Effects of different concentrate levels on milk yield, feed intake, live weight change, health and reproduction in dairy cows

In a 5-year feeding trial, different amounts of concentrates were fed to four groups, each with 24 cows which were at least in their second lactation. Throughout the whole lactation the concentrates were fed according to weekly milk yield exceeding a threshold yield of 16, 12, 8 or 4 kg milk per cow per day, respectively. The forage comprised maize silage and/or beet pulp silage and grass silage fed ad libitum. Average daily intakes of concentrates for the groups were 2.9, 4.7, 6.4 and 8.1 kg. The corresponding daily milk yields were 18.4, 20.6, 21.2 and 21.5 kg, respectively. Only the group with an average daily concentrate intake of 2.9 kg and a milk yield of 18.4 kg differed significantly in milk yield from the other three groups. No influence of the amount of concentrates on milk fat content was found. Milk protein content increased from 3.27 percent to 3.42 percent with increasing amounts of concentrates. In the two groups with higher intakes of concentrates the intake of forage was lower. Daily liver weight gain increased with the intake of concentrates. The amount of concentrates had no influence on health and reproductive performance