Vitamin and mineral supplementation and rate of gain during the first trimester of gestation affect concentrations of amino acids in maternal serum and allantoic fluid of beef heifers

Dietary Zinc Supplementation in Steers Modulates Labile Zinc Concentration and Zinc Transporter Gene Expression in Circulating Immune Cells

Zinc (Zn) is critical for immune function, and marginal Zn deficiency in calves can lead to suboptimal growth and increased disease susceptibility. However, in contrast to other trace minerals such as copper, tissue concentrations of Zn do not change readily in conditions of supplementation or marginal deficiency. Therefore, the evaluation of Zn status remains challenging. Zinc transporters are essential for maintaining intracellular Zn homeostasis, and their expression may indicate changes in Zn status in the animal. Here, we investigated the effects of dietary Zn supplementation on labile Zn concentration and Zn transporter gene expression in circulating immune cells isolated from feedlot steers. Eighteen Angus crossbred steers (261 ± 14 kg) were blocked by body weight and randomly assigned to two dietary treatments: a control diet (58 mg Zn/kg DM, no supplemental Zn) or control plus 150 mg Zn/kg DM (HiZn; 207 mg Zn/kg DM total). After 33 days, Zn supplementation increased labile Zn concentrations (as FluoZin-3 fluorescence) in monocytes, granulocytes, and CD4 T cells (P < 0.05) but had the opposite effect on CD8 and γδ T cells (P < 0.05). Zn transporter gene expression was analyzed on purified immune cell populations collected on days 27 or 28. ZIP11 and ZnT1 gene expression was lower (P < 0.05) in CD4 T cells from HiZn compared to controls. Expression of ZIP6 in CD8 T cells (P = 0.02) and ZnT7 in B cells (P = 0.01) was upregulated in HiZn, while ZnT9 tended (P = 0.06) to increase in B cells from HiZn. These results suggest dietary Zn concentration affects both circulating immune cell Zn concentrations and Zn transporter gene expression in healthy steers.

Amino Acid Content in the Muscles of the Red Deer (Cervus elaphus) from Three Types of Feeding Grounds

This study aimed to analyze the amino acid profile, with a particular focus on the nutritional value of the protein of the longissimus lumborum (LL) and the semimembranosus (SM) muscles of deer originating from three feeding grounds: forest (FFG); conventional (CFG) grounds; organic farm (OFG). This is the first time that deer from an organic farm feeding ground have been included in this study. The muscles were collected from 36 deer carcasses with equal proportions of sex and 31 months of age. This study demonstrated significantly higher essential amino acid (EAA) and non-essential amino acid (NEAA) contents in the muscles of deer from the FFG and CFG compared to the OFG. However, the EAA-to-NEAA ratio was significantly higher for the muscles of deer from the OFG. The muscles of the FFG and CFG deer were characterized by a higher concentration of lysine as well as acidic and tasty amino acids compared to the OFG deer, with the muscles of the latter exhibiting a higher percentage of branched-chain amino acids (BCAA). The results obtained can be used professionally by nutrition specialists in preventive and therapeutic diets and breeders to make decisions about farm location and deer feeding strategies.

Impact of replacing protein pellets with soybean grain on nutrient utilization and the rumen and blood parameters of feedlot cattle under tropical conditions

The aim of this study was to explore the effect of replacing protein pellets with soybean grain in high-concentrate diets with or without the addition of silage, on the intake, digestibility, and rumen and blood parameters of feedlot cattle in tropical regions. Four cannulated, crossbred steers were used, 4.5 ± 0.5 years old, with an average weight of 685.55 ± 111.78 kg. The steers were distributed in a 4 × 4 Latin square, in a 2 × 2 factorial scheme (two sources of protein: protein pellets or whole soybean grain, with or without added dietary bulk). There was no effect (P ≥ 0.109) from the interaction between the source of protein and the addition of silage to the diet on dry matter (DM) and nutrient intake, or the digestibility (P ≥ 0.625) of DM or crude protein (CP). However, both factors affected (P ≤ 0.052) the intake of DM, neutral detergent fiber (NDF), and non-fiber carbohydrates (NFC), as well as the independent digestibility (P ≤ 0.099) of fat, NFC, total carbohydrates (TC), and total cholesterol concentration. There was an effect (P ≤ 0.053) from the interaction between the source of protein and the addition of silage to the diet on the digestibility of NDF and total digestible nutrients (TDN), as well as on the glycose concentration (P = 0.003). Blood parameters (i.e. protein, albumin, creatinine, triglycerides, aspartate aminotransferase (AST), and alanine aminotransferase (ALT)) were not affected (P ≥ 0.139) by the source of protein, the addition of silage, or their interaction. Lastly, including 150 g/kg silage DM in a high-grain diet, and using soybean grain as a source of protein in substitution of protein pellet could be a suitable nutritional strategy to ensure adequate DM and nutrient intake and digestibility, with no detrimental effects on rumen and blood parameters of feedlot cattle in the tropics.

Some plasma biomarkers of residual feed intake in beef cattle remain consistent regardless of intake level

This study investigated whether plasma biomarkers of residual feed intake (RFI), identified under ad libitum feeding conditions in beef cattle, remained consistent during feed restriction. Sixty Charolais crossbred young bulls were divided into two groups for a crossover study. Group A was initially fed ad libitum (first test) and then restricted (second test) on the same diet, while Group B experienced the opposite sequence. Blood samples were collected from the 12 most divergent RFI animals in each group at the end of the first test and again after the second test. 12 plasma variables consistently increased, while three consistently decreased during feed restriction (FDR < 0.05). Only two metabolites, α-aminoadipic acid for Group A and 5-aminovaleric acid for Group B, were associated with RFI independent of feed intake level (FDR < 0.05), demonstrating moderate-to-high repeatability across feeding levels (intraclass correlation coefficient ≥ 0.59). Notably, both metabolites belong to the same metabolic pathway: lysine degradation. These metabolites consistently correlated with RFI, irrespective of fluctuations in feed intake, indicating a connection to individual metabolic processes influencing feed efficiency. These findings suggest that a portion of RFI phenotypic variance is inherent to an individual's metabolic efficiency beyond variations in feed intake.

Finishing of grazing crossbred steers supplemented with detoxified castor bean meal (Ricinus communis L.) in the rainy-dry transition period

This study evaluated levels of replacement of soybean meal by castor bean meal in the finishing crossbred steers on Brachiaria brizantha cv. Marandu pasture during the rainy-dry transition period. Forty Holstein-Zebu crossbred steers with an average initial weight of 395.93 ± 10 kg were randomly allocated to four treatment groups that were supplemented with concentrate levels of replacing (0, 290, 613, and 903 g/kg DM of the supplement; at 0.4% body weight [BW]). The experimental period was 120 days. A completely randomized experimental design was adopted; with regression analysis using the computational software package (SAS 9.2, USA). Intake and digestibility of dry matter (DM) and nutrients and animal performance were evaluated. The replacement levels did not influence (P > 0.05) the intakes of DM (kg/day), organic matter (OM, kg/day), neutral detergent fiber (NDF, kg/day and %BW), non-fibrous carbohydrates (NFC, kg/day), or total digestible nutrients (kg/day). However, the intake of crude protein (CP) and ether extract (EE, kg/day) decreased as the replacement levels were increased (P < 0.05). The digestibility of DM, OM, NDF, and EE did not change, whereas CP digestibility decreased linearly and NFC digestibility increased linearly (P < 0.05). The replacement levels did not affect (P > 0.05) final body weight, average daily gain, feed conversion, and carcass yield. Castor bean meal can replace up to 903 g/kg DM of soybean meal in the composition of the supplement without compromising the performance of steers on Marandu pasture during the rainy-dry transition period.

Maternal prepartum supplementation of protein and energy and body condition score modulated the performance of Bos indicus-influenced cow-calf pairs

Retrospective analyses were performed on a dataset of 1188 fall-calving, Brangus cow-calf pairs. Analyses 1 sorted cows according to their initial body condition score (BCS < 5 vs. ≥ 5) and whether they received (SUP) or not (NOSUP) prepartum supplementation of protein and energy. Analyses 2 sorted cows according to their calving BCS (BCS < 5 or ≥ 5) and BCS change from calving until the start of the breeding season (lost, maintained, or gained). Cows were not estrus synchronized and were assigned to natural breeding for 90 days. Prepartum supplementation increased (P = 0.04) pregnancy percentage in cows with initial BCS < 5 but not (P = 0.20) with initial BCS ≥ 5. Calf weaning weight was greatest (P ≤ 0.04) for calves born from SUP cows with an initial BCS ≥ 5 and did not differ (P ≥ 0.56) among all remaining groups. Among cows with calving BCS < 5, pregnancy percentage were less (P = 0.05) for cows that lost vs. maintained/gained BCS. Postpartum BCS change did not (P ≥ 0.16) impact pregnancy percentage of cows calving at BCS ≥ 5. Calf weaning weight increased (P < 0.01) for cows calving with BCS ≥ 5 vs. < 5 and was not impacted (P = 0.47) by postpartum BCS change. Therefore, precalving supplementation improved reproduction of cows with BCS below optimal and weaning weight of calves born from cows with BCS above optimal, whereas calving BCS was the major factor affecting postpartum BCS change and cow reproductive performance.

Characterizing pregnancy losses in Bos indicus beef females receiving a fixed-timed artificial insemination protocol

This experiment evaluated pregnancy losses from day 30 of gestation to calving in Bos indicus females, and evaluated if serum haptoglobin concentrations during early gestation impacts subsequent pregnancy losses. A total of 4926 Nelore females were used, being 1802 nulliparous heifers inseminated as yearlings (precocious heifers), 1356 nulliparous heifers inseminated at 24 months of age (conventional heifers), 887 suckling primiparous cows, and 881 suckling multiparous cows. Cows were assigned to an ovulation synchronization + fixed-time artificial insemination (FTAI) protocol from day -11 to 0 of the experiment. Pregnancy status was verified using transrectal ultrasonography on days 30 and 60 after FTAI, via transrectal palpation on day 150 after FTAI, and according to calf birth. Blood samples were collected from all animals diagnosed pregnant on day 30 after FTAI, and analyzed for serum concentrations of haptoglobin and pregnancy associated glycoproteins (PAG). Pregnancy loss was greater (P < 0.01) from day 60-150 of gestation (10.2 %) compared with day 30-60 of gestation (6.0 %) and with day 150 of gestation to calving (7.4 %), and differed (P = 0.04) between these latter two periods. Pregnancy loss from day 30-60 of gestation did not differ (P = 0.26) among parities, whereas total pregnancy losses (day 30 to calving) were greater (P < 0.01) in precocious (28.4 %) and conventional (27.1 %) heifers compared with primiparous (16.4 %) and multiparous (13.0 %) cows. Serum PAG concentrations on day 30 after FTAI were less (P ≤ 0.03) in cows that lost the pregnancy (5.63 ng/mL) from day 30-60 of gestation, as well as those that lost the pregnancy from day 30 to calving (8.59 ng/mL) compared with cohorts that maintained the pregnancy (9.39 and 9.32 ng/mL, respectively). No differences in serum PAG concentrations on day 30 after FTAI were noted (P ≥ 0.23) according to pregnancy losses from day 60 to calving. Serum haptoglobin concentration on day 30 after FTAI also did not differ (P ≥ 0.48) between cows that maintained or lost the pregnancy. This experiment provides novel information about pregnancy losses after day 30 of gestation in B. indicus cattle, with most losses occurring as fetal mortality and not affected by systemic inflammation during early gestation. Pregnancy losses were nearly doubled in precocious and conventional heifers compared with parous cows, demonstrating the relevance of this reproductive failure to B. indicus replacement heifers.

A system dynamics approach to model heat stress accumulation in dairy cows during a heatwave event

Climate change is expected to increase the number of heat wave events, leading to prolonged exposures to severe heat stress (HS) and the corresponding adverse effects on dairy cattle productivity. Modelling dairy cattle productivity under HS conditions is complicated because it requires comprehending the complexity, non-linearity, dynamicity, and delays in animal response. In this paper, we applied the System Dynamics methodology to understand the dynamics of animal response and system delays of observed milk yield (MY) in dairy cows under HS. Data on MY and temperature-humidity index were collected from a dairy cattle farm. Model development involved: (i) articulation of the problem, identification of the feedback mechanisms, and development of the dynamic hypothesis through a causal loop diagram; (ii) formulation of the quantitative model through a stock-and-flow structure; (iii) calibration of the model parameters; and (iv) analysis of results for individual cows. The model was successively evaluated with 20 cows in the case study farm, and the relevant parameters of their HS response were quantified with calibration. According to the evaluation of the results, the proposed model structure was able to capture the effect of HS for 11 cows with high accuracy with mean absolute percent error <5%, concordance correlation coefficient >0.6, and R2 > 0.6, except for two cows (ID #13 and #20) with R2 less than 0.6, implying that the rest of the nine animals do not exhibit heat-sensitive behaviour for the defined parameter space. The presented HS model considered non-linear feedback mechanisms as an attempt to help farmers and decision makers quantify the animal response to HS, predict MY under HS conditions, and distinguish the heat-sensitive cows from heat-tolerant cows at the farm level.

Trace mineral concentrations and accretion rates in the empty body and body tissues of growing Fleckvieh (German Simmental) bulls

This research project aimed to generate basic data for specifying the trace mineral requirements of Fleckvieh (German Simmental) bulls. Hence, the concentrations of the trace minerals iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn) in the empty-body and body tissue fractions of growing Fleckvieh bulls slaughtered at 120-780 kg live weight were determined. Results were used to calculate trace mineral accretion rates. Fe and Zn represented the largest shares in the animals' bodies. The Zn accretion increased, while Mn accretion steadily declined during cattle growth. Fe accretion attained a maximum at 400 kg live weight. Cu accretion declined until 600 kg live weight and then increased slightly afterwards. The provided data may be used to adjust the recommendations with respect to the trace mineral requirements of growing Fleckvieh bulls.

Effect of cutting management on the forage production and quality of tepary bean (Phaseolus acutifolius A. Gray)

Tepary bean (Phaseolus acutifolius A. Gray) is an underutilized drought tolerant annual legume, originating from the Sonoran Desert, that may be a beneficial forage/hay for beef cattle in the Southern Great Plains of the US (SGP). The SGP has erratic rainfall and periods of intermittent drought exacerbated by high summer temperatures. In 2020 and 2021, a split-plot design was used to evaluate 13 genotypes of tepary bean and a forage soybean (control) at El Reno, OK, USA to compare production of plant biomass and forage nutritive value parameters under seven harvest regimes. Genotypes were used as the main plot and cutting management as the sub-plot. Biomass production of all tepary bean genotypes equaled that of soybean (p > 0.05), while several genotypes had superior forage nutritive value traits (p ≤ 0.05). Overall, a 15-cm cutting height and 30-day harvest interval produced the best overall product (average dry biomass of 5.8 Mg ha-1 with average relative feed values (RFV) of 165). Although all harvest regimes reduced total seasonal biomass, forage nutritive value increased. However, the tradeoff between forage production and nutritive value may be unacceptable to most producers. Further agronomic and breeding research is needed to encourage producers to grow tepary bean as a forage/hay in the SGP.

Review: Harnessing extant energy and protein requirement modeling for sustainable beef production

Numerous mathematical nutrition models have been developed in the last sixty years to predict the dietary supply and requirement of farm animals' energy and protein. Although these models, usually developed by different groups, share similar concepts and data, their calculation routines (i.e., submodels) have rarely been combined into generalized models. This lack of mixing submodels is partly because different models have different attributes, including paradigms, structural decisions, inputs/outputs, and parameterization processes that could render them incompatible for merging. Another reason is that predictability might increase due to offsetting errors that cannot be thoroughly studied. Alternatively, combining concepts might be more accessible and safer than combining models' calculation routines because concepts can be incorporated into existing models without changing the modeling structure and calculation logic, though additional inputs might be needed. Instead of developing new models, improving the merging of extant models' concepts might curtail the time and effort needed to develop models capable of evaluating aspects of sustainability. Two areas of beef production research that are needed to ensure adequate diet formulation include accurate energy requirements of grazing animals (decrease methane emissions) and efficiency of energy use (reduce carcass waste and resource use) by growing cattle. A revised model for energy expenditure of grazing animals was proposed to incorporate the energy needed for physical activity, as the British feeding system recommended, and eating and rumination (HjEer) into the total energy requirement. Unfortunately, the proposed equation can only be solved iteratively through optimization because HjEer requires metabolizable energy (ME) intake. The other revised model expanded an existing model to estimate the partial efficiency of using ME for growth (kg) from protein proportion in the retained energy by including an animal degree of maturity and average daily gain (ADG) as used in the Australian feeding system. The revised kg model uses carcass composition, and it is less dependent on dietary ME content, but still requires an accurate assessment of the degree of maturity and ADG, which in turn depends on the kg. Therefore, it needs to be solved iteratively or using one-step delayed continuous calculation (i.e., use the previous day's ADG to compute the current day's kg). We believe that generalized models developed by merging different models' concepts might improve our understanding of the relationships of existing variables that were known for their importance but not included in extant models because of the lack of proper information or confidence at that time.

Effect of physically effective neutral detergent fiber on nutrient intake and digestibility, ruminal and blood parameters, and ingestive behavior of confined beef cattle

We aimed to evaluate the effect of levels of physically effective neutral detergent fiber from forage (NDFfor) on confined cattle's metabolism and ingestive behavior. Four crossbred steers (514.0 ± 4.54 kg BW) rumen-cannulated were used. The animals were randomly distributed in a 4×4 Latin square design, and the treatments were diets with 9.5%, 5.5%, 2.5%, and 0.0% NDF from whole plant corn silage. The trial was divided into 4 periods of 21 days. The dry matter, organic matter (OM), crude protein, neutral detergent fiber (NDF), physically effective NDF 8mm (peNDF8mm) and NDF1.18mm intakes, and the digestibility of OM and NDF showed a quadratic behavior. The rumen pH values showed a decreasing linear, and the time at pH below 5.8 increased linearly in the diets with lower NDFfor. The production of volatile fatty acids and the proportions of propionate and butyrate showed an increasing quadratic behavior. On the other hand, the proportion of acetate fitted a decreasing quadratic equation. With the lower participation of forage in the diets, the time spent on rumination activity decreased in a quadratic way, and the time spent in idleness increased in a quadratic way. The corn silage can be reduced to 135 g/kg DM in the diet to obtain a minimum of 5.5% of NDF from roughage.

Examination of the horizontal gene transfer dynamics of an integrative and conjugative element encoding multidrug resistance in Histophilus somni

Integrative and conjugative elements (ICEs) are self-transferable mobile genetic elements that play a significant role in disseminating antimicrobial resistance between bacteria via horizontal gene transfer. A recently identified ICE in a clinical isolate of Histophilus somni (ICEHs02) is 72 914 base pairs in length and harbours seven predicted antimicrobial resistance genes conferring resistance to tetracycline (tetR-tet(H)), florfenicol (floR), sulfonamide (Sul2), aminoglycosides (APH(3″)-Ib, APH(6)-Id, APH(3')-Ia), and copper (mco). This study investigated ICEHs02 host range, assessed effects of antimicrobial stressors on transfer frequency, and examined effects of ICEHs02 acquisition on hosts. Conjugation assays examined transfer frequency of ICEHs02 to H. somni and Pasteurella multocida strains. Polymerase chain reaction assays confirmed the presence of a circular intermediate, ICE-associated core genes, and cargo genes in recipient strains. Susceptibility testing examined ICEHs02-associated resistance phenotypes in recipient strains. Tetracycline and ciprofloxacin induction significantly increased the transfer rates of ICEHs02 in vitro. The copy numbers of the circular intermediate of ICEHs02 per chromosome exhibited significant increases of ∼37-fold after tetracycline exposure and ∼4-fold after ciprofloxacin treatment. The acquisition of ICEHs02 reduced the relative fitness of H. somni transconjugants (TG) by 28% (w = 0.72 ± 0.04) and the relative fitness of P. multocida TG was decreased by 15% (w = 0.85 ± 0.01).

Prediction models of intake and productive performance of non-castrated Nellore cattle finished in the feedlot system under tropical conditions

The objective of this study was to understand and predict the intake and performance of Nellore cattle finished in the feedlot. Individual data from 144 non-castrated male Nellore steers finished in the feedlot between the years 2016 and 2020 were used. Descriptive statistical analyses and Pearson's correlation were performed. The outliers were tested by evaluating the studentized residuals in relation to the values predicted by the equations. Residues that were outside the range of - 2.5 to 2.5 were removed. The goodness of fit of the developed equations was evaluated by the coefficients of determination (r²) and root mean square error (RMSE). The mean dry matter intake (DMI) was 10.2 kg/day, neutral detergent fiber intake (NDFI) was 3.4 kg/day, corresponding to 33.3% of DMI, crude protein intake (CPI) was 1.6 kg/day, and total digestible nutrient intake (TDNI) was 7.1 kg/day. The CPI to ADG ratio was 1.3 kg CPI/kg ADG and the TDNI to CPI ratio was 4.5 kg TDNI/kg CPI. The averages of productive performance were 1.3 kg/day for average daily gain (ADG), 152.6 kg for total weight gain (TWG), and 497.8 kg for final body weight (FBW) in average days in the confinement of 115.7 days. The intake measures correlated significantly with the performance measures, except for carcass yield and days in the feedlot. TWG had a high positive correlation with ADG (r = 0.84), while FBW had a positive correlation (r = 0.86) with hot carcass weight (HCW). Measures of intake, performance, and days in the feedlot can be used as predictors of DMI, FBW, HCW, TWG, and ADG. The prediction equations had satisfactory precision and accuracy for non-castrated Nellore cattle finished in feedlot systems under tropical conditions.

Growth performance, carcass, and meat quality traits of Tropical Milking criollo bulls fed with two energy-level diets

The aim of this study was to determine the effect of two energy-level diets on the beef performance of Tropical Milking criollo bulls grouped by weight and age in three periods: initial, middle, and final. Evidence on intensive beef production from Tropical Milking criollo cattle breeds are unknown, and productive alternatives for dairy producers in the hot tropics are needed. Bulls were fed in each period with low (LE, 2.2 Mcal ME/kg DM) and high (HE, 2.9 Mcal ME/kg DM) energy diets and content phase feeding protein of 14.5, 12.0, and 10.3%, respectively. For each period, ten bulls were randomly assigned to diets. In all periods, growth performance for final body weight, average daily gain, feed intake, and feed conversion were all superior in HE (p ≤ 0.05). For the final period, slaughter body, hot and cold carcass weights, and dressing were also superior in HE (p ≤ 0.05); for meat quality traits, differences were observed in muscles Longissimus dorsi, Semimembranosus, Infraspinatus, and Serratus ventralis for pH and tenderness (p ≤ 0.05), although not for diets. For color L*, a*, and b* system, neither diet nor muscle had effect on L* (p > 0.05); however, the diet-muscle interaction was significant for a* (p ≤ 0.05), and only muscle effect was detected for b* (p ≤ 0.05). Tropical Milking bulls responded positively to a high-energy diet, despite not being a beef breed.

The Effects of Long-term Molybdenum Exposure in Drinking Water on Molybdenum Metabolism and Production Performance of Beef Cattle Consuming a High Forage Diet

Fifty-four multiparous beef cows with calves were used to evaluate the effects of Mo source (feed or water) on reproduction, mineral status, and performance over two cow-calf production cycles (553 days). Cows were stratified by age, body weight, liver Cu, and Mo status and were then randomly assigned to one of six treatment groups. Treatments were (1) negative control (NC; basal diet with no supplemental Mo or Cu), (2) positive control (NC + Cu; 3 mg of supplemental Cu/kg DM), (3) NC + 500 µg Mo/L from Na2MoO4·2H2O supplied in drinking water, (4) NC + 1000 µg Mo/L of Na2MoO4·2H2O supplied in drinking water, (5) NC + Mo 1000-water + 3 mg of supplemental Cu/kg DM, and (6) NC + 3.0 mg of supplemental Mo/kg diet DM from Na2MoO4·2H2O. Animals were allowed ad libitum access to both harvested grass hay (DM basis: 6.6% crude protein; 0.15% S, 6.7 mg Cu/kg, 2.4 mg Mo/kg) and water throughout the experiment. Calves were weaned at approximately 6 months of age each year. Dietary Cu concentration below 10.0 mg Cu/kg DM total diet reduced liver and plasma Cu concentrations to values indicative of a marginal Cu deficiency in beef cows. However, no production parameters measured in this experiment were affected by treatment. Results suggest that Mo supplemented in water or feed at the concentrations used in this experiment had minimal impact on Cu status and overall performance.

In Situ Ruminal Digestion, Fermentation Parameters, and Forage Nutritive Value of Cool-Season Baleage Ensiled under Contrasting Inoculant Strategies

In southeastern USA, the use of baleage has increased as an alternative technology to hay production, thereby allowing for a timelier harvest of the conserved forage. A series of studies were conducted to determine the nutritive value, fermentation parameters, and in situ disappearance of the cool-season annual forage mixtures that were ensiled with or without silage inoculant for up to 120 d. The forage mixtures were wheat (Triticum aestivum L.) + brassica hybrid (Brassica rapa L. × napus L.) (WB), wheat + crimson clover (Trifolium incarnatum L.) (WC), and annual ryegrass (Lolium multiflorum Lam.) + oat (Avena sativa L.) + crimson clover (ROC). The inoculant strategy affected the CP concentration (p < 0.05), with it increasing in WB and decreasing in ROC. Among the mixtures, the DM concentration decreased by up to 5%, and the NDF and ADF concentrations decreased by up to 10% during the ensiling period. The pH averaged 5.0, 5.0, and 5.5 for the WC, WB, and ROC mixtures, respectively. Based on our results, the baleage of the cool-season annual forage mixtures may provide a viable high-quality option to sustain animal growth and performance.

The effect of supplementing CLOSTAT 500 (Bacillus subtilis PB6) to yearling steers in a commercial feedyard on health, Salmonella spp. prevalence, feedlot growth performance and carcass characteristics

British and British × Continental crossbred beef steers, n = 2,100; 313 ± 38 kg of initial body weight (BW) were used to evaluate the effects of Bacillus subtilis PB6 supplementation to yearling steers in a commercial feedyard on health, prevalence of Salmonella spp., growth performance, and carcass characteristics. Steers were blocked by arrival date and assigned randomly to pens within the block; pens were randomly assigned to 1 of 2 dietary treatments within block. Treatments, replicated in 15 pens/treatment with 70 steers/pen, included: 1) control (CON), diets containing no supplemental direct-fed microbials; 2) CLOSTAT (CLO), diets supplemented with 0.5 g/steer/d Bacillus subtilis PB6 (CLOSTAT 500, Kemin Industries, Des Moines, IA) to provide 6.6 × 109 CFU/g of the active ingredient. Supplementing CLO decreased the overall incidence of morbidity (P = 0.03), 10.38% (CLO) vs. 13.43% (CON), decreased the percentage of steers treated once for bovine respiratory disease (BRD; P < 0.01), 9.14% (CLO) vs. 12.76% (CON), and decreased the incidence of BRD retreatment (P = 0.03) compared with CON. Mortality did not differ among treatments (P = 0.23); however, overall deads and removals tended to be less for CLO than CON (53 heads vs. 73 heads respectively, P = 0.06). Prevalence of fecal Salmonella did not differ among treatments, (P ≥ 0.35); overall fecal Salmonella counts tended to be less for CLO (1.59 log (10) CFU/g) than CON (2.04 log (10) CFU/g; P = 0.07). Salmonella concentration in subiliac lymph nodes (n =150/treatment) was not different (P = 0.62) between CON (0.22 log (10) CFU/g) or CLO (0.19 log (10) CFU/g); however, there was a 46% reduction in the overall mean prevalence of lymph node Salmonella (P = 0.46; 15.48% vs. 28.66%) for CLO and CON, respectively. With deads and removals included, final BW was heavier for CLO steers than CON, (654 kg vs. 641 kg, respectively, P = 0.05), and average daily gain (ADG; P = 0.08) and gain efficiency (G:F; P = 0.06) tended to be greater for CLO than CON. With deads and removals excluded, final BW, ADG, and G:F did not differ among treatments (P ≥ 0.30). Carcass traits were not different between treatments (P ≥ 0.15). Supplementing CLO throughout the feeding period in a commercial feedyard improved the health outcomes of yearling steers by decreasing BRD and overall treatment rates, reducing the overall abundance of Salmonella, and resulting in fewer steers removed from the study compared with CON.

Foliage of Tropical Trees and Shrubs and Their Secondary Metabolites Modify In Vitro Ruminal Fermentation, Methane and Gas Production without a Tight Correlation with the Microbiota

Ruminants, mainly cattle, contribute to greenhouse gases (GHG) emissions as methane (CH₄) is produced by ruminal fermentation. Hence, various anti-methanogenic feed strategies have been studied, including the use of plants with secondary metabolites. This study evaluated in vitro ruminal fermentation metrics, microbial composition by digital droplet PCR (ddPCR) and the CH₄ production of the foliage of several tropical trees and shrubs: Leucaena leucocephala, Moringa oleifera, Albizia lebbeck, Enterolobium cyclocarpum, Piscidia piscipula, Brosimum alicastrum, Lysiloma latisiliquum, Guazuma ulmifolia, Cnidoscolus aconitifolius, Gliricidia sepium and Bursera simaruba, using Cynodon plectostachyus grass as control. The results showed a wide variation in the chemical composition of the foliage, as well as in the ruminal microbiota. The crude protein (CP) content ranged from 11 to 25%, whereas the content of condensed tannins (CT) and saponins (S) was from 0.02 to 7%, and 3.2 to 6.6%, respectively. The greatest dry matter degradability (DMD) after 72 h was 69% and the least 35%, the latter coinciding with the least gas production (GP). A negative correlation was found between the CT and CH₄ production, also between protozoa and fungi with the SGMT group of archaea. We concluded that the foliage of some tropical trees and shrubs has a high nutritional value and the potential to decrease CH₄ production due to its CT content.

Incorporating kernelized multi-omics data improves the accuracy of genomic prediction

Background

Genomic selection (GS) has revolutionized animal and plant breeding after the first implementation via early selection before measuring phenotypes. Besides genome, transcriptome and metabolome information are increasingly considered new sources for GS. Difficulties in building the model with multi-omics data for GS and the limit of specimen availability have both delayed the progress of investigating multi-omics.

Results

We utilized the Cosine kernel to map genomic and transcriptomic data as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${n}\times {n}$$\end{document}n×n symmetric matrix (G matrix and T matrix), combined with the best linear unbiased prediction (BLUP) for GS. Here, we defined five kernel-based prediction models: genomic BLUP (GBLUP), transcriptome-BLUP (TBLUP), multi-omics BLUP (MBLUP, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\boldsymbol M=\mathrm{ratio}\times\boldsymbol G+(1-\mathrm{ratio})\times\boldsymbol T$$\end{document}M=ratio×G+(1-ratio)×T), multi-omics single-step BLUP (mssBLUP), and weighted multi-omics single-step BLUP (wmssBLUP) to integrate transcribed individuals and genotyped resource population. The predictive accuracy evaluations in four traits of the Chinese Simmental beef cattle population showed that (1) MBLUP was far preferred to GBLUP (ratio = 1.0), (2) the prediction accuracy of wmssBLUP and mssBLUP had 4.18% and 3.37% average improvement over GBLUP, (3) We also found the accuracy of wmssBLUP increased with the growing proportion of transcribed cattle in the whole resource population.

Conclusions

We concluded that the inclusion of transcriptome data in GS had the potential to improve accuracy. Moreover, wmssBLUP is accepted to be a promising alternative for the present situation in which plenty of individuals are genotyped when fewer are transcribed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00756-6.

Diet Shift May Trigger LuxS/AI-2 Quorum Sensing in Rumen Bacteria

Recent studies have revealed that LuxS/AI-2 quorum sensing (QS) is the most universal cell-to-cell communication in rumen bacteria; however, it remains unknown how they respond to nutritional stress from a diet shift. This study aimed to explore whether a diet shift could trigger rumen bacterial LuxS/AI-2 QS and its influences on rumen fermentation characteristics and bacterial community diversity and composition. A total of fifteen Hu sheep were selected to undergo a pre-shift diet (Pre, concentrate to forage ratio 75:25) for one month and then abruptly switch to a post-shift diet (Post, concentrate to forage ratio 49:51). Results showed that the serum cortisol and immunoglobulin G concentrations were higher in Post than in Pre (p < 0.05). The microbial density, AI-2 concentration, biofilm formation, and the gene expression of ftsH were higher in Post when compared with Pre (p < 0.05), whilst the gene expression of luxS tended to be lower in Post (p = 0.054). The molar concentration of valerate and fermentation efficiency decreased after the diet shift, while the acetate to propionate ratio and the molar proportion of butyrate were higher in Post compared to Pre (p < 0.05). Moreover, the diet shift increased the richness of ruminal bacteria and the relative abundances of Roseburia, Prevotellaceae UCG-001, and Lachnospira, and decreased the relative abundances of Prevotella, Megasphaera, and Dialister (p < 0.05). A difference in trends was also observed in an analysis of similarity (R = 0.1208 and p = 0.064). This study suggests that a diet shift could trigger rumen bacterial LuxS/AI-2 QS by altering microbial density, AI-2 concentration, biofilm formation, and related gene expression, as well as affect the rumen fermentation pattern and bacterial community diversity and composition. This study may provide insight into a potential strategy for relieving nutritional stress via regulating bacterial communication.

Reduction of Enteric Methane Emissions in Heifers Fed Tropical Grass-Based Rations Supplemented with Palm Oil

Vegetable oils have been shown to reduce enteric methane (CH4) production by up to 20%. However, when the level of incorporation exceeds the threshold of 70 g/kg DM, dry matter intake (DMI) and nutrient digestibility may be reduced. The objective of this study was to determine the effects of the incorporation of three levels of palm oil (PO) on enteric CH4 emissions, rumen fermentation and apparent digestibility in heifers fed low-quality grass. Four rumen-cannulated heifers (Bos taurus × Bos indicus) were randomly assigned to four treatments: control (CON) and three increasing PO levels: 20, 40 and 60 g/kg in a 4 × 4 Latin square design with four periods of 22 days (14 days of adaptation to the ration), 5 days of feces and rumen fluid sampling (day 18, 4 h postprandial) and the last 3 days for measurements of CH4 in respiration chambers. With the exception of CP (p = 0.04), starch (p = 0.002) and EE (p < 0.001), the intake of nutrients was not affected by the inclusion of PO (p > 0.05). The apparent digestibility (AD) of nutrients was not affected by the inclusion of PO (p > 0.05), except for starch, which reduced its AD as the PO level was increased (p < 0.05). The gross energy intake was higher in PO-containing rations (p = 0.001), on the other hand, the digestible energy intake was similar between treatments (p > 0.05). In situ ruminal digestion kinetics and the potential degradability remained unchanged (p > 0.05), however, the effective degradability decreased with the inclusion of PO in the rations (p < 0.05). The ruminal pH and molar proportions of acetic, isovaleric and valeric acid were not different between treatments (p > 0.05). The ruminal concentration of propionic acid increased as the PO level increased, reaching its highest molar proportion with 60 g/kg PO (p < 0.05), however, the acetic/propionic ratio and the molar proportions of butyric acid and isobutyric acid decreased as the PO level increased (p < 0.05). The total daily CH4 production was lower in diets containing 20, 40 and 60 g/kg PO compared to the CON diet (p < 0.001). The production of CH4 per kg DMI and DOMI was greater (p < 0.05) for the CON diet compared to all three rations containing PO. The emission intensity, Ym, energy lost as CH4, emission factor (EF) and kg CO2 eq/year were reduced as an effect of the inclusion of PO (p < 0.05). Based on the results obtained, it is concluded that the incorporation of PO in cattle rations has the potential to reduce enteric methane emissions by 4% for every 10 g/kg PO in the ration, without affecting DMI, apparent digestibility or the consumption of digestible nutrient fractions.

Enhancing early life nutrition alters the hepatic transcriptome of Angus × Holstein-Friesian heifer calves

Early life nutrition has a major influence on subsequent lifetime performance in cattle. The aim of this experiment was to investigate the effect of plane of nutrition from 3 to 21 weeks of age on the liver transcriptome. Holstein-Friesian × Angus heifer calves with a mean (±SD) age and BW of 19 (±5) days and 51.2 (±7.8) kg, respectively, were assigned to either a high-energy diet to support a mean average daily gain (ADG) of 1.2 kg/day (HI; n = 15) or a moderate diet (MOD; n = 15) to support a mean ADG of 0.5 kg/day. At 145 ± 3 days of age, all calves were euthanised, liver tissue samples collected and flash-frozen in liquid nitrogen. Following RNA sequence analysis, the total number of differentially expressed genes (DEGs) (at false discovery rate (FDR) > 0.05) was 537; 308 upregulated and 229 downregulated in HI compared to MOD. The number of DEGs mapped to IPA (at FDR > 0.05) was 460; 264 upregulated and 196 downregulated. There was greater expression of genes associated with cellular development and metabolism in heifers on the HI compared to the MOD diet. The genes (fold change) of the somatotrophic axis; IGF1 (3.7), IGFALS (2.6) and GHR (1.5) were upregulated in the HI compared to MOD diet. The cytokine receptor genes, IL17RB (1.7) and IL20RA (3.3), were upregulated in the HI heifers, which were detected in a network interacting with metabolically regulated genes. The potential enhanced cell-to-cell communication evident from DEGs would increase the calves' ability to combat health challenges. The findings of this study indicate that enhancing the early life plane of nutrition in heifer calves results in the upregulation of genes that are associated with increased metabolic activity and thus metabolic capacity. Moreover, the interaction between metabolic and immune communication genes indicates that enhanced nutrition has the potential to improve the immune response in the liver which will play a central role in ensuring optimal lifetime performance.

Influence of body condition score and its change after parturition on pregnancy rates to fixed-timed artificial insemination in Bos indicus beef cows

This experiment evaluated pregnancy rates to fixed-time artificial insemination (FTAI) in Bos indicus beef cows according to their body condition score (BCS) at calving and subsequent change until 30 days after FTAI. Non-pregnant, suckling Nelore cows (n = 593 primiparous, 461 secundiparous, and 893 multiparous) were evaluated for BCS at calving and FTAI, and at 30 days after FTAI when cow pregnancy status was verified. Cow BCS at calving was subtracted from BCS recorded at pregnancy diagnosis, and cows classified as those that lost BCS (L), maintained BCS (M), or gained BCS (G) during this period. Cows that calved with BCS ≥ 5.0 had greater (P < 0.01) BCS throughout the experiment, and greater (P < 0.01) pregnancy rates to FTAI compared with cows that calved with BCS < 5.0 (54.8 vs. 34.2%). Pregnancy rates to FTAI were greater (P < 0.01) for G and M cows compared with L cows (50.0%, 47.5%, and 36.0%, respectively), and similar (P = 0.46) between G and M cows. Moreover, pregnancy rates to FTAI in G cows that calved with BCS < 5.0 were less compared with L (tendency; P = 0.08) and M cows (P < 0.01) that calved with BCS ≥ 5.0 (42.2%, 48.3%, and 58.3%, respectively). In summary, pregnancy rates to FTAI were greater in B. indicus cows that calved with a BCS ≥ 5.0 regardless of parity and post-calving BCS change, and greater in M and G cows within those that calved with BCS < 5.0 or ≥ 5.0.

Selection effect for growth traits on energy requirements in beef Nelore steers

Growth data of 77,372 Nelore steers were used to estimate the selection effect on energy requirements considering two beef production systems: cow-calf and slaughter cycles. All the animals had measures from 120 days to 7 years old. The parameters necessary to evaluate the selection effect on energy requirements were obtained by random regression analysis using Legendre polynomials. The models included additive direct and maternal effects, and animal and maternal permanent environmental effects as random terms. Contemporary group and dam age at calving (linear and quadratic effect) were included as fixed effects, and orthogonal Legendre polynomials of animal age (cubic regression) were considered random covariables. The coefficients from the model M3353_5 were used to calculate the genetic gains necessary to predict the increase in phenotypes. The selection was simulated for body weight (BW) and weight gain (WG) at different ages and energy requirements were calculated using NRC equations. The cost of feed was calculated for a cow-calf and slaughter cycle of production considering a system of Brachiaria decumbens pasture without supplementation. In slaughter system, the selection for weight of 365 days of age is the best option. In cow-calf systems, the selection W120 is the best choice.

Partial Substitution of Corn Grain in the Diet with Beet Pulp Reveals Increased Ruminal Acetate Proportion and Circulating Insulin Levels in Korean Cattle Steers

We investigated the effects of the partial substitution of corn grain in the diet with beet pulp on growth performance, ruminal fermentation characteristics, microbial profiles, and blood lipogenic parameters in fattening steers. Twelve Korean cattle steers (body weight, 485 ± 19.32 kg; age, 18.0 ± 0.17 months) were equally divided into corn grain (CG) and beet pulp (BP) groups. Approximately 75% of dry matter of the requirement was offered as a concentrate portion, and the remaining 25% was offered as oat straw. Eighty percent of the concentrate portion was provided by a pelleted basal concentrate, and the remaining 20% with corn grain for the CG group, or 18% beet pulp plus 2.0% rumen-protected fat for the BP group, respectively, by top dressing. The experiment was conducted for 14 weeks, including a 2-week acclimation period. Growth rate was not affected by beet pulp feeding (p = 0.55). The molar proportions of ruminal acetate (p < 0.05) on wk 4, the relative abundances of ruminal cellulolytic bacteria, including Fibrobacter succinogenes (p = 0.01) and Ruminococcus albus (p = 0.04) on wk 12, and serum insulin concentrations (p < 0.05) on wk 12 were higher in the BP group than in the CG group, whereas the molar proportions of propionate (p < 0.05) on wks 8 and 12 and serum nonesterified fatty acids (p < 0.05) on wk 12 were lower in the BP group. Beet pulp could be used as a lipogenic energy source without affecting growth performance during the fattening period of cattle.

Long-term administration of a commercial supplement enriched with bioactive compounds does not affect feed intake, health status, and growth performances in beef cattle

Abstract. Feed additives including natural bioactive compounds (BCs) in combination with vitamin E (VitE) and organic Se could mitigate animal stress associated with intensive livestock farming due to their anti-inflammatory and antioxidant properties. Yeast and yeast derivate are included in feed additives as probiotic products and digestion promoters. Scutellaria baicalensis is a source of bioactive compounds and has been tested in monogastrics, exhibiting many immunostimulating and hepato-protective activities. However, the literature lacks information regarding S. baicalensis effects on beef cattle performance and health status. The aim of the present study was to evaluate the impact on beef cattle's feed intake, health and oxidative status, and growth performances of the inclusion of a commercial supplement (CS) containing VitE, organic Se, yeast derivate, and S. baicalensis extract during the fattening and finishing period. A total of 143 Charolaise male cattle were allotted into 12 pens of 11–12 animals each and assigned to a control (463.9±21.48 body weight – BW) or a treated (469.8±17.91 BW) group. Each group included two replicates of three pens. The treated groups were supplemented with 20 gCSanimal-1d-1. Feed intake was measured monthly on a pen base during two consecutive days. Total mixed ration and fecal samples were collected at three time points (monthly, from November to February) and pooled by replicate for the analyses to monitor digestibility. Blood samples were individually collected at the beginning and at the end of the trial for oxidative status and metabolic profile determination. Final BW and carcass weight were individually recorded to calculate average daily gain, feed conversion ratio, and carcass yield. Similar feed digestibility between groups were observed during the whole experiment. Feed intake, growth performances, final body weight, average daily gain, feed conversion rate, oxidative status, and metabolic profile were not affected by the dietary inclusion of the tested CS indicating no detrimental effect of the treatment. Different doses of this product should be tested in the future in order to provide a more complete report on the product efficacy.

Ultrasound as a Potential Technology to Improve the Quality of Meat Produced from a Mexican Autochthonous Bovine Breed

The objective of this study was to evaluate the effect of high-intensity ultrasound (HIU) on the physicochemical and textural properties of meat from Rararumi Criollo, a Mexican autochthonous bovine breed. After slaughter, Longissimus dorsi and Triceps brachii muscles were separated from carcasses, cut into 2.5 cm slices and treated with HIU, except the control group, which was not sonicated. After treatment, samples were vacuum-sealed and stored at 4 °C for 0, 3, 6, 9, 12 and 15 d. HIU increased (p < 0.05) the luminosity and yellowness (b*) of meat. Higher b* (p < 0.05) was observed in L. dorsi than in T. brachii muscles. No effect (p > 0.05) of HIU was detected on drip loss, pH, the water holding capacity and the total collagen of meat. The shear force of HIU-treated meat was lower (p < 0.05) than control samples, indicating a tenderizing effect. There were differences between muscles. L. dorsi was more tender (p < 0.05), and it had higher pH and WHC values than T. brachii. Overall, HIU is a potential method for tenderizing Raramuri Criollo cattle meat without negative impacts on other quality characteristics. HIU is an emerging technology that could add value to indigenous breeds and provide a new opportunity for the growing meat market.

Bioprospecting microwave-alkaline hydrolysate cocktail of defatted soybean meal and jackfruit peel biomass as carrier additive of molasses-alginate-bead biofertilizer

The extraction of soluble hydrolysate protein and sugar from a biomass cocktail of defatted soybean meal (DSM) and jackfruit peel (JP) was examined using microwave-alkaline hydrolysis by varying the NaOH concentrations (0.04–0.11 M) and residence times (2–11 min). Based on the central composite design, the optimized parameters were achieved at 0.084 M NaOH concentration (100 mL), for 8.7 min at 300 W microwave power level to obtain the highest protein (5.31 mg/mL) and sugar concentrations (8.07 mg/mL) with > 75% recovery. Both raw and detoxified hydrolysate (using activated carbon) were correspondingly biocompatible with Enterobacter hormaechei strain 40a (P > 0.05) resulting in maximal cell counts of > 10 log CFU/mL. The optimized hydrolysate was prepared as an additive in molasses-alginate bead encapsulation of strain 40a. Further evaluation on phosphate and potassium solubilization performance of the encapsulated strain 40a exhibited comparable results with those of free cell counterpart (P > 0.05). The DSM-JP hydrolysate cocktail holds potential as a carrier additive of encapsulated-cell bead biofertilizers in order to sustain bacterial cell quality and consequently improve crop growth and productivity.

Effects of barley and corn as sources of silage and grain on dry matter intake, ruminal fermentation, and total-tract digestibility in growing beef heifers

The objective of this study was to evaluate the use of barley (BS) or corn (CS) silage when fed with dry-rolled barley grain (BG), corn grain (CG), or an equal blend (BCG) of BG and CG for backgrounding cattle. Ruminally cannulated heifers (n = 5) were assigned to an incomplete 6 × 6 Latin square design. Treatments contained either BS or CS in combination with BG, CG, or BCG. Samples were collected to determine dry matter intake, ruminal fermentation, total-tract nutrient digestibility, and nitrogen (N) balance. Interactions between cereal silage and cereal grain sources were detected for the molar proportions of propionate and butyrate where the magnitude of change with the type of cereal grain was increased in heifers fed CS relative to BS. Feeding CS increased estimated microbial N production (silage, P = 0.022) and fecal N excretion (silage, P = 0.042) over BS. Diets containing BG had greater dry matter, organic matter, starch, and gross energy digestibility values compared with CG, but values for BCG were not different (grain, P ≤ 0.043). Based on limited silage × grain interactions, use of CS in backgrounding diets may increase microbial N production relative to BS and dry-rolled CG may reduce apparent total-tract nutrient digestibility relative to dry-rolled BG.

Effects of the Duration of Zilpaterol Hydrochloride Supplementation and Days on Feed on Performance, Carcass Traits and Saleable Meat Yield of Nellore Bulls

Simple Summary

Zilpaterol hydrochloride (ZH) is a β-adrenergic agonist (βAA) to be feed to feedlot cattle at a rate of 8.3 mg/kg during the final 20 to 40 d of the finishing period followed by a minimum 3 d withdrawal period. This compound has the potential to increase animal performance, improve carcass weight and meat yield. Although significant information regarding the effects of duration of ZH supplementation and days on the feed of Bos taurus cattle has been provided, there is a lack of information relative to its effects on Bos indicus breeds such as Nellore cattle. The current study aimed to evaluate the effects of the duration of ZH supplementation and DOF on performance, carcass characteristics, and saleable meat yield of Nellore bulls. The HCW and total saleable meat yield linearly increased with the duration of ZH supplementation as well as when the length of the feedlot period increased. We recommend supplementing ZH for Nellore bulls at least for 20 days, independently of days on feed, to improve hot carcass weight, hindquarter, and saleable meat yields of Nellore bulls.

Abstract

This study evaluated the effects of the duration of ZH supplementation and days on feed (DOF) on performance, carcass characteristics, and saleable meat yield of Nellore young bulls. The fixed effects included the duration (0, 20, 30, or 40 d before slaughter plus a 3 d ZH withdrawal period—8.33 mg of ZH/kg of DM) and DOF (90 and 117 d). Feed efficiency (G:F) linearly increased when the duration of ZH supplementation increased (p < 0.01). Nellore bulls fed ZH had greater HCW (p < 0.01), dressing percentage (p < 0.01) and Longissimus muscle area (LMA) (p < 0.01), but less 12th-rib fat (p = 0.04) than the control group. The hot carcass weight (HCW) (p < 0.01), and dressing percentage increased linearly (p < 0.01) with the increase of duration of ZH supplementation. The HCW, ossification, and 12th-rib fat increased with DOF (p < 0.01). The ZH supplemented group had most of the individual cuts of hindquarters and total saleable meat increased compared with the control. Zilpaterol hydrochloride was effective in improving hot carcass weight, hindquarter, and saleable meat yields of Nellore bulls when fed for at least 20 d before slaughter, independently of days on feed.

Influence of Molybdenum in Drinking Water or Feed on Copper Metabolism in Cattle-A Review

Simple Summary

The majority of research examining the antagonist impact of molybdenum (Mo) on copper (Cu) absorption and metabolism in ruminants has been conducted by supplementing dietary Mo, alone or in combination with elevated dietary sulfur (S) concentrations, and monitoring the Cu status of the animals. However, little research has been conducted investigating the impact of Mo in water on Cu metabolism in ruminants. Based on the limited number of experiments available for this review, it appears that Mo in drinking water may have a lower antagonistic impact on Cu status in cattle when compared to Mo consumed in the diet. Therefore, this review will focus on the impact of Mo in drinking water on cattle performance and Mo and Cu metabolism.

Abstract

The majority of Mo research has focused on the antagonist effect of Mo, alone or in combination with elevated dietary S, on Cu absorption and metabolism in ruminants. Diets containing both >5.0 mg of Mo/kg DM and >0.33% S have been reported to reduce the Cu status in cattle and sheep. Therefore, due to the potential for inducing Cu deficiency, Mo and S concentrations in the diet should be monitored and kept within appropriate values. Elevated sulfate concentrations in drinking water can also be detrimental to livestock production, especially in ruminants. High concentrations of sulfate in water have been extensively studied in cattle because high-sulfate water induces polioencephalomalacia in ruminants. However, little research has been conducted investigating the impact of Mo in water on Cu metabolism in ruminants. Based on the limited number of published experiments, it appears that Mo in drinking water may have a lower antagonistic impact on the Cu status in cattle when compared to Mo consumed in the diet. This response may be due to a certain percentage of water bypassing the rumen when consumed by ruminants. Therefore, the objective of this review was to examine the impact of Mo in drinking water on cattle performance and Mo and Cu metabolism.

A high plane of nutrition during early life alters the hypothalamic transcriptome of heifer calves

The aim was to examine the effect of rapid body weight gain during early calfhood consistent with earlier sexual development on the transcriptional profile of the hypothalamus. Angus X Holstein-Friesian heifer calves (19 ± 5 days of age) were offered a high (HI, n = 14) or moderate (MOD, n = 15) plane of nutrition from 3 to 21 weeks of age to achieve a growth rate of 1.2 kg/d and 0.5 kg/d, respectively. Following euthanasia at 21 weeks, the arcuate nucleus (ARC) region was separated from the remainder of the hypothalamus and both were subjected to RNA-Seq. HI calves exhibited altered expression of 80 and 39 transcripts in the ARC and the remaining hypothalamus, respectively (P < 0.05) including downregulation of AGRP and NPY and upregulation of POMC, previously implicated in precocious sexual development. Stress-signaling pathways were amongst the most highly dysregulated. Organ morphology, reproductive system development and function, and developmental disorder were amongst the networks derived from differentially expressed genes (DEGs) in the ARC. Gene co-expression analysis revealed DEGs within the ARC (POMC, CBLN2, CHGA) and hypothalamus (PENK) as hub genes. In conclusion, enhanced nutrition during early calfhood alters the biochemical regulation of the hypothalamus consistent with advanced sexual development in the prepubertal heifer.

Influence of Residual Feed Intake and Cow Age on Dry Matter Intake Post-Weaning and Peak Lactation of Black Angus Cows

We evaluated heifer post-weaning residual feed intake (RFI) classification and cow age on dry matter intake (DMI) at two stages of production. Fifty-nine non-lactating, pregnant, (Study 1) and fifty-four lactating, non-pregnant (Study 2) commercial black Angus beef cows were grouped by age and RFI. Free-choice, hay pellets were fed in a GrowSafe feeding system. In Study 1, cow DMI (kg/d) and intake rate (g/min) displayed a cow age effect (p < 0.01) with an increase in DMI and intake rate with increasing cow age. In Study 2, cow DMI (kg/d) and intake rate (g/min) displayed a cow age effect (p < 0.02) with an increase in DMI and intake rate with increasing cow age. Milk production displayed a cow age × RFI interaction (p < 0.01) where both 5-6-year-old and 8-9-year-old low RFI cows produced more milk than high RFI cows. For both studies, intake and intake behavior were not influenced by RFI (p ≥ 0.16) or cow age × RFI interaction (p ≥ 0.21). In summary, heifer's post-weaning RFI had minimal effects on beef cattle DMI or intake behavior, however, some differences were observed in milk production.