|Van Vleck, Lloyd|
Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Abstract Only
Publication Acceptance Date: 8/21/1997
Publication Date: N/A
Interpretive Summary: A potential problem in selection is when selection for one trait is associ- ated with a decline in performance for another trait. Knowledge of the genetic correlations among traits is necessary to predict the amount of decline expected for one trait if selection is on a negatively correlated trait. This knowledge is also necessary to allocate selection emphasis between the two traits to maximize economic gain from selection. This study of 3,459 beef heifers and 4,080 steers sired by the same bulls estimated correlations between two classes of economically important traits: growth and reproduction in females and measures of carcass quality in steers. Most of the genetic correlations were small, i.e., neutral, especially for carcass measures with age at puberty and calving difficulty. Improved calving rate, however, was moderately associated with increased carcass fatness. A low to moderate genetic association was also found for heifer weaning weight and less tender meat. Few such corre- lations have been previously estimated. Thus, this study emphasizes the need to obtain data on traits in one sex that might be unfavorably correlated with traits measured on the other sex.
Technical Abstract: Genetic parameters of and among female growth and reproductive traits and male carcass traits were estimated from data on 3,459 beef heifers and 4,080 of their steer paternal half-sibs using using REML with a sire and dam model. Genetic correlations were positive for heifer weights with male hot carcass weight, estimated kidney, pelvic and heart fat percentage, rib eye area, adjusted fat thickness and taste panel tenderness were unfavor- ably correlated with heifer weaning weight, but showed no relationship with yearling weight. Age at puberty in females was not correlated with any carcass traits except taste panel tenderness. Calving rate was positively correlated with traits involving carcass fatness. Calving difficulty was unfavorably correlated with measures of carcass tenderness. Estimates of genetic correlations imply selection for some traits measured in one sex of beef cattle may yield undesirable responses in traits measured in the opposite sex.