Reproductive performance of synchronised lactating dairy cows
Z.Z. Xu, J.R. Burton, L.J. Burton, K.L. MacMillan
Livestock Improvement Corporation Ltd, Private Bag 3016, Hamilton,
New Zealand
Proceedings of the New Zealand Society of Animal Production. 1995,
55: 242-244
The objective of this trial was to evaluate the reproductive performance
of lactating dairy cows following oestrous synchronisation with a
combination of progesterone, oestradiol and prostaglandin. Cycling cows in
11 herds were randomly divided, with restriction to age, calving date,
condition score and breed, into synchronised (n=1332) groups. Those in the
synchronised group were each treated with an EAZI-BREEDŒ CIDR’
capsule for 8 days, with an injection of an analogue of prostaglandin
F2alpha, 2 days prior to CIDR removal. Control cows were left untreated.
Compared to the control cows, those in the synchronised group had a lower
conception rate to the first round of AB (52.9% vs. 64.3%), a lower
conception rate to all AB matings (53.2% vs. 63.9%), an increased number
of AB services per pregnancy to AB (2.0 vs. 1.6), and an increased
percentage of empty cows (7.3% vs. 5.1%). There was no difference
between synchronised and control groups in the percentage of cows pregnant
to AB (81.8% vs. 85.5%) or in the mean day of conception (20 vs. 21 days).
The oestrous synchronisation regime tested in this study caused a reduction
in fertility. This negated some of the potential gains from using such a
treatment programme.
Keywords: NZSAPAB;
oestrous synchronisation; conception rate; fertility; lactating dairy cows
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Last Updated 25-01-1997
