Apparent decline in fertility in heifers after repeated oestrus synchronisation with cloprostenol. |
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Authors: | J M Morrell D E Noakes E Zintzaras D W Dresser |
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Institution: | National Institute for Medical Research, Mill Hill, London. |
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Abstract: | Over several years groups of heifers which were repeatedly treated with the PGF2 alpha analogue, cloprostenol, to synchronise oestrus were artificially inseminated. When sperm treatment was optimised, a reduction in conception rate was observed which was related to the number of synchronisation treatments the animals had received. Although factors such as a seasonal reduction in fertility may have contributed to the effect, there appeared to be a decrease in the proportion of animals becoming pregnant after successive synchronisations. Possible explanations for this observation are suggested. |
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