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Zesterra® for Horse Breeding

The success of your breeding program depends on keeping your horses in prime condition year-round. This is essential for both mares and stallions. Even common, everyday stress can take its toll on the overall vitality of any horse if it’s not properly nourished and conditioned. When you add in the rigors of breeding season (for stallions) and the gestational period (for mares), this stress can double or even triple.

Combatting the physical manifestations of stress by keeping a balanced pH in the gut is the first step towards helping your breeding stock stay strong, healthy throughout the year. During every horse breeding season, horse owners look forward to getting the best breeding performance from their broodmares and stallions. With good management, effective nutritional practices, and other science-based practices, your mares will ideally conceive on the first breeding and then deliver a healthy foal. Here are some tips to help you achieve your goals during the horse breeding season.

How to Reduce Stress During Breeding

Stress is a negative reaction to any stimulus that disrupts mental and physical equilibrium. It usually causes a release of hormones like cortisol, increasing levels throughout the body. All horses experience stress before, during and after breeding. Stress can occur due to the long transportation times to the breeding shed, confinement in a stall, poor feeding, interaction with strange horses (live cover), a change of environment, and an increase in heat.

Stressful situations can lead to low reproductive efficiency as the increase of cortisol inhibits reproduction in all horses including those used for leisure, racing, work, and breeding. Heat stress may result in irregular reproductive cycles and can affect whether or not she conceives immediately. Similarly, heat stress can make stallions have lower sperm counts and overall semen quality. As a horse breeder, it’s vital to recognize the triggers and signs of stress and to know the best ways to reduce it.

Some of the most prominent behavioral signs of stress include:

  • Scratching on fences or stable walls
  • Cribbing
  • Kicking at stalls or fences
  • Flaring nostrils
  • Fidgeting
  • Restlessness
  • Raising the tail
  • Defecating frequently
  • Pawing on the ground
  • Repetitive head movements

The main triggers of stress in horses include:

  • The improper timing for feeding
  • Poor feed quality or improper feed ratios
  • Stress during reproduction
  • Isolation due to individual housing
  • Administering various types of medication
  • Experiencing extreme heat or cold

Feed-related stress is one of the most common issues experienced among the equine population. When horses aren’t permitted to have free-choice forage through grazing or consistent access to hay during the day, it could lead to gastric ulcer formation. Horses can also experience gastrointestinal disorders if they don’t have access to feed for even one to two hours. In mares, this food-related stress can cause a reduction in reproductive efficiency.

Using a 100% natural supplement like Zesterra® can help reduce the occurrence of equine ulcers in these key ways:

  • The ingredients in this supplement neutralize stomach acid.
  • It balances the pH in the stomach and prevents excess acid from moving into the sensitive lining of the gut.
  • Zesterra® prevents Leaky Gut Syndrome and conditions like colic.

What's the Best Way to Improve Fertility for Horse Breeding Programs?

Some ways you can improve fertility for horse breeding include the following:

  • Improve Nutrition: Good nutrition will provide the nutrients required to produce adequate sperm cells and increase the horse’s libido. Also, researchers have discovered that increasing the amount of omega-3 fatty acids in a horse’s diet improves fertility when artificial insemination is used. The omega-3 fatty acids make the sperm’s membrane more fluid and allow it to adapt to the stress of freezing and cooling. Feeding an adequate amount of omega-3 fatty acids with antioxidants can enhance reproduction in mares. Supplementation of these nutrients can also enhance pregnancy outcomes.
  • Maintain Adequate Health: Make sure the stallion is on a proper de-worming program. An older stallion will also benefit from taking a supplement like Zesterra®, which will help him absorb nutrients better and avoid dehydration and stress. The stallion should also receive all necessary vaccinations at least 30 days before the start of the breeding season to prevent side effects of vaccinations from influencing breeding performance. A good vaccination program is also necessary to help eliminate the contraction of infectious diseases — particularly when live cover is used, or the stallion is taken to a breeding center.
  • Monitor Reproductive Efficiency: Keeping accurate breeding records in addition to a proper breeding examination before the breeding season will help locate any performance issues early. For instance, stallions need to be examined for semen quality and reproductive health prior to the breeding season.

How to Conquer the Most Common Health Issues for Horse Breeding Operations

Doing the following can help ensure successful breeding operations:

  • Preventing the Spread of Disease: When horses are shipped into or out of a breeding facility, the likelihood of spreading diseases and germs increases. Respiratory diseases and viruses like equine herpes can spread rapidly through a brand of broodmares. To prevent the spread of disease, it is helpful to keep the barn size small. Instead of having one large barn, utilize two or three smaller ones. Separate the visiting broodmares from the farm’s resident band. The best way to prevent disease is to vaccinate the horses periodically and prepare a place to quarantine horses as soon as it is observed that there are any signs or symptoms of disease.
  • Reducing Stress: Due to the side effects of transportation such as stress and dehydration, some horses don’t deliver the expected breeding results. That’s why it is important to enhance a horse’s diet with an all-natural supplement like Zesterra®. It helps neutralize the acid in the stomach, balances the pH level and increases the absorption of nutrients that are essential for top breeding performance. Once this balance is restored, appetite increases and water consumption returns to normal.


Stallions have a difficult job. Producing viable sperm requires that a stallion is in top shape at all times. Some stallions have tremendous production expectations placed on them during peak breeding season. Considering it takes sperm approximately 60 days to mature before it’s ready for ejaculation, this means that even before breeding season begins they must be receiving adequate nutrition and have a low-stress environment.

Even a minor illness or stressful event can have an effect on his sperm’s viability, resulting in low sperm counts or even infertile sperm with poor morphology. They also must be handled carefully — rough handling, isolation or confinement (resulting in boredom) and environmental, nutritional, or social stress can all have a negative impact on sperm production and quality.

Single-hemisphere studs get an average of 6 to 7 months of “down time” to recover before breeding season begins again. In the case of stallions standing at stud for both hemispheres, they may only get a few weeks between the two seasons. A stud that stands in both hemispheres produces semen for an average of 11 months a year. This may not seem like a major issue, however, like mares, stallions have fertility cycles that change with the seasons.

Stallions experience a natural decline in sperm count in the fall and winter months — in fact, a decrease of approximately 50%. Because they are experiencing not only a lower drive to breed but also a lower sperm count, the year-round stud is put under a great deal of physical and mental stress. At this time it’s vital that facility managers don’t overburden him and ensure that he is receiving (and able to assimilate) the needed nutrients to continue working under these stressful conditions.


A mare must be in top condition going into breeding season. If she’s not, there is the very real chance that she’ll experience reduced fertility and may not conceive. This isn’t only frustrating but can be expensive.

There are three vital things that can help ensure a successful conception:

  • Is she in good body condition? A body condition score of 5 – 7 will help ensure she’s ready to conceive and carry a foal.
  • Are her heat cycles regular? Irregular heat cycles can indicate underlying issues that may have an impact on fertility.
  • Is she clear of uterine infections? Infections can prevent the embryo from successfully implanting or even cause birth defects.

In addition, a routine of regular vaccinations, hoof maintenance, dental care and deworming should be maintained year-round. This should always be done a few weeks in advance of breeding so that the vaccines can take effect and any necessary healing from dental work can occur.

Many breeders will start exposing their broodmares to increasingly longer light cycles prior to breeding season. This stimulates her to have regular cycles and ovulate consistently. This can require that she be indoors for the majority of the day in the late winter and early spring months. This type of confinement can lead to boredom and stress. Reducing stress through enrichment and ensuring she has a neutral stomach pH can help prevent the development of ulcers and immune system compromise.

Ultimately, a mare that has an optimal body condition score and a healthy immune system is more likely to conceive and carry to term a healthy, strong foal. Gut health is an integral part of this equation and must be part of the central focus of a good mare maintenance regimen.

Boost Your Horses' Breeding Performance

Get more details about our natural supplement that helps horses deliver better breeding. Speak to one of our Zesterra Specialists about your horse breeding challenges, and let us show you how to get better results starting today.

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