Beef Bulls Research Articles

Differential network analysis of bovine muscle reveals changes in gene coexpression patterns in response to changes in maternal nutrition

BackgroundCoexpression network analysis is a powerful tool to reveal transcriptional regulatory mechanisms, identify transcription factors, and discover gene functions. It can also be used to investigate changes in coexpression patterns in response to environmental insults or changes in experimental conditions. Maternal nutrition is considered a major intrauterine regulator of fetal developmental programming. The objective of this study was to investigate structural changes in gene coexpression networks in the muscle of bull beef calves gestated under diets with or without methionine supplementation. Both muscle transcriptome and methylome were evaluated using next generation sequencing.ResultsMaternal methionine supplementation significantly perturbed coexpression patterns in the offspring’s muscle. Indeed, we found that neither the connection strength nor the connectivity pattern of six modules (subnetworks) detected in the control diet were preserved in the methionine-rich diet. Functional characterization revealed that some of the unpreserved modules are implicated in myogenesis, adipogenesis, fibrogenesis, canonical Wnt/β-catenin pathway, ribosome structure, rRNA binding and processing, mitochondrial activities, ATP synthesis and NAD(P) H oxidoreductases, among other functions. The bisulfite sequencing analysis showed that nearly 2% of all evaluated cytosines were differentially methylated between maternal diets. Interestingly, there were significant differences in the levels of gene body DNA methylation between preserved and unpreserved modules.ConclusionsOverall, our findings provide evidence that maternal nutrition can significantly alter gene coexpression patterns in the offspring, and some of these perturbations are mediated by changes in DNA methylation.

Investigating conception rate for beef service sires bred to dairy cows and heifers

The widespread use of sexed semen on US dairy cows and heifers has led to an excess of replacement heifers' calves, and the sale prices for those calves are much lower than in the past. Females not selected to produce the next generation of replacement heifers are increasingly being bred to beef bulls to produce crossbred calves for beef production. The purpose of this study was to investigate the use of beef service sires bred to dairy cows and heifers and to provide a tool for dairy producers to evaluate beef service sires' conception. Sire conception rate (SCR) is a phenotypic evaluation of service sire fertility that is routinely calculated for US dairy bulls. A total of 268,174 breedings were available, which included 36 recognized beef breeds and 7 dairy breeds. Most of the beef-on-dairy inseminations (95.4%) were to Angus (AN) bulls. Because of the limited number of records among other breeds, we restricted our final evaluations to AN service sires bred to Holstein (HO) cows. Service-sire inbreeding and expected inbreeding of resulting embryo were set to zero because pedigree data for AN bulls were unavailable. There were 233,379 breedings from 1,344 AN service sire to 163,919 HO cows. A mean (SD) conception rate of 33.8% (47.3%) was observed compared with 34.3% (47.5%) for breedings with HO sires mated to HO cows. Publishable AN bulls were required to have ≥100 total matings, ≥10 matings in the most recent 12 mo, and breedings in at least 5 herds. Mean SCR reliability was 64.5% for 116 publishable bulls, with a maximum reliability of 99% based on 25,217 breedings. Average SCR was near zero (on AN base) with a range of -5.1 to 4.4. Breedings to HO heifers were also examined, which included 19,437 breedings (443 AN service sire and 15,971 HO heifers). A mean (SD) conception rate of 53.0% (49.9%) was observed, compared with 55.3% (49.7%) for breedings with a HO sire mated to a HO heifer. Beef sires were used more frequently in cows known to be problem breeders, which explains some of the difference in conception rate. Mean service number was 1.92 and 2.87 for HO heifers and 2.13 and 3.04 for HO cows mated to HO and AN sires, respectively. Mating dairy cows and heifers to beef bulls may be profitable if calf prices are higher, fertility is improved, or if practices such as sexed semen, genomic testing, and improved cow productive life allow herd owners to produce both higher quality dairy replacement and increased income from market calves.

Average daily gains and response to artificial insemination in beef replacement heifers with persistent subclinical Theileria orientalis Ikeda genotype infection

Theileria orientalis Ikeda genotype is a tick-borne hemoprotozoan that typically causes economic losses in dairy and beef cattle in Australia, New Zealand, and Japan. Clinical signs of theileriosis from T. orientalis Ikeda include anemia, icterus, ill-thrift, and death. The acute phase of the infection has been associated with a decrease in milk production in dairy cows, decreased libido in dairy bulls, decreased live weight gain in beef bulls, and increased mortality in naïve adults and calves. A sequela to acute infections within a herd is persistent subclinical infections and these have been associated with negative effects on reproduction in dairy cows and decreased mean daily gain in suckling beef calves. Prior to 2017, non-pathogenic genotypes of T. orientalis were present in the United States. In late 2017, T. orientalis Ikeda/genotype 2 was detected in beef cattle from multiple counties in Virginia and was associated with anemia, weakness, and death. As of 2020, T. orientalis Ikeda has been identified in beef cattle in 22 of 95 Virginia counties and 4 of 55 West Virginia counties. Beef production through primarily cow/calf operations is the second largest agricultural commodity in Virginia. After detection of T. orientalis Ikeda in a subpopulation of spring breeding beef heifers at a replacement breeding farm, we thoroughly investigated the fall breeding heifers. The objective of this study was to determine if persistent subclinical infection with T. orientalis Ikeda affected the average daily gain (ADG) from arriving on farm to pregnancy verification or conception rates to artificial insemination (AI) in beef replacement heifers.

Effects of managing mature beef bulls on divergent planes of nutrition on novel measures of bull fertility

Effects of managing mature beef bulls on divergent planes of nutrition on novel measures of bull fertility

Association of fibre degradation with ruminal dissolved hydrogen in growing beef bulls fed with two types of forages.

The present study investigated the association between fibre degradation and the concentration of dissolved molecular hydrogen (H2) in the rumen. Napier grass (NG) silage and corn stover (CS) silage were compared as forages with contrasting structures and degradation patterns. In the first experiment, CS silage had greater 48-h DM, neutral-detergent fibre (NDF) and acid-detergent fibre degradation, and total gas and methane (CH4) volumes, and lower 48-h H2 volume than NG silage in 48-h in vitro incubations. In the second experiment, twenty-four growing beef bulls were fed diets including 55 % (DM basis) NG or CS silages. Bulls fed the CS diet had greater DM intake (DMI), average daily gain, total-tract digestibility of OM and NDF, ruminal dissolved methane (dCH4) concentration and gene copies of protozoa, methanogens, Ruminococcus albus and R. flavefaciens, and had lower ruminal dH2 concentration, and molar proportions of valerate and isovalerate, in comparison with those fed the NG diet. There was a negative correlation between dH2 concentration and NDF digestibility in bulls fed the CS diet, and a lack of relationship between dH2 concentration and NDF digestibility with the NG diet. In summary, the fibre of CS silage was more easily degraded by rumen microorganisms than that of NG silage. Increased dCH4 concentration with the CS diet presumably led to the decreased ruminal dH2 concentration, which may be helpful for fibre degradation and growth of fibrolytic micro-organisms in the rumen.

Short communication: Animal-level factors associated with whether a dairy female is mated to a dairy or beef bull

When serving a female, the producer must decide whether to mate her to a dairy or beef bull. Tools assisting in this decision could be a useful component of the decision process. A database of 2,283,100 artificial inseminations from 806,725 dairy females was used to investigate what factors were associated with servicing a given female to a beef bull. The probability of being inseminated with a beef bull increased with each service and as the breeding season progressed. An older cow had greater odds of being served with a beef bull, as did cows that calved later in the year, had recently experienced dystocia, were a longer time calved, or were of a poor overall genetic merit compared with herdmates. Cows with low somatic cell count in the previous lactation compared with herdmates were less likely to be mated to a beef bull, as were cows that yielded relatively higher milk solids in the previous lactation. Relative to a first-parity cow, the odds of a fifth-parity cow being mated to a beef bull were 1.35, whereas those of a tenth-parity cow were 2.11. The odds of a female in the worst 10% for total genetic merit being mated to a beef bull were 2.90 times those of a female in the top 10%. Although dystocia was associated with the likelihood of being mated to a beef bull, the actual likelihood did not vary much by level of dystocia experienced. Relative to the first service, the odds of the third and fifth services being to a beef bull were 2.23 and 3.71, respectively. These probability estimates can form the back-end system supporting decisions on mating type for a female within a sire mating advice system but also in risk analysis of farm management.

Transcriptomic Profile of Primary Culture of Skeletal Muscle Cells Isolated from Semitendinosus Muscle of Beef and Dairy Bulls.

The aim of the study was to identify differences in the transcriptomic profiles of primary muscle cell cultures derived from the semitendinosus muscle of bulls of beef breeds (Limousin (LIM) and Hereford (HER)) and a dairy breed (Holstein-Friesian (HF)) (n = 4 for each breed). Finding a common expression pattern for proliferating cells may point to such an early orientation of the cattle beef phenotype at the transcriptome level of unfused myogenic cells. To check this hypothesis, microarray analyses were performed. The analysis revealed 825 upregulated and 1300 downregulated transcripts similar in both beef breeds (LIM and HER) and significantly different when compared with the dairy breed (HF) used as a reference. Ontological analyses showed that the largest group of genes were involved in muscle organ development. Muscle cells of beef breeds showed higher expression of genes involved in myogenesis (including erbb-3, myf5, myog, des, igf-1, tgfb2) and those encoding proteins comprising the contractile apparatus (acta1, actc1, myh3, myh11, myl1, myl2, myl4, tpm1, tnnt2, tnnc1). The obtained results confirmed our hypothesis that the expression profile of several groups of genes is common in beef breeds at the level of proliferating satellite cells but differs from that observed in typical dairy breeds.

Effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on clinical health, growth performance, and carcass traits of high-risk cattle during the feedlot receiving and finishing periods1

The study objective was to determine the effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on health, growth performance, and carcass characteristics of high-risk beef cattle during a 56-d feedlot receiving period and the subsequent finishing period. Four truckload blocks of crossbred beef bulls (n = 300) and steers [n = 84; body weight (BW) = 220 ± 16.2 kg] were sourced from regional auction markets and assigned randomly to treatments arranged in a 2 × 2 factorial. The generalized complete block design consisted of 12 pen replications per treatment with pen as the experimental unit. Treatments were: 1) placebo control (CON); 2) 13 g per animal daily of B. subtilis PB6 (CST); 3) 450 ppb dry matter (DM) chromium propionate (CHR); and 4) 13 g per animal daily of B. subtilis PB6 and 450 ppb DM chromium propionate (CST + CHR). Treatments were top dressed in feed bunks daily using 0.45 kg per animal ground corn carrier immediately following feed delivery. Data were analyzed using mixed models. During the receiving period, dry matter intake (DMI) increased (P ≤ 0.03) for CST during each interim period. Overall receiving period daily DMI was 0.35 kg per animal greater for CST (P = 0.01). Cattle fed CST had greater (P ≤ 0.06) BW on days 14, 28, and 56. Likewise, average daily gain (ADG) was improved for CST from day 0 to 14 (P = 0.04) and for the overall receiving period (days 0–56; P = 0.04). From days 0 to 14, CST tended (P = 0.08) to increase gain:feed. During the finishing period, CHR reduced (P = 0.02) final BW and ADG (day 56 to final; P = 0.01) and ADG was less for CHR over the entire feeding period (day 0 to final; P = 0.03). The main effect of both CST (P = 0.02) and CHR (P = 0.03) decreased the overall treatment rate for bovine respiratory disease (BRD), and CST reduced overall antimicrobial treatment cost by $3.50 per animal compared to CON (P = 0.03). Hot carcass weight (HCW) decreased (P = 0.01) in cattle fed CHR. The percentage of edible livers tended to increase (CST × CHR; P = 0.08) in the CST treatment. Feed intake and growth performance outcomes during the receiving period were improved by CST but not CHR supplementation. However, both CST and CHR supplementation decreased the BRD morbidity rate. During the finishing period, performance and HCW were reduced in cattle supplemented with CHR.

Effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on serum chemistry, complete blood count, and fecal Salmonella spp. count in high-risk cattle during the feedlot receiving and finishing periods.

The study objective was to determine the effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on serum chemistry, complete blood count, and fecal Salmonella spp. count in high-risk beef cattle during a 56-d feedlot receiving period and the subsequent finishing period. Four truckload blocks of crossbred beef bulls (n = 300) and steers [n = 84; total n = 384; average initial body weight (BW) = 220 ± 16.2 kg] were sourced from regional auction markets and assigned randomly to treatments arranged in a 2 × 2 factorial. Blood samples were collected from two bulls nearest to the median BW on arrival in each pen (n = 96) and fecal samples were collected from cattle in block 3 (n = 96). The generalized complete block design consisted of 12 pen replications per treatment with pen as the experimental unit. Treatments were: 1) negative control (CON); 2) 13 g per animal daily of prepared B. subtilis PB6 product (CST); 3) 450 ppb dry matter (DM) chromium propionate (CHR); and 4) 13 g per animal daily of prepared B. subtilis PB6 product and 450 ppb DM chromium propionate (CST + CHR). Treatments were top dressed in feed bunks daily using 0.45 kg per animal ground corn carrier immediately following feed delivery. Data were analyzed using mixed models with repeated measures. Day affected all serum chemistry variables (P ≤ 0.03) except total CO2 (P = 0.34) and all complete blood count variables during receiving (P ≤ 0.02) except percentage basophils (P ≥ 0.12). During the overall receiving period, serum calcium was decreased (P = 0.02) by CHR. Cattle fed CHR had greater total leukocyte count (P = 0.04) and neutrophil count (P = 0.02) during the overall receiving period. Fecal Salmonella spp. count was markedly reduced in cattle fed CST on day 28 (P = 0.01) and overall (P = 0.07). Overall, these data provide metabolic and hematologic insight into the unique challenges presented by lightweight, high-risk feeder cattle. Notably, CST was found to be effective in mitigating fecal enumeration and presumably replication of Salmonella spp. in the gastrointestinal tract.

Effects of Exogenous Glucoamylase Enzymes Alone or in Combination with a Neutral Protease on Apparent Total Tract Digestibility and Feces D-Lactate in Crossbred Angus Bulls Fed a Ration Rich in Rolled Corn.

Simple SummaryDietary enzyme supplementation, as a feed additive, has been well adopted in monogastric production to increase feed efficiency. However, in ruminants, considerably fewer studies have been done and fewer, if any, commercial enzymes have been adopted as a feeding strategy. Feedlot cattle are commonly fed high-starch diets, with varying starch digestibilities depending on type of grain, and degree of grain processing. Improvement in starch digestibility in low processed grain diets will undoubtedly warrant economic benefits to feedlot producers and reduce environmental impact of intensive beef production. In this study, we have shown that dietary glucoamylase supplementation improved 7 to 13% apparent digestibility of dry matter and starch in bulls fed rolled corn-based diets, suggesting that enzyme (glucoamylase) supplementation could be a promising strategy to improve starch efficiency for finishing beef cattle.The aim of this study was to evaluate the effect of two glucoamylases (GA) and the combination of one GA with a neutral protease on apparent total tract digestibility in beef bulls fed a total mixed ration (TMR) rich in rolled corn. Sixteen Angus beef bulls (266 ± 4.9 kg of initial BW, and 182 ± 1.7 d of age) were distributed in 4 blocks, each block consisted of 4 animals balanced by BW. The experimental design was a 4 × 4 Latin square (4 blocks and 4 periods, 2 w per period). Four treatments were tested; (1) control, (2) GA preparation from Trichoderma reesei (TrGA); (3) GA from Aspergillus fumigatus (AfuGA); (4) AfuGA in combination with a neutral protease from Bacillus amyloliquefaciens (BamPro). Apparent total tract digestibility and fecal D-lactate concentration were analyzed. Enzyme supplementation, regardless of enzyme type, increased apparent total tract digestibility of dry matter (from 66.7% to 73.1% ± 2.01), and starch (from 74.7% to 81.8% ± 2.25), without affecting feces D-lactate concentration. Irrespective of glucoamylase type, glucoamylase supplementation improved apparent digestibility of dry matter and starch, and the addition of a protease did not have additional benefits on nutrient digestibility.

Effect of relaxin on cryopreserved beef bull semen characteristics

This study aimed to improve the quality of cryopreserved beef bull (Piedmontese) semen by incorporation of relaxin in diluted semen before cryopreservation procedures. Semen samples were collected from 4 proven fertile bulls, using artificial vagina, once per week for 8 consecutive weeks and pooled together then diluted with Bullxcell® extender, and supplemented with different concentrations of relaxin (0 (control), 25, 50 and 100 ng/ml) before cooling, equilibration and freezing procedures. Frozen semen was thawed and assessed for motility by Computer-Assisted Sperm Analysis and vitality parameters such as acrosome, plasma membrane and DNA integrities, apoptosis, mitochondrial membrane potential, mucus penetration and SOD activity. The developmental potential of bovine embryos produced in vitro by using relaxin-treated was also investigated. In the present study, 50 and 100 ng/ml relaxin incorporation in extended bull semen before cryopreservation induced a reduction of sperm motility immediately after thawing (0h), whereas, during long incubation periods (1–2 h), relaxin showed a significant positive effect on sperm quality by improving the sperm motility and velocity parameters. Interestingly, sperm vitality was improved by 25 and 100 ng/ml relaxin and the blastocyst developmental rate was significantly increased in the 25 ng/ml relaxin group compared with controls (52/118, 44.0% vs. 32/116, 27.6%, respectively). These findings suggest a potential use of relaxin at the doses tested in the present study as an additive in the cryopreservation media of bull semen to improve sperm quality.

Scrotal circumference at weaning in beef bulls and subsequent ability to pass a breeding soundness examination as a yearling

Identifying bulls at weaning with higher likelihood ofpassing a breeding soundness examination as yearlings mayimprove management options to optimize production efficiency.The objective of this study was to evaluate the effect of weaning scrotal circumference and other factors collected at the time of weaning on the likelihood of passing a breeding soundness examination as a yearling. Data, at both weaning and time of breeding soundness examination, were collected from 1 operation (n = 466 bulls). A logistic regression model was used to evaluate the potential associations of relevant factors (actual weaning scrotal circumference, adjusted weaning scrotal circumference, weight per day of age at weaning, scrotal circumference per day of age at weaning, weaning weight, and breed) on the probability of passing a breeding soundness examination as a yearling. Overall, 92.3% of bulls passed the yearling breeding soundness examination on first evaluation. Weaning scrotal circumference was the only factor of those evaluated associated (P < 0.01) with the probability of passing the breeding soundness examination. No significant differences were found between the categories of weaning scrotal circumference. In the future, more research needs to evaluate predictive model development for weaning scrotal circumference and ability to pass breeding soundness examination.

Does increased scrotal circumference measurement in bulls reduce the age of puberty in their daughters?

#### Bottom line When reviewing the results from a recent bull breeding soundness examination visit to a beef cattle stud, you notice substantial differences in the scrotal circumference (SC) measurements between animals, despite them being the same age and of the same breed. You have often heard it stated that the age at which female offspring reach puberty decreases with an increase in sire SC. However, you would like to confirm this statement with evidence from the literature before discussing breeding recommendations with your client. In the [beef bull], does increased [scrotal circumference] measurement directly reduce [puberty age] in [daughters]? The keywords (bull OR cattle OR male OR beef OR “Bos Taurus”) AND (“scrotal circumference” OR “scrotal size”) AND (“puberty” OR “first service”) AND (progeny OR offspring OR heifer OR daughter) were used to search CAB abstracts and Scopus.

Growth and Development Patterns of the Skeleton in Simmental and Cross Young Beef Bulls

The age-related carcass-morphology and composition changes and the growth and development patterns of the axial and peripheral skeleton systems and the bones composing them in the Simmental and crossbred young beef bulls have been studied. In order to carry out the survey, the young bulls were divided into three groups of 15 animals each. The first (control) group included the purebred Simmental young bulls. The second (experimental) group was formed of the halfbred and crossbred young stock produced by crossbreeding between the Simmental cows and the Simmental beef bulls of German selection. The third (experimental) group was composed of the crosses of Simmental cows with Charolais bulls. The Charolais crosses had more energy for growth. Thus, their liveweights comprised 431.9, 523.4, and 620.6 kg at the ages of 12, 15, and 18 months, respectively, which were 7.8, 7.5, and 10.2% more than that in their peers of the maternal breed. The crossbred young stock in both groups was distinct for carcass morphology and composition, reaching a more advanced level of the carcass flesh-coverage mass in all the age intervals when compared that to the purebred Simmentals. The age-related changes in the absolute and relative masses of the young-bull carcass bones are caused by different intensities specific to bone growth in the axial and peripheral skeleton systems. For instance, the intensity of bone growth in the axial skeleton system tended to increase in the postnatal period, while the bone growth rates of the peripheral skeleton system decreased. Irregularity in developing the indicated skeleton systems is caused by different intensities specific to growth of certain bones and their complexes. The highest growth rate is usually typical for ribs and the vertebral column, while the slowest growth rate is most common for extremitas thoracica and extremas pelvina. The bone growth rates for the limb proximal structures generally exceed that for the distal bone structures. The age-related differences in the growth rates of certain skeleton structures can cause some changes in ratios between the linear body measurements of the young bulls.

Short communication: Pure-breeding with sexed semen and crossbreeding with semen from double-muscled sires to improve beef production from dairy herds: Weight and value of calves

The use of sexed semen to produce purebred replacement heifers allows a large proportion of dairy cows to be mated to double-muscled sires and for quantitative and qualitative improvements to be made to beef production from dairy herds. A survey of 1,285 crossbred calves showed that they are destined not only for veal production (like purebred dairy calves) but also for beef production. Crossbred calves obtained from Belgian Blue sires (sold on average at 34 d of age and 64 kg of weight) had a higher market value (€363/calf) than those obtained from double-muscled INRA 95 sires (€297/calf, used for veal production) and from Limousin sires (€216/calf for veal and €271/calf for beef production). As a sire breed, Simmental did not differ significantly from Belgian Blue, but as a dam breed, the crossbred calves fetched a higher price (€5.11/kg) than when Holstein was the dam breed (€4.50/kg). Compared with heifer calves, crossbred bull calves at sale were younger (34.1 vs. 37.2 d) and heavier (64.0 vs. 62.6 kg of live weight), fetched a higher price (€5.13 vs. €4.99/kg), and had a greater value (€328 vs. €312/calf). As the value of purebred dairy calves was about €80 to €100/calf, we are able to confirm that the combined use of sexed semen for pure-breeding and conventional beef semen for terminal crossbreeding can increase the income from dairy farms, especially when the sires are double-muscled beef bulls.

Мясная продуктивность бычков разных экстерьерно-конституциональных типов

Мясная продуктивность бычков разных экстерьерно-конституциональных типов

Plasma estradiol-17β, cortisol, and insulin concentrations and serum biochemical parameters surrounding puberty in Japanese Black beef bulls with normal and abnormal semen

The associations of semen abnormalities with circulating hormones (estrogens, glucocorticoid, insulin) and common biochemical parameters are unclear in beef bulls. We compared plasma concentrations of estradiol-17β, cortisol, and insulin and serum biochemical parameters surrounding puberty in Japanese Black beef bulls (n = 96) with normal post-thaw or abnormal semen (fresh and frozen). Blood samples were collected monthly from 4 to 24 months of age (n = 50) for the assays of plasma estradiol, cortisol, and insulin and every 3 months from 6 to 21 months of age (n = 92) for the serum biochemical analyses. Semen was collected weekly from 12 months until at least 18 months of age. Fresh semen was evaluated for semen volume, sperm progressive motility, concentrations, and morphological defects. The normal fresh semen was frozen by a standard method and examined for post-thaw sperm motility and fertility, which were evaluated for rates of transferable embryos. Bulls were classified as having either normal fresh semen or abnormal fresh semen (when at least one of the above test items was abnormal for 6 months). The normal fresh semen was categorized as having either normal post-thaw semen or low fertility post-thaw semen. The abnormal fresh semen was categorized as having sperm morphological defects, low motility, or morphological defects plus low motility. Plasma cortisol concentrations in the abnormal fresh semen group were higher than those of the normal fresh semen group (p < 0.0001). Plasma estradiol-17β and insulin concentrations in the low-fertility post-thaw semen group were lower than those of the normal post-thaw semen group (p < 0.0001). Serum aspartate aminotransferase and magnesium concentrations were greater for the abnormal fresh semen group vs. the normal fresh semen group (p < 0.005). These results suggest that fresh semen abnormality in pubertal beef bulls might be associated with increased circulating aspartate aminotransferase, magnesium and cortisol. Low-fertility post-thaw semen could have been involved with the lower peripheral estradiol and insulin levels in beef bulls.

To what extent does the composition of batches formed at the sorting facility influence the subsequent growth performance of young beef bulls? A French observational study

To meet the demands of the beef cattle sector in France, weaned beef calves are transported to sorting facilities and sorted into batches composed of animals of similar body weight (BW) before the beginning of the fattening period. This procedure aims to facilitate animal management. However, it leads to practices that affect animal welfare, health and performance, such as transporting weaned beef calves over long distances and mixing animals originating from different cow/calf farms. In contrast, other potentially beneficial practices, such as pre-weaning vaccination against bovine respiratory diseases (BRD), are seldom taken into consideration when batches are formed. This observational study, based on field data from 15,735 Charolais bulls, aimed to investigate which criteria should be favored for batch constitution by quantifying the effect of batch characteristics on the growth performance of young bulls during the fattening period. Clustering analysis was used to group young bulls exhibiting similar batch characteristics and define batch types. Associations between batch characteristics/batch types and individual growth performance/homogeneity of growth performance (mean and standard deviation (SD) of average daily gain (ADG) and fattening period duration) were studied using linear mixed models. The mean BW and the percentage of animals vaccinated against BRD before weaning were positively associated with ADG (+35 g/d for each additional 50 kg and +28 g/d for a high percentage of vaccinated animals, P < 0.05). In contrast, transportation distance was negatively associated with ADG (−12 g/d for each additional 120 km travelled). Mixing animals and BW homogeneity did not affect growth performance (P > 0.05). Only the mean BW and mixing animals negatively influenced the homogeneity of ADG (P < 0.01). The clustering analysis revealed that batches with the most BW heterogeneity, the least mixing, the shortest transportation distance and a high percentage of pre-weaning animals vaccinated against BRD had better growth performance compared to batches with the opposite characteristics (+61 g/d, P < 0.001). Our results suggest that major improvements of growth performance of fattening young bulls could be obtained by minimizing transportation distance, providing vaccination programs against BRD before weaning, and maintaining groups from the same cow/calf farm instead of constituting groups of animals with similar BW at the beginning of fattening.

Effects of supplement amount, with or without calcium salts of fatty acids, on growth performance and intake behavior of grazing Bos indicus bulls.

This study evaluated the effects of 2 supplement dry matter (DM) amounts, with or without calcium salts of fatty acids (CSFA), on growth performance, supplement and water intake behavior of grazing beef bulls. On day 0, 32 Nellore bulls were ranked by initial body weight (BW; 318 ± 11.2 kg), and then, randomly assigned to treatments (n = 8 bulls/treatment), in a 2 × 2 factorial design, which consisted of energy-based supplement DM amount of 0.3 (SP03) or 1.0 (SP1) % of BW with (+) or without (-) CSFA fortification (90 to 100 g/bull daily). During the experiment (98 d), all bulls were managed as single group and rotated between 2 Brachiaria pastures every 9 to 11 d. Each pasture contained an individual electronic data capture system with 2 feed bunks/treatment and 1 water through to determine individual supplement DM and water intake, as well number of visits, time spent at the feeder/waterer, and intake per visit (IPV). A supplement effect was detected (P = 0.02) for final BW. Bulls supplemented at 1.0% of BW, regardless of CSFA inclusion amount, were heavier at the end of the experiment vs. SP03 bulls. Overall average daily gain (ADG) was greater (P = 0.05) for SP03+ vs. SP03- bulls, and did not differ (P = 0.87) between SP1+ vs. SP1- bulls. No supplement amount, CSFA, or supplement amount × CSFA effects were observed (P ≥ 0.13) for supplement and water intake behavior, number of visits to the feeder or IPV. However, SP1 bulls spent (P = 0.05) more time at the feeder than SP1+ bulls, whereas bulls supplemented with CSFA tended (P = 0.10) to consume less water (as % of BW) than cohorts supplemented without CSFA. In summary, CSFA fortification into 0.3% of BW supplements increased ADG when compared with cohorts not offered CSFA. On the other hand, no benefits were observed when CSFA was included into 1.0% of BW supplements, primarily due to the lower than projected supplement, and consequently, CSFA intake. Moreover, CSFA fortification tended to reduced water intake, demonstrating a potential of this technology to increase performance of beef herds, while maintaining the utilization of natural resources.

Evaluation of serum metabolic parameters as predictors of bovine respiratory disease events in high-risk beef stocker calves

The primary objective of this study was to evaluate the association between serum metabolic parameters and the risk of bovine respiratory disease (BRD) in high-risk beef stocker calves. Jugular venous blood samples were collected from mixed-breed beef bull, steer, and heifer calves (n=468) at the time of arrival processing at a stocker facility in northeast Georgia. Serum samples were then submitted for determination of serum creatinine, total calcium, phosphorus, magnesium, albumin, serum urea nitrogen, glucose, cholesterol, beta-hydroxybutyrate (BHBA), non-esterified fatty acid (NEFA), sodium, potassium, and chloride concentrations, as well as sodium:potassium ratio and NEFA:cholesterol ratio. Calves were monitored for the development of signs consistent with BRD for 45 days following arrival. A multi-variable logistic regression model was created to evaluate the association between serum variables and subsequent risk of BRD. In this analysis, BRD was associated with higher serum potassium, lower serum urea nitrogen, and lower BHBA concentrations at arrival processing. The area under the receiver operating characteristic curve for the ability of the model to predict morbidity was 0.645. These data suggest that hydration status, nutrient balance, and degree of rumen development may play a role in the development of BRD in high-risk beef stocker calves.