Section 2
Chapter 1,246

Reproductive performance in dairy cows following postpartum treatment with gonadotrophin releasing hormone and/or prostaglandin: a field trial

Etherington, W.G.; Bosu, W.T.; Martin, S.W.; Cote, J.F.; Doig, P.A.; Leslie, K.E.

Canadian Journal of Comparative Medicine: Revue Canadienne de Medecine Comparee 48(3): 245-250


ISSN/ISBN: 0008-4050
PMID: 6383577
Accession: 001245152

Holstein Friesian cows (305) were given either 250 .mu.g gonadotrophin releasing hormone (GnRH) or saline on day 15 postpartum followed by 500 .mu.g cloprostenol or saline on day 24 postpartum. Four treatment groups were formed using random allocation: group 1, placebo (day 15)/placebo (day 24); group II, GnRH (day 15)/placebo (day 24); group III, placebo (day 15)/cloprostenol (day 24); group IV, GnRH (day 15)/cloprostenol (day 24). Double blind techniques were used during the follow-up period. Rectal palpation, to assess uterine involution and ovarian activity was performed just prior to each treatment and again at 28 days postpartum. In addition blood samples were collected at 15, 24 and 28 days postpartum for measurement of plasma progesterone. There were no significant differences among treatment groups with respect to services per conception, number of heats detected before 1st service and culling for infertility. Cows treated only with GnRH had an increased calving to 1st estrus and calving to 1st breeding interval, and tended to have an increased calving to conception interval. Treatment with cloprostenol significantly decreased calving to conception and calving to 1st observed estrus intervals. Treatment with GnRH on day 15 postpartum resulted in a significant increase in the subsequent incidence of pyometra and prebreeding anestrus. Cloprostenol treatment on day 24 potpartum resulted in a decreased incidence of pyometra, regardless of GnRH treatment and a decreased incidence of prebreeding anestrus in GnRH treated cows compared to cows receiving only GnRH at day 15 postpartum. In the herd studied, GnRH treatment at day 15 postpartum was generally detrimental whereas cloprostenol treatment at day 24 postpartum was generally beneficial to reproductive performance.

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