Feeding the Stallion

Feeding the Stallion
17 February 2020 | Foran Equine

To Maximise Performance and Fertility


Good nutrition and a well-balanced diet play a key role in maintaining a stallion in top health and condition to maximise performance and fertility. Fertility can be one of the traits first affected when nutrition is below the normal maintenance levels and a shortage of any nutrient can have a knock-on effect on fertility. Similarly, over-feeding the stallion can result in obesity, an increased risk of reduced libido and joint problems. Many factors need to be considered when designing a diet plan for a breeding stallion such as body condition, level of activity, temperament and fertility.

Breeding stallions can face considerable reproductive demands. Some first season sires commence covering before they are fully three years of age. In addition, very successful, proven sires can frequently cover up to four mares a day at the peak of the breeding season and may continue breeding into their later years when fertility may be subject to a natural decline.

To support fertility stallions must receive a well-balanced diet. Targeted nutritional intervention, including supplementing with omega 3 fatty acids and optimal dietary antioxidants such as Foran Equine FOR-REPRO Stallion may also be particularly beneficial for certain categories of stallions.

Body Condition

Body condition is an important indicator of a stallion’s nutritional status. The amount of energy (calories) an individual stallion requires during the breeding season can vary enormously.  For example, stallions covering 3-4 times a day will require considerably more calories than a stallion only covering a few mares a week. Similarly, if the stallion is still in full work during the breeding season, as can often be the case with sport horse stallions, this must be considered when designing a diet plan.

A stallion that either has a very low body condition score (BCS) or a very high BCS will not have the stamina, or potentially libido, needed to breed a full book of mares. A BCS of three out of five is generally accepted as ‘ideal’ for a breeding stallion.  Stallions that tend to lose weight or that are covering large numbers of mares may need to start the season with a slightly higher BCS to allow for some weight loss once the season commences. For stallions that are covering more than a few mares a week and those prone to weight loss a specifically formulated stud feed, such as Connolly’s RED MILLS Stud Mix or Cubes, is ideal.

On the other hand, obesity can be a major problem when it comes to a stallion’s libido, fertility and soundness during the breeding season. Stallions that are ‘good doers’ may not require large amounts of hard-feed, although it is critical that they still receive a fully balanced diet. In these situations a balancer, such as Connolly’s RED MILLS GROCARE Balancer, or a high specification supplement, such as Foran Equine Chevinal, will provide a highly concentrated source of amino acids, vitamins and minerals, without an excessive supply of calories.

Temperament & Gastric Health

The stallion’s diet may also need to be modified according to his temperament. Some stallions will get quite highly strung during the breeding season and will run or walk their paddock or box, whilst others will quietly graze and relax. Most stallions will thrive on the traditional grain-based feeds such as Connolly’s RED MILLS Stud Mix or Stud Cubes.  However, stallions that tend to be overly excitable or easily stressed will benefit from feeds that provide energy in a slow releasing format such as Connolly’s RED MILLS Horse Care Cubes, which are high in fibre and oil with lower levels of starch.  The addition of an L-tryptophan based calming supplement such as Foran Equine Nutri-Calm Gel or Syrup can be immensely useful for stallions that tend to be anxious or become easily stressed.

Due to their solitary lifestyle and restricted turnout, especially during the breeding period, stallions can be prone to gastric ulcers. Gastric ulcers can increase the incidence of aggression, stereotypes/vices and self-mutilation. The Connolly’s RED MILLS Horse Care Range has been specifically formulated to help maintain digestive health. As well as being low in starch all feeds in the Horse Care Range contain the unique RED MILLS Nutrition Care package which includes a long-lasting natural gastric acid buffer, protected yeast, and the prebiotics FOS and MOS to help support digestive health.


For a stallion to be considered successful, they must have a good success rate of getting mares in foal.  Despite the importance of fertility little research has been done on the effect of total diet on semen quality, however, a few studies do suggest certain nutrients may be of particular importance to a stallion’s fertility. One such study was recently carried out by a team in Washington State University where they found strong evidence to suggest that the inclusion of the Coenzyme Q10 (Ubiquinol)in the daily diet of breeding stallions improved multiple semen parameters including total motility, progressive motility and viability of spermatozoa.


Omega 3 Fatty Acids

Research has highlighted that omega 3 fatty acids may be beneficial for breeding stallions. Sperm have a relatively high lipid (fat) content and changes in lipid composition of the diet may have implications for sperm physiology. In a recent study researchers found that providing supplementary omega 3 fatty acids to stallions with poor fertility increased the volume of sperm in the ejaculate and the number of good quality sperm in post-thaw semen.

Omega 3 fatty acids act as a natural anti-inflammatory and are also well known for supporting the immune system.  The precursors to omega 3 fatty acids are naturally found in grass, however, because of their busy schedule, many stallions only have limited access to pasture. Therefore, providing additional omega 3 fatty acid may be beneficial. This can be easily achieved by top-dressing the feed with Foran’s Kentucky Karron Oil, a high quality emulsified flaxseed oil containing high levels of omega 3 and 6 in the correct ratio.


Recent research into the use of supplements to aid a stallion’s fertility has focused on the effect of oxidative stress on equine sperm and seminal fluid. Oxidative stress can be defined as a disturbance in the balance between the production of reactive oxygen species (free radicals) and the ability of the body to counteract their harmful effects through neutralisation by antioxidants.

Equine sperm cells are particularly vulnerable to oxidative stress due to the remarkably high concentration of polyunsaturated fatty acids in their plasma membrane; as much as 30% more than other species. This makes them very vulnerable to lipid peroxidation – which follows from exposure to free radicals. Oxidative stress also damages the DNA that resides within the sperm cells and thus, even if the damaged sperm succeed in creating a conception by fusing with the ovum (or egg), the embryo can be so damaged as to prevent it being viable and thus result in early embryonic death and pregnancy failure.

An effective and proven method of combatting the disastrous effects oxidative stress can have on spermatozoa is by including Ubiquinol CoQ10 in the daily diet of the breeding stallion. Foran Equine’s FOR-REPRO Stallion is the only supplement available which provides a quality source of Ubiquinol CoQ10, an essential feed element for normal body function, helping to support maintained semen quality throughout the breeding season. Along with its antioxidant role the active ingredient in FOR-REPRO, is also involved cellular energy synthesis. Sperm cells are highly motile, requiring high rates of energy production and producing potentially damaging free radicals as a result thus increasing the requirement for antioxidants in the daily diet to minimise the potential damage to the fragile spermatozoa.


Why should I include Ubiquinol CoQ10 in my stallions diet?


Horses have evolved over thousands of years as free ranging pasture grazers and can consume herbage for 17 to 20 hours per day. Pasture grasses and legumes naturally contain Ubiquinol CoQ10, so stallions managed with modern husbandry are likely receiving less than the necessary daily intake, particularly if they are actively and regularly engaged in an activity that utilises Ubiquinol CoQ10, like breeding.


What stallions will benefit the most from including Ubiquinol CoQ10 in the diet?


  • Older ageing stallions who may be experiencing a natural decline in fertility
  • Young unproven stallions where reproductive status is unknown
  • Busy stallions who are facing a full book and may suffer from reduced libido during the season
  • Those stallions who are expected to maintain a breeding schedule in both the northern and southern hemispheres
  • Sport horse stallions who are competing and collecting. Stallions whose semen is intended for AI use and whose quality may be adversely affected by the cooling and/or freezing processes that are necessary for transport

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Joint Health

Another common concern for stallions that are frequently covering is joint health, as repeated mounting of the mare or a dummy will place extra stress on the limbs, particularly the hind-limbs. Stallions suffering from hind-limb pain will typically become reluctant to mount and may take several attempts to successfully mount, which further exacerbates the problem. Several management strategies, such as ensuring a suitable surface in the covering shed or adjusting the height of the dummy mare, can help to reduce the strain placed on the hind-limbs during covering. The addition of a specific joint supplement such as Foran Equine Ost-o-Flex , particularly for busy or older stallions, may also be beneficial. Ost-O-Flex is a source of glucosamine, a key component of cartilage, plus MSM and marine collagen to help maintain joint mobility.