Evaluation of tropical forage legumes ( Medicago sativa, Dolichos lablab, Leucaena leucocephala and Desmanthus bicornutus) for growing goats

Abstract

A 56-day feeding trial was conducted to evaluate forage legumes ( Medicago sativa, Dolichos lablab, Leucaena leucocephala and Desmanthus bicornutus) as protein supplements to a sudangrass ( Sorghum bicolor) diet based on growth and feed performance of growing goats. Twenty-four castrated kids were used in the experiment with an average initial age of 135 days and body weight of 18.7 kg. Kids were Boer × Spanish crossbreds. Four dietary treatments were composed of sudangrass (60% of diet offered) supplemented with one of four forage legumes (40% of diet offered) and corn (0.2 kg/day). A split-plot design was employed with diet as the main plot, pens as experimental units (consisting of three pens per diet as replicates) and goats as samples (two goats per pen). Fixed effects of breed type, litter size born, parity of dam and initial age of kid as a linear covariate were added to the model for growth traits. All forage legumes had over 20% crude protein (CP). Final body weight was not affected by diet ( P > 0.05). Average daily gain (ADG) tended ( P < 0.10) to be more rapid for goats fed leucaena compared to desmanthus (least squares means of 93.9 and 60.9 g/day, respectively). Voluntary daily feed intakes of sudangrass and alfalfa were higher by 22 and 33 g ( P < 0.01 and <0.001) per goat for pens receiving alfalfa with sudangrass compared to combined mean intakes of pens fed experimental forage legumes. Intake of leucaena compared to desmanthus forage was higher by 97 g/day ( P < 0.001), demonstrating relatively poorer acceptability of desmanthus. Also, goats fed leucaena had better ( P < 0.05) gain efficiency (ADG/total feed intake) compared to goats fed desmanthus. Experimental results suggest that L. leucocephala had more potential for feeding growing goats in tropical regions compared to the other forage legumes evaluated.