Relative growth of incisor arcade breadth and eating rate in cattle and sheep

Abstract

ABSTRACTMaximum eating rate, rmaxin kj metabolizable energy per min, at a given body weight W kg, can be predicted in normally growing cattle when adult body weight, A kg, is known, by the formula of Taylor and Murray (1987) as rmax= 31μ0·86A0·73whereu= W/A is degree of maturity in body weight. When the pattern of normal growth is disturbed by fluctuating levels of food intake, a better prediction can be obtained in terms of incisor arcade breadth. This paper gives the allometric relationship between degree of maturity in body weight,u, and degree of maturity in incisor arcade breadth uD, fo r both cattle and sheep, asuD=u0·29.Combining this allometric relationship with that of Illius and Gordon (1987) gives the following formula for incisor arcade breadth, Du(mm), in the rth species at age,t, in relation to degree of maturity in body weight,uit, and adult body weight,Aikg): Dit= 7·8 uit0·29Ai0·36. Substituting uDand adult arcade breadth, Dadult, foruand A in the formula of Taylor and Murray (1987) gives the following more robust formula for predicting maximum eating rate, namely, rmax= 0·53u3DD2adut.