Managing fertility in the New Zealand dairy herd
C.W. HOLMES
Institute of Veterinary, Animal and Biomedical Sciences, Massey
University, New Zealand
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Proceedings of the New Zealand Society of Animal Production 2001. 61:
135-140
Effective mating management remains crucially important to
pastoral milk production systems in New Zealand (spring calving or
autumn calving). The incidence of most diseases has decreased since the
1940s, but infertility, especially the 'anoestrous problem', has
increased despite increased use of hormonal treatments and in
association with genetic selection for increased yields of milk. The
regular need to treat a high proportion of cows with hormones because
they are not cycling at the start of mating should be seen as a sign of
mismanagement in the system (genetics, health or feeding). 'Good herd
management' should be used to achieve good fertility with minimal use of
hormone treatments; this will include: -good prevention and control of
all diseases; all heifers must reach target live weights and puberty at
12 months; all cows must be at BCS 5 at calving, and be fed generously
in early lactation; excellent heat detection must be maintained for the
entire AI mating period; infertile cows must be culled, and fertility
included in the Breeding Worth. These aspects of 'good management' must
be seen as essential factors in the maintenance of good herd welfare,
and in the sustainable production of the high quality, clean and green
dairy products required by the world markets. A number of commercial
herds are showing that good fertility and good productivity can be
achieved with minimum use of hormone treatments, with present-day cows.
However, for some strains of cows, good feeding management may be
impossible on a diet of grazed pasture.
Keywords: NZSAPAB;
dairy; reproduction; milk yield; management
Last Updated 7/08/01
