Trends in monthly milkfat production of cows in seasonal dairy
herds in New Zealand
K.L. MacMillan, H.V. Henderson
Ruakura Animal Research Station Ministry of Agriculture and
Fisheries, Hamilton
Proceedings of the New Zealand Society of Animal Production.
1987, 47: 57-59
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.
Keywords: NZSAPAB;
Seasonal trends; milk volume; milkfat; milkfat test
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Last Updated 03-05-1997
