Impacto da condição corporal sobre a taxa de prenhez de vacas da raça nelore sob regime de pasto em programa de inseminaçã o artificial em tempo fixo (iatf)

Abstract

The aim of this study was to evaluate the impact of body condition on pregnancy rate of Nellore cows, commercial herd undergoing artificial insemination programs in fixed time (TAI). 181 cows were used multiparous Nellore, the coastal plains region of the state of Rio de Janeiro, with more than one hundred days after birth, kept on pasture and divided into two groups subjected to the same synchronization protocol for TAI (D0-2 , 0 mg of estradiol benzoate + device with 1.0 g bovine intravaginal progesterone implant removal D8-250μg of cloprostenol + + 300 IU of eCG, D9-Bz 1.0 mg. Estradiol, D10-TAI). The groups were divided according to body condition score (BCS with scale of 1-5) in Group I, n=96: BCS ≥ 3,0, Group II, n=85: BCS ≤ 2.5 ≥ 2.0. All females were exposed to bulls, from 24 hours to pass after TAI, remaining with them until the end of the breeding season. The overall pregnancy rate was 86.5% (83:96) and 65.9% (56:85) for group I and group II, respectively. Data were evaluated by chi-square analysis and the results show a statistically significant difference (P <0.05) between groups, which may be concluded that the females of poor body condition (BCS ≥ 2.0 ≤ 2.5 ), have lower pregnancy rates compared to those best condition (BCS ≥ 3) when subjected to TAI program.