Desempenho de novilhas leiteiras em pastagens anuais de inverno sob sistema de integração lavoura-pecuaria

Abstract

The objective of this work was to assess the rearing viability of dairy heifers grazing single or intercropped winter pastures, under crop-livestock integration system. The experiment was carried out in Castro, Parana state, Brazil. A complete block design was used, in a factorial arrangement, with two animal categories - light-weight, with 192±40.9 kg-, and heavy-weight animals, with 278±41.2 kg ., and two pasture types: annual ryegrass (Lolium multiflorum) intercropped with black oat (Avena strigosa), white clover (Trifolium repens) and red clover (Trifolium pratense); and single annual ryegrass pasture. A continuous grazing method with variable stocking was used, with 20-cm sward management height. Single annual ryegrass pasture provided an average daily gain (0.93±0.032 kg per day per animal) significantly higher than intercropped pastures (0.79±0.032 kg per day). Light animals had higher weight gain per hectare (3.54±0.163 kg ha -1 per day) than heavy animals (2.99±0.163 kg ha -1 per day), which was influenced by pasture type: light animals had best performance on single pasture, and heavy animals on intercropped pastures. Rearing dairy heifers is viable in the pasture phase of integrated crop-livestock systems.