Milk production and composition as influenced by soybean meal, rapeseed meal or rapeseed cake in concentrates for dairy cows

Twenty-four Red-and-White cows during the first trimester of lactation were assigned, based on the analogue principle, to 3 groups with 8 animals per group. The experiment was divided into 4 periods of 30 days each. Cows were fed grass silage and maize silage, fresh brewers' grains, and feed concentrates containing soybean meal (SBM) (group 1), rapeseed meal (RSM) (group 2) and rapeseed cake (RC) (group 3). The proportion of individual protein feeds was similar (7.08, 8.45 and 9.99%), with feed intake of 407, 510 and 618 g/day, respectively. Dry matter intake did not differ significantly and averaged 18.14 kg/day, with concentrate intake of 6.04, 6.43 and 6.19 kg/day, respectively. The yield of milk adjusted for fat and protein content was 21.77, 21.47 and 22.62 kg/day and did not differ significantly. There were no significant differences in protein and lactose content or in daily production of these components in milk. Compared to rapeseed cake, rapeseed meal significantly increased the whey protein content of milk (P<0.01), and compared to soybean meal it significantly increased milk clotting time (P<0.01). No significant differences were found in the content of other N fractions, milk acidity or milk density. There were no differences in plasma glucose, total protein, triglyceride or urea contents. It is concluded that giving soybean meal, rapeseed meal and rapeseed cake to cows with an average lactation yield of 6,000-6,500 kg milk and daily yield of 22-24 kg milk does not significantly modify cow yields, components or physical traits of milk. Giving rapeseed cake to the cows can increase milk fat content and daily synthesis of milk.