Consumption, botanical composition and nutritive value of the diet of cattle on mixed tropical pastures under three stocking rates

[摘要] The effects of three stocking rates on intake, botanical composition, and nutritive value of the diet of cattle on pastures of Brachiaria decumbens with Stylosanthes guianensis cv. Minerão and B. brizantha cv. Marandu with S. guianensis cv. Mineirão were evaluated. The experimental design was a randomized complete block with two field replications. The treatments were arranged as a 2 x 3 factorial with 2 grasses (B. decumbens and B. brizantha cv. Marandu) in association with S. guianensis cv. Minerão, three stocking rates (0.8, 1.2, and 1.6 AU/ha), and two sampling periods (July and October 1998, corresponding to the early and late dry season; and January and April 1999, corresponding to the mid and late rainy season). Weaned Nellore steers with an average initial weight 138 kg were used. There was no effect of stocking rate on the variables studied. Daily consumption of forage dry matter was higher on pastures with B. brizantha in October (late dry season) and in April (late rainy season). However, it was observed diets with higher nutritive value in B. decumbens pastures. More than 80% of the diet was composed of live grass leaves while legumes represented 2.1% of the diet, with a selection index of 0.08, indicating low contribution of this forage component to the grazing animals.

[学科分类] 兽医学

[关键词] Brachiaria;diet composition;dry season;IVOMD;rainy season;Stylosanthes    Introdução A introdução de leguminosas em pastagens tem sido sugerida como alternativa para suprir ou minimizar a deficiência de N desses ecossistemas;aumentando a capacidade de suporte e prolongando a produtividade;mas a falta de entendimento sobre as características morfofisiológicas contrastantes das espécies tem dificultado a sua adoção mais ampla