Published online by Cambridge University Press: 02 September 2010
In three successive experiments 32, 30 and 32 autumn-calving, single-suckled cows were subjected to individual planned weight reductions over winter on silage-based diets with various levels of concentrate supplement. At a similar level of weight loss, milk yield and calf gain were increased when protein supplements of low rumen degradability were given. On average, the inclusion of 0·75 kg fish meal in the diet improved calf gain by 0·13 kg/day. Results are discussed in terms of the effect of protein supplement on the efficiency of use of body reserves.