Breed variation and genetic parameters for growth and body development in diverse beef cattle genotypes

Abstract

Conformation scores can account for more than 20% of cattle price variation at Australian livestock sales. However, there are limited available references which define genetic factors relating objective live developmental traits to carcass composition. Weaning and post-weaning weight, height, length, girth, muscle (ratio of stifle to hip width) and fat depth of 1202 progeny from mature Hereford cows (637) mated to seven sire breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin and Belgian Blue) were examined for growth and development across ages. Crossbred Wagyu and Jersey were both lighter in weight and smaller in size (height, length and girth) than purebred Hereford and crossbred Angus, South Devon, Limousin and Belgian Blue. Within the five larger crossbreds, there were significant changes in relative weight from weaning to 600 days. Sire breeds differed in fat depth, with Angus being the fattest (9% on average fatter than Hereford and Wagyu), and Jersey 5% less fat than Hereford, followed by South Devon and Limousin (19% lower than Hereford) and Belgian Blue (39% lower than Hereford). Direct heritability ranged from 19 to 42% and was higher than the proportion of total phenotypic variance accounted for by maternal effects (which ranged from 0 to 17%) for most body measurement traits except for weight (38 v. 18%) and girth (36 v. 9%) traits at weaning, an indication of maternal effect on some body conformation traits at early ages. Muscularity (19 to 44%) and fat depth (26 to 43%) were moderately to highly heritable across ages. There were large differences for growth and the objective measures of body development between crossbreds with a degree of overlap among the progeny of the seven sire breeds. The variation between genetic (positive) and environmental (negative) correlations for dry versus wet season average daily gains in weight and fat, suggested the potential use of live-animal conformation traits for within breed selection of genetically superior animal in these traits across seasons.

Efficiency of selection for body weight in a cooperative village breeding program of Menz sheep under smallholder farming system

“…Integration of farmers' practices with our design did not adversely affect efficiency of the breeding program as can be seen from the genetic progress achieved in body weight. This can be explained by the high genetic (Janssens and Vandepitte, 2004;Afolayan et al, 2007) and phenotypic (Mavule et al, 2013b) correlations between body weights and linear size traits in sheep. A significant correspondence between farmers' and experts' selection criteria for the Menz sheep has also been observed in an earlier study (Gizaw et al, 2011).…”

The value of muscular and skeletal scores in the live animal and carcass classification scores as indicators of carcass composition in cattle

“…Similarly, Herring et al (1994) reported non-significant negative correlations between percentage retail product and both hip height and a visual frame size. Afolayan et al (2007) found that the correlation of body dimensions with muscularity was near zero.…”

“…Accurate prediction of carcass value or quality based on body composition would enable the early selection of efficient animals by beef producers as well as seedstock breeders (Afolayan et al, 2007). Live-animal indicators of carcass meat yield and distribution include visual muscular and skeletal scores, whereas carcass indicators are conformation and fat scores.…”

Performance of steer progeny of sires differing in genetic potential for fatness and meat yield following post-weaning growth at different rates. 1. Growth and live-animal composition

“…Gregory et al 1978Gregory et al , 1994Cundiff 2006) showing the variation among breeds and various types of cattle ('biological types') for growth and carcass attributes. Variation among breeds and genetic parameters for growth and body development for a diverse range of genotypes studied in Australia were reported by Afolayan et al (2007). Mean differences in the performance of progeny groups from designed matings can be predicted by the use of trait EBV as generated by BREEDPLAN (Graser et al 2005).…”

“…Gregory et al 1978Gregory et al , 1994Afolayan et al 2007). Thus, although some caution must be maintained, we can be reasonably confident that the samples of progeny we examined from the various carcass types are not atypical of the breeds from which their sires were drawn, a similar conclusion to that of Graham et al (2009) who reported the results of the Victorian site of this project.…”