Fix That Cycle

Last Updated on February 26, 2022 by Allison Price

To ease hormonal issues associated with estrus and to plan her breeding, regulate your mare’s cycles.

You can regulate your mare’s fertility by determining when she should have that foal. Another reason is to resolve behavioral issues associated with estrus.

Are you noticing problems with your mare when she is in season? Is her behavior changing during estrus? Her cycle can be controlled.

Heat Cycles: How They Work

Mares are more likely to experience heat cycles in the spring and summer, when the days are longer and hotter. Your mare will experience heat (estrus), for about six days and then go out for fifteen days in a recurring pattern. Her developing follicles secrete the hormone estrogen during heat. She’s also under the influence progesterone (the so-called “happyhormone”).

She acts in ways that attract a stallion because of the estrogen she releases during heat. These behaviors, such as frequent urination and squealing, tail swishing, and threatening other horses, can hinder her ability to train and perform well.

To minimize these behaviors, you may want to regulate her heat cycle. If breeding is your goal, it may be necessary to control when she enters estrus so that you can achieve the desired foaling date. Your veterinarian will be able to help you with heat-cycle management.

Methods of Control

These are some ways to regulate your mare’s heat cycles:

Oral altrenogest. Giving your child this synthetic progesterone every day orally will keep her from going into heat. Heat cycles will return if you stop giving it.

Injectable estrogen. These injections are administered by compounding pharmacies at intervals of one to three times per week. They have different degrees of reliability.

Sterile oil in the uterus. This can suppress estrus for up to 60 days.

Injectable Oxytocin. Daily injections for up to a week (generally at a particular point in the cycle), can keep your mare from heat for up 90 days.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top