|Van Vleck, Lloyd|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/1998
Publication Date: N/A
Interpretive Summary: Results from this study of beef cattle indicate there may be unfavorable genetic correlations between traits of female weight and male carcass fatness and tenderness. These results may present possible problems for producers selecting animals on the basis of weaning or yearling weights or those attempting to improve the leanness or palatability of steers. Calv- ing difficulty was also estimated to have an unfavorable genetic corre- lation with carcass tenderness. Various methods have been proposed to deal with economically important, but antagonistic, traits in beef cattle. Selection indexes which incorporate both female productivity and male carcass value may be one solution. Producers also might choose to restrict change in some traits while improving others. Specialized sire and dam lines may also be used in some situations.
Technical Abstract: Data from 3,459 beef heifers and 4,080 of their steer paternal half-sibs were used to estimate genetic parameters of and among female growth and reproductive traits and male carcass traits. Estimates of heritability for adjusted 205-d weight, adjusted 365-d weight, age at puberty, calving rate and calving difficulty measured on females were .14, .37, .46, .13 and .18, ,respectively, with estimates for calving rate and calving difficulty ex- pressed on a normal scale. Estiamtes of heritability for hot carcass weight, retail product percentage, fat percentage, bone percentage, rib eye area , actual kidney, pelvic and heart fat percentage, adjusted fat thick- ness, marbling score, Warner-Bratzler shear force, taste panel tenderness, taste panel juiciness and taste panel flavor measured on steers at an average age of 447 d (weaning age = 185, days on feed = 262) were .47, .66, .58, .51, .60, .46, .47, .71, .21, .30, .00 and .04, respectively. Genetic ccorrelations were positive for heifer weights with hot carcass weight, estimated kidney, pelvic and heart fat percentage, rib eye area, adjusted fat thickness and taste panel flavor, and negative with retail product percentage of steers. Age at puberty was not genetically correlated with any carcass traits except taste panel tenderness and flavor. Calving rate had moderate positive genetic correlations with traits involving carcass fatness. Heifer weaning weight and calving difficulty were moderately, but unfavorably correlated with measures of carcass tenderness. These results imply selection for some traits measured in one sex of beef cattle may result in undesirable responses in traits measured in the opposite sex.