Effect of proportion and digestibility of grass-clover silage on feed intake, milk yield, and nitrogen excretion in lactating dairy cows

The aim of the current study was to examine effect proportion and digestibility grass-clover silage on dry matter intake (DMI), milk yield nitrogen (N) excretion in lactating dairy cows. In total, 36 Danish Holstein cows, 12 primiparous 24 multiparous, were included study. At beginning experiment cows average (mean ± SD) 122 81 days (DIM). divided into 9 groups (4 each group) based parity DIM, randomly assigned one four dietary treatments a 4 x Latin square design with replications. differed forage source as follows: 1) low digestible silage; 2) high 3) 4) silage. Different proportions obtained by exchanging maize (30:70 or 70:30 DM basis). digestibilities silages using two differing harvest time, spring growth first re-growth, these expected have digestibility, respectively. periods, all lasting for 3 weeks which 17 d used adaption last sampling recording. Feed water well recorded daily, samples collected determination composition. addition, faeces blood chemical analyses. Replacing increased DMI protein but reduced fat, whereas decreased protein. Milk yields (kg kg energy-corrected (ECM)) not affected diet, probably due increase observed offered grass-clover. Excretion N urine silage, result greater crude (CP) concentration than compared Thus, surprisingly seemed only minor production However, confounded used, different cuts likely clover proportion, could results. Finally, urinary CP concentration.