Pasture Height of A Tropical Erect Grass Affecting Young Lamb Herbage Intake And Performance

Abstract

Tropical erect grass pastures have high forage production potential in subtropical and tropical regions of the world. However, in this kind of pasture, the body weight gain of weaned lambs is usually below of their potential. We determined the effect of pasture height of an erect tropical grass, consequently its structure, on intake and performance of young lambs. The experiment was repeated in two years. Thirty young weaned lambs (4-5 months) were assigned, each year, to three Panicum maximum pasture heights: 1) Tall-75 cm; 2) Medium-50 cm and 3) Short-25 cm. Herbage mass, pasture height, plant morphological composition, pasture nutritional quality, lamb’s average daily gain, gain per hectare and herbage intake were measured. The experiment was installed in a completely randomized design, evaluated in two periods each year. The Short treatment presented, on average and for longer, the highest leaf:stem ratio (1.3 ± 0.23) and average daily gain (91 ± 10 g/day) in relation to the Medium and Tall treatments (68 ± 10 and 40 ± 13 g, respectively). There was a significant interaction between treatment*period for herbage intake. The Tall treatment showed a marked decrease in intake from the first to the second period. The pasture height management interferes in the speed at which the number of stems increases of a tropical erect grass, in relation to leaves. For a better performance of weaned young lambs during summer-autumn period, it is important to manage tropical erect grass pastures at lower height than is generally recommended, lower than 25 cm.