The Horse's Heat - when the mare's hormones become noticeable!

A loud squeal echoes across the paddock. With warmer temperatures and more daylight, spring again noticeably lures the mare's hormonal household to the surface. Many horse owners then tell of bitchy or ticklish characteristics of the animals that can make handling and sometimes even riding difficult. Others hardly notice their horse's rossy period. In fact, this circumstance varies from animal to animal. In any case, there are interesting facts about this, which make the topic quite extensive. We have summarised the most important details for you.

The Horse's Heat - Definition

It is an indication that the female horse is ready to conceive or mate. Many mares show symptoms that are easily recognisable to the stallion, such as flashing (opening and closing of the pubic area under the tail).

As mentioned above, this condition in the horse is triggered by hormones. These are produced by follicles in the ovary. Ovulation occurs towards the end of the equine period. The ovum is released from the mature follicle. It then travels from there via the fallopian tube into the uterus. This period is the late rut. If you want a foal, this is the best time to have a broodmare covered by a stallion or inseminated by a veterinarian. Result: pregnant mare.

If the horse is not covered, everything will return and the mare will be in heat again at normal intervals.

Duration of the "exceptional" state

The length of the horse's heat varies from about 3 - 7 days. In the regular course, the cycle repeats itself every 21 days. During the dark winter months, the animal does not show any pronounced horse characteristics and normally no new follicles are formed. This is because the cycle is dormant due to limited daylight.

The very first "rossiness" appears at about two to two and a half years of age. From this point on, sexual maturity begins. Once a horse has reached a proud age, it often no longer shows any rutting behaviour throughout the year.

So you recognize the horse's heat


- Increased urination

- Standing with hind legs apart

- Lifting the tail or laying the tail to one side

- Flashing (see above)

- Mucous discharge

- Possibly behavioural abnormalities e.g. bitchy, clingy, ticklish, tense etc....

- Signs become more pronounced when the stallion is close by

These characteristics show up differently from horse to horse.

In order to test whether a broodmare is in heat, a test stallion is used in studs, for example. It is not uncommon for horses in heat to react to geldings or other mares with symptoms.

If a mare is inseminated and not covered by natural insemination, the veterinarian must routinely examine the uterus with an ultrasound.

This will help determine the exact stage of the cycle and when the animal will be in heat.

Interesting and important:

Even the mare that is already pregnant may initially still show signs of being in heat. However, ovulation is suppressed during pregnancy.

If the broodmare has been pregnant for a longer period of time, the veterinarian should always carry out a pregnancy examination in order to detect a possible loss of foal in time.

Failure to come into heat

- age-related

- Silent heat (normal cycle, but hardly noticeable symptoms)

- Too lean or too fat horse (be careful: the nutritional condition also regulates!)

- Pathological changes (cysts, tumours).


If you have doubts, it makes sense to consult a vet.

If a healthy animal (e.g. a brood mare) does not get in heat, hormone treatment may help.

Too much of a good thing

Unfortunately, there are also mares whose behavioural patterns are very extreme during the heat. These mares show themselves to be unfocused, constantly under power, defiant and even stubborn under saddle.

In the big sport, drugs are sometimes used to suppress the recurring cycle pattern.

Before this, however, it is important to rule out that other influences have triggered this "misbehaviour", e.g. unsuitable equipment, rider errors or pain in the back or limbs.

Once this has been clarified, the following options are available to curb the "too much":

- Hormone treatment (e.g. Regumate)

- Immunisation (vaccine specifically stops the cycle)

- alternative medicine with homeopathy or herbal medicine (e.g. monk's pepper)

- Surgical removal of the ovary

- Placement of vitreous implant


Monk's pepper is popularly fed for hormonal fluctuations. It reduces the sex drive and has a balancing effect on the horse. Monk's pepper is also known as chaste mud or chaste tree. It was already known in the Middle Ages for its libido-dampening effect.


Monk's pepper is freely available, herbal and does not harm the animal.


In extreme cases, it may not be enough.

So if more is needed, many equine athletes turn to Regumate. The hormone preparation is often used for horses with persistent grouse behaviour. In this way, performance can continue.


Regumate is a quick fix for a short period of time and can be self-administered by the owner.


Expensive for prolonged use and actually not recommended as a permanent medication.

Vaccination is not yet fully developed in this country. There is still a lack of data on side effects and whether later fertility is affected.

The implant is simply a glass ball. The veterinarian inserts it into the mare's uterus shortly after the heat. The subsequent heifers do not occur.


Simple, long-term and cheap solution without chemicals. Can be removed again by the doctor at any time.


Only about 66-70% of mares respond.

Last but not least, surgery.


The permanent rosacea is lifted, tumour and cyst formation in the ovarian area are no longer possible.


Expensive and surgery is also a risk for the animal!


If you notice an "increase" in sexual drive in your four-legged darling, you don't have to resort to chemicals. For many mares, the administration of monk's pepper flowers is often enough to get mood swings under control. The rule is: consult your vet beforehand to rule out any illnesses! If he knows your horse well, he can certainly help you with the right method.

It would also be "horse(wo)manlike" if you simply slowed down with your mare during the breeding season. After all, understanding is part of a good partnership.