How to Feed and Manage Stallions: Nutrition Guide

Stallions have unique nutrition and behavioral needs because of their high activity level and potential to become aggressive towards herdmates and humans. Often housed alone, stallions can develop stereotypic behaviours that further complicate their management.

Young colts require consistent and skilled handling to make them easier to manage as adult stallions. Owners should acclimate them to human contact from a young age to introduce training and establish safe behaviors towards handlers.

Stallions require secure housing to prevent aggressive behavior, but ample pasture turnout is important to give these horses an opportunity to expend energy and engage in normal grazing behaviour. Pasture is also a cost-effective source of calories for the higher energy needs of stallions.

Proper feeding of stallions also plays a crucial role in their well-being and reproductive success. Breeding stallions have higher nutritional requirements for energy, protein, and antioxidants such as vitamin E and selenium. Stallions in training have even higher energy demands.

This article will guide you through the basics of feeding and managing stallions effectively. For personalized guidance, consult with an equine nutritionist to formulate a balanced nutrition program that best meets your stallion’s needs.

Feeding and Management of Stallions

Whether you are dealing with a high-performance athlete or a breeding stallion, understanding their unique nutritional and behavioral needs is key to their health and well-being.

Stallions have specific dietary requirements that vary depending on their age, workload, and health status. Some of the factors that equine nutritionists look at to estimate a stallion’s nutritional needs include:

• Current Breeding Status: Breeding stallions have higher nutritional needs compared to non-breeding stallions
• Type of Breeding: Stallions used for live cover are presumed to have higher energy needs than those used for artificial insemination
• Natural Activity Level: Stallions that are more active in their everyday life or those with a high-strung temperament have higher nutritional needs
• Exercise Program: Stallions engaged in training programs will expend more calories than those solely used for breeding
• Body Condition: Underweight stallions may have reduced fertility and need to gain weight to meet reproductive goals

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Energy Requirements

The most significant distinction in the nutritional needs of stallions compared to other horses is their higher energy requirement.

As outlined by the National Research Council in the Nutrient Requirements of Horses, the typical energy requirements for a 500 kg (1,100 lb) horse are as follows: ^[5]

• Non-exercising gelding: 16.65 megacalories (mcal) per day
• Non-breeding, non-exercising stallion: 18.2 megacalories (mcal) per day
• Breeding, non-exercising stallion: 21.8 megacalories (mcal) per day
• Breeding, moderately exercising stallion: 26.9 megacalories (mcal) per day

The NRC provides general guidelines based on an average horse. It is important to consider individual differences in activity and temperament when determining your stallion’s calorie requirements.

Maintenance Requirements

Although non-breeding stallions are not expending energy for breeding, compared to geldings they have a higher basal metabolic rate, resulting in a higher calorie requirement.

This is described as an elevated maintenance energy requirement. The main reason for their higher metabolic rate is their larger muscle mass which is a direct effect of testosterone. ^[25]

Breeding Requirements

Breeding stallions have even higher energy requirements due to their reproductive activities. Energy requirements for breeding horses depend on the frequency of breeding and whether they are used for artificial insemination or live cover. ^[5][11][12]

Popular Thoroughbred stallions used for live cover may breed up to 5 times per day during the breeding season. ^[2]

Exercise Requirements

In addition to breeding programs, some stallions are used for competition or are engaged in regular training regimens. The calorie requirement for these horses can be calculated by adding together the energy needed for elevated maintenance, reproductive activities, and their exercise level. ^[11]

Additional Nutrition Requirements

In addition to increased energy requirements, stallions also have higher needs for protein and some vitamins and minerals. ^[5]

The following table shows the daily nutrient requirements for a typical 500 kg (1,100 lb) stallion in three conditions: non-breeding, breeding, and breeding with moderate exercise.

Protein720 grams789 grams837 grams

Vitamin E and selenium requirements are higher for breeding stallions to improve sperm and semen quality and to provide additional antioxidant support. ^[4]

How to Feed Non-Breeding Stallions

Non-breeding stallions require more energy for maintenance compared to equivalent geldings. These horses may have different temperaments and higher natural activity levels, which results in a greater calorie expenditure. ^[5][6][7] However, the main reason behind the increased calorie and protein requirements is their higher muscle mass and the effects of testosterone.

Housing conditions can also impact the nutritional needs of these horses. For instance, a high-strung stallion housed in a large pasture might use more energy than a relaxed stallion confined to a stall.

In general, more active stallions will need more calories to maintain optimal body condition. For a non-breeding stallion, the ideal body condition score is between 5 – 6 on the 9-point Henneke scale. ^[4]

Providing an average-quality forage can typically meet the energy requirements of non-breeding stallions. When choosing hay for your non-breeding stallion, look for hays that provide a moderate amount of protein (~10%), and energy (~2.0 Mcal per kg dry matter).

If you are unsure whether your hay meets your stallion’s nutritional needs, you can submit a sample for analysis to determine its nutritional content.

Sample Diet

The following example feeding program is intended for a 500 kg (1,100 lb) non-breeding stallion at maintenance (not exercising) with normal body condition.

Although forage can typically meet the energy and protein needs of non-breeding stallions, a forage-only diet will be deficient in several vitamins and minerals. ^[5]

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Horse owners should include salt in their stallion’s daily ration and also offer free-choice loose salt to ensure sodium requirements are met. Adequate salt intake also supports hydration and reduces the risk of colic.

How to Feed Breeding Stallions

Breeding stallions need roughly 20% more energy in their diet than non-breeding stallions to account for reproductive activities. For an average 500 kg (1100 lb) horse, the energy requirement is approximately 21 Mcal per day. ^[5]

Maintaining good body condition is particularly important in breeding stallions to support breeding performance. Although not extensively researched in horses, studies in humans show that excessively high or low body condition can impact fertility. ^[8][9]

The ideal body condition score for breeding stallions is between 5 and 6 on the 9-point Henneke scale. ^[10][11]

Sample Diet

The following example diet is intended for a 500 kg (1,100 lb) breeding stallion at maintenance (not exercising) with normal body condition.

Energy Sources

This example diet uses high-quality forage along with beet pulp and oil to meet the elevated energy requirements of breeding stallions.

When choosing a hay for your breeding stallion, look for a hay with higher protein (~13%), and energy (~2.25 Mcal/kg) content. Grass hay harvested at an early growth stage, or mixed hays (i.e. timothy/alfalfa or orchard/alfalfa) are palatable, high-protein options for breeding stallions.

If your forage is not sufficient to keep your stallion in good body condition, add supplemental feeds to bridge the gap. Beet pulp is a highly fermentable fiber that provides slow-release calories and supports hindgut health. Other energy-dense fibre sources to consider are:

• Soybean hulls
• Alfalfa cubes or pellets
• Wheat bran

Mad Barn’s W-3 Oil is also added to this sample feeding program to provide an additional source of cool calories. Oils can be top-dressed on forages and feeds to increase the energy density of the diet.

Feeding an oil that contains omega-3 fatty acids can further support reproductive performance in breeding horses. The DHA found in W-3 Oil has been shown to enhance sperm characteristics, including motility and total sperm count. ^[18][19]

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Protein Sources

Breeding stallions need adequate protein and amino acids in their diet to support the production of high-quality semen. A protein deficiency can lead to reduced fertility, among other health problems.

If your horse’s hay has low protein content (less than 8% crude protein), consider increasing pasture access. Pasture grass is a cost-effective way to meet your stallion’s energy and protein needs while providing stallions with an opportunity to express their natural behaviours.

Alternatively, alfalfa hay, cubes, or pellets can be used to meet protein requirements. Other high-protein feeds for stallions include:

• Soybean meal
• Flaxseed meal
• Canola meal

For example, a stallion on an 8% crude protein hay would need to be fed 500 grams (1 lb) of soybean meal or 1.5 kg (3.3 lb) of alfalfa cubes to ensure protein requirements are optimally met.

Transitioning to a Breeding Diet

Prior to breeding season, consult with an equine nutritionist to determine whether your stallion’s diet should be adjusted to support breeding activities. To meet the vitamin E and selenium needs of breeding stallions, start supplementing these nutrients at higher levels at least three months before the breeding season begins.

When transitioning non-breeding stallions to a breeding program diet, keep in mind that dietary changes must be implemented gradually to prevent digestive disturbances. Forage changes, such as adding alfalfa hay, should be made over at least 10 – 14 days to reduce the risk of colic.

Consider the following transition schedule when making forage changes:

• Days 1 – 3: 75% current hay; 25% new hay
• Days 4 – 6: 50% current hay; 50% new hay
• Days 7 – 9: 25% current hay; 75% new hay
• Day 10: 100% new hay

Introducing beet pulp, rice bran, or any other fiber source into a horse’s diet should follow a similar gradual transition schedule.

Fat supplements also need to be added slowly to allow your horse’s digestive system to adapt. Start with 1 – 2 oz (30 – 60 mL) of oil and increase the amount every 3 – 4 days until you reach the desired feeding rate.

Additional Supplements for Stallions

The best way to support your stallion’s health and semen quality is by feeding a balanced diet that provides adequate energy, protein, fiber, vitamins and minerals.

Once your stallion’s diet is balanced, you may consider other supplements to support reproductive health and breeding performance. Several supplements, including antioxidants, omega-3 fatty acids, and CBD have been researched for their effects on fertility, behavior, and welfare in stallions.

Antioxidants

Antioxidants are important compounds that neutralizing free radical damage to cells, helping to maintain overall health. The antioxidants vitamin E and selenium are particularly important for supporting semen quality in horses. ^[5][14]

Other antioxidants, such as vitamin C and L-carnitine may also help to reduce the number of abnormal sperm in stallions with low semen quality. ^[15]

L-Carnitine supplementation in subfertile stallions has also been shown to improve characteristics such as sperm motility, count and membrane integrity. ^[16][23]

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Omega-3 Fatty Acids

Research indicates that dietary supplementation with omega-3 fatty acids, particularly docosahexaenoic acid (DHA), can enhance semen quality in breeding stallions. This improvement is attributed to improved lipid composition in semen. ^[17]

Improvements are usually observed in stallions with poor semen quality, and it is not clear whether there will be a significant effect on the breeding performance of stallions with already good semen quality. ^[11] More research is needed to determine the optimal supplementation protocol for omega-3 fatty acids to support semen quality.

Mad Barn’s W-3 Oil provides 1,500 mg DHA and 1,500 IU of natural vitamin E per serving. Feeding W-3 Oil can offer the combined advantages of omega-3 fatty acids and antioxidant supplementation.

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• Skin & coat condition
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Cannabidiol (CBD)

Supplementation with cannabidiol (CBD), a non-psychoactive component of the hemp plant, is an emerging area of research in stallion management. CBD is purported to have a positive impact on stallion behavior, potentially reducing aggression and making these horses easier to handle.

In one study, young stallions receiving CBD supplements for 70 days exhibited fewer instances of biting compared to a control group.

Additional behavioral modifications were noted, such as an increase in low-pitched vocalizations and a higher frequency of Flehman’s responses. ^[22] In stallions, the Flehmen response is commonly associated with detecting the scent of a mare’s urine to determine her reproductive status, such as whether she is in estrus and potentially ready to mate.

Other studies have found that CBD supplementation does not affect spermatogenesis (sperm production), testosterone levels, or libido. ^[20][21]

Stallion Management

Breeders and stallion owners must carefully balance their stallion’s welfare with management practices to ensure the safety of handlers and other horses.

In the wild, stallions typically exist within a social structure, either as the sole male among a band of mares or within bachelor groups comprised solely of stallions. But domesticated stallions are often housed in isolation to reduce the risk of injury. ^[13]

However, social deprivation can be counter-productive, leading to increased aggression and development of stereotypic behaviours such as wood chewing or weaving. ^[12]

Some strategies to reduce stress and improve the welfare of stallions include:

• Allowing physical contact between stallions housed in adjacent stalls by constructing partitions with vertical metal bars that enable their head, neck and limbs to fit through ^[13]
• Allowing young stallions to keep contact with preferred group mates beyond two years of age, even if just for a few hours per day ^[13]
• Providing ample time on pasture or on a dry lot to allow for more voluntary activity, which may improve mood balance
• Splitting their daily feed ration into multiple small meals to keep stallions occupied while also minimizing feed waste
• Avoiding high-starch grains to reduce the risk of digestive upset, which can contribute to aggressive behaviour ^[11]

Management of Colts

Colts are defined as young male horses, typically under the age of four years, before they reach full maturity. After they turn four, they are referred as stallions, so long as they have not been castrated.

Young colts have the same nutritional needs as fillies (young female horses). However, as colts reach puberty, shifts in hormone levels can lead to behavioral changes, requiring changes in how these horses are managed.

Puberty in colts typically begins at around 83 weeks of age (approximately 1.5 years old), marked by changes in levels of hormones, such as luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone. ^[1][3]

Testosterone is a steroid hormone produced by Leydig cells of the testes. While its primary function is to support sperm development, it also influences expression of sexual behaviour. As your colt approaches puberty, you might observe behavioral changes indicative of this hormonal shift, such as increased aggression and mounting behavior within the herd.

Management Changes

To mitigate the risk of injuries associated with aggressive behaviors, it is common practice to house colts individually from the age of 2 years. ^[13] However, this isolation can inadvertently exacerbate aggressive behaviour, making them more difficult to handle.

Horses are social creatures and thrive in environments where they can interact with other horses. Their natural inclination is to live in herds, where they establish complex social structures and form bonds that are crucial for their mental and emotional well-being.

Horses evolved as prey animals and herds were important for protection, offering safety in numbers to deter predators. Additionally, contact with other horses allows these animal’s to express natural behaviors, such as mutual grooming.

When kept in isolation, horses may develop behavioral issues due to stress and a lack of stimulation. Equine behaviorists recommend providing opportunities for social contact, whether through shared turnout time, over-the-fence interactions, or other forms of contact with appropriate companions.

Effective management of colts also involves ensuring they become accustomed to human interaction early on. ^[13]

Castration

For those not planning to breed their colts, castration can help make them more manageable and easier to train. It is recommended to castrate horses between six months and one year of age.

Consult with your veterinarian to prepare your colt for the procedure. Ensure they are in good health with appropriate deworming and immunizations, especially vaccination against tetanus.

Males that are gelded at an older age may continue to exhibit aggressive or sexual behaviours. If left intact for too long, up to 65% of geldings continue to express undesirable behaviours. ^[24]

Summary

• Breeding and non-breeding stallions have higher requirements for energy and protein compared to geldings.
• Increased energy requirements can generally be met by feeding high quality forage or supplementing with alfalfa hay.
• Fiber-rich feeds such as beet pulp can also be added to provide more energy. Oils rich in omega-3 fatty acids also provide calories while supporting sperm quality.
• To support fertility and overall well-being, ensure your stallion is meeting all of his vitamin and mineral requirements, particularly for the antioxidants selenium and vitamin E.
• Stallions should be handled by people familiar with their unique psyche.
• Facilitating social interactions through group turnout or stalls that allow contact with other horse may reduce aggression and stereotypic behaviors over time.

For personalized advise on the feeding and management of your stallion, submit their diet online for a free consultation with our expert team of equine nutritionists and veterinarians.