02320naa a2200241 a 450000100080000000500110000800800410001910000180006024501280007826000090020652016170021565000160183265000120184865000180186065000150187865300190189365300190191265300380193170000170196970000190198670000190200577300540202417880822017-04-03       1987    bl ---       0--  u    #d1 aBOLTON, R. C.  aGenotype x environment interactions involving proportion of Brahman breeding and season of birth. I.calf growth to weaning.  c1987  aPerformance to weaning was evaluated on 489 spring-born and 416 fall-born crossbred calves of three proportion of Brahman breeding (0, 1/4 and 1/2 Brahman) over a 3-yr period. The calves were produced by appropriate matings of Angus (A), Hereford (H), Brahman (B), 1/2B-1/2A and 1/2B-1/2H bulls to Angus and Hereford cows. Interactions between proportion of Brahaman breeding and season of birth existed (P&lt.01) for all traits except birth weight. Birth weights of 1/4 and 1/2 Brahman calves were 1.4 and 3.8 kg heavier (P&lt.05), respectively, than O Brahman calves. Spring-born calves that were 1/4 and 1/2 Brahman outhained (P&lt.05) O Brahman calves 36 and 69 g/d, respectively and were 9 and 18 kg, respectively, heavier (P&lt.05) at weaning, whereas preweaning average daily gains and weaning weights were similar among fall-born crossbread calf groups. Among spring-born calves, 1/4 and 1/2 Brahman calves were 2.6 and 6.6 cm, respectively, taller (P&lt.05) than O Brahman calves, whereas amonf fall-born calves O and 1/4 Brahman calves had similar hip heights and 1/2 Brahman calves were 3.7 and 2.8 cm taller (P&lt.05) than O and 1/4 Brahman calves, respectively. Conformation and condition scores were similar for crossbred groups among spring-born calves, whereas conformation and condition scores decreased as proportion of Brahman breeding increased among fall-born calves. These data indicated that genotype x environment interactions are important in beef producxtion and increased proportions of Brahman breeding were advantagenous in a spring-calving program but not in a fall calving program.  abeef cattle  aBrahman  aGado de Corte  aProdução  aCalvong season  aCross breeding  aGenotype environment interactiopn1 aFRAHM, R. R.1 aCASTREE, J. W.1 aCOLEMAN, S. W.  tJournal Animal Sciencegv.65, n.1, p.42-47, 1987.