Alternativas de suplementação para recria de novilhas de corte em pastagem natural visando peso para acasalamento

Abstract

Demand for beef is growing worldwide due to increased population and purchasing power, which leads to improvement in the diet of the population and consequently increased demand for meat products. In Rio Grande do Sul, livestock still has extensive production characteristics, being essential the increase of the production efficiency for better meet the growing demand for meat. Using forage management techniques coupled with the use of supplements, researchers seek alternatives to assist in the conservation and rational exploitation of pastures. The aim of this work was to reach 65% of adult weight (AW) at 22 months, with heifers of 18 months starting age and different initial weights (210 or 255 kg), reared in natural grasslands managed by rotational grazing method with two rest intervals (375 GD and 750 GD) which determined the treatments. The heifers received protein-energy supplementation and or protein-energy more corn. Herbage mass and canopy height were decreasing in the rest interval 375GD while in the 750 GD there was a maintenance of the mass and height r during most of the experimental period. The forage intake was similar between rest intervals, since the quality of the apparently consumed pasture had the lowest ADF content in the diet of heifers managed in the 750 GD which also dispended longer time in grazing activities, rumination and visited more stations per minute. The ultimate goal was achieved only in heifers managed in the rest interval 750 GD in order to conclude that to reach 65% of the PA, under the conditions of this experiment, the light heifers managed 375 GD rest interval must enter the second winter with at least 52% PA and heavy heifers 60% PA or extend supplementation for more than 21 days.