Search

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]

Corn silage is the predominant mechanically harvested forage source for feedlot cattle production in the United States because of high yield. Alternatively, because of multiple cuttings per year and lower annual cost, the use of alfalfa or other forages, may increase opportunities for manure spreading, perennial soil cover, pollinator habitat, and greater carbon sequestration. The objective of this trial was to determine the feeding value of alfalfa haylage when replacing corn silage in growing cattle diets. One-hundred-sixty-five Angus crossbred steers [326 ± 51 kg of body weight (BW)] were blocked by initial BW and randomly assigned to one of 28 pens at the University of Minnesota feedlot. Pens were randomly assigned to dietary growing treatments. The control diet was comprised of (DM basis) 50% corn silage, 19.25% rolled corn grain, 19.25% high moisture corn, 7% dried distillers grains plus solubles, and 4.5% liquid supplement (corn silage control, CS Control). For alfalfa haylage (AH) diets, AH substituted corn silage at 33% (AH 33), 66% (AH 66), or 100% (AH 100). Growth performance measurements [dry matter intake (DMI), average daily gain (ADG) and gain to feed (G:F) ratio] were assessed for 42 to 70 d depending on BW block. Afterwards, steers were fed a common finishing diet until harvested. There was a linear increase in DMI (P  < 0.01) with increasing AH inclusion. Replacing CS with AH linearly decreased (P  ≤ 0.05) ADG and G:F. No differences (P  ≥ 0.10) were observed in finishing performance or carcass traits. Results from this study demonstrated that greater substitution of corn silage with alfalfa haylage in growing diets resulted in greater intake but reduced rate of gain and gain:feed. Despite slower rate of gain, cattle fed alfalfa haylage at increasing proportions during the growing period were able to compensate in BW gains during the finishing period and reached harvest weight and backfat thickness at similar days on feed than those fed corn silage. Based on these results the energy value of corn silage and alfalfa haylage were 3.05 and 2.39 Mcal ME/kg of DM, respectively, when included at 50% of the diet DM. [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. 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]

This study investigated the effects of feeding an avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40, 35, and 25% of the preparation, respectively) on plasmatic haptoglobin, ruminal short chain fatty acids (SCFA), and ammonia-N (NH3-N) concentrations of beef steers during a 21-d step-up adaptation to a high-grain diet. Eight ruminally cannulated Angus crossbred beef steers (658 ± 79 kg BW) were randomly assigned to treatments in a crossover design to be transitioned from a diet containing bermudagrass hay [Cynodon dactylon (L.) Pers.] plus 0.45 kg/d of molasses with 0 (CON) or 3 g/d of PAP (PAP) to a high-grain diet. Transition consisted of three 7-d steps of increased inclusion of cracked corn (35, 60, and 80% diet DM for STEP1, STEP2, and STEP3, respectively). On each transition d and 7 d after STEP3 (STEP3-7d), ruminal fluid samples were obtained every 3 h for 24 h. Blood samples were collected on d 0, 1, and 3 relative to each transition for haptoglobin determinations. Haptoglobin plasmatic concentrations increased (P = 0.03) on d 2 and 3 vs. d 1 during STEP2 and on STEP3 compared to STEP1 and STEP2 (P = 0.01). Steers receiving PAP had greater (P < 0.01) ruminal NH3-N concentration in STEP1; however, there were no effects of treatment on SCFA (P > 0.10). Total SCFA concentrations were affected by the step-up diets (P < 0.01); propionate concentration (Pro) was greater in STEP2 through STEP3-7d vs. STEP1 (P < 0.01), whereas acetate concentration (Ac) and Ac:Pro linearly decreased from STEP1 to STEP3-7d (P < 0.01). Feeding 3 g/d of polyclonal antibody preparations against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides in a 21-d step-up adaptation to high-grain diets did not affect plasmatic haptoglobin or ruminal SCFA concentrations; however, it increased ruminal NH3-3 concentrations. [ABSTRACT FROM AUTHOR]