Breeding The Problem Mare With AI

Achieving pregnancy via artificial insemination (AI) of a problem mare can be a challenging endeavor, said Juan Samper, DVM, MSc, PhD, Dipl. ACT, of Langley, British Columbia, in his presentation at the 2008 American Association of Equine Practitioners convention, held Dec. 6-10 in San Diego, Calif. However, he added, if the proper diagnostic and treatment approaches are taken, the chances for success can be improved.

The solution for a problem mare is rarely natural cover either by hand breeding or pasture breeding, he said. "In my opinion, a mare that fails to become pregnant by AI with good semen quality and does so by natural cover without human intervention is an example of poor or inadequate breeding management by the personnel performing the AI," said Samper.

Proper breeding management involves three basic fundamentals:

  • Diagnostic procedures to determine the soundness of both male and female.
  • Necessary therapies both before and after breeding.
  • Determination of the optimal time of insemination.

Often overlooked when breeding a problem mare by AI, Samper said, is the stallion. Mare owners often study pedigree and performance in depth when selecting a stallion, but they often pay little or no attention to the horse's semen quality. Research has shown there is a great range in the fertility of stallions with cooled or frozen semen. In addition, he added, AI breeding should be approached under the assumption that one is dealing with semen that is of mediocre or poor quality. It is highly important that insemination of the problem mare be performed only once and as close to ovulation as possible.

In discussing what constitutes a problem breeder, Samper said that age can often be a factor. "Mares in their midteen years start to have a reduction in their fertility potential and, therefore, must be considered potential candidates for repeat breeding," he noted.

Here is how Samper describes a problem breeder: "I consider a mare a problem breeder when she has been bred in two consecutive cycles with good-quality semen and at the appropriate time. Signs that a mare is a candidate for potential problems could include one or all of the following: 1) irregular interovulatory intervals (too long or too short); 2) presence of free fluid (in the uterus) before and/or after insemination; 3) a significant increase in the amount of uterine edema (fluid swelling) after insemination; or 4) presence or persistence of marked endometrial edema post-ovulation."

Samper then went into detail concerning the approaches that are available to veterinarians for treating the above conditions. A recurring theme was that there must be a thorough analysis of the problem mare's breeding history and an in-depth examination of her overall reproductive health. In the wake of that approach, Samper said, both veterinarian and owner must dedicate themselves to proper treatment and close observation. Knowledge of physiology, pathology, and pharmacology are imperative in order to diagnose problems, implement appropriate therapies, and monitor the response to treatment.

He concluded with this comment: "Mare owners and veterinarians must realize that breeding a problem mare is a challenging procedure that requires dedication and knowledge of several areas of veterinary medicine and strict adhesion to basic and sound medical principles. The constant and persistent use of sound techniques and clinical practices will result in the establishment of pregnancy in many of these difficult mares. However, poor practices or not enough dedication will result in frustration for both owners and veterinarians."

About the Author

Les Sellnow

Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at or by calling 800/582-5604.

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