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A foal and mare at the CSU Equine Reproduction Laboratory
Mare Breeding Services

Mare breeding services at the ERL include breeding by live-cover or by artificial insemination with fresh, shipped-cooled or frozen-thawed semen. Mare breeding services are provided on an outpatient (trailer-in) or inpatient basis (mare housed at the Equine Reproduction Laboratory). All services are charged on a per-procedure basis.

In order to determine the optimal time of breeding, when mares are in heat, they are examined with transrectal palpation and ultrasonography as frequently as deemed necessary based on the method of breeding. Mares being bred with natural cover or artificial insemination with fresh semen are generally examined every other day while they are in heat.

Mares being bred with shipped-cooled semen are generally examined on a daily basis while they are in heat. Mares being bred with frozen-thawed semen are generally examined on a daily basis when they first enter heat and then two or three times daily when a pre-ovulatory follicle develops. After breeding, mares are examined for pregnancy 12 or 14 days after ovulation.

Routine hormone treatments are administered as necessary to bring mares into heat (i.e. prostaglandin) and to hasten ovulation (i.e. human chorionic gonadotropin or deslorelin). In addition, uterine treatments (i.e. antibiotic therapy and/or uterine lavage) are performed as deemed necessary based on transrectal ultrasonography examinations (i.e. presence of uterine fluid) or other diagnostic techniques (i.e. uterine culture cytology).​

Learn more about breeding mares.

Information and Contract

Equine Reproduction Laboratory
ERL Giving Fund
Contact Us:
​3101 Rampart Road
Fort Collins, Colorado 80523-1693

​(970) 491-8626

(970) 491-7005