Relationship of beef sire expected progeny difference to maternal performance of crossbred daughters.

Cumulative milk production of crossbred daughters of sires of several breeds was estimated using weigh-suckle-weigh procedures. Pooled-across-breed analyses were conducted to determine, in retrospect, relationships of sire EPD values for milk and total maternal value to daughter milk yield and daughter's offspring weaning weight. The pooled coefficient for regression of daughter 214-d milk yield on sire milk EPD was 13.4 kg/kg (residual correlation was .14). The overall mean estimated milk yield was 1,262 kg, suggesting that a difference in sire milk EPD of 1 kg corresponded to a difference of approximately 1% in cumulative daughter milk yield. The pooled coefficient for regression of daughter's offspring 214-d weight on sire total maternal EPD was 1.18 kg/kg (residual correlation was .17). All regression and correlation coefficient stated above were significantly greater than zero. Breeders who use sire milk and total maternal EPD values as selection tools should expect such selection to be effective, on average, but should also expect that a substantial proportion of individuals or small groups may not rank as predicted.