Is your mare possessed with a split personality? Sweet as an angel one day then more like the wicked witch of Oz the next? Many dedicated gelding owners vow to never own a mare. Their most common objection concerning mares is, "Every time they come into heat they’re impossible to work with and they’re just too unpredictable!" Even many long time mare owners can be heard grumbling about their mare’s roller coaster moods and erratic performance by often jumping in with the classic explanation for their problems, "She must be in heat."

Mares don’t actually have PMS, premenstrual syndrome, but they do share the same hormonal caused mood swings as humans. However, humans and horses seem to experience the rise and fall of estrogen and progesterone differently. In humans PMS occurs when estrogen levels have dropped and progesterone begins to rise. This swing of increased progesterone levels contribute to complaints such as water retention, low energy, and emotional instability in women, while high levels of estrogen produces a sense of well being and vigor. On the other hand, most mare owners grumble about

"Marish attitudes" during the 10 days or so before ovulation when estrogen levels rise and peak just before ovulation. Once the mare ovulates and she goes out of heat, progesterone begins to rise and will peak about 10 days later at which time the mare will usually be more pleasurable to work around.

Many temperament and performance problems are linked to the estrous cycle in mares, but with careful observation you may find that her problems actually don’t occur during estrus itself, but rather may indicate the anestrous phase of her cycle. In fact it often turns out that your mare’s poor behavior has nothing to do with her reproductive cycle at all!

Logging Behavior Changes

While the majority of mares undergo a fairly normal swing in their moods during their monthly estrus cycles most remain manageable. In fact, this change in behavior is extremely helpful to the breeder in determining when the mare should be bred. However, if your mare’s behavior is dangerous in anyway or makes handling her on a daily basis a living hell, it is time to find out exactly what is going on with her. This will require you keeping a daily log; along with your veterinarian and anyone else who may be involved with your mare’s daily care and training. Depending on your situation, it may well include your trainer, riding instructor, the stable owner, your farrier, and the person responsible in providing your mare’s daily feed.

Compose your records to be as detailed as possible rather than summarizing your comments. Instead of merely stating that she was "good today" list what was so good about the day. "Attitude was good when girth was tightened, didn’t pin her ears," or "humped her back when cued to go forward." Make your list as complete as possible. Was she responsive to cues? Was she unusually spooky today and what did she react to? Not only record how she is while being handled but also at liberty in her stall or while turned out to pasture. How does she react to other horses? After keeping your daily log for at least a full month, preferably two months, you and your veterinarian can look for any patterns and assess whether or not your mare’s behavior is or is not related to her reproductive cycle.

Hormone Roller Coaster

Mares can differ widely in their estral behavior. Some show very little outward signs of heat while others can be quite dramatic. Somewhat akin to handling a stallion, a small number of mares can even become extremely oppositional to everything in their environment. Others only appear dull and unresponsive to cues from the rider. It has also been noted that a very few mares do actually experience some pain at the time of ovulation. Symptoms can range from various degrees of colic to basic tenderness and touchiness over the back and loins. In any case, the mare will usually react the same way from one cycle to another.

In the mare there is a fluctuation of hormones that directly affect her behavior. As her heat cycle progresses she naturally becomes more aggressive, irritable, distracted and domineering. Individually, each mare may vary in the intensity and type of behavior she exhibits," explains Dr. Paul Schaumberg D.V.M., of Kootenai Veterinary Hospital in Libby, Montana. In the horse’s natural environment this can be quite important. "These behavior changes benefit her by temporarily moving her position up in the herd status and increasing her chances of being bred.

Contributed By: Mirror KB Ranch