Genetic variation in monoamine oxidase A and analysis of association with behaviour traits in beef cattle

Husbandry of beef cattle requires animals that do not behave aggressively or timidly. The enzyme monoamine oxidase A and the coding gene (MAOA) play an important role in the complex regulation of behaviour. The complete coding region and a part of the non‐coding sequence of the bovine MAOA gene have been analysed in 20 German Angus and 20 German Simmental bulls and cows with the aim of detecting genetic variability. These two cattle breeds are known to differ regarding their behaviour during handling. Five single nucleotide polymorphisms (SNPs) were identified, three of which were found in the coding region of the gene (exons III and XV). One of the SNPs located in exon XV ( NC_007331.3 :g.80340C>T) was found to be a non‐synonymous mutation. The minor allele frequency of this resulting amino acid substitution was significantly different between 543 German Angus and 417 German Simmental calves (0.39 and 0.49, respectively). The potential functional impact of this polymorphism has been tested by in silico analysis, as well as by association analysis using behaviour scores of the genotyped calves for three behaviour tests that assessed the animals’ temperament during tethering, weighing or social separation. In silico analysis did not deliver consistent results arguing for or against a functional impact of the studied amino acid substitution on the function of the biological protein. No significant association was found between this MAOA polymorphism and the behaviour‐related scores analysed in the study.     

Estimation of genetic parameters for beef traits from field data

Data of the progeny testing for meat production of the Swiss A.I.-Federation were used in order to estimate genetic parameters. A heritability of carcass gain between 0.21 and 0.25 was found. Very small heritabilities of carcass grades were found (<0.1). Positive genetic correlations between carcass gain and carcass grades seem to exist.The average coefficient of relationship among the sires ($\text{R}$) can be considered in the estimation of the heritability by dividing the variance component of sires (σ_s²) by 1 — R. In this analysis the results were hardly influenced at all, due to the very small average relationship of only 1%.     

Estimation of direct and maternal (co)variance components for growth traits in Australian Simmental beef cattle

SUMMARY: Field data on weight recordings provided by the Australian Simmental Breeders Association was analysed. From a data set of 64,962 animals, which had either birth (BW), weaning (WW), yearling (YW), or final weight (FW) records a subset of 17 herds comprising 18,083 animals was used to obtain uni- and bivariate estimates of variance components. This subset had to be subdivided into six further subsets, called group herds. The models used allowed for additive genetic, maternal genetic, and permanent environmental effects and for a covariance between additive direct and maternal genetic effects. Estimates were pooled across group herds. The results for BW, WW, YW, FW were .33, .35, .37, and .30, respectively, for heritabilities and .074, .18, and .11 for maternal heritabilities (not estimated for FW). Significant correlations between direct and maternal genetic effects (rAM) existed for WW and YW in the magnitude of -.39 and -.22. However, further research is needed due to the problems associated with the estimation of r(AM) . ZUSAMMENFASSUNG: Sch?tzung direkter und maternaler (Ko)Varianz-Komponenten für Wachstumsmerkmale bei australischem Fleckvieh Gegenstand der Untersuchung waren im Feld erhobene Gewichte, die von der Australischen Simmental Breeders Association bereitgestellt worden waren. Aus einer Datei von 64.962 Tieren, die entweder ein Geburtsgewicht (GG), ein Absetzgewicht (AG), ein J?hrlingsgewicht (JG) oder ein Endgewicht (EG) aufwiesen, wurde ein Teildatensatz von 18.083 Tieren extrahiert und einer uni- und bivariaten Sch?tzung von Varianzkomponenten unterzogen. Diese Datei mu?te weiterhin in sechs verschiedene Dateien aufgeteilt werden; diese wurden Gruppenherden genannt. Die verwendeten Modelle erlaubten additiv-genetische, maternal-genetische und permanente Umwelteffekte sowie das Vorhandensein einer Kovarianz zwischen additiv-genetischem und maternal-genetischem Effekt. Die Sch?tzwerte wurden über die Gruppenherden gepoolt. Die Ergebnisse in der Reihenfolge GG, AG, JG und EG waren 0,33, 0,35, 0,37 und 0,30 für die Heritabilit?ten sowie 0,074, 0,18 und 0,11 für die maternalen Heritabilit?ten (nicht gesch?tzt für EG). Signifikante Korrelationen zwischen direktem und maternal-genetischem Effekt (r(AM) ) existierten für AG und JG in der Gr??enordnung von -0,39 und -0,22. Trotz dieses Ergebnisses sind weitere Untersuchungen n?tig, weil die Sch?tzung von r(AM) problematisch ist.     

Sample size calculations for Bayesian prediction of bovine viral-diarrhoea-virus infection in beef herds

We used a Bayesian classification approach to predict the bovine viral-diarrhoea-virus infection status of a herd when the prevalence of persistently infected animals in such herds is very small (e.g. <1%). An example of the approach is presented using data on beef herds in Wyoming, USA. The approach uses past covariate information (serum-neutralization titres collected on animals in 16 herds) within a predictive model for classification of a future observable herd. Simulations to estimate misclassification probabilities for different misclassification costs and prevalences of infected herds can be used as a guide to the sample size needed for classification of a future herd.     

Lack of evidence for cytoplasmic effects for four traits of Polypay sheep

Analyses of birth and weaning weights, fleece weights of ewes, and number born per litter of Polypay sheep collected at the U.S. Sheep Experimental Station from 1978 through 1998, confirmed previous analyses of three other dual-purpose breeds that cytoplasmic effects do not contribute to variation in these four traits. In general, estimates of genetic parameters that would be needed for national genetic evaluation were similar to previous estimates for Columbia, Rambouillet, and Targhee sheep, although estimates of direct heritability for Polypay were somewhat less for birth weight, slightly greater for weaning weight, significantly greater for fleece weight, and the same for number born as for those three breeds. For birth weight only, evidence was found for important dam x year or dam x number born interactions, which are essentially litter effects, as was found for the other dual-purpose breeds. There were 11,896, 11,104, 7,748, and 7,831 records for birth and weaning weights, fleece weight, and number born per litter, with 255 to 316 sires of animals with records. There were 260 and 261 cytoplasmic lines for fleece weight and number born, and 861 and 882 for weaning and birth weights.     

Parameter estimation for carcass traits including growth information of Simmental beef cattle using restricted maximum likelihood with a multiple-trait model.

(Co)variance component estimates were computed for retail cuts per day of age (kilograms per day), cutability (percentage of carcass weight), and marbling score (1 through 11) using a multiple-trait sire model. Restricted maximum likelihood estimates of (co)variance components were obtained via an expectation-maximization algorithm. Carcass data consisted of 8,265 progeny records collected by U.S. Simmental producers. Growth trait information (birth weight, weaning weight, and[or] postweaning gain) for those progeny with carcass data and an additional 5,405 contemporaries formed the complete data set for analysis. A total of 420 sires were represented. Three models differing in number of traits were investigated: 1) carcass traits with growth traits, 2) carcass traits only, and 3) single trait. The final models did not include postweaning gain because of convergence problems. Parameter estimates for all three models were essentially the same. Heritability estimates were .30, .18, and .23 for retail cuts per day, cutability, and marbling score, respectively. Correlations between growth and carcass traits were low except for those with retail cuts per day, which were moderate and positive. The additional information gained by adding growth traits to the carcass-traits-only evaluation lowered prediction error variances most for retail cuts per day. Little change in prediction error variances was found for cutability and marbling score. Inclusion of growth traits in future sire evaluations for carcass traits will benefit the evaluation of retail cuts per day but have considerably less effect on cutability and marbling score.     

Genome-wide association study of swine farrowing traits. Part II: Bayesian analysis of marker data

Reproductive efficiency has a great impact on the economic success of pork (sus scrofa) production. Number born alive (NBA) and average piglet birth weight (ABW) contribute greatly to reproductive efficiency. To better understand the underlying genetics of birth traits, a genome-wide association study (GWAS) was undertaken. Samples of DNA were collected and tested using the Illumina PorcineSNP60 BeadChip from 1,152 first parity gilts. Traits included total number born (TNB), NBA, number born dead (NBD), number stillborn (NSB), number of mummies (MUM), total litter birth weight (LBW), and ABW. A total of 41,151 SNP were tested using a Bayesian approach. Beginning with the first 5 SNP on SSC1 and ending with the last 5 SNP on the SSCX, SNP were assigned to groups of 5 consecutive SNP by chromosome-position order and analyzed again using a Bayesian approach. From that analysis, 5-SNP groups were selected having no overlap with another 5-SNP groups and no overlap across chromosomes. These selected 5-SNP non-overlapping groups were defined as QTL. Of the available 8,814 QTL, 124 were found to be statistically significant (P < 0.01). Multiple testing was considered using the probability of false positives. Eleven QTL were found for TNB, 3 on SSC1, 3 on SSC4, 1 on SSC13, 1 on SSC14, 2 on SSC15, and 1 on SSC17. Statistical testing for NBA identified 14 QTL, 4 on SSC1, 1 on SSC4, 1 on SSC6, 1 on SSC10, 1on SSC13, 3 on SSC15, and 3 on SSC17. A single NBD QTL was found on SSC11. No QTL were identified for NSB or MUM. Thirty-three QTL were found for LBW, 3 on SSC1, 1 on SSC2, 1 on SSC3, 5 on SSC4, 2 on SSC5, 5 on SSC6, 3 on SSC7, 2 on SSC9, 1 on SSC10, 2 on SSC14, 6 on SSC15, and 2 on SSC17. A total of 65 QTL were found for ABW, 9 on SSC1, 3 on SSC2, 9 on SSC5, 5 on SSC6, 1 on SSC7, 2 on SSC8, 2 on SSC9, 3 on SSC10, 1 on SSC11, 3 on SSC12, 2 on SSC13, 8 on SSC14, 8 on SSC15, 1 on SSC17, and 8 on SSC18. Several candidate genes have been identified that overlap QTL locations among TNB, NBA, NBD, and ABW. These QTL when combined with information on genes found in the same regions should provide useful information that could be used for marker assisted selection, marker assisted management, or genomic selection applications in commercial pig populations.     

Evaluation of performance characteristics in a diallel among Simmental, Limousin, Polled Hereford and Brahman beef cattle. II. Carcass traits

Evaluations of steer and heifer progeny from a diallel mating design of Simmental, Limousin, Polled Hereford and Brahman beef cattle over 5 yr are presented. Traits evaluated included final weight, hot carcass weight, ribeye area, 12th rib fat thickness, marbling score, yield grade, dressing percentage and percentage of kidney, pelvic and heart fat. Progeny of Simmental sires were heavier at slaughter than those with Brahman sires (P less than .05), but no differences were found for carcass weight. Dressing percentage was higher for Limousin crosses compared with progeny of other sire breeds (P less than .05). Similar results were found for dam breeds, except that progeny of Limousin dams had heavier carcasses with a higher dressing percentage (P less than .05) than Brahman crosses. Crosses of Limousin and Simmental had larger ribeye areas (P less than .05) compared with calves of the other breeds. Progeny of Polled Hereford dams had higher marbling scores and were fatter than progeny of dams of other breeds (P less than .05). Heterosis estimates were significant for all Brahman crosses for final weight, carcass weight and ribeye area, but these contrasts were negligible for other traits. Estimates of general combining ability were positive and significant for Simmental for final weight, carcass weight, ribeye area and marbling score and were significant and negative for Limousin for final weight, fat thickness and yield grade. Maternal values were generally small.     

Whole-genome QTL scan for ultrasound and carcass merit traits in beef cattle using Bayesian shrinkage method

Fine mapping of quantitative trait loci (QTL) for 16 ultrasound measurements and carcass merit traits that were collected from 418 hybrid steers was conducted using 1207 SNP markers covering the entire genome. These SNP markers were evaluated using a Bayesian shrinkage estimation method and the empirical critical significant thresholds (α = 0.05 and α = 0.01) were determined by permutation based on 3500 permuted datasets for each trait to control the genome-wide type I error rates. The analyses identified a total of 105 QTLs (p < 0.05) for seven ultrasound measure traits including ultrasound backfat, ultrasound marbling and ultrasound ribeye area and 113 QTLs for seven carcass merit traits of carcass weight, grade fat, average backfat, ribeye area, lean meat yield, marbling and yield grade. Proportion of phenotypic variance accounted for by a single QTL ranged from 0.06% for mean ultrasound backfat to 4.83% for carcass marbling (CMAR) score, while proportion of the phenotypic variance accounted for by all significant (p < 0.05) QTL identified for a single trait ranged from 4.54% for carcass weight to 23.87% for CMAR.     

Investigations on functional traits in Simmental: 1. Treatment costs for ten different diseases

SUMMARY: All health-related events and treatment costs (by veterinarian and non-veterinarian) were recorded through fortnightly interviews with the herdsmen of 104 Simmental dairy farms in Upper Bavaria from autumn 1987 to spring 1990. The data include 8381 calvings and the subsequent time period. For ten different disease-classes the sum of all treatment costs from calving up to either the subsequent calving or up to culling were computed. A multiplicative model with three covariates was fitted to these observations. The covariates are farm, parity and type of end of lactation (culling or subsequent calving). Farm effects are significant for almost all diseases. The average sum of treatment costs per calving with an associated disease was estimated as the average expected value for this sum, where averaging is over the farms. These costs range from 29 DM (claw disorders) up to 137 DM (dystocia). The average costs per calving (with or without disease) range from 1.59 DM (injuries of the udder) to 10.90 DM (fertility problems). Corresponding costs per cow and year are 1.74 DM and 12.24 DM. ZUSAMMENFASSUNG: Auf 104 Fleckviehbetrieben wurden insgesamt 8381 Kalbungen, alle auf diese Kalbungen folgenden Erkrankungen und die zugeh?rigen Behandlungskosten erhoben. Für zehn verschiedene Erkrankungsarten wurden jeweils alle Behandlungskosten innerhalb einer Zwischenkalbezit aufsummiert. An diese Beobachtungswerte wurde jeweils ein multiplikatives Modell mit den Einflu?faktoren Betrieb, Laktationsnumner und Art der Zwischenkalbezeit (beendet durch Kalbung bzw. durch Abgang) angep?t. Im Gegensatz zu den beiden anderen Faktoren erweist sich der Betrieb bei fast allen Erkrankungsarten als signifikant. Die durchschnittlichen Kosten innerhalb einer betroffenen Zwischenkalbezeit wurden als durchschnittlicher Erwartungswert über alle Betriebe berechnet. Diese Kosten liegen je nach Erkrankungsart in einem Bereich, der von ca. 29 DM (Klauenerkrankungen) bis zu ca. 137 DM (Schwergeburt) reicht. Umgerechnet auf eine beliebige Kalbung (mit oder ohne folgende Erkrankung) entstehen Kosten zwischen 1,59 DM (Euterverletzungen) und 10,90 DM (Fruchtbarkeitsprobleme). Je Kuh und Jahr betragen die entsprechenden Werte 1,74 DM und 12,24 DM.     

Prediction of fertility from calfhood traits of Angus and Simmental heifers.

The objectives of this study were to quantify the relationships between traits observed before the first breeding season and fertility of 946 Angus and 351 Simmental heifers and to use those traits to develop prediction equations for heifer fertility. Logistic regression methodology was used. Traits investigated were Julian birth date, age of the heifer's dam, birth weight, actual weaning and yearling weights, weaning and yearling weight ratios, 205-d weight, 365-d weight, and birth-weaning, weaning-yearling, and birth-yearling ADG and relative growth rate (RGR). In both breeds heifers that were younger at the start of the breeding season were less likely to conceive, but this effect was more important for Angus (logistic regression coefficient, b = -.032; P less than .01) than for Simmentals (b = -.015; P = .06). Weaning weight ratio was positively associated with heifer fertility (b = .025; P = .01 and b = .028, P = .04, respectively, for Angus and Simmental), whereas actual weaning weight was related curvilinearly to fertility of Angus heifers. The likelihood of conception was highest for Angus heifers weighing greater than or equal to 240 kg at weaning. The only postweaning trait associated with heifer fertility was weaning-yearling RGR. The likelihood of conception was highest for Angus heifers growing between .15 and .30% per day (P = .01), whereas fertility increased continuously (P = .04) for Simmental heifers as weaning-yearling RGR decreased. The maximum variations in fertility explained by models including all possible explanatory variables were 11.5 and 9.2% for Angus and Simmental, respectively. Results suggested that growth-related traits were relatively more important as a predictor of fertility for Simmental heifers and that age at the start of the breeding season was more important for Angus heifers. The combination of Julian birth date and weaning-yearling RGR produced the best models to predict heifer fertility for both breeds.     

Direct and maternal genetic effects for carcass traits in beef cattle.

Carcass measurements were taken on 1,537 steers produced over four generations in a rotational crossbreeding study. Breed direct and maternal additive and heterotic genetic effects were estimated for hot carcass weight (HCWT), retail yield (RY), longissimus muscle area (LM), fat thickness (FT), marbling score (MS), and Warner-Bratzler shear force (WBS). Angus (A), Brahman (B), Charolais (C), and Hereford (H) breeds were involved in straightbred, first-cross, and two-, three-, and four-breed rotational crossbred matings with each crossbred combination including the B. Breed direct (Ig) and maternal (Mg) additive genetic effects and direct (Ih) and maternal (Mh) heterotic genetic effects were estimated using a multiple-regression model. The Ig and Mg effects were expressed as deviations from the overall mean. The IgC effects (Ig for C breed) were significant for HCWT, RY, and LM and resulted in leaner, heavier carcasses. The IgA and IgH effects were, in general, negative (P < .05) for HCWT, RY, LM, and WBS, and positive (P < .01) for FT and MS. The IgB effects were large and undesirable for HCWT, RY, LM, MS, and WBS (P < .01). The majority of Ih effects were beneficial (P < .05) for HCWT, RY, LM, and WBS. The Ih effects exhibited by B combinations were of greater (P < .05) magnitude with positive influences for HCWT, RY, and LM and desirable effects for WBS. The maternal additive and heterotic effects were of lesser importance than the direct additive and heterotic effects for the carcass traits studied.     

Genetic parameters for carcass traits and their live animal indicators in Simmental cattle

The objective of this study was to estimate parameters required for genetic evaluation of Simmental carcass merit using carcass and live animal data. Carcass weight, fat thickness, longissimus muscle area, and marbling score were available from 5,750 steers and 1,504 heifers sired by Simmental bulls. Additionally, yearling ultrasound measurements of fat thickness, longissimus muscle area, and estimated percentage of intramuscular fat were available on Simmental bulls (n = 3,409) and heifers (n = 1,503). An extended pedigree was used to construct the relationship matrix (n = 23,968) linking bulls and heifers with ultrasound data to steers and heifers with carcass data. All data were obtained from the American Simmental Association. No animal had both ultrasound and carcass data. Using an animal model and treating corresponding ultrasound and carcass traits separately, genetic parameters were estimated using restricted maximum likelihood. Heritability estimates for carcass traits were 0.48 +/- 0.06, 0.35 +/- 0.05, 0.46 +/- 0.05, and 0.54 +/- 0.05 for carcass weight, fat thickness, longissimus muscle area, and marbling score, respectively. Heritability estimates for bull (heifer) ultrasound traits were 0.53 +/- 0.07 (0.69 +/- 0.09), 0.37 +/- 0.06 (0.51 +/- 0.09), and 0.47 +/- 0.06 (0.52 +/- 0.09) for fat thickness, longissimus muscle area, and intramuscular fat percentage, respectively. Heritability of weight at scan was 0.47 +/- 0.05. Using a bivariate weight model including scan weight of bulls and heifers with carcass weight of slaughter animals, a genetic correlation of 0.77 +/- 0.10 was obtained. Models for fat thickness, longissimus muscle area, and marbling score were each trivariate, including ultrasound measurements on yearling bulls and heifers, and corresponding carcass traits of slaughter animals. Genetic correlations of carcass fat thickness with bull and heifer ultrasound fat were 0.79 +/- 0.13 and 0.83 +/- 0.12, respectively. Genetic correlations of carcass longissimus muscle area with bull and heifer ultrasound longissimus muscle area were 0.80 +/- 0.11 and 0.54 +/- 0.12, respectively. Genetic correlations of carcass marbling score with bull and heifer ultrasound intramuscular fat percentage were 0.74 +/- 0.11 and 0.69 +/- 0.13, respectively. These results provide the parameter estimates necessary for genetic evaluation of Simmental carcass merit using both data from steer and heifer carcasses, and their ultrasound indicators on yearling bulls and heifers.     

A region on bovine chromosome 15 influences beef longissimus tenderness in steers.

A genome scan was conducted using 196 microsatellite DNA markers spanning 29 autosomal bovine chromosomes and Warner-Bratzler shear force collected at d 2 and 14 postmortem on steaks from the longissimus muscle of 294 progeny from one Brahman x Hereford bull mated to Bos taurus cows to identify QTL for beef tenderness. One QTL was identified and located 28 cM (95% confidence interval is 17 to 40 cM) from the most centromeric marker on BTA15. The QTL interacted significantly with slaughter group. The difference in shear force of steaks aged 14 d postmortem between progeny with the Brahman paternally inherited allele vs those with Hereford was 1.19 phenotypic standard deviations (explained 26% of phenotypic variance) for one slaughter group and was not significant for three other slaughter groups. Apparently, unknown environmental factors present for three of the four slaughter groups were capable of masking the effect of this QTL. The sensitivity of the QTL effect to environmental factors may complicate utilization of markers for genetic improvement. Future research to elucidate the cause of the QTL x slaughter group interaction may lead to improved strategies for controlling variation in meat tenderness via marker-assisted selection, postmortem processing, or live animal management.     

Serological evidence for exposure to bovine viral diarrhoea virus in sheep co-grazed with beef cattle in New Zealand

ABSTRACT

Aims: To determine whether sheep that co-grazed with cattle that were suspected to be positive for bovine viral diarrhoea (BVD) virus had serological evidence of exposure to the virus.

Methods: Eighteen commercial farms that routinely co-grazed cattle and sheep in the same paddocks were recruited through purposive sampling. The recruiting veterinarians identified nine farms with cattle herds that were known or highly suspected to be positive for BVD and nine farms that were considered to be free of BVD. Blood samples were taken from 15 ewes aged 1 year on each farm and samples were submitted to a commercial diagnostic laboratory to test for antibodies against pestiviruses using an ELISA. All samples that were positive were then tested using a virus neutralisation test (VNT)for antibodies against BVD virus.

Results: Of the 270 blood samples, 17 were positive for pestivirus antibodies by ELISA and these originated from two farms that were known or suspected to have BVD virus-positive cattle. None of the samples from the nine flocks co-grazed with cattle herds that were known or suspected to be BVD virus-negative were positive for pestivirus antibodies. Within the two positive farms, 2/15 samples from the first farm and 15/15 samples from the second farm were antibody-positive. When the 17 positive blood samples were submitted for VNT, all 15 samples from the second farm tested positive for BVD virus antibodies with the highest titre being 1:512.

Conclusions and clinical relevance: In this small sample of New Zealand sheep and beef farms with suspected BVD infection in cattle, there was evidence of pestivirus exposure in co-grazed sheep. Although we were unable to confirm the origin of the exposure in these sheep, these findings highlight that farmers who are trying to eradicate BVD from their cattle should be mindful that the infection may also be circulating in sheep, and both populations should be considered a possible risk to each other for generating transient and persistent infections. Further work is needed to estimate the true prevalence of New Zealand sheep flocks that are affected by BVD and the associated economic impacts.     

Genetic analysis of bovine respiratory disease in beef calves during the first year of life.

The prevalence of bovine respiratory disease (BRD) was assessed in a population of 10,142 beef calves representing nine pure breeds and three composite populations born in 1983 through 1988. Twenty-four percent of the calves experienced at least one episode of respiratory disease during the 1st yr of life; frequencies over the six birth years ranged from 14 to 38%. The timing of respiratory disease outbreaks differed among birth years; in 4 of the 6 yr, more illness occurred in the pasture before weaning than in the feedlot after weaning. Frequencies of BRD during preweaning and postweaning periods were analyzed separately. Pure breeds and composite populations within a single preweaning location differed in frequency of illness during the preweaning period. However, not all possible breed comparisons could be made because preweaning location differed for the breed groups, and preweaning location had a significant effect on the frequency of respiratory disease in the preweaning period. The preweaning location effect did not carry through to the postweaning period. Pinzgauers had the highest BRD frequency within the feedlot (24.6%). The heritability estimates of BRD during the preweaning and postweaning periods did not differ significantly from 0 (.10 +/- .02 and .06 +/- .07, respectively). Although it is likely that response to selection for resistance to BRD would be slight using the animal's history of BRD as the selection criterion, including information on relatives or additional immune traits may improve the accuracy of an estimated breeding value for BRD resistance.