Mare Heat - What to Look For

How to Tell if a Mare is in Heat

©  2008 Cherry Hill   © Copyright Information

Hi Cherry,

I feel really stupid asking this, but...I just bought my first horse after 3 years of riding a GELDING. But my horse is a mare. How can I tell when she goes into heat? Is there anything special I should do for her? Please help. Thank you so much.   K

Hi K:

     Mares are seasonally polyestrous, that means they cycle (have estrous cycles) many (poly) times per year but only during breeding season (seasonally).  Depending where you live, this usually means during late spring, summer and early fall.  During those seasons the mare will have a heat cycle (estrous cycle) about once every 21-23 days and during that cycle, she will have from 3-8 days of standing heat (estrus, note the difference in spelling between the cycle and the standing heat) where she would be receptive to a stallion for breeding. 

Each mare is so different, just like women, about how they express their heat. Some have PMS - Pouty Mare Syndrome!  Not an official term or syndrome, but you get the idea.  Some mares are grouchy just before estrus, some during and some after.  One of my mares behaves almost like a gelding.  One is a real "hormone queen" and can get quite anxious and irritable during her heat cycle.  The others are more normal in their expression - not a big behavioral change.

Now that it is winter, make note of your mare's anestrus behavior - that refers to the time period when her reproductive system is quiet or shut down for the winter, she is not cycling.  Get to know the "winter mare" personality.

Then as spring approaches, jot notes on a calendar.  You might notice that a pattern emerges of days when your mare is sweet, cooperative and easy to work with and other days when she is impatient, preoccupied with something other than what you are doing with her, or downright grouchy and mean. 

If you have a mare that is extreme, you might want to plan your training sessions around her worst days.  Extra grouchy mares might kick, bite or swish their tails when you groom or handle them - so be on alert for this.  However, it is very likely, your mare will show very little change at all when she is in heat.

You don't need to do anything special for her when she is in heat.  Just be sure, like always, that you provide her with her normal ration, free choice mineral salt, water, and daily exercise.  If you were to leave a mare cooped up that is in heat, when you do take her out, you might have your hands full.