Nutritive Value of Hyparrhenia anamesa Dominated Natural Pasture and its Impacts on Seminal Traits of Horro Rams

摘要

Evaluation of pasture is often suggested to improve the productive and reproductive performance of livestock and proper utilization of the grazing land. However, this has got little attention in western Ethiopia. Here, a study was conducted to evaluate the nutritive value of Hyparrhenia anamesa grass dominated natural pasture and its impacts on seminal traits of Horro rams, at Bako Agricultural, Technical and Vocational Education and Training College, west Ethiopia. One hectare of grazing land was demarcated and eighteen yearling Horro rams were allowed to graze for a grazing period of 120 days. The biomass yield of the grazing pasture was estimated using multistage systems where pastures were harvested from five quadrates (1 × 1 m size) from within the demarcated grazing land. Chemical composition of the pasture was analysed using standard laboratory procedures. Data on seminal attributes were taken every two weeks during the grazing period. The result showed that natural pasture was poor both in dry matter yield (0.346 t/ha) and Crude Protein (6.07%), lower in in vitro digestible organic matter (54.61% of DM) and high in acid detergent fiber (67.78%). The total ash content and metabolizable energy (ME) were 8.96% and 8.19 MJ/kg DM, respectively. Both head and total spermatozoa abnormalities have showed significant variation across the grazing period. This study demonstrated that the natural pasture dominated with Hyparrhenia anamesa grass cannot support optimal seminal attributes, due to both inadequate quantity and low quality of the pasture mainly during dry period. Overall results suggest the importance of supplementation and/or looking for other management option to enhance the reproductive performance of Horro rams while not further degrading pasture productivity.