Evaluation of two-breed composites alongside Angus or Hereford controls for growth, reproduction, maternal, and carcass traits

摘要

Abstract Angus (A) and Hereford (H) cows at one location and A cows at a second location were used to generate purebred controls and six first-cross (F1) types of calf. Foundation sires were A, H, Friesian (F), Jersey (J), and South Devon (Sd) at Location 1, generating FH, FA, JA, SdA, and HA (plus AH) Fl calves, and at Location 2 sires were A and Blonde d'Aquitaine (Ba), generating BaA F1s. Sire breeds were selected as potentially contributing to productive crossbred cows, based on previous F1 cow comparisons. In subsequent years F2, F3, and F4 calves were produced from each of the two-breed crosses, with overlapping generations and contemporary controls providing balanced comparisons of breed types and generations. The experiment consisted of 395 unique sires and 5243 calves born in 1973–88 at Location 1 and 105 different sires and 2404 calves born in 1976–86 at Location 2. Growth, reproduction, maternal, and carcass traits were studied. Heterosis was estimated from HA (plus AH) and purebred A and H ani...