Body composition of young sheep. 3. Effect of intake and pasture species on body composition and ruminal development of Merino lambs

Abstract

Four-month-old Merino lambs were fed at three levels on pelleted lucerne or tall fescue hay of similar organic matter digestibility for 42 days. Measurements were made, after slaughter, of carcase and internal organ composition and rumen characteristics. Regressions of body component weights and of percentage composition on empty body weight (EBW) were calculated. Lambs fed lucerne either to maintain weight or to gain weight had more water, protein and ash at the same empty body weight than lambs fed fescue. Although lambs fed lucerne produced a lower acetate : propionate ratio in the VFA, there were few differences in rumen characteristics of lambs on the two feeds. There was evidence that lambs fed lucerne made more efficient use of digestible energy intake for energy storage.