Abstract

Short lactation length is one of the main reasons for the low milk yield per cow in New Zealand. This experiment used replicated farmlets to measure the effects of extending the lactation, and feeding extra silage on the dairy farm system. On the 4th April 54 lower yielding cows were dried- off and divided into two equal herds (D). The remaining 64 cows were also divided into two equal herds, and milked for another 54 days (M). Each of the four herds was grazed on a self- contained farmlet, at 2.9 cows/ha. D herds received only grazed pasture (16 kg dry matter (DM)/cow/day allowance), while M herds received pasture (30 kg DM/cow/day allowance) plus silage (5.5 kg DM/cow/day). At the end of the experiment the M system produced 57.7 kg milksolids (fat+protein) per cow, but had lower (P<0.05) average pasture cover (by 584 kg DM/ha) and lower (P<0.001) body condition scores (by 0.33/cow) than the D system. Extra milk can be produced from extra days in milk, but the extra feed required must be planned and monitored very carefully, to prevent losses in body condition and pasture cover.

C, Pinares, and CW Holmes

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 239-241, 1996