COMPARATIVE GROWTH AND HEAT TOLERANCE OF CROSSBRED GOATS IN RIO DE JANEIRO STATE

This study evaluated the comparative growth of 125 feedlot goats of distinct genetic groups (GG): 34 1/2 Saanen (SA) + 1/2 Parda Alpine (PA), 33 1/2 SA + 1/2 Anglo-Nubian (AN), 30 3/4 SA + 1/4 PA, and 28 three cross 1/2 Boer (BO) + 1/4 AN + 1/4 SA. There was a significative difference (P<0.01) in birth weight (BW), weaning weight (WW), and slaughter weight (SW) between GC. The BW, WW and SW were significantly influenced (P<0.01) by kid sex and birth type. There was a significant difference (P<0.01) between pre-weaning and post-weaning daily weight gain. The weight gain during these periods was significantly influenced (P<0.01) by GG, kid sex and birth type. Pre-weaning average daily weight gains were higher (P<0.01) compared to post-weaning. There was a difference in body temperature (BT), respiratory rate (RR) and heart rate (HR) between GC in the morning (P<0.05) and in the afternoon (P<0.01). The 1/2 SA + 1/2 AN and three cross goats had lower BT, RR and HR than 1/2 SA + 1/2 PA and 3/4 SA + 1/4 PA animals. Application of the heat tolerance index proposed by Baccari Junior showed a higher index for 1/2 SA + 1/2 AN and three cross goats compared tot SA + 1/2 PA and 3/4 SA + 1/2 PA animals, demonstrating that the former are more tolerant to the climate conditions of the Baixada Fluminense, Rio de Janeiro State.