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Calf-fed Holstein steers (n = 115; 449 ± 20 kg) were utilized in a serial harvest experiment. A baseline group of five steers was harvested after 226 d on feed (DOF), which was designated day 0. The remaining cattle were assigned randomly to 11 harvest groups, with slaughter every 28 d. Cattle were either not (CON) or were fed zilpaterol hydrochloride for 20 d followed by a 3 d withdrawal (ZH). There were five steers per treatment in each slaughter group ranging from days 28 to 308. Whole carcasses were divided into lean, bone, internal cavity, hide, and fat trim components. Apparent mineral retention (Ca, P, Mg, K, and S) within the body was calculated as the difference between mineral concentration at slaughter and day 0. Mineral concentration at day 0 was determined from body composition of steers harvested at day 0 multiplied by individual live body weight (BW) at day 0. All data were analyzed as a 2 × 11 factorial arrangement with individual animal as the experimental unit. Orthogonal contrasts were used to analyze linear and quadratic contrasts over time (11 slaughter dates). There were no differences in concentration of Ca, P, and Mg in bone tissue as feeding duration increased (P ≥ 0.89); concentration of K, Mg, and S in lean tissue did fluctuate across DOF (P < 0.01). Averaged across treatment and DOF, 99% of Ca, 92% of P, 78% of Mg, and 23% of S present in the body were in bone tissue; 67% of K and 49% of S were in lean tissue. Expressed as gram per day, apparent retention of all minerals decreased linearly across DOF (P < 0.01). Expressed relative to empty body weight (EBW) gain, apparent Ca, P, and K retention decreased linearly as BW increased (P < 0.01) whereas Mg and S increased linearly (P < 0.01). Apparent retention of Ca was greater for CON cattle (greater bone fraction) and apparent retention of K was greater for ZH cattle (greater muscle fraction) when expressed relative to EBW gain (P ≤ 0.02), demonstrating the increase in lean gain by ZH cattle. There were no differences in apparent retention of Ca, P, Mg, K, or S due to treatment (P ≥ 0.14) or time (P ≥ 0.11) when expressed relative to protein gain. Apparent retention averaged 14.4 g Ca, 7.5 g P, 0.45 g Mg, 1.3 g K, and 1.0 g S/100 g protein gain. Expressing apparent mineral retention on a protein gain basis minimized effects of rate and type of gain, allowing for better comparison across treatments and time. Feeding zilpaterol hydrochloride did not affect apparent mineral retention when expressed relative to protein gain. [ABSTRACT FROM AUTHOR]

A pooled analysis was performed to evaluate whether corn silage fed at 15% or 45% of diet DM impacted liver abscesses prevalence at slaughter in five previous experiments. Cattle fed 15% corn silage had 7.8% abscessed livers compared to 4.1% for cattle fed 45% corn silage when all diets contained tylosin. While improved due to increased corn silage inclusion, the objective of the current finishing study was to determine the impact of silage inclusion in finishing diets with and without tylosin on performance and incidence of abscessed livers in beef cattle. A total of 640 (BW = 334 ± 25 kg) steers were used in a generalized randomized block design with a 2 × 2 factorial treatment design. Treatments included two concentrations of corn silage (15% and 45% of diet DM), with or without tylosin for liver abscesses. This study used 32 pens of cattle with 20 steers per pen and 8 pens per treatment. There was a tendency for an interaction for feed efficiency (G:F; P = 0.10) where cattle fed 15% corn silage had a 2% increase in G:F when tylosin was added to the diet, but no improvements in G:F were observed when tylosin was added to diets containing 45% silage. There was an interaction between silage and tylosin inclusion for abscessed livers (P = 0.05). Cattle fed 15% corn silage without tylosin had the greatest incidence of abscessed livers (34.5%) compared to other treatments (P = 0.05), and the incidence of abscessed livers was decreased to 19% if tylosin was fed with 15% corn silage. Feeding 45% silage was effective at lowering the incidence of abscessed livers (P = 0.05) which was 12.4%, regardless of whether tylosin was fed. Feeding corn silage at 45% of diet DM (77.5% concentrate) was as effective as feeding tylosin to cattle on a 92.5% concentrate diet. Feeding corn silage at greater inclusions decreased daily gain (P ≤ 0.01) but increased final body weight when fed to an equal fatness (cattle fed 45% CS were fed 28 d longer). Feeding corn silage at 45% was more economical compared to feeding 15% corn silage, especially as corn prices increase, provided shrink is well managed. Feeding elevated concentrations of corn silage may be an economically viable method to reduce incidence of liver abscesses without antibiotic use for smaller operations that can manage more corn silage in finishing diets. [ABSTRACT FROM AUTHOR]

An experiment was conducted over 2 yr to measure performance and greenhouse gas (GHG) emissions of weaned calves from two cow-calf production systems. Crossbred steers and heifers (n = 270, initial body weight (BW) = 207 kg, SD = 35) were used in a randomized complete block design, with treatments applied to the cow-calf system. Treatments were: 1) a traditional system consisting of April to June calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to September calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). Calves from both production systems were weaned at the same age and grown (diet NEg = 1.05 Mcal kg–1) for approximately 117 d. The calves then transitioned to a high-grain finishing diet (year 1: NEg = 1.32 Mcal kg–1; year 2: NEg = 1.39 Mcal kg–1) and fed to a targeted 1.52 cm backfat. Growth performance in the grower phase resulted in greater (P < 0.01) average daily gain (1.39 vs. 1.22 ± 0.02 kg), greater gain:feed (P < 0.01; 0.157 vs. 0.137 ± 0.003) for ALT calves compared to TRAD calves, However, a lower initial BW (P < 0.01; 185 vs. 229 ± 4.9 kg) resulted in a lower ending BW (P < 0.01; 347 vs. 371 ± 2.9 kg) for ALT calves compared to TRAD calves in spite of improved growth performance. In the finisher phase, ALT calves gained less (1.52 vs. 1.81 ± 0.218 kg; P = 0.02), were less efficient (0.139 vs. 173 ± 0.0151; P = 0.01) but exhibited similar hot carcass weights (HCW) (388 vs. 381 ± 3.8 kg; P = 0.14) compared to TRAD calves. Each pen of calves was put into a large pen-scale chamber that continuously measured carbon dioxide (CO2) and methane (CH4) for 5 d during the grower and finisher phases. The average CH4 and CO2 production per unit of feed intake was used to calculate total GHG emissions over the entire grower and finisher phase. Overall, there were no differences (P ≥ 0.17) between treatments for CH4 per day and per kilogram dry matter intake (DMI). However, ALT calves tended to produce less (P ≤ 0.10) CO2 per day and per kilogram DMI than TRAD calves. Overall, methane emissions were greater in ALT calves (110.7 vs. 92.2 ± 8.3 g CH4 kg–1 HCW; P = 0.04) than TRAD calves. The ALT calves required 27 additional days on feed to market, which resulted in more total CH4 per animal across the entire feeding period (P = 0.02) than TRAD calves. Production systems that reduce days to market to achieve similar HCW may reduce GHG emissions. [ABSTRACT FROM AUTHOR]

An experiment was conducted to measure production responses of an alternative cow-calf production system integrated into a cropping system without access to perennial forage compared to a traditional cow-calf system utilizing perennial forage. Multiparous, cross-bred beef cows (n = 160; average age = 6.2 ± 2.8 yr) were utilized in a randomized complete block experimental design and unstructured treatment design. Upon initiation, cows were blocked by age and stratified by source, assigned randomly to one of two production systems, each with four replicates (n = 20 cows/replicate). Once allotted to their treatment groups, cows remained in their experimental units for the duration of the experiment. Treatments were: 1) a traditional system consisting of April to May calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to August calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). There were no differences (P ≥ 0.27) in calving rates (91.8 vs. 86.7 ± 2.92%), pregnancy rates (89.3 vs. 89.9 ± 2.66%), and weaning rates (87.2 vs. 82.3 ± 3.29%) for TRAD vs. ALT, respectively. However, there was an increase (P = 0.04) in the rate of twin offspring in ALT (2.9 vs. 9.4 ± 2.36% for TRAD vs. ALT, respectively). One calf from the set of twins was selected randomly at birth to be removed from the experiment, so the production data are only from single calves. There was no difference (P = 0.47) in calf body weight at birth (40 vs. 39 ± 0.7 kg for TRAD vs. ALT, respectively). At weaning, calves in the ALT system were lighter (P < 0.01) at the same day of age (184 vs. 229 ± 5.5 kg) compared to TRAD calves. Cows from the ALT system had fewer (P < 0.01) kg weaned per cow exposed to bull (150 vs. 199 ± 7.2 kg) compared to TRAD cows. Apart from the twinning rate, no differences in reproductive performance were observed among systems. However, reduced weaning weights and kilogram of weaned calf per cow exposed may negatively impact revenue to the cow-calf enterprise of the ALT system. [ABSTRACT FROM AUTHOR]

Two studies were conducted to determine interactions of urea inclusion to a dried distillers grains plus solubles (DDGS; 29.4% crude protein, 5.48% ether extract) supplement fed at two amounts and two frequencies to steers on a high forage diet. In Exp. 1, 120 (247 kg; SD = 20) steers were fed individually for 84 d. Steers received ad libitum grass hay (6.8% crude protein) and one of eight treatments. Treatment design was a 2 × 2 × 2 factorial. Supplement was fed daily or three times per week, amount of supplement fed was 6.36 kg dry matter (DM)/week [0.37% body weight (BW); LO] or 12.73 kg DM/week (0.74% BW; HI) and contained either no urea or 1.3% urea on a DM basis. Steer BW was measured at the start and end of the trial and hay DM intake (DMI) was measured weekly. In Exp. 2, ruminally cannulated steers (310 kg; SD = 25) were used in a row-column design with eight steers and six 14-d periods. Treatments assigned were the same as Exp. 1, except that supplement was fed at 0.4% of BW (LO) or 0.8% of BW (HI) and supplement was fed either daily (DY) or every other day (ALT). Hay DMI, rumen ammonia-N, rumen pH, in situ neutral detergent fiber (NDF) disappearance, and rumination were measured. In Exp. 1, average daily gain (ADG) was affected by amount of supplement with steers on HI gaining 0.30 kg/d more (P < 0.01) than LO. Hay DMI was reduced by increased amount of supplement (0.39 kg/d; P < 0.01) and by decreased frequency of supplementation (0.54 kg/d; P < 0.01). In Exp. 2, hay DMI was also reduced due to increased amount of supplement and decreased frequency of supplementation (P < 0.01). Rumen pH was decreased on the day of supplement feeding for steers on ALT (P < 0.01) and reduced for steers fed HI vs. LO. There was no difference in NDF digestibility between DY and ALT (P > 0.05). For ALT steers, there was reduction (P < 0.01) in in situ NDF disappearance for the HI compared to LO amount of supplementation on the day of supplementation. Infrequent supplementation of DDGS results in no difference in ADG but decreased hay DMI compared to daily supplementation. Urea had no effect on digestion or ADG, suggesting rumen degradable protein was not deficient when supplementing DDGS. There is little change in rumen fermentation parameters between frequency of supplement feeding, indicating that forage digestion is not impacted by supplementation frequency. Dried distillers grains can be supplemented infrequently without a reduction in animal performance. [ABSTRACT FROM AUTHOR]

One hundred twenty individually fed steers (initial BW 283 kg ± 32) were utilized in an 84-d growing trial to evaluate the effects of increased metabolizable lysine from non-enzymatically browned soybean meal (SoyPass) in grass hay-based diets containing wet distillers grains plus solubles (WDGS). The treatments were arranged as a 2 × 3 factorial with two levels of protein supplement as 20% (low; DL20) or 35% (high; DL35) of dietary DM using WDGS as the basal protein source, and three increments of SoyPass (SP) replacing 0%, 30%, or 60% of the WDGS DM in the protein supplement yielding six dietary treatments. Average daily gain (ADG), dry matter intake (DMI), gain:feed (G:F), and plasma urea N (PUN) data were analyzed using the MIXED procedure of SAS as a 2 × 3 factorial. Animal was the experimental unit and fixed effects included body weight block, dietary inclusion of distillers grains (DL20, DL35), dietary inclusion of SoyPass (SP) (3 levels), and DL × SP inclusion interactions. Linear and quadratic interactions between DL and SP inclusion were analyzed using covariate regression. No interactions were detected for ADG between SP and DL (P = 0.76). Additionally, SP had no effect on ADG (P = 0.49). However, ADG was increased for steers consuming the DL35 diet compared to DL20 (1.13 vs. 0.86 kg/d, respectively; P < 0.01). A DL × SP interaction was detected for DMI (P = 0.01). As SP replaced WDGS in the DL35 diet, DMI increased linearly from 8.10 to 8.93 kg/d (P = 0.02). In the DL20 diet, DMI was not different as SP replaced WDGS (P ≥ 0.11). Therefore, G:F tended to decrease linearly (P = 0.06) as SP replaced WDGS in the DL35 diet, while no difference (P ≥ 0.11) was detected in the DL20 diet, suggesting SP contained less energy than WDGS but did improve dietary lysine balance. Furthermore, plasma urea nitrogen (PUN) increased linearly as SP replaced WDGS in the DL20 diet (P < 0.01) but was not affected by SP substitution in the DL35 diet (P ≥ 0.19). When WDGS is fed at a low (20% DM) or high (35% DM) inclusion rate in a forage-based diet, replacing the distillers with a source of protected amino acids supplied through heat-treated soybean meal, did not improve performance. A more concentrated or energy-dense form of amino acids may be beneficial in forage-based growing cattle diets containing 20% distillers grains but is not needed in diets with 35% distillers grains. [ABSTRACT FROM AUTHOR]

Crossbred, calf-fed steers (n = 480; initial body weight = 292 ± 19 kg) were used in a randomized block design finishing experiment with a 2 × 3 arrangement of treatments to evaluate the impact of constant inclusion or decreasing inclusion of modified distillers grains plus solubles (MDGS) with high-quality or low-quality roughage on finishing cattle performance. Dietary treatments included two roughage sources to provide similar neutral detergent fiber (NDF) from forage (6% corn stalks versus 12% corn silage DM basis) in three diets containing 0, 15, or decreasing inclusion of distillers (30, 15, then 0% across the feeding period). A total of 48 (10 steers/pen) pens were used with 8 pens/treatment. There was an interaction (P = 0.04) between roughage source and MDGS inclusion for dry matter intake (DMI). Cattle fed stalks with decreasing inclusions of MDGS (30-0%) had greater DMI than those fed silage as roughage source, but at 0% inclusion of MDGS there was no difference between roughage sources. No other significant interactions were observed, so main effects will be presented. Cattle fed the diet with 0% MDGS inclusion had reduced (P < 0.05) hot carcass weight (HCW), DMI, average daily gain (ADG), and 12th rib fat, and poorer G:F compared with cattle fed diets where MDGS was at 15% inclusion continuously or when MDGS decreased from 30% to 0%. For the treatment where MDGS was decreased from 30% to 0%, performance differed from that of cattle fed 15% distillers continuously. Cattle fed decreasing inclusions of MDGS (30-0%) had less (P < 0.01) DMI, ADG and tended (P = 0.07) to have lighter HCW. But G:F was not (P = 0.25) affected compared with when distillers was fed at 15% continuously. Marbling score was impacted by distillers inclusion (P = 0.03), where cattle fed 15% MDGS had greater (P = 0.01) marbling score than 0% inclusion and tended (P = 0.06) to be greater than cattle fed 30-0% MDGS. Even though there are differences in marbling score across treatments, all three treatments were within the choice grade and reflect ADG differences across treatments. Cattle fed silage consumed less, gained the same, and had greater G:F (P < 0.01). Based on numerically less HCW, ADG, and poorer G:F, these data suggest that feeding 6% corn stalks did not produce similar performance as feeding 12% corn silage. These data suggest that feeding 15% distillers was not enough to offset decreased quality roughage (stalks) compared with silage as roughage which contradicts previous studies when 30% distillers were fed. [ABSTRACT FROM AUTHOR]

A 2-year study conducted at the Eastern Nebraska Research and Extension Center near Mead, Nebraska determined the effects of backgrounding rate of gain and implanting during the winter or summer phases on animal performance and carcass traits. The study design was a 2 x 3 factorial arrangement with the factors of winter gain (0.45 or 0.90 kg/d; LG and HG, respectively) and three implant strategies. The implant strategies included a 36 mg zeranol (Ralgro; Merck Animal Health, De Soto, KS) implant during the winter phase and 40 mg trenbolone acetate and 8 mg estradiol (Revalor-G; Merck Animal Health) implant during the summer phase (STRNG), no implant during the winter phase and Rev-G during the summer phase (MED), and no implant during the winter or summer phases (NONE). The study used 240 (initial BW = 247 kg, SD = 5.9 kg YR 1; BW = 255 kg, SD = 10.9 kg YR 2) weaned steers each year that were fed one of two backgrounding diets consisting of bromegrass hay and 10% MDGS (LG) or 30% MDGS (HG). Steers were backgrounded in the feedlot for a 148-day winter phase followed by a 56-day summer phase where they grazed smooth bromegrass paddocks. Upon arrival in the feedlot for the finishing phase, steers received 200 mg TBA and 40 mg estradiol (Revalor-XS; Merck Animal Health) and were fed a common diet for the entire finishing phase. In the winter phase, steers fed the HG diet had a greater ADG, ending BW, DMI, and improved G:F over steers fed LG (P < 0.01). Steers that received a Ralgro implant during the winter phase (STRNG) were observed to have an 13% improved ADG (P < 0.01), a 10% increase in G:F (P < 0.01), and an additional 14 kg of BW for the winter phase. There were no interactions between the rate of gain and implant strategy (P = 0.15) during the winter period. In the summer, HG steers had maintained greater ending BW than LG, although LG steers had greater ADG than HG (0.70 and 0.53 kg, respectively; P < 0.01) due to compensatory gain. Steers assigned to HG during the winter phase had a greater IBW for the finishing phase. Steers fed HG during the winter and administered an implant at both backgrounding phases (STRNG) had the greatest HCW with no differences in ADG or G:F during the finishing phase. Combining a strong implant program and an increased rate of gain during winter backgrounding resulted in 34 kg of additional HCW at marketing. Implant strategy and rate of gain during the winter growing period had additive effects to increase animal performance through all phases. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine the effects of diet composition and time of urine spot sampling on estimates of urinary purine derivative (PD) excretion. In Exp. 1, 116 individually fed crossbred heifers (407 ± 32 kg) were arranged in a randomized block design (82 d). Treatments were arranged in a 2 × 3 factorial design, with two urine spot sample collection times (0700 and 1700 hours; AM and PM) and three diets: 85% steam-flaked corn (SFC); 85% SFC + 1.5% urea (UREA); or 25% SFC, 30% wet corn gluten feed, and 30% corn bran (BYPROD). In Exp. 2, six ruminally and duodenally fistulated steers (474 ± 37 kg) were arranged in a replicated 3 × 3 Latin square design, with dietary treatments identical to Exp. 1 (63 d). Treatment diets were selected to result in varied amounts of microbial crude protein (MCP) in order to evaluate the accuracy of using estimates of urinary PD excretion to predict MCP. Urine spot samples were collected at 0700, 1200, 1700, and 2200 hours. No urine collection time × diet interactions occurred (P > 0.20) for any variable in either experiment. In Exp. 1, dry matter intake (DMI) was greatest with BYRPOD (10.40 kg/d) and lowest with SFC (7.90 kg/d; P < 0.05). Feed efficiencies were greatest for UREA (0.182) and least for SFC (0.141; P < 0.05). Urinary PD:creatinine (PD:C) ratio was greatest for BYPROD (1.25) and least for SFC (0.94; P < 0.05). Urine spot sampling time had a significant (P < 0.05) impact on PD:C, 1.03 for AM and 1.22 for PM samples. In Exp. 2, DMI was greater (P < 0.05) with BYPROD than with SFC and tended (P = 0.07) to be greater with BYPROD than with UREA. Ruminal pH was greatest for BYPROD (5.94; P < 0.05). Flow of MCP was 636, 829, and 1,056 g/d for SFC, UREA, and BYPROD, with BYPROD being greater (P < 0.05) than SFC and tending (P = 0.06) to be greater than UREA. Urinary PD:C was greater (P < 0.05) for BYPROD than SFC and tended (P = 0.09) to be greater for UREA than SFC. Urinary PD:C increased linearly (P < 0.05) with sampling time. Diets formulated to affect DMI and MCP flow resulted in differences in urinary PD excretion, and these results related well with MCP flow estimated from duodenal purines. Collecting spot samples of urine later in the day resulted in greater estimates of urinary PD excretion; purine and PD flows appear to increase with time after one morning feeding per day. This method is well suited to evaluating relative differences between treatments but should not be extrapolated to assume absolute values. [ABSTRACT FROM AUTHOR]

To determine the effects of harvest method and ammoniation (3.7% of dry matter) on consumption and waste of baled corn residue, a 6 × 6 Latin square with a 3 × 2 factorial treatment structure was conducted. Six treatments consisted of either nonammoniated or ammoniated residue, harvested one of three ways: conventional rake and bale (CONV), New Holland Cornrower with two rows of stem chopped into the windrow with tailings (2ROW), or EZBale system (EZB) with a disengaged combine spreader and tailings dropped in a windrow. Open cows were grouped by body weight to produce a light block of two pens (448 kg ± 49.6) and a heavy block of four pens (649 kg ± 65.9). One bale was fed to each pen during each of six 7-d periods using round bale ring feeders with closed bottom panels. Residue falling around (waste) and remaining in (refusals) the feeder was collected. The daily nutrient intake was estimated as the difference between what was offered and what remained (waste plus refusals). Crude protein (CP) of residue offered did not differ (P = 0.58) among harvest methods. The digestible organic matter (DOM) content of residue offered in 2ROW and EZB bales did not differ (P = 0.86) and was greater (P < 0.01) than CONV. Ammoniation increased (P < 0.01) CP and DOM content of the residue offered. Total wasted and refused residue did not differ (P = 0.12) between 2ROW (29%) and EZB (37%), while CONV (42%) was greater (P = 0.02) than 2ROW but did not differ (P = 0.34) from EZB. Ammoniation reduced (P = 0.03) total waste and refusals from 41% to 32%. The nutrient content of both waste and refusals did not differ (P ≥ 0.34) among harvest methods and, with the exception of CP, was not affected (P ≥ 0.15) by ammoniation. The CP content of the waste was greater (P = 0.02) and refusals tended to be greater (P = 0.08) from ammoniated bales. The CP intake of 2ROW was greater (P ≤ 0.02) than both EZB and CONV, while EZB tended (P = 0.06) to be greater than CONV. The CP intake of all ammoniated residues was greater (P < 0.01) than the nonammoniated residue. The DOM intake of nonammoniated 2ROW and EZB did not differ (P = 0.61) but was greater than nonammoniated CONV (P < 0.01). Ammoniation increased (P < 0.01) DOM intake. Overall, ammoniation had much larger effects than harvest method, resulting in reduced waste and refusals and greater intake of DOM and CP. However, the combination of both ammoniation and selective harvest (2ROW or EZB) was needed to result in energy and protein intakes that would meet the needs of a mature cow in mid-gestation. [ABSTRACT FROM AUTHOR]

A feedlot study was conducted comparing a natural feed additive at varying corn silage (CS) inclusions on receiving and finishing cattle performance. The study utilized 480 crossbred steers (initial shrunk body weight [BW] = 296 kg; SD = 24.1 kg) in 48 pens with 10 steers/pen and 8 pens per treatment. Treatments were designed as a 2 × 3 factorial with 3 inclusions of CS (14%, 47%, 80%; dry matter [DM] basis) with or without (+, −) the inclusion of a feed additive containing fumaric acid and palm oil (FAPO). All treatment diets contained 16% modified distillers grains plus solubles and 4% supplement with dry-rolled corn replacing CS on a DM basis. All steers were fed the 80 CS diet and adapted to 47% and 14% CS over a 10- and 24-d period, respectively. Cattle fed 80 CS were fed for 238 days, 47 CS for 195 days, and 14% CS were fed for 168 days to a common backfat of 1.28 cm (P ≥ 0.59). There were no interactions for CS inclusion and the inclusion of FAPO on final body weight (FBW), DMI, ADG, G:F, hot carcass weight (HCW), LM area, marbling, or calculated yield grade (CYG; P ≥ 0.15). There was no significant difference for FBW, DMI, ADG, G:F, HCW, marbling, or CYG for cattle fed with or without FAPO (P ≥ 0.13). However, there was a quadratic response for FBW, ADG, G:F, HCW, marbling, and CYG with increased inclusion of CS (P ≤ 0.04). Inclusion of FAPO had no effect on performance. Feeding CS at greater inclusions decreased daily gain and feed efficiency but increased FBW when fed to an equal fat endpoint. CS gave greater returns ($/animal) when fed at 80% of diet DM. Feeding greater amounts of CS can be an economical way to finish cattle. In this study, FAPO did not affect animal performance, carcass characteristics, or economic return. [ABSTRACT FROM AUTHOR]

The article presents a study examining he evaluation of terminal-sired calves by artificial insemination or natural service reared in limited resource environments. Topics discussed include dietary needs of the increasing global population; terminal breeding programs that involve selling all steer and heifer calves at weaning with intentions of entering the feedlots; and role of forage quality and nutrient intake.

The article presents a study examining forage production and calf gains when grazing oats following corn harvest. Topics discussed include benefits of grazing livestock on fall planted double-cropped annual forages (DCAFs); methods to determine forage production, and to determine stocking rates; and oat forage biomass production.

To determine the effect of harvest method and ammoniation on both in vivo and in vitro digestibility of corn residue, six corn residue treatments consisting of three different harvest methods either with or without anhydrous ammonia chemical treatment (5.5% of dry matter [DM]) were evaluated. The harvest methods included conventional rake-and-bale (CONV) and New Holland Cornrower with eight rows (8ROW) or two rows (2ROW) of corn stalks chopped into the windrow containing the tailings (leaf, husk, and upper stem) from eight rows of harvested corn (ammoniated bales of each harvest method resulted in treatments COVAM, 8RAM, and 2RAM). Nine crossbred wether lambs (49.2 ± 0.5 kg BW) were fed 64.2% corn residue, 29.8% wet corn gluten feed, 3.3% smooth-bromegrass hay, and 2.8% mineral mix (DM basis) in a 9 × 6 Latin rectangle metabolism study with a 3 × 2 factorial treatment to measure total tract disappearance. Six 21-d periods consisted of 14-d adaptation and 7-d total fecal collection, and lambs were fed ad libitum (110% of the previous day's DM intake [DMI]) during days 1 to 12 and reduced to 95% of ad libitum intake for days 13 to 21. There was a harvest method by ammoniation interaction (P < 0.01) for ad libitum DMI (days 7 to 11). Ammoniation increased (P < 0.01) intake across all harvest methods, where 2RAM DMI was 4.1%, COVAM was 3.6%, and 8RAM was 3.1%, which were all different (P < 0.01) from each other, but all untreated residues were consumed at 2.6% of BW (P ≥ 0.92) regardless of harvest method. There were no interactions (P > 0.34) between harvest method and ammoniation for any total tract or in vitro digestibility estimate. Harvest method affected (P < 0.04) DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility, where 2ROW was greater than both CONV and 8ROW, which did not differ. The organic matter (OM) digestibility (P = 0.12) and digestible energy (DE; P = 0.30) followed the same numerical trend. Both in vitro DM digestibility (IVDMD) and in vitro OM digestibility (IVOMD) of the residue were affected (P < 0.01) by harvest method, with 2ROW being greater (P < 0.01) than both CONV and 8ROW. For IVDMD, 8ROW was not (P = 0.77) different from CONV, but 8ROW IVOMD was lower (P = 0.03) than CONV. Ammoniation improved (P < 0.01) DM, OM, NDF, and ADF digestibility of all harvest methods, resulting in a 26% increase (P < 0.01) in DE due to ammoniation. Similar digestibility improvements were observed in vitro with ammoniation improving IVDMD and IVOMD by 23% and 20%, respectively. Both selective harvest methods and ammoniation can improve the feeding value of baled corn residue. [ABSTRACT FROM AUTHOR]

The amount of rumen undegradable protein (RUP) in corn silage and the extent to which it is digested in the small intestine are uncertain. Three studies were conducted to determine RUP content of corn silage, and the effects of supplementing increasing concentrations of RUP on the growing performance of calves fed a corn silage diet. Experiments 1 and 2 used in situ methods to evaluate the RUP content of corn silage. In experiment 1, corn silages harvested at 37% or 42% dry matter (DM) were compared. In experiment 2, dry-rolled corn (89.4% DM) was reconstituted to 75%, 70%, 65%, and 50% DM and ensiled in mini-silos (2,265 cm3) for 30, 90, 180, or 270 d to simulate the corn grain within corn silage, dry-rolled corn is more mature than corn grain harvested in corn silage. Experiment 3 used 60 steers (275 kg initial body weight, SD = 18) in an 83-d growing study to evaluate the effects of supplementing 0.4%, 1.7%, 3.0%, 4.2%, or 5.5% RUP (% of diet DM) on performance. In experiment 1, RUP as a % of DM was not different between the two corn silages (P ≥ 0.12), averaging 0.59% for samples refluxed in a neutral detergent solution (NDS) and 1.8% for samples not refluxed in NDS. Dry matter digestibility (DMD) also did not differ (P ≥ 0.19), averaging 67.4%. In experiment 2, as moisture content of the corn grain increased, DMD increased linearly (P < 0.01) and RUP content decreased linearly (P < 0.01). The DMD increased quadratically (P = 0.02), whereas RUP content decreased linearly (P < 0.01) as days of ensiling increased. In experiment 3, there were no differences in DM intake (DMI; P ≥ 0.33) among treatments for period 1 (d 1 to 37). However, average daily gain (ADG) and gain-to-feed ratio (G:F) both linearly increased (P < 0.01) as RUP supplement inclusion increased. There were no differences in DMI (P ≥ 0.16), ADG (P ≥ 0.11), or G:F (P ≥ 0.64) in period 2 (d 38 to 83). For the overall growing period (d 1 to 83), a linear increase was observed for ending body weight (P = 0.01), ADG (P < 0.01), and G:F (P < 0.01) as RUP supplement inclusion increased from 0.4% to 5.5% of diet DM. The RUP content of corn silage is lower than previously reported. Data collected suggest the crude protein within corn silage is 13% RUP, and approximately 1/2 is digestible. The moisture content of corn silage at the time of harvest and the amount of time corn silage is stored continually impact protein availability. Supplementing growing calves fed corn silage with RUP will improve performance. [ABSTRACT FROM AUTHOR]

A metabolism experiment was conducted to evaluate the effects of daily feeding of encapsulated Megasphaera elsdenii (M. elsdenii) NCIMB 41125 along with a one-time dose of Lactipro NXT (MS Biotec) on dry matter intake (DMI), rumen pH, in vitro lactate disappearance, volatile fatty acid (VFA) concentration, and lactate concentration. Ruminally cannulated crossbred steers (n = 40, initial BW 437 ± 98 kg) were individually fed a finisher diet consisting of 70% steam-flaked corn, 18% modified distillers grain plus soluble, and 7% alfalfa hay. Treatments were control (Con) steers which were given no M. elsdenii and four treatments that received LactiproNXT on day 1 and were given 0 (Drench), 1×106 (Low), 1×107 (Medium), or 1×108 (High) CFU of encapsulated M. elsdenii daily throughout the experiment fed as a top-dress. Adaptation to the finishing diet was accomplished in 19 days for Con steers and 9 days for steers in the Drench, Low, Medium, and High treatments. The experiment included five continuous periods: step-up (d 1-19); finishing (d 20-88); feed restriction (d 89, 24-h full feed restriction); challenge (d 90, cattle were fed at 150% of max DMI from finishing period); and recovery (d 91-94). Data were analyzed using the MIXED procedure of SAS with linear and quadratic effects of dose with drench as the intercept. There were no significant differences for DMI in the step-up, finishing, or challenge period. In the recovery period, DMI was greater for Low, Med, and High compared with Drench (P = 0.07) and there was a tendency for a linear increase in DMI with increasing the dose of M. elsdenii (P = 0.11). Recovery period DMI, expressed as a percentage of pre-challenge intake, was greater (P = 0.05) in steers fed M. elsdenii daily compared with Drench steers, and increased linearly (P = 0.06) as dose of M. elsdenii increased. Rumen pH in steers fed M. elsdenii daily was greater (P < 0.01) during the feeding period and tended to be greater during the challenge (P = 0.14) and recovery (P = 0.11) periods when compared with the Drench treatment. In vitro lactate disappearance tended to be greater (P = 0.13) in steers given M. elsdenii daily when compared with Con and Drench on d 88. For days 90, 91, and 92 combined, a treatment effect was observed for in vitro lactate disappearance with steers in the Low, Med, and High treatments having greater (P < 0.05) disappearance than Con steers, and Med steers having greater (P < 0.05) disappearance than all other treatments. An accelerated step up is possible with the drench and daily feeding of M. elsdenii. Daily feeding of M. elsdenii has a positive effect on cattle during and after an acidosis challenge event. [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]