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POSTWEANING GROWTH OF BRAHMAN AND SANTA GERTRUDIS STEERS UNDER FEEDLOTS IN THE SUBTROPICS

  • Takahashi, J. (Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine) ;
  • Rojas, S.S. (Department of Animal Nutrition, Faculty of Veterinary Science, National University of Asuncion) ;
  • Castellani, P.G. (Department of Animal Nutrition, Faculty of Veterinary Science, National University of Asuncion) ;
  • Denis, F.C. (Department of Animal Nutrition, Faculty of Veterinary Science, National University of Asuncion)
  • Received : 1988.07.15
  • Accepted : 1988.10.19
  • Published : 1988.09.01

Abstract

Postweaning performances of steer from 11 to 18 months of age under intensive feedlot condition were examined in Brahman and Santa Gertudis cattle breeds which have been established in Paraguay. Fitting of growth data in each breed to an empirical growth model with non-linear least square analysis resulted in the following age(t; months) - weight(w; kg) function made out each breed: w=638.26($1-2.341e^{-0.010965t}$) for Brahman and w=716.38($1-2.365e^{-0.10741t}$) for Santa Gertrudis. The estimated mature size of Brahman steers(638 kg) was 11% lower than that of Santa Gertrudis steers(716 kg). However, slightly larger k value (rate of maturing) of Brahman steer in the mechanistic model suggested relatively earlier maturing tendency in the breed. No significant differences in dressing percentage (Brahman, 59.3%; Santa Gertrudis, 58.8%) of chilled carcass weight to live-weight were observed between breed.

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