Voluntary intake and digestion of ryegrass straw by llama × guanaco crossbreds and sheep

Publisher Website
Google Scholar
Abstract
SUMMARY: The voluntary feed and water intakes of five llama × guanaco crossbreds (New World camelids) and five sheep, and their abilities to digest various feed components and to utilize nitrogen, were compared using a diet of threshed ryegrass straw in New Zealand in 1987.The camelids ate more than the sheep, but intakes were similar relative to metabolic live weight (mean 37·6 g dry matter/kg W0·75 per day). They drank 0·62 times as much water as sheep per kg W0·75, and 0·57 times as much per g DM intake (P < 0·05). Mean apparent digestibilities of dry matter (47.7%), energy (41·6%) and cell-wall fractions (48·4%) were similar in both species, in spite of the sheep selecting a higher-N component of the diet. Variation in digestibility (e.g. organic matter digestibility) among individual sheep was inversely associated with the percentage of cell-wall constituents consumed. The faeces of camelids contained a significantly higher proportion of particles longer than 0·5mm than those of the sheep (17 v. 11% total DM), indicating a slightly larger threshold to passage from the forestomachs in the camelids.All animals were in negative N balance during the trial, but net loss of N was less in the camelids than in the sheep (27·6 and 49·5 g N/100 g N intake, respectively; P < 0·05), because of lower urinary N excretion (36·5 and 60·3 g N/100 g N intake, respectively; P < 0·05) of the camelids. The results suggest that camelids may be better suited than ruminants for production from poor-quality feeds, especially if water supply is limited.