.001). Steers fed 4% FER had greater (P < 0.001) DM, OM, NDF, ADF, and CP apparent total tract digestibility than CON. Similarly, 4% FER steers had greater (P ≤ 0.02) DM, OM, NDF, and ADF digestibility than 2% FER. Results show that although inclusion of FER increased apparent total tract digestibility of nutrients, DMI and overall performance of growing beef cattle were negatively affected, mainly when FER was included at 4% of the diet DM. [ABSTRACT FROM AUTHOR]

While much effort has been devoted to both the characterization of ruminal fermentation dynamics and the evaluation of bermudagrass production, independently, there is a lack of information regarding ruminal digestive kinetics using beef cattle in southern forage systems. Thus, the objective of our study was to evaluate in situ digestive kinetics of four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars in heifers consuming typical southern forages. (Coastal, Tifton 44, Tifton 85, and Russell). Ruminally fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection). On d 31 of periods 2 and 3, an in-situ experiment was conducted as a randomized complete block design with a 3-factor factorial treatment structure. The first factor (n = 4) was diet consumed by the animal (described above). The second factor (n = 4) was the incubated forage (same cultivars as the in vivo experiment). The third factor was incubation timepoint (n = 19; 0, 0.25, 0.50, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24, 48, 72, 96, 120, 144, and 168 h). Four in situ bags were incubated in each animal at each timepoint; two were used for NDF, ADF, and ADL, and two were used for CP determination. Data were analyzed using SAS v. 9.4. There was a decreased (P < 0.05) potentially degradable fraction from COS (30.0%) compared with T85 (55.1%), T44 (48.1%), or RUS (47.1%). Similarly, COS presented the greatest (P < 0.05) undegradable fraction (37.0%) and T85 the least (15.9%), with RUS and T44 intermediate (25.0 and 21.9%, respectively). There was no effect of bermudagrass cultivar, however, on the rate constant of digestion (0.94%/h; P = 0.26) or lag time (3.2 h; P = 0.38). A visual appraisal of the degradation curve suggests that the asymptote of digestion was not reached at the measured 168 h. Results are interpreted to mean that T44 is the preferable bermudagrass cultivar, followed by T85 and RUS, while COS is the least favorable. Further, given the lack of visible asymptote, we speculate that bermudagrass likely passes the rumen before full digestion is realized. [ABSTRACT FROM AUTHOR]

The development of newer alfalfa cultivars with improved adaptation to local growing conditions and dual-purpose applications has increased alfalfa incorporation into grass systems in the southern United States. The complementary growth of both species helps to extend the forage production season length, decreasing producer reliance on supplementation. The objective was to determine forage mass (FM) and nutritive value, botanical composition, and structural responses of alfalfa-bermudagrass systems managed under five stockpiling strategies (6-, 8-, 10-, 12- and 14-weeks of accumulation) in Shorter, AL. A randomized complete block design with eight replications was used. Harvested forage samples were manually separated into individual components and placed into 60° C until constant weight, then weighed. Measurements of ground cover, and alfalfa density and persistence were taken prior to plot harvest. There was a treatment × year interaction (P= 0.009) and greater FM was observed for 10- and 12-wks of regrowth (4,279 and 4244 kg DM/ha, respectively) in Year 2. This response was associated with greater (P < 0.001) bermudagrass percentage in the mixture in Year 2 than 1 (averaged 57 vs 23%, respectively). Weeds remained below 4% in both years. There was a direct relationship between increased regrowth period length with leaf shattering and lodging. Over 10-wks of regrowth, percentage of lodging was >30% and rate of leaf shattering doubled. This response directly affected leaf area index observed for the alfalfa-bermudagrass mixtures at 14-wk with a reduction of 30% when compared to 6-wks regrowth (2.6 vs 3.9, respectively). Greater (P < 0.001) digestibility was associated with shorter regrowth period (6-wk), although the values observed ranged from 62 to 87% which represents high nutritive value forage that can meet higher animal requirements. Based on results, stockpiling alfalfa-bermudagrass mixtures using varying accumulation period lengths may be a viable system to provide high quality feed and extend the grazing season length into the fall and winter. This can also be an important strategy aiming to increase diversity and sustainability in forage-based livestock systems. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa) has shown promise in the Southeastern United States when interseeded into bermudagrass (Cynodon dactylon) to reduce reliance on synthetic N fertilization while also providing a high-quality grazable forage. However, data is limited when grazing alfalfa interseeded into different bermudagrass bases with stockers in the Southeastern U.S. A two-year grazing evaluation was conducted in a randomized complete block design with two replications from June-October 2020 (Y1) and April-October 2021 (Y2) at the University of Georgia Tifton Campus Better Grazing Program in Tifton, GA, to compare stocker cattle performance when grazing 'Bulldog 805' alfalfa interseeded into either 'Russell' or 'Tifton-85' bermudagrass (RAG and TAG, respectively). Paddocks (1-ha) were split into 4 (0.25-ha) sections and rotationally grazed to 10 cm using the put-and-take stocking method with two tester steers for each treatment (Y1 BW=228.3±27.02 kg; Y2 BW=183.1±20.8 kg). Paddock sections were evaluated pre- and post-grazing for herbage availability, botanical composition, and nutritive value. Stocker steers were weighed at study initiation, conclusion, and on a 28d interval for calculation of ADG and gain/ha. Data were analyzed using the PROC MIXED procedure of SAS 9.4. Differences for herbage mass, gain/ha, and stocking density were not detected seasonally but were observed within grazing cycle with RAG being greater in the earlier season, TAG being greater in the later portion of the grazing season, and no difference during the grazing cycles that occurred in the hot summer months. This study suggests that the bermudagrass variety utilized in the alfalfa-bermudagrass mixture will influence stocking management decisions. [ABSTRACT FROM AUTHOR]

Grazing of dual-purpose wheat is an established management system in the Great Plains regions of the United States. Varietal and climatic differences between regions has limited use of dual-purpose systems in the Southeast. The objective of this study was to evaluate four wheat varieties, [feed wheat (mixed variety, Feed), seed wheat ('GA Gore') and two forage varieties, 'AGS 2024' (AGS) and 'Pioneer 26R41' (Pioneer)], under three grazing treatments [no-grazing (NG), low frequency (LF), high frequency (HF)]. The experiment was a randomized complete block design (n = 4) using mob-grazing. Forage samples were taken using three 0.1m2-quadrats before (Pre) and after (Post) each grazing event. Crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined on all Pre samples. Wheat grain yield was determined at the end of the season. Data were analyzed using PROC GLIMMIX of SAS (SAS Inst. Cary, NC), a < 0.05. Pre-grazed, AGS seasonal forage production was greater (P < 0.01) than all other varieties (1,517 kg/ha vs 1,031 kg/ha, respectively). Post-grazing biomass from AGS and Pioneer was greater than GA Gore (817 vs 512 kg DM/ha, respectively; P = 0.04). Pre-grazing, Feed, GA Gore and Pioneer had greater (P < 0.01) CP than AGS (31.6 vs. 30.1%, respectively). The concentration of NDF was greatest for AGS (39.1%) compared with all other varieties (34.9%, P < 0.01). Grazing frequency did not affect CP (P = 0.67). The NG plots had greater NDF and ADF than LF and HF (37.5 vs. 35.2% and 19.8 vs. 18.6%, respectively; P < 0.01). Pioneer had the greatest grain yield but was not different from AGS (57.6 and 52.4 kg/ha, respectively; P = 0.41). Management of wheat as a dual-purpose crop is feasible in the Southeast. More information is needed to determine the economic impact of this management practice. [ABSTRACT FROM AUTHOR]

The effects of a nutritional packet containing a direct-fed microbial combined with vitamins/electrolytes offered to beef steers in a calf-fed system on apparent total tract nutrient digestibility were evaluated. Angus crossbred steer-calves (n = 60; BW = 234 ± 4 kg) were assigned to a randomized complete block design (block = body weight; steer = experimental unit) and stratified into 2 treatments: a) control (no packet, finely-ground corn carrier only); and b) 30 g of DM/animal-daily of a nutritional packet [liveyeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), Vitamin C (5.4 g/kg of Ascorbic acid), Vitamin B1 (13.33 g/kg of Thiamine hydrochloride), and electrolytes of NaCl (80 g/kg) and KCl (80 g/kg)]. Animals were individually offered [electronic feed-bunks (Smart-Feed/C-Lock Inc.)] a steamflaked corn-based finishing diet ad libitum, once daily for 233 d. Treatments were offered during the first (phase-1) and last (phase-2) 60 d on feed. At the conclusion of each phase, feed samples were collected once daily (1400 h), while fecal samples twice daily (0700 and 1700 h) from each steer during 4 consecutive days. Fecal and feed sample composites were dehydrated (55oC), ground (1 mm), and analyzed to assess DM, OM, NDF, ADF, and hemicellulose. The 288-h indigestible NDF was used as dietary internal marker to estimate fecal output and used to calculate nutrient digestibility. Data were analyzed using the GLIMMIX procedure of SAS. Intake of DM, OM, and fiber components during both digestibility trials were not affected (P = 0.56) by treatments. Steers offered the nutritional packet had increased (P < 0.01) apparent total tract digestibility of DM, OM, NDF, ADF, and hemicellulose by at least 2.4, 2.4, 8.3, 10, and 7.5%, respectively, in both digestibility phases. Superior nutrient digestibility without affecting nutrient intake may justify a potential enhanced carcass energy deposition. [ABSTRACT FROM AUTHOR]