How forage characteristics influence behaviour and intake in small ruminants: a review

Small ruminant production systems vary widely, from high producing dairy goats to suckling ewes on rangelands. However, in all environments feed characteristics influence animals' motivation to eat, dietary choices and ultimately nutrient intake. This review highlights the common feed factors that influence feeding behaviour and intake, although their expression and consequences depend on the environment. The main characteristics of feeding behaviour are described in terms of the satiation process and motivation to eat. The main feed factors that influence intake are then reviewed. The relationship between the nutritive value of forages and their voluntary intake is well established. The relationship between nutritive value and palatability of feeds is discussed in the light of recent work on how feed characteristics are learned. At pasture, ease of prehension of the sward influences rate of intake and dietary choices. On heterogeneous resources, animals grate selectively and choose a diet of higher quality than that on offer. Recently more effort has been made to model intake and foraging decisions. Management of the sating circuit has become an important factor in a heterogeneous environment. In conclusion, modelling and predicting intake for small ruminants in different environments are briefly discussed.