Energy requirements for maintenance and growth of entire male Bali cattle in East Timor

Abstract

The metabolisable energy (ME) requirements for maintenance and growth of entire male Bali cattle (Bos javanicus) were determined by regressing liveweight change on ME intake. Cattle were fed either a diet (DM basis) of 52.5% urea-treated rice straw plus 47.5% fresh leucaena forage (Expt 1), or fresh leucaena forage alone (Expt 2). In each experiment, liveweight change and feed intake were measured over 4 weeks, after a 1-week introductory period, and feed constituent digestibilities were measured during the final week. In Expt 1, 10 bulls between 1.5 and 3 years of age and weighing 123.7 ± 11.79 kg (mean ± s.d.) were allocated to DM intakes estimated to provide 0.75, 1.0, 1.25, 1.5, 1.75, or 2.0 times the estimated ME requirement for maintenance (based on calculations made from published CSIRO equations for tropical cattle species other than B. javanicus), with either one or two bulls per treatment. In Expt 2, the bulls were given treatments estimated to provide 0.85, 1.0, 1.4, 1.8, or 2.2 times the ME requirement for maintenance, with two bulls allocated to each treatment. The measured ME requirements for maintenance were 0.42 ± 0.369 and 0.40 ± 0.153 MJ/kg LW0.75.day (coefficient ± standard error, Expts 1 and 2, respectively). The ME requirement for ‘production’ (i.e. positive liveweight change of male Bali cattle under the specific conditions of the experiment) was calculated to be 39.2 MJ/kg liveweight gain in Expt 2. The calculated efficiency of use of dietary ME for production in Expt 2, was 0.34