Comparison of two estrus synchronization programs in a large, confinement-housed dairy herd.
OBJECTIVE
To compare pregnancy rates, seasonal effects, and economic benefits of 2 estrus synchronization programs for a confinement-housed dairy herd.


METHODS
Prospective cohort study.


METHODS
200 lactating Holstein cows.


METHODS
Cows eligible for breeding were palpated per rectum and randomly assigned to 2 treatment groups during 4 seasonal periods. Cows in one group (Ovsynch) received injections of gonadotropin releasing hormone (GnRH) on day 0, prostaglandin F2 alpha on day 7, and a second injection of GnRH on day 8. Cows in the other group (PP) that had a palpable corpus luteum were given prostaglandin F2 alpha. Estrus detection was not performed on the Ovsynch cows, which were artificially inseminated at a predetermined time after the second GnRH injection. Cows in the PP group were observed for signs of estrus, and only those that were detected in estrus were inseminated.


RESULTS
Pregnancy rates and insemination rates were significantly improved for cows in the Ovsynch group, compared with cows in the PP group.


CONCLUSIONS
The Ovsynch program was an economically advantageous method for controlling reproduction that resulted in pregnancies without the need for estrus detection.
Britt
J S
JS
Department of Medical Science, School of Veterinary Medicine, University of Wisconsin-Madison 53706-1102, USA.
Gaska
J
J
D000822:Animal Husbandry / Q000191:economics / Q000379:methods; D000818:Animals; D002417:Cattle / Q000502:physiology*; D015331:Cohort Studies; D003612:Dairying / Q000191:economics / Q000379:methods*; D015237:Dinoprost / Q000494:pharmacology; D004971:Estrus / Q000187:drug effects / Q000502:physiology; D004973:Estrus Synchronization; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D006799:Housing, Animal; D007315:Insemination, Artificial / Q000662:veterinary; D007774:Lactation / Q000502:physiology; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D011897:Random Allocation; D012621:Seasons
D007987:Gonadotropin-Releasing Hormone; D015237:Dinoprost