Ganancias de peso de novillos en Brachiaria decumbens (Stapf) en el Piedemonte amazonico de colombia

摘要

Live weight (LW) gain of Zebu steers (275 kg initial LW), submitted to alternate grazing of Brachiaria decumbens, was determined at the Macagual Hesearcn Center in Florencia (Caqueta, Colombia), located at 1 deg 4 min N and 75 deg 31 min W. Three stocking rates were used (2.0, 2.5, and 3.0 steers/ha), in three 1-year grazing cycles. Each 2-ha pasture was divided in half and grazed alternately at 35-day intervals. Animals were weighed separately at 60-day intervals, without previous fast, and the slopes of weight curves were submitted to analysis of variance. A completely randomized design, without replicates, was used. Sources of variation were animals and stocking rates and, within stocking rates, animals were considered as source of error. LW gains were higher (P < 0.05) during the first year (533 g/animal per day), compared with the second (406 g/animal per day) and third years (383 g/animal per day). No effect of stocking rate (P < 0.05) was observed. Average LW gain/animal per year was 150 kg. Average values found in 11 samples of B. decumbens were 5.69% for crude protein content; 38.2% for acid detergent fiber; and 64.2% for true in vitro dry matter digestibility. Pastures were only used 63% of the time because of constant spittlebug attacks.