The Effects of Straw Withdrawal on Some Rumen Parameters in Sheep Fed High Concentrate Diet

Abstract

A study was conducted to investigate the effects of sudden withdrawal of straw in a feeding regime comprising of high concentrate and straw. Five Suffolk sheep, with average weight of 69±5kg (Mean + standard deviation) were fed a high concentrate diet with straw ad libitum for six weeks. At the end of the sixth week ruminal fluid sampling was done to determine the diurnal variation in ruminal pH, ammonia and volatile fatty acids. Straw was withdrawn from the feeding regime for the following three weeks when the sheep were maintained on high concentrate alone. At the end of the three weeks, ruminal fluid sampling was done and the samples were analysed for the same parameters as before. The two sets of data (before and after the withdrawal of straw) were compared by two­ tailed students’t-test using a Statview computer application. It was found that, removal of straw from the diet led to significantly lower ruminal pH (P<0 .0 11. total VFAs (P <0.05}, Acetate (P<0.05), butyrate (P<0.05), ciliate protozoa counts (P<0.001) at various sampling hours. Also, there was significantly higher propionate (P<0.05) and ammonia (P<0.001) when straw was withdrawn compared to when straw was offered. It is hereby concluded that long term adaptation to high concentrate feeding alone may not be sufficient in the maintenance of a stable intra-ruminal condition and that incorporation of low quality roughage in high concentrate feeding regime is desirable