Country View Equine Clinic
1346 S. Fish Hatchery Rd, Oregon, WI 53575

Phone: (608) 291-0505 Fax: (608) 291-0855

M-F: 8AM-5PM, 24/7 Emergency Services


Notes on Equine Reproduction

Mare Owner
April to June is peak breeding time naturally; mares will settle best during this time frame.

Prime breeding age for mares is 4 - 10 years of age. Mares over 13 years who have never foaled may be more difficult to get in foal.

2 weeks out of heat, 1 week in heat. In heat time varies from 4 - 10 days. Mare will ovulate last day or two of heat.

Natural cover usually breeds mare every other day to cover ovulation time. Artificial insemination (AI) watches follicular growth on ovary and times breeding near ovulation.

Best to do during the heat cycle before the cycle in which you want to breed her.

Artificial Insemination
Mare will need to be ultrasounded to determine ovulation time.
Start ultrasound on 3rd day of cycle
a. Mare shows heat well and owner knows it is the third day.
b. Mare is placed on Regumate® for 10 days then given Lutalyse® and ultrasounded 5 days later. Start Regumate on Monday or Tuesday to insure breeding time on week days, and avoid shipping troubles over weekends.

When follicle is 35 mm or more in size we can induce ovulation with HcG. This will better time insemination.

Mare owner orders semen when told follicle is large enough to induce ovulation; semen will usually arrive 12 - 24 hours after order.

Semen will be evaluated on arrival.

Sperm will live 48 - 72 hours when shipped correctly. Fertility decreases continually after 24 hours.

Mare will be bred one to two times then ultrasounded again to insure ovulation has occurred.

Pregnancy can be confirmed 14 - 21 days later.

Short cycling
PGF (Lutalyse®) can be given to bring a mare into heat. Must be given at least 5 days after the last day she was in heat in order to work. It will not work in mares that are in spring transition.

Questions to ask stallion owner
Request information sheet about semen volume, concentration etc.

What days do you collect on?

Is stallion showing at the same time?

Will there be an early end to his breeding season?

How many mares are booked?

What container is used?

Pay every shipment? Get 3 shipments with one fee?

Guaranteed live foal? Pay again next year if not pregnant?

Is semen checked every time before shipping?

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