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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 CH4reduction, 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 CH4production. 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-1organic 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 × 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 × level interactions were detected in acetate, propionate, and butyric molar proportion, total VFA, CH4production, 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 CH4production (P < 0.05), while increasing inclusion of roots and stems increased CH4production (P < 0.01). Quadratic reductions in CH4production 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 CH4production without significantly compromising the digestibility.

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 ultrasonography 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 12thrib 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.

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 vitromethane 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.

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 silage-based diet. Treatments included: corn silage only (CS), corn silage + Brassica carinatameal (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.

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 carinatameal (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.

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 Bacillusspp. 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. subtilisand B. licheniformison 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) Bacillusspp. 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 CH4measurements. No effect of treatment (P> 0.05) was observed for dry matter intake, average daily gain, or gain-to-feed 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 CH4between the two treatments. Accordingly, feeding Bacillusspp. did not affect cattle performance, nutrient utilization, or enteric CH4emissions in beef heifers when included at 310 mg/kg of dietary dry matter.

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 (39ºC, 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.

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 × 109CFU/animal/d), B10 (probiotic at a dosage of 10 × 109CFU/animal/d), and B30 (probiotic at a dosage of 30 × 109CFU/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× 109CFU per day (B2) may have positive results in reducing CH4and improving digestibility. However, confirmation of these results will be required by in vivo methane emissions data.

The study aimed to investigate the effect of supplementing polyclonal antibodies (PAP) of avian origin against the ruminal methanogens Methanobrevibacter gottschalkiiHo (PAP-Ho) and M. ruminantiumM1 (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.Supplementation with polyclonal antibodies against ruminal methanogens has the potential to decrease enteric methane emissions in cattle. Results from the study may have significant implications for the development of passive immunization as an effective strategy to decrease methane emissions in ruminants.Methane is produced by methanogens, a type of microorganism that inhabits environments with low or no oxygen, for instance, the rumen of cattle. Methane is a greenhouse gas, and its emission contributes to climate change. Antibodies are proteins produced by the immune system when foreign bodies, called antigens, enter the body. Antibodies bind antigens and inhibit their negative actions. This study aimed to determine if oral supplementation of cattle with antibodies produced against 2 species of ruminal methanogens can decrease methane emissions from cattle. Different mixtures and doses of the 2 antibodies were supplemented to Angus crossbred animals for 21 d. Ruminal fluid from each animal was collected and incubated for 48 h to determine methane production and concentration of fermentation metabolites. There was no difference between supplementing low or high levels of antibodies. Supplementation with antibodies can result in up to 13% lower methane emissions and, in addition, production of fermentation metabolites was also affected. In summary, even a low dose of antibodies against methanogens could potentially decrease methane emissions from cattle and could become a technology to mitigate the negative effects of methane on climate.

Two experiments were conducted to evaluate the effect of nonprotein nitrogen (NPN) supplementation on in vitro fermentation and animal performance using a backgrounding diet. In experiment 1, incubations were conducted on three separate days (replicates). Treatments were control (CTL, without NPN), urea (U), urea–biuret (UB), and urea–biuret–nitrate (UBN) mixtures. Except for control, treatments were isonitrogenous using 1% U inclusion as a reference. Ruminal fluid was collected from two Angus-crossbred steers fed a backgrounding diet plus 100 g of a UBN mixture for at least 35 d. The concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3–N), in vitro organic matter digestibility (IVOMD), and total gas and methane (CH4) production were determined at 24 h of incubation. In experiment 2, 72 Angus-crossbred yearling steers (303 ± 29 kg of body weight [BW]) were stratified by BW and randomly allocated in nine pens (eight animals/pen and three pens/treatment). Steers consumed a backgrounding diet formulated to match the diet used in the in vitro fermentation experiment. Treatments were U, UB, and UBN and were isonitrogenous using 1% U inclusion as a reference. Steers were adapted to the NPN supplementation for 17 d. Then, digestibility evaluation was performed after 13 d of full NPN supplementation for 4 d using 36 steers (12 steers/treatment). After that, steer performance was evaluated for 56 d (24 steers/treatment). In experiment 1, NPN supplementation increased the concentration of NH3–N and VFA (P< 0.01) without affecting the IVOMD (P= 0.48), total gas (P= 0.51), and CH4production (P= 0.57). Additionally, in vitro fermentation parameters did not differ (P> 0.05) among NPN sources. In experiment 2, NPN supplementation did not change dry matter and nutrient intake (P> 0.05). However, UB and UBN showed lower (P< 0.05) nutrient digestibility than U, except for starch (P=0.20). Dry matter intake (P=0.28), average daily gain (P=0.88), and gain:feed (P=0.63) did not differ among steers receiving NPN mixtures. In conclusion, tested NPN mixtures have the potential to be included in the backgrounding diets without any apparent negative effects on animal performance and warrant further studies to evaluate other variables to fully assess the response of feeding these novel NPN mixtures.NPN supplementation increased in vitro fermentation, but the source of NPN did not have differential effects on in vitro fermentation and in vivo animal performance. Novel sources of NPN mixtures can be included in backgrounding diets without affecting animal performance compared to urea.Nonprotein nitrogen (NPN) supplements can be used as a nitrogen source for ruminants fed low-protein diets. The most common NPN source is urea, included typically at a range between 0.5% and 1% of the diet dry matter in growing beef cattle. Although other NPN sources and mixtures are available, there is scarce information regarding their use in ruminant production. Two experiments were conducted to evaluate the effect of NPN sources on in vitro fermentation and animal performance using a backgrounding diet. In experiment 1, three different incubations were performed for 24 h. Treatments were control (without NPN), urea (U), urea–biuret (UB), and urea–biuret–nitrate (UBN) mixtures. In experiment 2, 72 crossbred yearling steers were randomly assigned to one of the following treatments: U, UB, and UBN mixtures. Diets were formulated to contain the same nitrogen concentration in both experiments. In experiment 1, supplementation of NPN increased the in vitro fermentation, but there were no differences among NPN sources. In experiment 2, steers performed similarly among NPN sources. These findings suggest that NPN mixtures have the potential to be included in the backgrounding diets without detrimental effects. Further studies should evaluate other variables (e.g., fermentation dynamic and microbial protein supply) when using these novel mixtures.

Changing climatic conditions are imposing risks and diminishing yields in agriculture. Sorghum (Sorghum bicolor) silage is a feasible option for backgrounding beef cattle in terms of economic risk management and animal productivity when compared with corn (Zea mays) silage, due to its drought adaptability. Similarly, Brassica carinatameal has proven to be a viable alternative as a protein supplement in forage-based beef cattle systems, when included at 10% of the diet dry matter (DM). However, research is scarce regarding its inclusion in silage-based diets for backgrounding animals. The objective of this trial was to compare a processor-chopped sorghum silage (SS) against a typical corn silage (CS) in a digestibility and performance trial while supplementing two protein sources; one traditionally used like cottonseed meal (CSM) and one novel like B. carinatameal (BCM). A total of 84 Angus crossbred heifers (307 ± 33 kg BW) were evaluated in a randomized block design with a 2 × 2 factorial treatment arrangement with type of silage and protein source as factors. Diets were fed ad libitum, consisting of 89% silage source plus 10% protein source, and 1% mineral inclusion on DM basis. The experimental period consisted of 14 d of adaptation followed by 5 d of apparent total tract digestibility measurements and 56 d of animal performance and intake behavior measurements. Heifers fed SS showed greater number of daily meals but decreased meal sizes (P≤ 0.05), not differing in meal length (P> 0.10) when compared with CS. Dry matter and organic matter (OM) digestibility showed a silage type × protein source interaction (P≤ 0.01), where in CS diets, OM tended to be more digestible with CSM vs. BCM, and it did not differ between protein sources in SS based diets. There was an effect of protein (P≤ 0.01) on ADF digestibility, where CSM was greater than BCM. No effect of treatment was observed (P≥ 0.10) on DM intake. Average daily gain (ADG) and gain-to-feed ratio were greater for CS than SS (P≤ 0.01) regardless of protein source. Although heifers fed CS had greater feed efficiency and digestibility, SS can still be considered a viable option for backgrounding beef heifers, obtaining adequate ADG rates of 0.945 kg/d. Lastly, BCM did not differ from CSM in terms of feed efficiency and animal performance, proving to be a viable alternative protein source in silage-based diets.As climatic conditions are changing rapidly, certain areas of the United States, such as the southeast, are experiencing a negative impact in agricultural terms, as yields are decreasing, imposing a greater risk for farmers due to increased feed costs and decreased availability of feedstuffs. This study shows the viability of sorghum and carinata (and its meal byproduct) as alternative crops in the region. The study provides supports for future increments in the planted area of these alternative crops, with impact in beef cattle operations, increasing the resilience of beef production systems in the southeastern United States.Increased atmospheric CO2, rising temperatures, and altered patterns of precipitation can limit the production of certain crops commonly used in agriculture, increasing risk, cost, and availability of feedstuffs. The search for alternative plants that could thrive in these changing scenarios is necessary to provide producers with a broader array of options to feed cattle. In this study, sorghum silage was compared with corn silage as the main dietary ingredient, with either Brassica carinata(carinata) or cottonseed meal as the protein source for growing beef heifers. Variables assessed included intake behavior, digestibility, and performance of beef heifers. Heifers fed sorghum silage gained less than heifers fed corn silage, though they grew at an adequate rate for a replacement heifer. Carinata meal showed similar performance results compared with cottonseed meal, despite some of its fiber components being less digestible in the total tract. Therefore, sorghum silage has potential to be a viable feedstuff for growing beef heifers although it may result in decreased performance compared with corn silage. Alternatively, carinata meal can be a practical alternative to cottonseed meal as a protein source in terms of animal performance. This could translate in an increase in the planted area of both sorghum and carinata in Southern United States, as they are adapted to drought and high temperatures, enhancing the resilience of beef production systems in a context of increased climate variability.

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.There is an opportunity to increase alfalfa acreage to enhance beef systems through ecosystem services while increasing revenues per hectare through reduced crop costs and greater periods of time to spread manure from beef cattle operations.The potential for growing systems in beef cattle operations depends on the development of cost-effective alternatives for adding value to cattle after weaning. Alfalfa provides several ecosystem services to beef operations through greater opportunities for manure spreading, longer soil cover, pollinator habitat, and greater carbon sequestration compared to corn silage, which is the predominant mechanically harvested forage source for intensive cattle production in the United States. Increasing alfalfa haylage use in growing beef cattle diets requires understanding the effects of replacing corn silage with alfalfa haylage on ADG and feed cost of gain and carcass quality. The objective of this study was to compare the feeding value of alfalfa haylage vs. that of corn silage in growing diets while examining carry-over effects on the finishing period in terms of animal performance and carcass traits.

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 oryzaeprebiotic (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.Dietary inclusion of an Aspergillus oryzaeprebiotic affects animal responses of growing heifers differently depending on the basal diet.This experiment evaluated the effects of the dietary inclusion or not of Aspergillus oryzaeprebiotic (AOP; 2 g/d) in two contrasting diets: sorghum silage-based (SS) vs. byproducts-based (BP), on growth performance, nutrient digestibility, and feeding behavior of growing heifers. A total of 84 Angus crossbred heifers were used in the study. Heifers fed with the BP diets had greater feed intake, average daily gain, and final body weight. In addition, heifers fed with the BP diets had reduced number of visits to the feed bunk but consumed more in each visit than heifers fed with the SS diets. Additionally, heifers fed with the BP diets had lesser chewing activity measured in total min/d and in min/kg of dry matter intake; however, chewing activity measured in min/kg of neutral detergent fiber was not influenced by treatments. The inclusion of AOP increased the gain:feed ratio by 15% in heifers fed with the BP diet but did not influence this variable in the SS diet. The inclusion of AOP increased nutrient digestibility in heifers fed with the SS diet and decreased nutrient digestibility in heifers fed with the BP diet. These results show that feeding AOP can enhance growth performance in beef heifers in a diet-dependent manner.

The aim of the study was to compare the growth of the periovulatory follicle in crossbreed cows receiving either a low dose of hCG (150 IU; Chorulon®, Merck) or a low dose of FSH (20 mg)Folltropin®, Vetoquinol) vs. a control group when applied at CIDR removal during an estrus synchronization protocol. At d0, a CIDR (Eazi-Breed CIDR®, Zoetis) was placed, a dose of GnRH (Factrel®, Zoetis) was applied i.m. and transrectal ultrasound was conducted to evaluate cyclicity status. On d7, cows (n = 79) were randomly assigned to three treatments (Control n = 27, FSH n = 26, and hCG n = 26) according to body condition score (1 to 9 scale) and cyclicity status. On the same day, CIDR was removed, a dose of prostaglandin analog (Lutalyse HighCon Injection®, Zoetis) was administered i.m. and an Estrotect™ patch was placed between the hip and tail head. Transrectal ultrasound was conducted to evaluate the diameter of the preovulatory follicle (DPF) at d7 and every 12h from d8 until ovulation was detected. Five cows that did not ovulate were removed from the study. Data were analyzed using GLIMMIX and LIFETEST procedures (SAS). The diameter at ovulation was not different among treatments (Control: 13.02 ± 0.53 mm; FSH: 12.38 ± 0.54 mm; hCG; 11.69 ± 0.47 mm; P = >0.10). Also, the time to ovulation was not different among treatments (P = 0.65; Figure 1a). However, cows of the control group presented estrus signs earlier than FSH and hCG groups (P = 0.02, Figure 1b). In conclusion, the use of a low dose of hCG or FSH at the time of CIDR removal did not increase the DPF or the time to ovulation.

Eighty-four Angus crossbred heifers (13 ± 1 mo, 329.5 ± 61.92 kg of BW) were used in a generalized randomized block design with a 2 × 2 factorial arrangement of treatments. The objective was to evaluate the effect of a feed additive inclusion under two growing diets. Factors included: 1) diet type (whole plant sorghum silage- or byproducts-based diet) and 2) feed additive inclusion [Amaferm (Aspergillus oryzae (extract)] included at 0 or 0.02% of the diet DM. This resulted in four treatments: sorghum-control (SC), sorghum-amaferm (SA), byproducts-control (BC) and byproducts-amaferm (BA). Heifers were housed in 12 pens (108 m2/pen; 7 heifers/ pen) equipped with GrowSafe technology, to measure individual dry matter intake (DMI). After a 14-d adaptation, BW was measured every 14 d, during 56 days, and chewing activity was monitored through collar-mounted HR-Tags (SCR Engineers Ltd., Netanya, Israel). Apparent total tract digestibility was measured on 10 heifers per treatment after the 56-d performance period, using indigestible NDF as a marker. Heifers fed the byproducts diet had (P ≤ 0.01) greater DMI as % of BW (2.92 vs. 2.59%) and greater average daily gain (1.16 vs. 0.68 kg/d). Amaferm improved gain-to-feed ratio by 15% in the byproducts diet (P ≤ 0.05) but it had no effect in the sorghum silage diet (P = 0.59). Conversely, Amaferm inclusion increased apparent total tract organic matter digestibility in the sorghum silage diet (SC = 49.8 vs. SA = 55.9%; P ≤ 0.01), whereas reduced it in the byproducts diet (BC = 65.8 vs. BA = 61.7%; P ≤ 0.05). Heifers fed a sorghum silage-based diet had (P ≤ 0.01) 39 and 63% greater chewing in min/d and min/kg of DMI, respectively; however, chewing in min/kg of NDF intake was similar across diets (average 111.3 min/kg of NDF intake).