Pasture type in relation to live-weight gain, carcass composition, iodine nutrition and some rumen characteristics of sheep IV. Some rumen characteristics of the sheep

Abstract

1. A preliminary study has been made of some aspects of rumen development and fermentation patterns in groups of ewes and lambs fed perennial rye-grass (P), perennial rye-grass plus white clover (P + C), short-rotation rye-grass (S) and short-rotation rye-grass plus white clover (S + C).(2) For ewes there was a significant effect on the weight of the rumen contents from the grass species. The treatment (P) which caused the lowest live weight gave the highest rumen contents weight. There were also significant pasture effects on empty live weight both from grass species differences and from the addition of clover.3. No difference in rumen dry-matter percentages was found between the four groups.4. There was no significant difference in the concentration of volatile fatty acids in the rumens of the P and S fed ewes but the addition of white clover had a significant effect.5. The S + C sheep had a lower proportion of acetic acid, a greater proportion of propionic and butyric acids and greater development of the rumen papillae than the P animals.6. With the lambs there were no significant differences in rumen characteristics caused by grasses but the addition of white clover caused a greater live weight and a reduction in the weight of the rumen contents.7. These results are discussed in relation to present knowledge of ruminant metabolism.