The performance of Bonsmara bulls tested in Phase C of the South African Performance Testing Scheme (intensive test in which individual feed intakes are measured) was compared with the performance of the half-sib bulls tested in Phase D (comparable to commercial feedlot conditions). Birth weight and yearling weight did not differ significantly between bulls tested in the two phases. Although bulls entering Phase C were selected for weaning weight, the ADG (average daily gain) and Kleiber ratios (ADG/yearling weight0.75) of bulls in Phase D were significantly higher than those of bulls in Phase C. Preweaning performance should thus not be used to predict postweaning performance. As the genetic correlations between half-sibs in Phases C and D for yearling weight (1.104 Â± 0.141), ADG (1.008 Â± 0.005) and the Kleiber ratio (0.777 Â± 0.179) were close to unity, it is concluded that the progeny of bulls performing well in Phase C will perform well under intensive feedlot conditions.
"Experientia docet" - Experience is the best teacher