The effect in sheep of physical form and stage of growth on the sites of digestion of a dried grass

I .The efyect of grinding and pelleting artificially dried S 24 perennial rye-grass (LoZium perenne L.) cut at two stages of maturity on sites of digestion of organic matter, energy and carbohydratc were studied in sheep with re-entrant intestinal cannulas fitted at the proximal duodenum and terminal ileum.Chopped and pelleted grasses at both stages of maturity were each given at 900 g dry matter/zq h to each of five sheep; the two forms of the early-cut grass were also given at 1400 g dry msltter/zq h each to four of the fivc shccp. 2.With the carly-cut grass, grinding and pelleting caused a depression in digestibility of organic matter (low level, P < 0 .0 5 ; high level, P < woor), lo the proportion of the digested organic matter disappearing before the small intestine (low level only, P < 0.05) and significantly increased that disappearing in the caccum and colon (low level, P 4 0.05 ; high level, P < OYJOI).Increase in stagc of maturity significantly depressed digestibility of organic matter ( P < 0001) with both forms of grass and, with the chopped form, significantly increased the proportion of digestible organic matter disappearing in the caecum and colon (P < 0.01).Increase in level of feeding of the pelleted, early-cut grass significantly lowered organic matter digestibility ( P < O .O ~) , reduced the proportion of digestible organic matter disappearing in the small intestine ( P 4 005) and increased that occurring in the caecum and colon ( P < 0.05). 3.With the early-cut grass, grinding and pelleting caused 3 depression in digestibility of gross energy only at the higher level of intake ( P < O O I ) , and reduced the proportion of apparently digestible energy disappearing before the small intestine (IOW level, P < 0.001 ; high level, P < 0.05).Only with the chopped form did stagc of maturity affect sites of energy digestion; with the more mature grass disappearance of energy in the reticulo-rumen declined