Problem Breeding Mare Table Topic (AAEP 2012)

Problem Breeding Mare Table Topic (AAEP 2012)

The problem breeding mare table topic at the 2012 American Association of Equine Practitioners' convention, held Dec. 1-5 in Anaheim, Calif., focused on challenges practitioners face when breeding subfertile mares.

Photo: Anne M. Eberhardt/The Horse

The problem breeding mare table topic at the 2012 American Association of Equine Practitioners' convention, held Dec. 1-5 in Anaheim, Calif., focused on challenges practitioners face when breeding subfertile mares. Attendees discussed one of their biggest nemeses, the anovulatory follicle (an ovulation abnormality that results in an egg remaining trapped in the follicular cavity and not entering the oviduct, where fertilization occurs), with regards to its potential association with inflammation (endometrial or systemic), prostaglandins (either administered or from inflammation), or endocrine disorders. Veterinarians must differentiate anovulatory follicles from large, mid-diestrus (between one estrus period and the next) follicles.

Attendees also discussed ovulation induction agents, with half of the practitioners there preferring to use deslorelin acetate and the other half preferring to use human chorionic gonadotropin (hCG) hormone, with variable doses of each. Several practitioners expressed a preference for deslorelin in artificial insemination situations using frozen semen, due to a perceived more predictable ovulation window. Because of cost, many practitioners in the audience said they still use compounded deslorelin despite there being an FDA-approved product on the market.

With regards to measuring mares' progesterone levels, some practitioners questioned its value to the client, in relation to cost. Stall-side progesterone assays lack sensitivity at lower levels and are thus less useful.

Attendees also discussed oviductal dysfunction. Five practitioners in the room were familiar with applying prostaglandin E2 to the oviducts laparoscopically. This procedure, in theory, improves oocyte and embryo transit to the uterus but is currently cost-prohibitive in some areas due to the price of the prostaglandin E2.

Finally, attendees discussed dormant beta-Streptococcus infection (the most common bacteria causing endometritis, inflammation of the innermost lining of the uterus). In dormancy, the bacteria's slow metabolic rate resists antimicrobial treatment. New research suggests a method for "activating" these bacteria, allowing for successful treatment. The practitioners discussed biofilm formation by other types of bacteria (e.g., Pseudomonas aeruginosa). Treatments for these infections include mucolytic agents (which dissolve mucus) such as N-acetylcysteine and dimethylsulfoxide and chelators such as Tricide and Tris-EDTA.

This table topic was moderated by Kristina Lu, VMD, Dipl. ACT, a theriogenologist at the McGee Fertility Center at the Hagyard Equine Medical Institute in Lexington, Ky., and Lloyd Kloppe, DVM, Dipl. ACT, a theriogenologist at Durango Equine Vet Clinic, in Buckeye, Ariz.

 

About the Author

Kristina G. Lu, VMD, Dipl. ACT

Kristina G. Lu, VMD, Dipl. ACT, practices with Hagyard Equine Medical Institute, Lexington, Ky.

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