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Non-protein nitrogen (NPN) supplements improve animal performance in backgrounding diets. However, there is scarce information regarding the effect of different NPN sources and combinations on ruminal fermentation profile. The current study aimed to evaluate the effect of different NPN sources and their combinations on in vitro fermentation, microbial N synthesis, and methane (CH4) production in a backgrounding diet. Incubations were conducted on three separate days for 24 h using corn silage and cotton gin byproduct (70% and 30% of DM, respectively) as substrate. Treatments were control (without NPN), urea, and five different proportions of urea–biuret and nitrate (100:0, 75:25, 50:50, 25:75, and 0:100). Each treatment, except control, was formulated to be isonitrogenous and equivalent to 1% urea inclusion. Ruminal fluid was collected from two ruminally cannulated Angus crossbred steers fed ad libitum corn silage and cotton gin byproduct plus 100 g of a urea–biuret–nitrate mixture. The concentration of volatile fatty acids (VFAs) and ammonia nitrogen (NH 3 -N) were determined at 12 and 24 h of incubation. Final pH, in vitro dry and organic matter digestibility, total gas production, and concentration of CH4 were determined at 24 h. The supplementation of NPN increased (P  < 0.05) the concentration of NH3-N at 12 and 24 h. Although NPN supplementation increased (P  < 0.05) the concentration of total VFA and acetate at 12 h, treatments did not differ (P  > 0.05) at 24 h. Supplementation of NPN increased (P  < 0.05) the proportion of acetate at 12 and 24 h but tended to reduce (P  = 0.054) the proportion of propionate only at 12 h. Digestibility and pH were not different (P  > 0.05) among treatments. Increasing nitrates in the NPN supplement increased (P  < 0.05) the proportion of acetate and reduced (P  < 0.05) the proportion of butyrate at 12 and 24 h. The supplementation of NPN increased (P  < 0.05) microbial N synthesis. Furthermore, increasing nitrate proportion in the NPN supplement increased (P  < 0.05) the microbial N synthesis and efficiency of N use. Supplementation of NPN did not modify (P  > 0.05) total gas or CH4 production. However, increasing nitrate proportion in the NPN supplement linearly reduced (P  < 0.05) CH4 production. Supplementation of NPN increased NH3-N concentration and microbial N while increasing the inclusion of nitrate decreased the production of CH4 and increased the microbial N synthesis in a corn silage-based substrate under in vitro conditions. [ABSTRACT FROM AUTHOR]

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The study aimed to investigate the effect of supplementing polyclonal antibodies (PAP) of avian origin against the ruminal methanogens Methanobrevibacter gottschalkii Ho (PAP-Ho) and M. ruminantium M1 (PAP-M1) on ruminal fermentation profile and methane production in Angus crossbred cattle (13 steers and 1 heifer). The experiment was conducted using a randomized block design with a 3 × 2 + 1 factorial arrangement, replicated in 3 periods. The factors included proportions of PAP against Ho and M1 in the mixture (100:0, 50:50, and 0:100 Ho:M1) and level of each mixture (3- or 6-mL per d). Cattle in control treatment did not receive PAP supplementation. Ruminal fluid was collected from the animals on days 0, 14, and 21 of treatment to determine of ruminal fermentation profile and ex vivo methane production. There was no effect of level of inclusion on ex vivo methane production. Supplementation with PAP-M1, either alone or in combination with PAP-Ho, decreased ex vivo methane output compared to the control group. Furthermore, in vivo molar proportion of propionate tended to be greater with PAP-M1, alone or combined with PAP-Ho, when compared with the control group. The study concluded that polyclonal antibodies against ruminal methanogens have the potential to decrease enteric methane emissions in cattle. The research provided important insights into the potential use of PAP as a strategy for reducing greenhouse gas emissions from cattle. Further research is needed to confirm these findings and to determine the practicality and feasibility of using PAP. [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]

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]

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]

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]

As a novel oilseed crop in Florida, Brassica carinata has the capacity of producing high-quality jet biofuel, with a protein-dense meal (~40% crude protein; CP) obtained as a by-product of oil extraction. Characterization of the meal protein is limited, yet necessary for formulation of beef cattle diets; therefore, the objective of this experiment was to determine ruminal and postruminal digestibility of protein from B. carinata. Eight ruminally cannulated Angus crossbred steers (473 ± 119 kg) were used in a duplicated 4 × 4 Latin square design, in which in situ ruminal and postruminal degradability of nutrients were evaluated. The three-step in vitro procedure was used to compare CP and amino acid (AA) degradation in B. carinata meal pellets (BCM) with that of cottonseed meal (CSM), dry distillers grains with solubles (DDGS), and soybean meal (SBM). In situ bags were incubated in the rumen for 0 to 96 hr, with the undegraded supplement remaining after 16 hr subjected to serial in vitro enzymatic solutions. Data were analyzed using the MIXED procedure of SAS. Ruminal rate of degradation of dry matter, organic matter, and CP was greatest (P ˂ 0.01; 10.9, 11.3, and 11.5 %/h, respectively) for SBM. Rumen degradable protein (RDP) content did not differ (P = 0.20; 47.8% and 55.1%, respectively) between CSM and DDGS, but was decreased (P ˂ 0.01) compared with SBM and BCM, which did not differ (P = 0.99; 72.3% and 71.8% RDP, respectively). Compared with DDGS, SBM had greater (P < 0.01) intestinal digestibility of rumen undegradable protein (RUP). Intestinally absorbable digestible protein (IADP) was greatest (P < 0.01) for CSM, with SBM and BCM having the least IADP. Total tract digestibility of CP (TTDP) was greater (P < 0.01) for SBM compared with CSM and DDGS. The contribution of RUP to intestinally absorbable AA was 7.2 and 3.1 g of lysine and methionine per kilogram of CP in BCM, respectively. The evaluation of B. carinata meal as protein supplemented for cattle consuming a forage-based diet resulted in 71.8% RDP and 97.1% TTDP, thus indicating its viability as a high-quality protein supplement for beef cattle. [ABSTRACT FROM AUTHOR]