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Background: Generally, the forages used in cow-calf and backgrounding cattle operations have low crude protein and high fiber concentration, limiting animal performance and increasing greenhouse gas emissions. Chlorella spp., a green microalga, shows promising potential to provide nutrients, especially nitrogen, to low-protein diets. However, information is limited regarding the effects of Chlorella spp. on the in vitro fermentation and methane (CH4) production of diets. Objective: To evaluate the effects of increasing inclusion levels of algae (Chlorella spp.) on ruminal in vitro fermentation profile and CH4 production of a corn silage-based diet. Methods: Incubations were conducted on three separate days using corn silage and gin trash as substrate (70:30 ratio, respectively). Treatments were control (without algae) and 1, 5, and 10% of algae inclusion in the substrate replacing the basal diet. Ruminal fluid was collected from two ruminally cannulated Angus crossbred steers fed ad libitum a corn silage and gin trash diet. Final pH, concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), total gas, and CH4 production were determined after 24 h of incubation. Variables were evaluated using the MIXED procedure of SAS software, and means were compared using orthogonal polynomial contrasts. Results: Algae inclusion linearly increased (p<0.01) the IVOMD. However, the final pH and concentration of VFA and NH3-N did not differ (p>0.05) among algae levels. Molar proportion of VFA and the acetate:propionate ratio was not affected (p>0.05) by increasing algae inclusion. Finally, total gas and CH4 production were not different (p>0.05) among treatments. Conclusion: The inclusion of Chlorella spp. does not modify the ruminal in vitro fermentation profile nor the CH4 production of a corn silage-based diet. [ABSTRACT FROM AUTHOR]

Feedlots have a crucial role in meeting the increasing global demand for meat. Despite ongoing efforts to improve feed efficiency in finishing diets, cattle in feedlots may experience methane (CH4) losses ranging from 2 to 12% of dietary gross energy (GE). Identifying strategies to mitigate energy losses in finishing diets is imperative for ensuring the sustainability of beef production. Anacardic acid, contained in the cashew nutshell extract (CNSE) has shown promising results in reducing CH4 emissions in forage-based diets; however, its impact on high-grain diets remains to be analyzed. Therefore, this study aimed to evaluate CNSE addition (5 g steer-1 d-1) in a finishing diet (85:15% grain: forage) on in vivo enteric CH4 emissions, apparent total tract digestibility, and feeding behavior. It was hypothesized that CNSE addition to a finishing diet would reduce enteric CH4 emissions without reducing feed intake or nutrient digestibility. To this aim, Angus crossbred steers (n = 16; 599 ± 40 kg) were used in a crossover design with two periods of 56 d each. Steers were adapted (14 d) to the finishing diet and assigned to receive CNSE or no additive (CON). The diet was offered twice daily as a total mixed ration (TMR) in the feed bunk, while CNSE was independently delivered through the Super Smart Feed system (C-Lock, Inc, Rapid City, SD) using ground corn gluten feed as a carrier. In vivo CH4 emissions, apparent total tract digestibility of nutrients, and feeding behavior were analyzed. Data were recorded during 35 d after the adaptation, followed by 7 d of washout, and analyzed as a crossover design using the MIXED procedure of SAS. Compared with CON, the addition of CNSE increased meal duration (P = 0.03), bunk visit duration (P < 0.01), and dry matter intake (DMI) of TMR (P = 0.03) by 25, 23, and 7%, respectively. Dry matter digestibility was increased (P = 0.02) by CNSE addition. Steers receiving CNSE, had a reduction in enteric CH4 emission rate (g/d; P < 0.001), yield (g/kg of DMI; P < 0.001), and intensity (g/kg of average daily gain; P < 0.01) in 29, 32, and 39% respectively. The loss of dietary GE as CH4 was reduced in CNSE (3.2 vs. 4.7%) compared with CON (P < 0.01). This study showed that CNSE at the evaluated inclusion rate, reduced CH4 yield and emission intensity by more than 31% in beef steers receiving a finishing diet. Moreover, given that CNSE addition promoted a longer feed bunk occupancy and a greater TMR intake, it could be suggested that the observed CH4 mitigation may be linked to shifts in ruminal fermentation rather than changes in DMI. [ABSTRACT FROM AUTHOR]

Our previous studies showed that processing sorghum silage at harvest and storing for approximately 150d, improved average daily gain (ADG), feed efficiency (FE) and apparent total tract digestibility (ATTD) of starch when included as the basal ingredient in diets fed to growing Angus heifers. However, differences in animal performance and nutrient digestibility disappeared when the same sorghum silage was fed again after 1yr of storage. An experiment was performed to evaluate the effects of kernel processing and storage time on ruminal in situ degradability of sorghum silage (SS). A grain sorghum (ADV2450IG, Advanta seeds, Irving, TX) was harvested (Claas Jaguar 930, Harsewinkel, Germany) at the late-dough stage of grain maturity. Treatments were applied at harvest and consisted of sorghum berry processing (PRO) with a specific SS kernel processor (196 mm rolls of 125 teeth each, 40% speed differential, 1.1 mm roll gap), or not processed at all (NPR). Silage was chopped at 15 mm theoretical length of cut and ensiled in polyethylene ag bags (60 m long and 2.74m diameter), for 455 d. Samples were taken from each treatment on d 0, 66, 112, 157, 202, 246, 291, 336, 381, 426, and 455 and were kept frozen until analyzed. Samples were dried but not ground, to avoid affecting treatments. Ruminal in situ degradability of dry matter (DM) and starch was determined by incubating nylon bags for 24 h in duplicate, in the rumen of four ruminally cannulated steers consuming a corn silage-based diet. Data were analyzed as a randomized block design with repeated measures. The fixed effect of treatment, day and their interaction were included in the model and the repeated subject was considered the animal within treatment. A storage day × treatment interaction was detected for in situ DM degradability (P < 0.001). The PRO treatment increased (P < 0.05) in situ DM degradability at 66 and 202 d of storage and tended to increase it (P = 0.07) at 157 and 291 d of storage. An effect of storage day (P < 0.05) was observed for in situ starch degradability and because there was no interaction with treatment (P = 0.43), treatments means were compared across storage days. No differences were detected in ruminal in situ digestibility of DM or starch when silage was stored for 202 d, when compared with d 0 (P = 0.43), while starch degradability increased when silage was stored for 202 and 291 d (P < 0.03). At 381 d of storage, no differences were detected for starch degradability when compared with d 0. In conclusion, berry processing of sorghum when harvested for silage, increased ruminal in situ DM degradability. However, those differences disappear after more than 200 d of storage, in agreement with animal performance data previously reported by our group. [ABSTRACT FROM AUTHOR]

The inclusion of Aspergillus oryzae prebiotic (AOP; Amaferm, Biozyme Inc., St Joseph, MO) in ruminant diets has been proven to stimulate cellulolytic ruminal microorganisms, although, its positive effect on nutrient digestibility seems to be diet dependent. Our objective was to evaluate how AOP influences the apparent total tract digestibility of dry matter (DM) and neutral detergent fiber (NDF) at varying levels of intake, for diets with different forage sources and inclusion levels. Data were compiled from 3 experiments containing 4 diets for backgrounding cattle, assessing the use of AOP as a feed additive. The studies were Exp. 1): corn silage-based diet (CS; n = 24 steers), Exp. 2-A): sorghum silage-based diet (SS; n = 20 heifers), Exp. 2-B): citrus pulp and cotton gin byproducts-based diet (BP; n = 20 heifers), and Exp. 3): bermudagrass hay-based diet (BH; n = 24 steers). Separate ANCOVA analyses by diet were conducted using SAS, including in the model the effect of treatment (TRT; AOP vs. No AOP) and the interaction between TRT and level of intake (dry matter intake; DMI). Level of intake was calculated as percentage of body weight (DMI/BW). Least square mean differences between treatments were conducted at different levels of intake at which both treatments were represented. For apparent total tract digestibility of DM and NDF (NDFD), the TRT × DMI/BW interaction was significant (P ≤ 0.05) in the case of the CS and SS diets, but not in the BP and BH diets (P ≥ 0.10). For both silage diets, NDF and DM digestibility decreased as the level of intake increased. Consequently, the positive effect of AOP on NDFD was greater at increased levels of intake (3.3 and 3.5% of the BW for CS and SS, respectively), resulting in 9.8% improvement on NDFD for the CS diet (P = 0.04, 37.9 vs. 41.6% for No AOP vs. AOP, respectively) and 25% improvement in the SS diet (P = 0.01, 42.5 vs. 53.2% for No AOP vs. AOP, respectively). At a moderate intake (2.5% of the BW), AOP improved NDFD by 6.0 and 14.1% for the CS and SS diets, respectively (P ≤ 0.05). While at reduced intake (1.8 and 1.7% of BW, for CS and SS), NDFD did not differ (P ≥ 0.10) between treatments for either CS (47.9%) or SS (56.5%) diets. In conclusion, the inclusion of AOP in silagebased diets attenuates the decline on apparent total tract digestibility of NDF associated with increased feed intake, helping to maintain digestibility closer to its maximum potential. Whereas, at reduced levels of intake, it is more unlikely to observe a positive effect of AOP on fiber digestibility. [ABSTRACT FROM AUTHOR]

Eighty-four Angus crossbred heifers (13 ± 1 mo of age, 329.5 ± 61.92 kg of body weight [BW]) were used in a generalized randomized block design with a 2 × 2 factorial arrangement of treatments. The factors evaluated were: 1) diet type (whole plant sorghum silage [ SS ] vs. byproducts-based [ BP ]), and 2) feed additive: Aspergillus oryzae prebiotic (AOP; 2 g/d) vs. Negative control (CTL; 0 g/d), resulting in four treatments: sorghum silage-control (SC), sorghum silage-AOP (SA), byproducts-control (BC), and byproducts-AOP (BA). Heifers were stratified by body weight (BW), randomly assigned to treatments (21 heifers per treatment) and housed in 12 pens equipped with two GrowSafe feed bunks each to measure individual dry matter intake (DMI). After a 14-d adaptation, BW was measured every 14 d for 56 d. Chewing activity was monitored through collar-mounted HR-Tags (heat-related tags). Following the performance period, apparent total tract digestibility was measured in 40 heifers, using indigestible neutral detergent fiber as a marker. Heifers fed with the BP diets had greater DMI (2.92% vs. 2.59% of BW, P < 0.01) and average daily gain (ADG ; 1.16 vs. 0.68 kg, P ≤ 0.01) than heifers fed with SS diets. Compared with BP-fed animals, heifers consuming the SS diets had 23 more visits/d to the feed bunks (P ≤ 0.01), consumed 53% less dry matter on each visit (P ≤ 0.01), and spent 39% more min chewing/d and 63% more min chewing/kg of DMI (P ≤ 0.01). However, chewing measured in min/kg of neutral detergent fiber intake was not affected by treatment (average 111.3 min/kg of NDF intake). Feeding AOP improved gain:feed (GF) by 15% in BP-fed heifers (0.120 vs. 0.104 kg/kg; P < 0.05). Inclusion of AOP increased organic matter digestibility (OMD) in SS diets (55.88% vs. 49.83%; P < 0.01), whereas it decreased OMD in BP diets (61.67% vs. 65.77%; P < 0.05). In conclusion, ADG and GF of BP-fed heifers was greater than SS-fed heifers, and GF was greater with AOP supplementation in BP-fed heifers. Improvement in GF in BP-fed heifers was likely not related to differences in nutrient digestibility as AOP inclusion did not enhance digestibility in the BP diet. Additionally, the effects of the AOP inclusion appear to be diet-dependent, where the 15% improvement in GF by AOP occurred in heifers fed with the more fermentable diet. Therefore, further research should explore the mechanisms responsible for the observed improvements in growth performance when feeding AOP to BP-fed heifers. [ABSTRACT FROM AUTHOR]

This study aimed to identify the impact of supplementing rumen-protected methionine (RPM) during the periconceptional period on beef cows in their progeny. Evidence suggests that changes in maternal nutrition in the periconceptional period have effects during the postnatal growth phase in cattle. We hypothesized that feeding RPM during the periconceptional period would program bovine gestation to enhance progeny growth. A total of 114 beef cows were fed a roughage-based diet and randomized to receive corn gluten supplemented with 15 g of RPM (Smartamine M, Adisseo) or not (CON) from d -7 to +7 relative to artificial insemination (AI) with female sex-sorted semen. Pregnancy diagnoses were conducted using transrectal ultrason-ography 30 and 60 d after AI. Female calves (n = 34) remained with their dams until weaning. A month after weaning, calves were weighed every 14 d during an 8-mo period, and wither height (WH), body length (BL), and heart girth (HG) were measured. Dry matter intake (DMI), average daily gain (ADG), and residual feed intake (RFI) were measured during a 56-d performance test. At the end of the performance test, the 12th rib back fat (BF), ribeye area (REA), intramuscular fat (IMF), and rump fat (RF) were determined via ultrasound. A treatment-by-day interaction tendency (P = 0.10) was observed in HG, having larger HG in the RPM treatment from d 336-adj of age (CON = 154.52 ± 1.46 cm; RPM = 158.36 ± 1.34 cm). During the performance test, animals in the RPM treatment were heavier (CON = 437.25 ± 2.46 kg; RPM = 442.79 ± 2.34 kg; P = 0.01) at the end of the test. However, no treatment difference (P > 0.05) was observed in DMI (CON = 12.06 ± 0.19 kg/d; RPM = 12.14 ± 0.18 kg/d), ADG (CON = 1.50 ± 0.03 kg; RPM = 1.55 ± 0.03 kg) and RFI (CON = -0.12 ± 0.15; RPM = 0.11 ± 0.14). No treatment difference (P > 0.05) was observed in BF, REA, and IMF. However, RF was greater in the control treatment (CON = 1.16 ± 0.07 cm; RPM = 0.91 ± 0.06 cm), and a tendency of having a thicker BF in control was observed (Table 1). In conclusion, supplementing RPM enhanced final body weight during the performance test; furthermore, a treatment-by-day interaction tendency was observed in HG. On the contrary, CON progeny had more RF and a tendency to have a thicker BF. [ABSTRACT FROM AUTHOR]

By 2050, the US beef industry must produce an extra 40 million tons of beef to satisfy the global demand, while reducing methane (CH4) emissions. This surplus of cattle will be provided mostly by cow-calf operations, which rely primarily on grazing. Those pastures are often infested with weeds such as pigweed (Amaranthus spinosus), one of the most invasive in the US, known for its increased polyphenols concentration. Despite the known effect of polyphenols on CH4 reduction, few studies have explored pigweed as a feed additive. Our objective was to evaluate the effect of in vitro addition of pigweed on ruminal fermentation, digestibility, and CH4 production. We collected ruminal fluid from three American Aberdeen steers (374 ± 21 kg) receiving a backgrounding diet (80:20% corn silage:cotton gin trash, as fed). We incubated (24 h, 39°C) diet (0.7 g) plus the inclusion of 0, 2.5, 5, or 10% (of diet DM) of roots, stems, leaves, seeds, or the whole pigweed plant (WHO). Volatile fatty acids (VFA), CH4 (mmol g-1 organic matter), ammonia, pH, gas, in vitro dry matter, and organic matter digestibility (IVDMD and IVOMD) were determined. Using the MIXED procedure of SAS, data were analyzed as a randomized complete block design with a 5 x 4 factorial arrangement of treatments with plant part (n = 5) and inclusion level (n = 4) as fixed main factors. Incubation and bottle within incubation were random effects. Polynomial orthogonal contrasts were used to determine linear, quadratic, and cubic effects of inclusion level. Plant x level interactions were detected in acetate, propionate, and butyric molar proportion, total VFA, CH4 production, and IVDMD (P < 0.01). Increasing levels of stems increased acetate concentration (P = 0.03), while those from WHO led to a linear reduction of acetate (P < 0.01). The inclusion of 2.5% of leaves, seeds, and WHO increased propionate concentration (P = 0.05), but greater levels decreased it (P < 0.01). Increasing levels of all parts decreased acetate:propionate proportion (P < 0.001). Increasing levels of WHO resulted in a linear reduction of CH4 production (P < 0.05), while increasing inclusion of roots and stems increased CH4 production (P < 0.01). Quadratic reductions in CH4 production were observed after increasing the addition of leaves, seeds, and WHO (P < 0.001). Increasing levels of leaves and roots decreased ammonia concentration (P < 0.01) while stems increased it (P = 0.01). Except for stems and roots, there was a linear decrease in IVDMD with increasing levels of all parts (P < 0.001). The inclusion of low levels of seeds, leaves, and WHO promoted ruminal changes leading to a reduction of CH4 production without significantly compromising the digestibility. [ABSTRACT FROM AUTHOR]

As the demand of nutrients by the population will continue to grow over the years, efficient practices are required in the food chain to satisfy the demand. This practice involves the intensification of production systems. Moreover, intensification can potentially harm the animal or environment if the resources are used to the limit. The latter, product of pushing to the limit the ruminal environment. Dietary buffers and tannins offer a key role addressing issues related to intensification. This study aimed to evaluate the effects of two dietary buffers and tannins. Ruminal fermentation parameters, in vitro methane production, ruminal pH, in vitro organic matter digestibility were measured. Eight ruminally cannulated steers were used in a duplicated 4 x 4 Latin square design. Steers were fed with a basal diet comprised of 35.5% corn silage, 18.7% protein supplement, 21.5% corn grain, 22% bermuda hay, 1% mineral supplement (DM basis). Four treatments were used: BICARB (Basal diet + 1.2% DM Sodium Bicarbonate), BRIC-050 (Basal diet + 1.2% DM BRIC), BRIC-150 (Basal diet + 1.2% DM BRIC + 0.15 % DM Tannins), TAN (Basal diet + 0.15% DM Tannins). Steers were housed in individual pens and received every morning a TMR and water ad libitum. The experiment consisted of 4 periods with 16 days total, composed by 3 d of covariates, 7 d of treatment adaptation, 1 d of 50% feed restriction, 1 d SARA challenge, 4 d of recovery, and 20 d of washout between periods. Two in vitro batch culture were performed in every period at the last day of covariates and last day of recovery, collecting ruminal fluid from each animal. Treatments with BICARB promoted a higher pH than TAN during the adaptation at 4 h after feeding (P = 0.01). Moreover, BRIC-150 showed similar results with a tendency to increase (P = 0.07) when compared with TAN. During the feed restriction BRIC-150 showed a greater pH (P = 0.01) when compared with TAN. While, for BICARB and BRIC-050 pH tended to be greater (P = 0.06) than TAN. During the SARA challenge and the recovery, treatments with buffer tended to have greater pH (P < 0.1). A significant reduction ammonia nitrogen was observed for BICARB and TAN compared with BRIC-050 and BRIC-150 (P < 0.01). Overall, the three buffers tested showed similar results in terms of maintaining a greater pH than treatment without buffer. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of feeding an avian-derived polyclonal antibody preparation (PAP ; CAMAS, Inc.) against Streptococcus bovis , Fusobacterium necrophorum , and lipopolysaccharides (LPS ; 40%, 35%, and 25% of the preparation, respectively) on growth performance (Exp. 1) and apparent total tract digestibility of nutrients (Exp. 2) of beef cattle consuming a backgrounding diet. In Exp. 1, Angus crossbred heifers (n = 70; 360 ± 24 kg of initial body weight; BW) and steers (n = 20; 386 ± 24 kg of BW) were used in a generalized randomized block design. Heifers and steers were allocated to 1 of 18 concrete-surfaced pens (6 pens per treatment) to receive a common ad libitum diet (35% cottonseed hulls, 34% dry-rolled corn, and 20% corn gluten pellets; 15.9% crude protein on a dry matter [ DM ] basis, 1.58 Mcal/kg DM of net energy [ NE ] of maintenance, and 0.98 Mcal/kg DM of NE of gain) and 1 of the 3 treatments consisting of feeding 1 (PAP1), 3 (PAP3), or 0 g (CON) of PAP per day for 56 d. Feed intake was recorded daily and BW was obtained on days −1, 0, 14, 28, 42, 55, and 56 to assess average daily gain (ADG), dry matter intake (DMI), and gain:feed (G:F). Plasma concentrations of glucose and haptoglobin were measured on days 0, 14, 28, 42, and 56. In Exp. 2, 25 Angus crossbreed steers (390 ± 24 kg BW) were used in a completely randomized design to receive the same diet and treatments from Exp. 1 (CON: n = 8; PAP1: n = 9; and PAP3: n = 8). Following a 14-d adaptation to diets, feed and fecal samples were collected to determine apparent total tract nutrient digestibility. In Exp. 1, overall BW, DMI, ADG, G:F, and plasmatic measurements did not differ among treatments over the 56-d period (P ≥ 0.16). However, from days 0 to 14, a quadratic effect was observed for ADG, in which cattle receiving PAP1 had greater (P = 0.04) ADG compared with CON. In Exp. 2, no difference in DMI was observed (P = 0.88), yet DM, organic matter, neutral and acid detergent fiber, and starch digestibility were least (P ≤ 0.05) for PAP3, whereas digestibility of neutral detergent fiber was greatest (P < 0.01) for PAP1. In summary, feeding 1 g/d of a PAP against S. bovis , F. necrophorum , and LPS improved growth performance in the first 14 d and increased fiber digestibility of beef cattle consuming a backgrounding diet. Further research is needed to understand the impaired responses on nutrient digestibility when greater doses are provided. [ABSTRACT FROM AUTHOR]

The search for alternatives to mitigate enteric methane emissions remains a top priority to ensure the continued sustainability of the livestock industry. Exploration of new direct-fed microbials with potential in ruminant nutrition is an active and promising area of research. This study aimed to evaluate the effects of feeding a novel probiotic on ruminal fermentation parameters, in vitro methane production, and nutrient utilization in beef steers. A total of 12 ruminally cannulated American Aberdeen steers (348 ± 37 kg BW) were used in a 4 × 4 Latin square design, with each period lasting for 35 d. The steers were fed a basal diet comprised of 82% corn silage, 12% cotton gin trash, 5% cottonseed meal, and 1% vitamin and mineral supplement on a dry matter (DM) basis. Four treatments were used in this study: CTL (no additive), B2 (probiotic at a dosage of 2 × 109 CFU/animal/d), B10 (probiotic at a dosage of 10 × 109 CFU/animal/d), and B30 (probiotic at a dosage of 30 × 109 CFU/animal/d). Steers were housed in two pens and were sorted daily to receive the treatments individually in a carrier of corn silage (250 g/d). The experiment consisted of 4 periods, with 21 d of adaptation to the treatments, 7 d of measurements, and 7 d of washout between periods. During the study, two in vitro batch culture incubations were performed in each period collecting ruminal fluid from each animal individually (experimental unit): one on d 0 before steers received the treatments, and one after 21 d of adaptation. The incubations on day 0 were used as a baseline. The use of this probiotic did not affect (P > 0.05) in vitro ruminal fluid pH, volatile fatty acids, or acetate to propionate ratio. However, there was a cubic effect (P < 0.05) on in vitro organic matter digestibility with the inclusion of probiotic, and the greatest digestibility was observed in the B2 treatment. The concentration of ammonia nitrogen linearly increased (P < 0.05) with the inclusion of probiotic with CTL and B2 treatments showing the least values. While there was no effect (P > 0.05) on total gas production among treatments, methane production (CH4) was decreased (P < 0.05), showing a quadratic effect where the B2 treatment showed the least values. These results suggest that adding this novel probiotic to beef steers fed a corn silage-based diet at a dose of 2× 109 CFU per day (B2) may have positive results in reducing CH4 and improving digestibility. However, confirmation of these results will be required by in vivo methane emissions data. [ABSTRACT FROM AUTHOR]

The value of carinata, a non-food oilseed crop, has been demonstrated as a high-quality jet fuel alternative and successful cover crop in the southeastern U.S.; however, research is limited regarding carinata as an alternative for commonly used protein sources in livestock. Eighty-four Angus crossbred heifers were used in a generalized randomized block design to evaluate the effects of supplementing carinata meal compared with cottonseed meal on performance, intake, and digestibility in a backgrounding corn silagebased diet. Treatments included: corn silage only (CS), corn silage + Brassica carinata meal (BCM) at 10% (BCM10) or 20 % (BCM20) inclusion, or corn silage + cottonseed meal at 10% inclusion (CSM). Protein sources were mixed with corn silage prior to delivery and provided ad libitum, with individual intake measured using the GrowSafe system. Data were analyzed using Proc Glimmix of SAS. An effect of treatment was observed (P < 0.01) for final body weight (BW), average daily gain, and gain to feed ratio, where CS was least. Dry matter intake (DMI; kg/d) was greatest (P = 0.01) for BCM10 compared with CS, yet BCM20 and CSM did not differ from CS or BCM10. No effect of treatment was observed on DMI as a percentage of BW (P = 0.35) or residual feed intake (P = 0.94). Heifers receiving CSM had the greatest (P < 0.01) intake of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Intake of crude protein (CP; P < 0.01) was least for CS and greatest for BCM20 and CSM, with BCM10 intermediate. Digestibility of all nutrients was least (P < 0.01) for CS, and greatest (P < 0.01) for BCM20 in CP and NDF, only, where BCM10 and CSM did not differ. Digestibility of DM, OM, and ADF was less (P < 0.01) in BCM10, greater in BCM20, while CSM did not differ between BCM10 and BCM20. Carinata supplemented at 10% diet DM performed similarly to cottonseed meal in backgrounding beef heifers fed a corn silage-based diet, thereby enhancing its value in the southeastern U.S. [ABSTRACT FROM AUTHOR]

The value of carinata, a non-food oilseed crop, has been demonstrated as a high-quality jet fuel alternative and successful cover crop in the southeastern U.S.; however, research is limited regarding carinata as an alternative for commonly used protein sources in livestock. Thirty-two Angus crossbred steers were used in a generalized randomized block design to evaluate the effects of supplementing carinata meal compared with cottonseed meal on performance, carcass characteristics, and meat sensory attributes in a finishing diet. Treatments included: either 90% basal diet + 10% inclusion of Brassica carinata meal (BCM) or 90% basal diet + 10% inclusion of cottonseed meal (CSM), on a dry matter (DM) basis. The basal diet consisted of 40% cracked corn, 35% soyhull pellets, 5% gin trash, 5% bermudagrass hay, and 5% vitamin-mineral supplement. Treatments were premixed before delivery and provided ad libitum, with individual intake measured using the GrowSafe system. Data were analyzed using Proc Glimmix of SAS. Protein source did not affect (P > 0.05) final body weight, dry matter intake, average daily gain, gain to feed ratio, or residual feed intake. Protein supplementation did not affect (P > 0.05) initial or final evaluations of longissimus muscle area (LMA), rib fat thickness (RF), and intramuscular fat performed via ultrasound during the performance portion of the experiment. Hot carcass weight (P = 0.10) dressing percentage (P = 0.61), LMA (P = 0.33), RF (P = 0.42), yield grade (P = 0.47), and marbling score (P = 0.89) were not affected by protein source. No effect of protein source was observed (P > 0.05) on slice shear force, juiciness, beef flavor, tenderness, connective tissue, off-flavor, crude fat, thaw loss, cook loss, lightness, redness, or yellowness. The frequency of Prime (P = 0.76), upper 2/3 Choice (P = 0.71), low Choice (P = 0.46), and Select (P = 0.34) USDA quality grades did not differ with protein source. carinata meal inclusion at 10% of the diet DM performed similarly to cottonseed meal in steers fed a finishing diet, thereby enhancing its value in the southeastern U.S. [ABSTRACT FROM AUTHOR]

Beef cattle are a major contributor to methane (CH4) emissions. Enteric CH4 is produced by archaea, mostly hosted by ruminal protozoa, thus, changes in protozoa counts have been associated with CH4 production. Therefore, reliable ruminal protozoa count (PROT) is essential to evaluate CH4-mitigation strategies. Typically, PROT are done by fixation with methyl-green-formalin-saline solution (MFS), which reveals ciliate numbers but not ruminal protozoa viability (VIAB). The Trypan Blue Exclusion Method (TBEM) involves an intracellular probe that dyes the cytoplasm of apoptotic eukaryotic cells with membrane damage, but few studies report its use for PROT. Therefore, our objectives were to establish culture conditions to use the TBEM for PROT and VIAB under different diets (Exp. 1) and feed additives. In Exp. 1 ruminal fluid was collected from 4 Angus-crossbred ruminally cannulated steers receiving a high-grain diet (NOYE) alone or supplemented with 28 g/d of a product of yeast fermentation (YEAST). Filtered and diluted ruminal fluid was incubated (39°C, 95% CO2) with (SUB) or without (NOSUB) the substrate diet in three types of containers; 125 mL bottles (BOT), Erlenmeyer (ERL), or 16 × 125 mm Hungate tubes (TUB). After 8, 12, 24, and 48 h PROT and VIAB were determined using the TBEM, gas production, and CH4 concentration were measured. Exp. 2 involved in vitro batch culture incubations with a silage-based substrate (CON), plus a 50:50% mix of condensed and hydrolysable tannins (TAN), cashew nutshell extract (CNSE), or citral (CIT) at 0.3, 0.02, and 0.2% of substrate DM, respectively. At 0 and 48 h PROT, VIAB, volatile fatty acids (VFA), CH4, in vitro organic matter digestibility (IVOMD), and gas were determined. In Exp-1, PROT and VIAB were greater in TUB (P = 0.01) at 24 h and in BOT at 48 h (P < 0.01), particularly with SUB (P < 0.01). Supplementation of YEAST reduced VIAB in BOT and TUB compared with ERL (P < 0.01). In Exp. 2, TAN (P < 0.01) and CIT (p 0.05) reduced PROT and VIAB at 24 and 48 h (P < 0.01). Additionally, TAN reduced gas production (P < 0.01), and IVOMD (P < 0.01) coinciding with previous studies reporting protozoa reduction. Protozoa/mL were similar to previous reports with MFS in cows (1.5 × 104) and steers (3.7 × 103). In both experiments, PROT and VIAB reductions by YEAST, TAN and CIT coincided with a reduction of CH4, gas, and IVOMD. Differences in PROT with some studies using MFS might be associated with losses of small Entodinium during initial filtrations. When cultured in BOT with substrate, TBEM is a viable, simple, rapid, and cost-effective methodology to evaluate PROT and VIAB after a nutritional challenge. The ability to assess membrane disruptions associated with protozoa apoptosis in the TBEM is one its greatest advantages. [ABSTRACT FROM AUTHOR]

Direct-fed microbials have been used in an effort to improve livestock production efficiency and reduce environmental impact. Among other species, spore forming bacteria such as Bacillus spp. present handling and processing advantages to be used as a probiotic. Several studies have demonstrated positive effects of Bacillus spp. on dairy cattle production. However, there is lack of information about its effects on beef cattle. Thus, the objective of this study was to evaluate the effect of a probiotic composed by a mixture of B. subtilis and B. licheniformis on beef cattle performance, nutrient utilization, and enteric methane emissions (CH4). For this purpose, a total of 108 Angus crossbred heifers (318 ± 40.4 kg of BW) were used in a generalized randomized block design. The heifers were fed a sorghum silage-based diet containing 1 of the 2 following treatments: 1) control (CTL, no additive), or 2) Bacillus spp. probiotic (BSL, 310 mg/kg of diet DM), in an attempt to provide an average of 3 g·animal-1·d-1. The experimental period consisted in 7 d of adaptation to the pens, followed by 77 d of performance data collection, 5 d of apparent total tract digestibility measurements, and 5 d of CH4 measurements. No effect of treatment (P > 0.05) was observed for dry matter intake, average daily gain, or gain-tofeed ratio. The inclusion of the probiotic did not affect (P > 0.05) apparent total tract digestibility of dry matter, organic matter, neutral detergent fiber and crude protein, whereas starch digestibility decreased (P = 0.027) with the probiotic inclusion. No differences (P > 0.05) were observed for CH4 between the two treatments. Accordingly, feeding Bacillus spp. did not affect cattle performance, nutrient utilization, or enteric CH4 emissions in beef heifers when included at 310 mg/kg of dietary dry matter. [ABSTRACT FROM AUTHOR]

Garlic (Allium sativum) contains secondary compounds known to modify rumen fermentation parameters and decrease methane (CH4) emissions; however, results from previous research on the effects of garlic-byproduct supplementation are quite variable. The objective of this experiment was to evaluate the effects of increasing inclusion levels and processing methods of dried raw garlic on in vitro ruminal fermentation and CH4 production. The experiment was designed as a randomized complete block design, where 24 h incubations were conducted on three separate days, with corn silage and gin trash (80:20, respectively) used as basal substrate. Treatments were arranged in a 3 × 3 factorial with garlic inclusion (0, 2.5, and 5% of the diet) and processing method (freeze-dried, oven-dried, and autoclaved) as factors. Three ruminally cannulated steers were fed ad libitum a corn silage and gin trash diet, for at least 35 d prior to collection of ruminal fluid used as inoculum. Final pH, concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), total gas production, and CH4 concentrations were determined at the end of incubation. Data were analyzed using the Mixed procedure of SAS. Final pH and concentration of total VFA were not affected (P > 0.05) by the processing method nor inclusion level of garlic. Increasing garlic inclusion decreased NH3-N concentration (P < 0.05), reduced (P < 0.05) the proportion of acetate, tended to increase (P < 0.10) the proportion of propionate, and tended to decrease (P < 0.10) the acetate:propionate ratio. Neither garlic inclusion level nor processing methods modified IVOMD, total gas production, or CH4 concentration. Modifications in VFA molar proportions and NH3-N concentration may be related to differences in N concentration in the incubated substrates. In conclusion, neither processing method nor garlic level inclusion modified CH4 production or nutrient digestibility. [ABSTRACT FROM AUTHOR]

The value of carinata, a non-food oilseed crop, has been demonstrated as a high-quality jet fuel alternative and successful cover crop in the southeastern U.S.; however, research is limited regarding carinata as an alternative for commonly used protein sources in livestock. Eighty-four Angus crossbred heifers were used in a generalized randomized block design to evaluate the effects of replacing cottonseed meal with carinata meal on performance, intake, and digestibility in backgrounding corn silage-based diet. Treatments included: corn silage only (C), corn silage + Brassica carinata meal (BCM) at 10% (CS-BCM10) or 20 % (CS-BCM20) inclusion, or corn silage + cottonseed meal at 10% inclusion (CS-CSM). Protein sources were mixed on an as fed basis with corn silage prior to delivery and provided ad libitum, with individual intake measured using the GrowSafe system. Data were analyzed using Proc Glimmix of SAS. An effect of treatment was observed for final body weight (BW; P < 0.01), average daily gain (P < 0.01), and gain to feed ratio (P < 0.01), where CS was least. Dry matter intake (DMI; P = 0.01) was greatest for CS-BCM10. No effect of treatment was observed for residual feed intake (P = 0.94), time ruminating (P = 0.32), or DMI as a percentage of BW (P = 0.10). Intake of nutrients was greatest (P < 0.01) for CS-CSM, except crude protein (CP), which was least (P < 0.01) for CS. Dry and organic matter digestibility was decreased (P < 0.01) in CS but did not differ from CS-BCM10, whereas CP digestibility was greatest (P < 0.01) in CS-BCM20, and neutral and acid detergent fiber digestibility was least (P < 0.01) for CS. Carinata performed similarly to cottonseed meal in backgrounding beef heifers fed a corn silage-based diet, thereby enhancing its value in the southeastern U.S. [ABSTRACT FROM AUTHOR]