Effect of feeding Leucaena leucocephala leaves and twigs on energy utilization by goats

Fifteen intact male goats of Jamunapari breeds, 12–15 months old weighing 22.0 kg were divided into three groups of five animals in each in a completely randomized design to determine the effect of feeding Leucaena leucocephala leaves and twigs (LLLT) on heat production (HP) and energy balance (EB). Animals in treatment I (Control) was supplied with a conventional ration consisting of a concentrate mixture and vegetative parts of Zea mays and in treatments II and III received similar rations except that LLLT provided about 0.40 and 0.50 parts crude protein (CP) of total protein in ration, respectively by replacing 0.50 and 1.00 parts each of the solvent extracted groundnut cake and wheat bran in the concentrate mixture, respectively. The dry matter (DM) supplemented through LLLT was 0, 121 and 224 g in treatments I, II and III, respectively and it corresponds to 0, 0.19 and 0.34 parts of total DM intake. Supplementation of increasing amount of LLLT did not affect (P=0.303) DM intake but digestibility of DM decreased (P=0.002) linearly. The digestible energy (DE) intake was not affected (P=0.161) due to supplementation of LLLT. Urinary energy (UE) loss per kg metabolic body size per day and as proportion of gross energy (GE) or DE intake increased (P<0.001) linearly with increased LLLT supplementation. Average methane production varied from 15.2 to 17.3 L/d. Methane energy loss per kg metabolic body size per day decreased (P=0.024) linearly with increased supplementation of LLLT, however, as proportion of GE or DE did not show any effect of treatment. Metabolizable energy (ME) intake per kg metabolic body size per day was unaffected (P=0.113) by the treatments which corresponded to 1.63, 1.35 and 1.38 times of maintenance in treatments I, II and III, respectively indicated that animals were in well-fed condition. Heat production (HP) and energy balance (EB) were not affected by the supplementation treatment. It is concluded that supplementation of 224 g of LLLT in the diet of goats, which provided DM at a proportion of 0.34 or CP at a proportion of 0.59, did not affect HP and EB.