The effect of concentrate supplementation on high-yielding dairy cows under two systems of grazing

Abstract

Summary An experiment with 36 high-yielding spring-calving cows studied the effect of 1 or 6 kg/day of concentrates offered to cows on either continuously stocked grazing or rotational strip grazing. A 4 × 4 latin-square design with periods of 3 weeks duration was adopted. Mean yield was 29 kg/day of fat corrected milk (FCM). The continuously stocked cows had higher milk yields, consumed more herbage organic matter, grazed longer, with bites of smaller size and responded less in total intake to the higher level of concentrates than the strip-grazed cows. The higher concentrate treatment increased milk yields but reduced fat contents so that the average response was 0·26 kg FCM/kg concentrate. There was no difference in response to concentrate allowance between grazing treatments. The differences recorded between grazing systems were attributable mainly to differences in green herbage allowance, which was greater with continuous grazing.