EFFECT OF GRAIN PROCESSING ON MILK PRODUCTION AND COMPOSITION [French]

摘要

The effect of grain processing (ground [G] or roiled [R]) was analysed on 22 multiparous cows in mid-lactation used in a 2*2 latin-square design experiment During each 3-wk period, cows were offered a diet composed of a mixture of corn silage, grass silage and brewer's grain (75/15/10, ad libitum), of hay (ad libitum) and of dried sugar beet pulp (2 kg/d). The quantities of concentrate (75% barley and 25% meal) were calculated according to milk production level and did not vary during the trial. In group G, 100 g/d of buffer compound was added to the diet. Grain processing had effect neither on time spent to eat the concentrate (4.1 min/kg on average) nor on milk yield (33.1 and 32.7 kg/d, respectively, in group G and R) nor on milk fat content (38.4 and 37.7 g/kg, respectively). pH of rumen juice and concentrations of volatile fatty acids were identical in the 2 groups.