Search

Early puberty is associated with improved long-term reproductive performance. Predicting who will achieve early puberty is limited to intensive, invasive serial blood collections for measurement of reproductive hormones. The vaginal genome during pubertal development has potential as biomarkers of early estrus in the pre-pubertal period. Pre-pubertal gilts (n =13) were followed from d74 ± 3 of age until first estrus or d214 ± 1 of age. Blood, vaginal epithelia, and anogenital distance were collected at five timepoints during reproductive development (d74, d104, d130, d160 and first estrus or end of trial). Total RNA was isolated from vaginal epithelia and relative gene expression of two toll-like receptors (TLR-4 and TLR-5), tacykinin precursor-3 (TAC-3), insulin-like growth factor-1 (IGF-1), and estrogen receptor (ERα)-alpha was quantified by real time RT-PCR, relative to expression of RPLP0. Four gilts exhibited estrus early (< d184), 3 were average (d194 to 195), 3 were late (d203 to 213), and 3 were deemed anestrus. Comparison of expression of each gene relative to d70 was performed using the PCR package in RStudio (version 1.2.5025) and Fisher's exact t-test for TLR-4, TLR-5 and TAC-3, and ANOVA for ER-alpha and IGF-1. Correlation analysis examined the relationship between anogenital distance and age at first estrus. A single blood draw for serum progesterone was obtained 8 days after recorded first estrus or end of trial; the presence of serum progesterone supports the visual identification of standing estrus. Expression of IGF-1 and TAC-3 were up-regulated 9- and 7-fold, respectively at d160 ( P < 0.05). Expression of ERα tended to be upregulated 3-fold at d104 ( P = 0.08) and expression of TLR-4 and TLR-5 was not detected until first estrus. Anogenital distance was positively correlated to the first estrus. These transcripts associated with reproduction warrant further investigation into use as biomarkers to detect early estrus., Competing Interests: Conflicts of interest: The authors have no conflict of interest to disclose.

The objective of this study was to evaluate differences in the performance of offspring of boars selected with an index emphasizing resilience and boars selected based on a traditional index, emphasizing feed efficiency and carcass quality (traditional) index vs. a customized (resilience) index. The resilience index was identical to the traditional index, except that extra emphasis was placed on piglet vitality (increased by 66%), growth rate (decreased by 14%), and feed intake (increased substantially by 5,157%). Sows were mated to either boars selected based on the resilience index or boars selected on the traditional index. Weaned offspring were vaccinated for Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and experimentally infected with PRRSV RFLP 1-7-4 four weeks later. Offspring were allocated to pens ( n ~ 27 pigs/pen; n  = 27 pens/group) by sire-selection group for a total of 1,458 pigs in 54 pens. The weight of each pen was recorded on 0, 42, and 110 d postinfection (DPI) and used to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR). Mortalities were recorded from 0 to 110 DPI and necropsies were routinely performed to characterize pathogens present within the barn. Pigs classified as full value (i.e., >104 kg and void of defects) were slaughtered and hot carcass weight (HCW), backfat, loin depth, and lean weight were obtained from the slaughter plant. Effects of progeny group on performance, carcass characteristics, and mortality rate were estimated with a mixed linear model. Differences between progeny groups in ADG ( P  > 0.27), HCW ( P  = 0.68), backfat ( P  = 0.13), or loin depth ( P  = 0.39), and mortality rate ( P  = 0.29) were not detected. From 0 to 42 DPI, offspring of boars selected based on the resilience index had higher ADFI (0.06 kg/d, P  = 0.01) and higher FCR (0.12, P  = 0.01). In summary, results from this study do not support selection of boars for increased feed intake, piglet viability, and robustness in order to prevent losses caused by PRRSV, but selection response was only measured after one generation of male selection. The impact of multiple generations of selection, or the development of an index including traits derived from data collected under disease-challenged conditions should be explored. The data collected for this study are a valuable resource to explore additional genetic selection strategies for enhanced resilience to a multifactorial PRRS challenge., Competing Interests: E.A.L., D.H., and S.D. are employed by Pipestone Applied Research or were at the time of project completion, a company with a vested interest in conducting research trials. J.D and J.M.E.E. are employed by Topigs Norsvin USA, a company that markets breeding stock to the commercial swine industry., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

To determine the influence of the source of gestational and postnatal Cu and Zn supplementation on cow and calf performance, cows ( n = 287) were assigned to one of the following two treatments: (1) inorganic (INORG) treatment, in which cows were supplemented with 15 mg of Cu (as CuSO 4 ) and 15 mg of Zn (as ZnSO 4 ) per kg of diet DM, or (2) organic (ORG) treatment, in which cows were supplemented with 15 mg of Cu (as Cu proteinate; Bioplex Cu, Alltech, Inc., Nicholasville, KY, USA) and 15 mg of Zn (as Zn proteinate; Bioplex Zn, Alltech, Inc., Nicholasville, KY, USA) per kg of diet DM. The treatments were initiated prior to breeding and continued throughout gestation until weaning. Liver biopsies were collected for analysis of mineral content. Cow body condition score (BCS), body weight (BW), pregnancy data, calf weaning weight (WW), and antibody response of the calves were recorded. The cows receiving the INORG treatment had a greater BW ( p < 0.05) and BCS (p < 0.01) at breeding in Year 2, while the cows on the ORG treatment had a greater ( p < 0.05) BW at weaning in Year 2. The cows that received the ORG mineral had improved ( p < 0.05) conception rates in Year 1. The calves receiving the ORG treatment had heavier ( p < 0.05) 205-day adjusted WWs.

The objective of this study was to compare the influence of beef production systems using additive combinations of growth-promotant technologies on meat quality. Steer calves ( n  = 120) were assigned to 1 of 4 treatments: 1) no technology (NT; control), 2) antibiotic treated (ANT; NT plus therapeutic antibiotics, monensin, and tylosin), 3) implant treated (IMP; ANT plus a series of three implants), and 4) beta-agonist treated (BA; IMP plus ractopamine-HCl). Muscle biopsy samples from the longissimus lumborum were extracted from a subset ( n  = 4 per treatment) of steers to evaluate expression of calpain-1, calpain-2, and calpastatin using real-time RT-PCR. Following carcass chilling, objective color ( L *, a *, and b *) was evaluated. The right strip loin was removed from each carcass, portioned into 2.54-cm steaks, and designated to 7, 14, or 21 d postmortem aging periods for analysis of cook loss and Warner-Bratzler shear force ( WBSF ). The anterior face of each strip loin was used for analysis of crude fat and moisture. Treatment influenced ( P  < 0.001) L *, a *, and b *. The NT and IMP treatments had greater ( P  < 0.01) L * values, ANT was intermediate, and BA had the lowest ( P  < 0.01) L * values. The NT and IMP treatments had higher ( P  < 0.01) a * and b * values compared with ANT, which were higher ( P  < 0.01) than BA. Steaks from implanted steers (IMP and BA) tended ( P ≤ 0.067) to exhibit higher a * and b * than steaks from nonimplanted steers. Cattle in the NT and ANT treatments produced steaks with increased ( P  < 0.01) crude fat percentage compared with the IMP and BA treatments, which were similar ( P  > 0.05). Percent moisture of NT steaks was lower ( P  < 0.01) than all other treatments, ANT was intermediate, and IMP and BA were similar ( P  > 0.05) and had the highest ( P  < 0.01) moisture content. Cook loss tended to be greater ( P  = 0.088) for implanted steers (IMP and BA) compared to nonimplanted steers (NT and ANT). Steaks from NT and ANT treatments were more tender ( P  < 0.05) than IMP and BA, which were similar ( P  > 0.05). Thus, WBSF was lower ( P  < 0.001) in nonimplanted than implanted steaks. Expression of calpastatin was increased ( P ≤ 0.025) in ANT and BA treatments, and there was a tendency for expression of calpain-2 to be increased ( P  = 0.081) in ANT compared to NT. These results suggest that production systems with limited use of growth promoting technology produced strip loins with more crude fat, less moisture and cook loss, and improved tenderness., Competing Interests: The authors declare no real or perceived conflict of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science.)

This study investigated the impacts of metabolizable protein (MP) restriction in primiparous heifers during mid- and/or late-gestation on progeny performance and carcass characteristics. Heifers were allocated to 12 pens in a randomized complete block design. The factorial treatment structure included two stages of gestation (mid- and late-) and two levels of dietary protein (control (CON); ~101% of MP requirements and restricted (RES); ~80% of MP requirements). Half of the pens on each treatment were randomly reassigned to the other treatment at the end of mid-gestation. Progeny were finished in a GrowSafe feeding system and carcass measurements were collected. Gestation treatment x time interactions indicated that MP restriction negatively influenced heifer body weight (BW), body condition score, and longissimus muscle (LM) area (p < 0.05), but not fat thickness (p > 0.05). Treatment did not affect the feeding period, initial or final BW, dry matter intake, or average daily gain of progeny (p > 0.05). The progeny of dams on the RES treatment in late gestation had a greater LM area (p = 0.04), but not when adjusted on a hot carcass weight basis (p > 0.10). Minimal differences in the animal performance and carcass characteristics suggest that the level of MP restriction imposed during mid- and late-gestation in this study did not have a significant developmental programming effect.

Pooling individual samples prior to DNA extraction can mitigate the cost of DNA extraction and genotyping; however, these methods need to accurately generate equal representation of individuals within pools. The objective of this study was to determine accuracy of pool construction of blood samples based on white blood cell counts compared to two common DNA quantification methods. Fifty individual bovine blood samples were collected, and then pooled with all individuals represented in each pool. Pools were constructed with the target of equal representation of each individual animal based on number of white blood cells, spectrophotometric readings, spectrofluorometric readings, and whole blood volume with 9 pools per method and a total of 36 pools. Pools and individual samples that comprised the pools were genotyped using a commercially available genotyping array. ASReml was used to estimate variance components for individual animal contribution to pools. The correlation between animal contributions between two pools was estimated using bivariate analysis with starting values set to the result of a univariate analysis. Adonis test on distance matrix from the animal correlation showed clustering with method, and higher correlations between methods than within ( P < 1 × 10 -6 ). White blood cell count was predictive of sample representation when compared to pooling based on DNA concentration. Therefore, constructing pools using white blood cell counts prior to DNA extraction may reduce cost associated with DNA extraction and genotyping and improve representation of individuals in a pool., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Abrams, McDaneld, Keele, Chitko-McKown, Kuehn and Gonda.)

Ultrasound technology provides cattle breeders with a quick, noninvasive, and inexpensive way to measure carcass data on live animals. Ultrasound data are used as indicator traits in cattle genetic evaluations for economically relevant carcass traits. Ultrasound cattle genetic evaluations assume homogeneous additive genetic and residual variance. Thus, the objective was to partition phenotypic variance in ultrasound carcass measurements into components for additive genetic effects, technicians, contemporary groups within technicians, and residual and to examine the homogeneity of these variances among image interpretation laboratories. Records of longissimus muscle area (LMA), percentage of intramuscular fat (IMF), and subcutaneous fat depth (SFD), measured using ultrasound, were provided by the American Angus Association ( n = 65,967), American Hereford Association ( n = 43,182), and American Simmental Association ( n = 48,298). The data also included contemporary group, technician, imaging lab, and a three-generation pedigree for each animal. Variance components for ultrasound carcass measurements were first estimated with univariate animal models for each breed and imaging laboratory using derivative-free restricted maximum likelihood. Then, treating data from each imaging laboratory as separate traits, genetic correlations between laboratories for LMA, percentage of IMF, and subcutaneous fat were estimated with trivariate animal models. The technician explained 12-27%, 5-23%, and 4-26% of the variance for IMF, SFD, and LMA, respectively, across all three breeds. Variance due to technician was often greater than variance due to additive genetic effects but almost always less than that explained by the contemporary group. Within breeds, estimates of additive genetic variance for LMA, SFD, and IMF differed (range divided by mean) among laboratories by 4.5%, 21.5%, and 39.4 % (Angus); 31.6%, 15.0%, and 49.1% (Hereford); and 19.9%, 46.6%, and 55.3% (Simmental), respectively. Likewise, estimates of residual variance for LMA, SFD, and IMF differed among laboratories by 43.4%, 22.9%, and 43.3% (Angus); 24.9%, 15.2%, and 79.2% (Hereford); and 26.4%, 32.5%, and 46.2% (Simmental), respectively. Genetic correlations between labs across breeds ranged from 0.79 to 0.95 for IMF, 0.26 to 0.94 for SFD, and 0.78 to 0.98 for LMA. The impact of the observed heterogeneity of variance between labs on genetic evaluation requires further study., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Individuals often respond differently to the same vaccine; some of this variation may be caused by genetic differences among animals. Our objective was to estimate heritability and identify genomic regions associated with humoral response to an Escherichia coli O157:H7 vaccine in beef cattle. Crossbred beef cattle (n = 651) were vaccinated with a commercially available E. coli O157:H7 vaccine. Serum was collected at time of initial vaccination (d 0), booster (d 21), and d 56 after initial vaccination. Total antibodies specific to siderophore receptor and porin proteins in the vaccine were quantified by enzyme-linked immunosorbent assay. Genomic DNA was isolated from whole blood and genotyped with the bovine GeneSeek Genomic Profiler-High Density 78K or 26K Single Nucleotide Polymorphism BeadChip and imputed to 777,000 SNP genotypes. Heritability was estimated by restricted maximum likelihood (REML) using both 1) pedigree and 2) genomic relationships among individuals. Fixed effects were contemporary group, calf age, sex, principal components from SNP genotype data, and pedigree-derived heterozygosity effects. Additive and dominance effects of SNPs were estimated individually while accounting for contemporary group, sex, and the top 20 principal components calculated from the genomic relationship matrix. Heritability of initial response to vaccination (d 21 -d 0) was 0.10 ± 0.175 using pedigree relationships and 0.14 ± 0.149 using genomic relationships, but neither estimate was statistically different from zero. Heritability of booster (d 56 -d 21) and overall (d 56 -d 0) responses were low and not statistically significant from zero. There were no clusters of linked SNP associated with vaccine response, but eight regionally isolated SNPs were significantly associated with initial or overall response to vaccination. Regional genetic variation for initial response to an E. coli O157:H7 vaccine was observed, although overall heritability of this response was not statistically significant from zero.

The ability of ruminants to utilize cellulosic biomass is a result of the metabolic activities of symbiotic microbial communities that reside in the rumen. To gain further insight into this complex microbial ecosystem, a selection-based batch culturing approach was used to identify candidate cellulose-utilizing bacterial consortia. Prior to culturing with cellulose, rumen contents sampled from three beef cows maintained on a forage diet shared 252 Operational Taxonomic Units (OTUs), accounting for 41.6-50.0% of bacterial 16S rRNA gene sequences in their respective samples. Despite this high level of overlap, only one OTU was enriched in cellulose-supplemented cultures from all rumen samples. Otherwise, each set of replicate cellulose supplemented cultures originating from a sampled rumen environment was found to have a distinct bacterial composition. Two of the seven most enriched OTUs were closely matched to well-established rumen cellulose utilizers ( Ruminococcus flavefaciens and Fibrobacter succinogenes ), while the others did not show high nucleotide sequence identity to currently defined bacterial species. The latter were affiliated to Prevotella (1 OTU), Ruminococcaceae (3 OTUs), and the candidate phylum Saccharibacteria (1 OTU), respectively. While further investigations will be necessary to elucidate the metabolic function(s) of each enriched OTU, these results together further support cellulose utilization as a ruminal metabolic trait shared across vast phylogenetic distances, and that the rumen is an environment conducive to the selection of a broad range of microbial adaptations for the digestion of plant structural polysaccharides., Competing Interests: The authors declare no conflict of interest. The funding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

The objective of this study was to determine whether altered maternal energy supply during mid-gestation results in differences in muscle histology or genes regulating fetal adipose and muscle development. In total, 22 Angus cross-bred heifers (BW=527.73±8.3 kg) were assigned randomly to the three dietary treatments providing 146% (HIGH; n=7), 87% (INT; n=7) or 72% (LOW; n=8) of the energy requirements for heifers from day 85 to day 180 of gestation. Fetuses were removed via cesarean section at day 180 of gestation and longissimus muscle (LM) and subcutaneous fat were collected and prepared for analysis of gene expression. Samples from the LM and semitendinosus (ST) were evaluated for muscle fiber diameter, area and number. The right hind limb was dissected and analyzed to determine compositional analysis. Fetal growth and muscle histology characteristics of the LM and ST were similar among treatments. Preadipocyte factor-1 expression was up-regulated in fetal LM (P<0.05) of HIGH fetuses as compared with INT, whereas LOW fetuses showed increased CCAAT/enhancer-binding protein-β (C/EBP-β) expression in LM as compared with INT (P<0.05). Peroxisome proliferator-activated receptor γand C/EBP-α did not differ as a result of dietary treatment in LM or subcutaneous fat samples. There was a tendency for increased expression of fatty acid synthase in LM of LOW fetuses as compared with INT (P<0.10). Myogenin was more highly expressed (P<0.05) in LM of the LOW fetuses, whereas μ-calpain expression was increased in the HIGH treatment compared with INT. A tendency for increased expression of IGF-II was observed for both LOW and HIGH fetuses compared with INT (P<0.10). Expression of stearoyl-CoA desaturase, myoblast determination protein 1, myogenic factor 5, myogenic regulatory factor-4, m-calpain, calpastatin, IGF-I and myostatin was similar between treatments. Collectively, these results suggest that fetal growth characteristics are not affected by the level of maternal nutritional manipulation imposed in this study during mid-gestation. However, differences in expression of fetal genes regulating adipose and muscle tissue growth and development could lead to differences in postnatal composition and warrants further investigation.

Objective: To identify differentially expressed genes between axially impacted and control articular cartilage taken from porcine patellae maintained in organ culture for 14 days., Methods: Porcine patellae were impacted perpendicular to the articular surface to create an impact injury. Intact patellae (control and impacted) were maintained in culture for 14 days. Total RNA was then extracted from the articular cartilage beneath the impaction and used to prepare two Serial Analysis of Gene Expression (SAGE) libraries. Approximately 42,500 SAGE long tags were sequenced from the libraries. The expression of select genes was confirmed by quantitative real-time PCR analysis., Results: Thirty-nine SAGE tags were significantly differentially expressed in the impacted and control libraries, representing 30 different annotated pig genes. These genes represented gene products associated with matrix molecules, iron and phosphate transport, protein biosynthesis, skeletal development, cell proliferation, lipid metabolism and the inflammatory response. Twenty-three of the 30 genes were down-regulated in the impacted library and five were up-regulated in the impacted library. Quantitative real-time PCR follow-up of four genes supported the results found with SAGE., Conclusion: We have identified 30 putative genes differentially expressed in a porcine impact injury model and validated these findings for four of these genes using real-time PCR. Results using this impact injury model have contributed further evidence that damaged chondrocytes may de-differentiate into fibroblast-like cells and proliferate in an attempt to repair themselves. Additional work is underway to study these genes in further detail at earlier time points to provide a more complete story about the fate of chondrocytes in articular cartilage following an injury.

The objective of this study was to estimate genetic variability of Mycobacterium avium ssp. paratuberculosis infection in US Holsteins. Blood and fecal samples were collected primarily from daughters of 12 bulls in their second or third lactation. Routine disease testing of the sires documented that they were not infected. Herds without a "suspect" or positive ELISA (sample/positive ratio > or = 0.10) or positive fecal culture test were deleted from the data set. The remaining 4,603 cows from 238 herds and 46 sires were used to estimate heritability of M. paratuberculosis infection. Heritability was estimated with 3 Johne's disease diagnostic tests: 1) fecal culture alone, 2) serum antibody ELISA alone, and 3) both tests (combined) with a positive animal defined as all animals with either a positive fecal culture or ELISA test. Four statistical models were used to estimate heritability: 1) linear (ELISA), 2) threshold (fecal culture and combined), 3) ordered threshold (ELISA), and 4) bivariate linear-threshold (ELISA-fecal culture). A sire model and Bayesian approach using Markov chain Monte Carlo methods were used in each case. Heritability of infection based on the fecal culture test was 0.153 [posterior standard deviation (PSD) = 0.115]. Heritability with the ELISA was 0.159 (PSD = 0.090) with a linear model and 0.091 (PSD = 0.053) with an ordered threshold model. Heritability of the combined tests was 0.102 (PSD = 0.066). Heritability estimates of fecal culture and ELISA with the bivariate model varied slightly from estimates obtained with the univariate models (0.125 and 0.183, respectively), with a corresponding increase in precision (PSD = 0.096 and 0.082, respectively). This study demonstrates that exploitable genetic variation exists in dairy cattle for M. paratuberculosis infection susceptibility.