Effect of weaning age on growth and carcass characteristics of beef steers

[摘要] The objective of this trial was to evaluate the effect of weaning age on growth and carcass characteristics of calves from primiparous Bos indicus x Bos taurus crossbred cows. Heifers were divided in two groups according to the order of access to pasture and rotationally grazed pastures of ryegrass (Lolium multiflorum Lam) and arrowleaf clover (Trifolium vesiculosum cv. Yuchi) from weaning until their first mating season (two winter/spring seasons); animals were then transferred to native pasture in the following summer-autumn season. Calves were randomly assigned, according to breed and heifers grazing group order, to one of two weaning ages: early weaning (EW) - 07 calves weaned at 70 days of age with an average body weight of 83.2 kg or conventional weaning (CW) -10 calves weaned at 180 days of age and with an average body weight of 152.0 kg in a completely randomized design. Steers were slaughtered with two years of age. Heifers grazing group did not affect calves performance. Calves in the CW treatment were heavier (202.1 kg) at one year old than those on EW (183.0 kg), but no significant difference was observed when animals were slaughtered at two years of age (CW=408.5 kg vs. EW=411.2 kg). Carcass traits such as fat thickness, conformation, "Hilton Quote" classification, and hot yield did not differ comparing EW with CW steers. Therefore, early weaning did not affect performance and carcass characteristics of steers slaughtered at two years of age.

[学科分类] 兽医学

[关键词] compensatory growth;early weaning;improved pastures;supplementary feeding    Introdução O desmame precoce é uma prática de manejo utilizada para incrementar os índices reprodutivos dos rebanhos de cria por meio da redução da exigência energética da vaca em situações de excesso de carga animal (Simeone & Lobato;1996) e de vacas com baixa condição corporal (Pio de Almeida et al