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Factors affecting the monetary return from programmes for synchronising oestrus in dairy cows with gonadotrophin-releasing hormone and prostaglandin F
  1. R. A. Laven, BVetMed, PhD1,
  2. J. Stewart, BVSc2 and
  3. C. Dyer, BSc, PhD3
  1. 1SAC Veterinary Services, St Mary’s Industrial Estate, Dumfries DG1 1DX
  2. 2Intervet UK, Walton Manor, Walton, Milton Keynes, Buckinghamshire MK7 7AJ
  3. 3ADAS Gleadthorpe, Meden Vale, Mansfield, Nottinghamshire NG20 9PF


Synchronisation, using a combination of gonadotrophin-releasing hormone and prostaglandin F injections, is commonly used to control the reproductive cycle of dairy cows. A simple model that could predict the monetary return from synchronisation would be a valuable tool in determining whether it would be worthwhile. This study used data from three controlled clinical trials to investigate the effects of six factors (interval between calving and synchronisation, 21-day submission rate, number of cows synchronised, average age, pregnancy rate of non-synchronised cows and season) on the return from synchronisation. The results suggests that the herd’s submission and pregnancy rates, the time between calving and synchronisation, and the number of cows synchronised can all significantly affect the return from synchronisation, but only time since calving significantly affected the return in all three trials. They also suggest that there is no simple linear relationship between these factors and the return from synchronisation.

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  • Dr Laven’s present address is Farm Services Department, IVABS, Private Bag 11222, Palmerston North, New Zealand

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