How to manage mares in season

How to manage mares in season


Managing Your Mare's Season

Mares are seasonal breeders, they will typically only come into season between the months of March-October but this can vary between horses. This is due to the fact that their reproductive cycles are influenced by various factors, including changes in daylight length, environmental conditions and higher grass nutrient levels. The main reason for this seasonal breeding behaviour is to optimise the chances of survival and successful reproduction for both the mare and her offspring. Foals conceived outside of this time frame would be unlikely to survive in the world post birth, due to unfavourable environmental conditions.


Mares have a relatively short reproductive cycle. On average, mares will come into season every 21 days, her seasons typically last for an average of 5-7 days. Mares will typically go through one transitional cycle at the start of the breeding season and one transitional cycle at the end of the breeding season, which can result in erratic oestrus behaviours.


Signs of your mare coming into season


  • Tail raising
  • Passing frequent small amounts of strong smelling urine
  • Increased interest in stallions (or geldings)
  • Aggression/irritability 
  • Anxiety
  • Increased spooky & reactive behaviours
  • Unpredictable behaviour
  • Becoming difficult to ride or handle
  • Easily distracted
  • Lethargy/Decreased energy levels
  • Loss of appetite
  • Sensitivity to touch
  • Adopting a breeding position


On some occasions mares will not show any signs of being in season, which is known as a silent heat. This can be frustrating for breeding purposes as it makes ovulation much more difficult to pinpoint. 

Ingredients to avoid

Inflammation of the uterus when your mare is in season can be very uncomfortable and painful, therefore it is a good idea to avoid inflammatory ingredients which may contribute to the worsening of this. Some ingredients to look out for include:



Anti-inflammatory ingredients can be added to the diet to help manage pain and inflammation. Some good anti-inflammatory ingredients for mares include rosehip and garlic. Raspberry leaf is also a great ingredient for mares that struggle with their seasons; not only does it help regulate hormone levels but also helps maintain smooth muscle tone in the uterus to help your mare feel more comfortable.


If your mare is uncomfortable it is a good idea to adapt her workload accordingly. A horse who is in pain will not be able to perform at their best and pushing her too hard can result in injury to both horse and rider. For these reasons many owners of competition mares will make use of synthetic hormones to ensure their mare’s cycle does not interrupt their competition schedule.


Extra care should also be taken when grooming and tacking up as your mare may become more touch sensitive while she is in season. If your mare experiences considerable amounts of discomfort whilst in season it is a good idea to consult with a vet, as there may be an underlying reason for this that needs to be addressed. A vet can carry out a scan of the reproductive tract to see if there are any underlying conditions and may be able to prescribe medications that will help with this.


Managing Appetite Reduction

Many mares will lose their appetite while in season. This is common and not a huge concern. If your mare struggles to consume adequate amounts of forage this may make her more susceptible to developing gastric ulcers. In this case we would recommend adding something with a high mucilage content to the diet such as chia seeds or marshmallow root. This will form a protective gel-like layer over the sensitive stomach lining to protect it from excess acid exposure and minimise the risk of developing gastric ulcers.


Managing behavioural changes

Behavioural changes are very common during seasons. Many mares may become aggressive, depressed or more reactive as a result of changes in hormone levels and discomfort associated with her season. In many cases this can make your mare much more difficult to handle and ride.


Owners often resort to using synthetic hormones such as Regumate as a means of dealing with their mare’s difficult or hormonal behaviours. When fed continually throughout the breeding season, Regumate will surpress oestrus and stop your mare from coming into season. If used strategically, synthetic hormones such as Regumate can also be used to help regulate a mare’s season, if she suffers from irregular seasons. This is quite common in the breeding industry as irregular seasons make it a lot more difficult to pinpoint ovulation (the time at which your mare will be fertile). 


Ideally, using synthetic hormones to manage behavioural changes in mares should be used as a last resort. There are many natural remedies now available to help support these mares.


Long term use of synthetic hormones in mares has been linked to reduction in fertility meaning it may be difficult for mares to successfully come into foal following use of the drug. It can also take a while for her cycle to become regular again following withdrawal of synthetic hormones. 


Care should be taken if using synthetic hormones such as Regumate to help manage your mare’s seasons. Women of child bearing age should avoid handling the drug and anyone who does handle Regumate should always wear appropriate PPE as it has been linked to infertility in humans.


If you are looking for a suitable natural alternative for helping to manage your mare’s mood, we have you covered! Moody Madam supplement contains the perfect blend of hormone balancing and calming ingredients to help support your mare through her seasons and maintain the mellow mindset you know and love.

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