Intake, digestibility, performance, and feeding behavior of lambs fed diets containing silages of different tropical forage species

The study evaluates the effects of including four silages of tropical forages in the diet of lambs in semi-arid region of Brazil on their intake, digestibility, production performance, and feeding behavior. Thirty-two crossbred lambs with an average age of six months and an average initial weight of 17.6±2.63kg were distributed in a completely randomized experimental design with four treatments and eight replicates. Treatments consisted of diets with four forage plant species preserved in silage form: old man saltbush (Atriplex nummularia Lindl), buffelgrass (Cenchrus ciliares L.), gliricidia (Gliricidia sepium (Jacq)), and pornunça (Manihot sp.). Each treatment was composed of a different silage, containing 50% silage and 50% of a concentrate based on corn and soybean meal. The highest (P<0.05) dry matter (DM) and organic matter (OM) intakes were obtained with the animals fed diets containing old man saltbush silage compared to the buffelgrass and gliricidia silages. The animals fed pornunça silage had similar (P>0.05) DM and OM intakes to those fed old man saltbush and gliricidia silages, but higher (P<0.05) than those consuming buffelgrass silage. Lambs fed diets based on different silages of tropical forages showed similar (P>0.05) digestibility coefficients of DM and neutral detergent fiber. The time expended ruminating and chewing in minutes/day was highest (P<0.05) with old man saltbush silage in comparison to gliricidia and pornunça silages. Lambs fed diets with buffelgrass silage expended similar amounts of time ruminating and chewing (P>0.05) to those fed the other silages (old man saltbush silage, gliricidia, and pornunça). The highest values (P<0.05) for daily weight gain were observed in the animals fed the old man saltbush silage. The results of this study demonstrate the potential to use the old man saltbush, gliricidia, and pornunça forage plants as silage in lamb diets.