Energy sources in low intake supplements on the productive and reproductive performance of Zebu cows

Resumo

The aim of this study was to evaluate the productive and reproductive performance of primiparous zebu cows supplemented on Brachiaria brizantha cv. Marandu with supplements of low intake composed of different energy sources in the postpartum period. Sixty cow-calf pairs were divided into three treatments, a standard mineral salt supplement, a supplement based on ground corn and another containing protected fat, under the same conditions of pasture. The cows had an average initial age of 36 months and 295.9 ± 20 kg of initial body weight. The evaluation period lasted from November 2006 to May 2007, the 24 days after delivery until weaning of calves to 192 days of age. Cows fed the supplement based on ground corn (351 g day-1) and protected fat (357 g day-1) showed a similar increase in body weight, which was higher in relation cows fed with the mineral mixture (179 g day-1). Mineral mixture supplementation resulted in body condition score loss of cows between 80 and 136 days after calving. Cows fed energy supplements of low consumption produced more milk, weaned heavier calves and showed higher pregnancy rate than those fed only with the mineral mixture. The use of 3% calcium salts of fatty acids in energy supplements of low consumption did not alter the productive and reproductive performance of primiparous Zebu cows.