Effect of Feeding Frequency on Forage Fiber and Nitrogen U T I L I Z a T I O N in Sheep 1

Four crossbred wether Iambs (38 kg) with permanent ruminal and abomasal cannulae were used in a 4 • 4 Latin square arrangement of treatments to determine the effect of feeding frequency (FF) on forage fiber and N utilization. Lambs were offered 900 g of good quality (vegetative) Kentucky-31 tall fescue hay in equal portions either 2, 4, 8 or 16 times daily. Water consumption increased (P<.OS; linear) with increased FF. Apparent total tract digestibilities of dry matter, organic matter and cell wall constituents were not affected (P>.O5) by FF, but apparent total tract digestibility of crude protein decreased (P<.05; linear) with increased FF. Ruminal and postruminal digestion of acid detergent fiber (percent of total tract digestion) differed (P<.05; cubic) among FF treatments. Although N retention was not affected (P>.O5) by FF, increased FF decreased (P<.05; linear) mean ruminal ammonia-N concentrations. Both the quantity of total N reaching the abomasum and the efficiency of microbial crude protein synthesis tended to increase (P>.05) with increased FF. In addition, the daily quantity of microbial N reaching the abomasum was affected (P<.05; cubic) by FF. Ruminal pH was not affected (P>.05) by FF, whereas total volatile fatty acid concentrations (VFA) decreased (P<.05; linear) with increased FF. Responses in molar proportions of individual VFA to FF were variable, and suggest that increasing FF elicits significant changes in the distribution of fermentation end-productg These data are interpreted to suggest that frequent feeding of a good quality forage may enhance the supply of crude protein to the intestine of the ruminant. (