Effect of herbage allowance on dairy cow performance

A.M. Bryant

Ruakura Animal Research Station, Hamilton

Proceedings of the New Zealand Society of Animal Production. 1980, 40: 50-58

One of four groups of 15 cows was offered an area of pasture each day to provide a herbage allowance of approximately 50 kg DM/cow, while the other groups were offered 75, 50 or 25% of this area. Treatments were applied in three experiments for 28 d in early and mid lactation and 21 d in late lactation beginning 31, 94 and 189 d after calving. In each experiment the yield of milk, fat, protein and lactose, liveweight change, herbage intake and herbage mass following grazing decreased as allowance was reduced. The response in milk composition varied between experiments.

The regression coefficient relating DOM intake and yield of FCM did not differ between experiments and indicated that 1 kg increase in FCM required an increase in DOM intake of 0.54 kg, implying that 1 kg increase in milkfat and milk solids required 13.5 and 4.5 kg DOM, respectively. This relationship, together with the reduction in percentage utilization of pasture as herbage allowance increased, meant that production per hectare of milk and its constituents declined much more than production per cow increased.

Keywords: NZSAPAB;

Last Updated 12-09-1998