Pregnancy Rates in Tranquilized Maiden Thoroughbred Mares

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

doi:10.1016/j.jevs.2010.02.004

« Previous Next »Journal of Equine Veterinary Science
Volume 30, Issue 4 , Pages 187-190, April 2010

Pregnancy Rates in Tranquilized Maiden Thoroughbred Mares

T.L. Blanchard, DVM, MS, Dipl ACT
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
- Reprint Requests: T. Blanchard, DVM, MS, Dipl ACT, Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4475.
J.A. Thompson, DVM, DVSc, Dipl ACT, Dipl ACVPM (Epidemiology)
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
S.P. Brinsko, DVM, MS, PhD, Dipl ACT
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
D.D. Varner, DVM, MS, Dipl ACT
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
C.C. Love, DVM, PhD, Dipl ACT
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
J. Ramsey, BS, MA
- Hill ‘n’ Dale Farm, 4252 Spurr Road, Lexington, KY
A. O'Meara, BS
- Hill ‘n’ Dale Farm, 4252 Spurr Road, Lexington, KY

Abstract

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) (χ² = 1.048; P > .05). We concluded that tranquilization of maiden Thoroughbred mares immediately before mating did not adversely affect fertility.

Keywords: Equine, Maiden mare, Thoroughbred, Tranquilization, Fertility