Abstract

A recent grazing experiment at Ruakura with dairy cows involved in each of 3 years, 8 farms of 6.48 ha. Linear regression procedures were used to derive relationships between milkfat yield to 31 December, amount of feed on the farm at various times, length of rotation during winter months, and average herd live weight and condition at calving. Fat production was closely related to feed on the farm during July to September but not to feed present in May, June, October or November, or to live weight and condition at calving. The amount of feed present in August or September was not significantly related to that present in May. Feed present in September increased as the area grazed each day by the herd increased in May, and decreased in July and August. For a given amount of feed on the farm during July to September, early calving herds produced more milkfat per cow and per hectare by 31 December but at a lower level per day than late calving herds.

HH, Meyer, TG Harvey, and JE Smeaton

Proceedings of the New Zealand Society of Animal Production, Volume 43, , 87-90, 1983