Abstract

Records from cows in herds which were production tested by the Auckland and Taranaki Livestock Improvement Associations from 1960 to 1984 were used in regression analyses to estimate trends in milkfat (mfat) production each month from August to May. The average annual increase in production was 0.84 kg mfat/cow in Auckland compared to 0.75 in Taranaki. This meant that over the period from 1960 to 1984, the estimated increases in production were 20.2 and 18.0 kg mfat/cow in Auckland and Taranaki respectively. In Auckland 14.2 kg of this increase occurred in September, October and November. The increase in Taranaki in these 3 months was 10.6 kg mfat/cow. Annual increases in production per cow would be greater if the rate of decline in daily production during summer (from December to February) could be reduced. No consistent increases in production have occurred during the autumn because of highly variable seasonal factors.

BJ, Ridler, LJ Stachurski, IM Brookes, and CW Holmes

Proceedings of the New Zealand Society of Animal Production, Volume 47, , 43-44, 1987