The Veterinary Record, Vol 145, Issue 19, 551-554
Copyright © 1999 by British Veterinary Association

Field trial of a planned breeding regimen for dairy cows, using gonadotrophin-releasing hormone and prostaglandin F₂

¹ Intervet UK Ltd, Science Park, Milton Road, Cambridge BS40 5DU
² ADAS Bridgets, Martyr Worthy, Winchester, Hampshire

A planned breeding regimen, using gondadotrophin-releasing hormone (GNRH), prostaglandin F_2' and a second dose of GnRH, followed by a fixed time insemination, was evaluated in comparison with a negative control on eight commercial dairy farms in the south of England. Fertility data were collected from the 220 cows in the planned breeding group and from 220 matched control cows inseminated at observed oestrus. The planned regimen induced visible oestrus in the vast majority of the cows, and serving the cows at this oestrus reduced the calving to conception interval by 15 days, resulting in 12 per cent more cows being pregnant by 125 days after calving, and 6 per cent more by 150 days. The results from the individual farms suggested that more benefit may be derived from using the regimen in herds with only average fertility indices. There was also evidence to suggest that the second GnRH injection was important, even in cows that came on heat and were served before the fixed time insemination.

This article has been cited by other articles:

				D. J. Brusveen, A. P. Cunha, C. D. Silva, P. M. Cunha, R. A. Sterry, E. P. B. Silva, J. N. Guenther, and M. C. Wiltbank Altering the Time of the Second Gonadotropin-Releasing Hormone Injection and Artificial Insemination (AI) During Ovsynch Affects Pregnancies per AI in Lactating Dairy Cows J Dairy Sci, March 1, 2008; 91(3): 1044 - 1052. [Abstract] [Full Text] [PDF]

				A. R. Rabiee, I. J. Lean, and M. A. Stevenson Efficacy of Ovsynch Program on Reproductive Performance in Dairy Cattle: A Meta-Analysis J Dairy Sci, August 1, 2005; 88(8): 2754 - 2770. [Abstract] [Full Text] [PDF]