Pregnancy Rates in Tranquilized Maiden Thoroughbred Mares Academic Article uri icon


  • In Thoroughbred breeding, it is sometimes necessary to tranquilize a maiden mare to accomplish safe breeding by natural service. To determine whether tranquilization adversely affected fertility of maiden mares, pregnancy rates achieved in 792 matings of 531 maiden Thoroughbred mares were evaluated. One hundred sixty-three matings were accomplished after administration of a tranquilizer cocktail (20 mg acepromazine, 100 mg xylazine, and 10 mg butorphanol tartrate, injected intravenously), whereas 598 matings were accomplished without tranquilization. Pregnancy rate/cycle did not differ between maiden mares tranquilized before (64%; 105/163) and mares not tranquilized before mating (69%; 434/629) (2 = 1.048; P > .05). We concluded that tranquilization of maiden Thoroughbred mares immediately before mating did not adversely affect fertility. 2010 Elsevier Inc.

published proceedings

  • Journal of Equine Veterinary Science

author list (cited authors)

  • Blanchard, T. L., Thompson, J. A., Brinsko, S. P., Varner, D. D., Love, C. C., Ramsey, J., & O'Meara, A.

complete list of authors

  • Blanchard, TL||Thompson, JA||Brinsko, SP||Varner, DD||Love, CC||Ramsey, J||O'Meara, A

publication date

  • January 1, 2010 11:11 AM