Productivity and production efficiency of cows of different genetic groups submitted to cultivated pastures during pre or postpartum

Abstract

We assessed through the weight of cows and calves up to weaning at 90 days and the reproductive performance from pregnancy to weaning, the productivity and efficiency of 94 Charolais (CH), Nellore (NE), ½CH ½NE e ½NE ½CH cows submitted the following feeding systems: cows kept on native pasture (NP); cows kept on cultivated pasture (CP), composed of oat (Avena sativa), ryegrass (Lollium multiflorum) and clover (Trifolium vesiculosum) from July 15 to September 15 and the remainder of the trial on natural pasture (CPN); and cows kept on cultivated pasture during September 15 to November 15, and the remainder on native pasture (NPC). Cows kept on CP produced 22.6% more calves than cows kept exclusively on NP, and were more efficient (P<.05) for calf production index (efficiency of herds) with 57 vs 37 kg of calves/cow kept in the herd. For the production of kg of calves per cow, cows kept postpartum on CP (69 kg) were higher (P <0.05) to those kept on the cultivated pasture during antepartum (61 kg) and both superior to cows maintained exclusively on NP (53 kg). Between purebred cows the Charolais were more productive with higher index production of calves requiring less cows for the production of one calf. Between crossbred cows there was no difference in the variables studied (P>.05), being higher than the purebreds in productivity and production efficiency.