Performance of Small Ruminants Fed Crop Residue Supplemented with Tree Leaves and Shrubs

Abstract

Three experiments were conducted to determine the performance of small ruminants fed crop residue supplemented with tree leaves and shrubs. Experiment 1 was undertaken to determine the chemical composition of eight browse species harvested during the dry and wet seasons of Ghana. Also, the chemical compositions of untreated rice straw (RS), sodium hydroxide treated rice straw (STS) and urea ammoniated rice straw (UTS) were determined. Samples were analyzed for Dry matter, Crude protein, Neutral detergent fibre, Cellulose, Lignin, Ash and in vitro dry matter digestibility. The mean DM value of the dry season browse species (38.9%) was significantly higher (p< 0.05) than that of the wet season species (33 .0%). The mean CP value for the dry season species (17.9%) was however not significantly different (p> 0.05) from that of the wet season species (15.0%). Similarly, there were no differences (p> 0.05) between the other parameters. Crude protein ranged from 12.9% in Khaya to 21.9% in Milletia for the dry season samples and 11.8% in Khaya to 17.1% in Ritchiea for the wet season \ samples. The IVDMD (75.1 and 80%)was highest in Securinega virosa for dry and wet season samples respectively and lowest in Milletia (40.7 and 41.1%) for dry and wet season samples respectively. Experiment 2 compared the effects of ammoniation and browse supplementation on rumen metabolites and rumen degradation in sheep. With the exception of Delonix and Milletia, all the browse species had dry matter degradability (DMD) values above 60% while UTS had a value of 55%. The N degradation characteristics gave a range 50 to 83.5% for the browse species, 47.3 and 60.9% for STS and UTS respectively There were no difference between the mean pH levels and peak ammonia nitrogen levels for animals on STS supplemented with browse and those on UTS. The feeding value of STS supplemented with browse was compared with that of UTS in Experiment 3. Parameters investigated included dry matter intake, liveweight changes and nutrient digestibility. Although the DMI of UTS (433.8g/d) was higher than that for STS with browse, which ranged between 339 to 392.5g/d, the liveweight changes and nutrient digestibilities showed no significant differences (p> 0.05). Straw treated with NaOH and supplemented with browse can help maintain the weights and provide some amount of growth in small ruminants during the dry season.