Stallion Behavior and Handling: From Management to Ground Manners

Keeping stallions happy, healthy, and appropriately managed requires an understanding of their unique behavior compared to mares and geldings. Stallions often exhibit instinctive behaviors shaped by evolutionary pressures and social dynamics in the wild.

Contrary to their natural environment with established herds and plenty of room to roam, domesticated stallions are often housed alone with limited social interactions.

In addition, breeding in domesticated environments is typically closely managed by handlers and very different from natural mating behaviors.

Limiting a stallion’s ability to express natural behaviors can lead to behavioral problems such as aggression or reluctance to breed. Clear and effective training of “ground manners” and providing adequate housing, turnout and socialization opportunities can help prevent these issues.

While handling stallions can present occasional challenges, effective training and management is key to fostering a positive relationship between stallions and caretakers.

Natural Stallion Behavior

Horses, including stallions, evolved to live in well-defined social groups with ample space to roam around. A stallion’s home range in the wild may be up to 50 km2 (12,355 acres), significantly larger than what is often offered to domestic horses. ^[1]

In the wild, some stallions lead small harems of mares and their offspring, while others form bachelor bands consisting solely of other stallions. ^[2] Harem stallions tend to have higher testosterone levels and spend less time grazing and resting than bachelor stallions. ^[3][4]

Understanding the behavior of horses in the wild can help contextualize stallion instincts and behavior displayed in a domestic setting.

Examples of natural stallion behavior include: ^{[1][3][5][6][7][8]}

• Band Protection: Stallions in harems exhibit protective behavior, defending their mares from outside males and predators
• Social Hierarchy: Dominance fluctuates within a band and depends on factors such as herd composition, availability of resources, a stallion’s willingness to fight or work for a resource, the presence of “allied” horses, and more
• Ritualized Aggression: Stallions often engage in ritualized behaviors, such as posturing, vocalizations, and mock fights, to establish dominance and maintain social order within the band
• Increased Vigilance: In the wild, stallions are among the most vigilant of all the horses in a band. They constantly watch for signs of danger while keeping a close eye on mares in estrus during breeding season

Breeding Behavior

Breeding behavior in stallions encompasses a range of actions and responses associated with mating, courtship, and reproductive activities. These behaviors are influenced by hormonal changes, social dynamics, environmental factors, and individual differences.

The two main breeding strategies that stallions exhibit in the wild are maintenance of a harem and opportunistic breeding. ^[9]

Harems

A harem is a social grouping of mares and their offspring with a single stallion. The stallion engages in pair-bonding and establishes and maintains a territory with their harem. ^[10]

Juvenile males born to the harem will leave either voluntarily or by force of the dominant stallion when they come of age. Juvenile females may be allowed to remain with the band into adulthood.

Stallions who maintain a harem may be more aggressive with other stallions and typically have higher testosterone levels than bachelor stallions. ^[3][4]

Opportunistic Breeding

Also called “sneak” breeding, this breeding behavior is typically conducted by bachelors who have not formed their own harem. It involves opportunistic breeding of mares or fillies in another stallion’s harem.

Stallions attempting to engage in this type of breeding may attempt to “disguise” themselves by demonstrating juvenile behaviors such as play fighting. ^[9] They may also try to present themselves using the body language typically seen in mares to avoid suspicion. ^[9]

Equine Courtship Behaviors

Stallions in a harem closely monitor and tend to mares in estrus (“heat”). Common monitoring behavior includes examining a mare’s urine and feces and performing the Flehmen response to detect whether she is in estrus.

This behavior often correlates to the estrus cycle of mares. After smelling the urine or feces of a mare in estrus, the stallion typically “marks” their territory by urinating or defecating. ^[11]

Once estrus has been detected, the stallion then tends the mare, following her closely and monitoring her behavior to determine the optimal time to breed. ^[9]

Reproductive Behaviors

Stallions instinctively recognize signs that a mare is in estrus and ready to breed. They often respond with behaviors such as nuzzling, nipping the mare’s flanks or hocks, or touching muzzle-to-muzzle before eventually mounting. ^[9]

A mare who is not in estrus will not be receptive to these behaviors and may kick out at the stallion or otherwise evade his advances. ^[12] It’s important to make sure your mare is in estrus before attempting a live cover breeding to reduce the risk of injury to both horses and handlers.

In preparation for breeding, stallions may exhibit signs of sexual interest, such as dropping their penis or masturbating.

Domesticated Breeding Stallions

Compared to wild stallions, domesticated stallions often have more limited social interactions.

Domesticated stallions typically have limited access to mares for mating, usually confined to a brief precopulatory period. This differs markedly from the extensive repertoire of pre-breeding behaviors expressed in the wild.

Similar to wild stallions, those in domesticated settings also exhibit differences in behavior and testosterone levels depending on whether they are housed near mares or other stallions. ^[3]

Research shows housing stallions near or allowing increased exposure to mares results in higher testosterone concentrations and improved sexual behavior in horses. ^[13]

Like stallions in the wild, domestically managed stallions often exhibit signs of sexual interest such as dropping their penis or masturbating. However, it’s worth noting these behaviours do not always indicate sexual interest. They may also be linked to emotional states or natural physiological cycles such as sleep. ^[#][15]

Behaviors such as dropping the penis or masturbating are often punished or discouraged in breeding and performance stallions. ^[16] However, it’s important to allow the expression of natural behaviors in breeding stallions.

Punishing or otherwise discouraging these types of behaviors can lead to lack of interest in breeding. Further, it can cause undue stress that may manifest as aggression or other dangerous behavior. ^[17]

Breeding Shed Behavior

Mating in the breeding shed environment is very different from what wild stallions experience in their natural habitat. Many domestic stallions do not get to breed with live mares at all, instead having their semen collected via a “phantom/dummy mare” or artificial vagina (A.V.). When a stallion breeds directly with a mare, this is known as a live cover breeding.

In the wild, the timing and pace of breeding is controlled by the mare, as dictated by an intricate series of behaviors. ^[9] Conversely, behavior in the breeding shed is closely managed by handlers.

Common stallion precopulatory behaviors in the breeding shed include: ^[17][18]

• Vocalization
• Nipping
• Striking
• Prancing

While these natural behaviors may appear aggressive, they are a natural component of breeding shed behavior and should not be discouraged unless they pose a risk to the mare or handlers.

These risks can also be mitigated by protective gear, such as breeding pads to guard the mare’s withers and breeding boots for both mare and stallion to cover the hooves. Handlers may choose to wear helmets, body protectors or steel-toed shoes to protect themselves.

The act of breeding for domestic horses typically lasts 2 – 5 minutes and may include: ^[18]

1. Interest in the mare (typically immediate)
2. Erection (typically within 2 minutes)
3. Mount readiness (typically within 5 – 10 seconds of erection)
4. Ejaculation (typically on first mount)

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Common Stallion Behavioral Challenges

Improper handling of stallions can lead to behavioral challenges that may negatively impact daily handling and the breeding routine. Effective behavioral management and training can lead to better performance of stallions and a safer outcome for both horses and humans.

Hesitant, Slow Breeders

Stallions that are slow or hesitant to breed typically exhibit behaviors such as: ^[9]

• Being easily distracted
• Being playful or aggressive with their handler
• Appearing uninterested, finicky or distracted during the act of breeding
• Anxious expressions

In addition, there is a common misconception that oral behaviors, such as licking, chewing, and yawning during breeding are signs of relaxation. In fact, these behaviors may indicate the stallion was stressed by some or all of the breeding process. ^[19][20]

These behaviors may be transient, improving after a few successful breedings. However, some stallions will have consistently slow responses to breeding throughout their careers.

Aggression

Aggressive behavior from breeding stallions requires prompt, effective and consistent responses from human handlers, as it poses a risk to both mares and handlers. Examples of aggressive behaviors may include: ^[17][18]

• Biting
• Kicking
• Rushing or charging to mount
• Rearing

Discomfort and poor handling techniques can lead to aggression and frustration behaviors during breeding, as a stallion’s natural urge to breed conflicts with the anticipation of discomfort that may accompany the process. ^[17]

Strategies to Improve Breeding Performance

There are steps horse owners and caretakers can take to improve breeding performance in stallions. The choice of teaser mare, mare behavior, and the breeding environment all play a role in how the stallion responds to the breeding shed.

Teaser Mares

Choosing the “teaser” mare wisely is important for stallions with breeding issues.

Choosing a mare who is naturally in estrus, rather than an ovariectomized mare, may provide more stimulus for stallions that struggle to breed. ^[9] Conversely, ovariectomized mares may be a better choice for stallions who are aggressive or overly enthusiastic breeders.

Mare Behavior

Other interventions such as allowing natural mare behavior may provide support for shy or slow stallions.

To allow the mare to exhibit the most natural breeding behavior possible, avoid interventions such as hobbles, lip chains and twitches. ^[9] Besides restricting natural behavior, these techniques also have the potential to cause pain, injury, fear or stress to the mare. ^[21]

Environmental Stimulation

It can also be helpful to remove distractions from the breeding shed, such as noisy equipment or excess staff or onlookers. ^[17] This can help keep the stallion focused on the task at hand, and encourage a more natural breeding experience.

Identify Pain and Discomfort

For horses that are persistently slow or aggressive breeders, consult with your veterinarian to diagnose and treat any medical conditions that may be causing pain or discomfort. Potential sources of discomfort include: ^[9]

• Sore feet
• Sore back
• Dental discomfort
• Gastric ulcers
• Respiratory issues

Ground Manners

Ground handling skills are often referred to as “ground manners”. However, this term implies that horses have sufficient cognition to comprehend concepts like manners and respect.

Recent research suggests horses do not misbehave with the intent of disrespecting their handler. Rather, handling decisions made under the assumption horses are capable of acting with such ulterior motives can actually lead to poor training outcomes. ^[20][22]

Given this, equine welfare experts are moving to update language used in the horse training community. Handlers and trainers are encouraged to consider shifting focus around ground training to “ground handling skills,” rather than “ground manners.” Doing so aims to foster a more positive working relationship between handlers and their equine charges, which may support better training outcomes.

Reliably trained ground handling skills are essential for breeding stallions and underlie a safe and successful breeding experience. These skills must be taught early and reinforced regularly by well trained staff.

A stallion with good ground handling skills should: ^[18]

• Maintain attention to their handler
• Easily take direction from the handler during all breeding activities
• Safely tolerate genital checks and washing
• Wait for the handler’s cue to approach and mount

Ensuring that staff are confident and properly trained in appropriate stallion handling techniques, training and behavior may help reduce the risk of a dangerous situation occurring during breeding. ^[23]

Safe Stallion Handling Practices

Stallion handling practices that can promote the safety of handlers include: ^{[9][17][20][21][25]}

• Teach a routine: breeding should be a predictable activity to help the stallion understand when it is time to breed and when it is not. This is accomplished by following the same specific routine every time the stallion breeds
• Reduce stimulation: efforts to make breeding less exciting may help keep both horses calm. Strategies may include using the urine of a mare in estrus to stimulate the stallion rather than a live mare, or using an ovariectomized mare instead of a mare in estrus
• Reward desired behaviors: rewards may include praise, food reinforcement, the act of breeding itself, or other things that the horse perceives as positive feedback. Avoid punishment, particularly of natural breeding behaviours
• Communicate effectively: ensure training cues are clear, consistent and appropriately timed; address dangerous behavior promptly and consistently

Remove the stallion from the breeding shed if behavioral interventions cannot ensure a safe breeding experience for horse and handler.

Behavioral Seasonality

In the wild, horses breed during specific seasons, typically between the months of March and August in the Northern hemisphere. ^[26]

Seasonal breeding stems from a drive to conserve energy during the winter, when nutrient availability was historically limited. Not only do stallions show less sexual activity in the winter months, but they also spend less time eating, moving, and socializing in general. ^[27]

In addition to changes in sexual behavior, sperm characteristics change seasonally. If stallions are used for breeding in the off-season, they may need to be managed differently to maintain adequate conception rates. ^[28]

Sexual behavior can be stimulated in stallions during the winter by presentation of urine from a mare in estrus. These behaviors may also be inhibited by presenting urine from mares that are not in estrus. ^[25]

Light exposure to mimic longer spring and summer days may also help to favorably modify a stallion’s reproductive cycle. ^[29] The seasonal changes in reproductive activity are caused by hormonal changes triggered by day length. ^[30]

Housing

Domestically managed stallions living in groups engage in similar social behaviors to their counterparts in the wild. This highlights the importance of social interaction among stallions. ^[31]

Social interaction and turnout are deeply important for all horses regardless of sex or reproductive status. Providing sufficient turnout and social opportunities optimizes equine health and improves behavioral and physiological performance in breeding stallions.

However, typical stallion management often involves social isolation and does not allow stallions to form bonds with other horses or engage in natural social behaviors. Contrary to popular belief, stallions who are isolated from other horses may be more aggressive towards humans and horses. ^[32]

Social isolation may also lead to: ^{[32][33][34][35]}

• Increased vigilance and stress behaviour
• A higher incidence of stereotypies such as cribbing or weaving
• Self-mutilation
• Reduced reproductive efficiency

Scientific Evidence

Several studies have found that stallions can be safely housed in groups and can form strong social bonds with other stallions. This may provide a dynamic similar to what is seen in bachelor bands that form in the wild.

In one study, researchers observed the behaviors of group-housed stallions compared to singly stabled stallions when turned out in a group on pasture. Group-housed stallions often stayed close to their former pasture mates and made use of more subtle aggressive interactions to resolve disputes, while stallions who were previously isolated showed more overtly aggressive behavior in group turnout. ^[36][37]

However, when turned out with other horses, stallions who were previously housed alone also showed more social grooming and play behavior after adapting to their new group housing, suggesting an increased motivation for social contact in these stallions. ^[36][37]

Many stallions can be successfully housed in groups of other stallions. If mixing stallions with geldings, it is best to group aggressive stallions with calmer geldings who are less likely to challenge them. ^[38]

If group housing is not possible, owners may consider alternative opportunities for social interaction such as “social stalls” with partitions that allow physical contact, or turnout in adjacent paddocks where stallions can touch noses and interact with other stallions or geldings over the fenceline. ^[38]

As with any horse, it’s important to monitor the social dynamic and environment of group housed stallions to ensure a safe social experience. Group housed horses should be matched appropriately to avoid disparate ages, temperaments, or personalities causing stress or leading to injury.

Like all horses, stallions require daily turnout, even if only turned out individually. Turnout is critical to equine health and wellbeing. It reduces the risk of stereotypies and certain diseases, strengthens the musculoskeletal system and improves digestive function. ^[39][40][41]

Housing and Breeding Performance

Social groups and housing location of breeding stallions should be considered carefully. Stallions who are group-housed without any exposure to mares may demonstrate decreased libido. ^[35] Thus, stallions who are difficult to manage due to high libido may benefit from group housing with reduced exposure to mares.

Conversely, you can consider housing shy or slow stallions near mares to increase their confidence and interest in breeding. This can be accomplished by housing them next to mares in a pasture with a sturdy fence line or in stalls near mares. ^[9]

Summary

While some of their behavior differs from mares and geldings, stallions can be relatively safe and easy to handle if managed and trained appropriately. However, mishandling or poor training can lead to behavioral issues and safety concerns.

• When creating breeding routines, it is important to consider the differences between the housing, socialization and mating opportunities of wild stallions and domestic ones
• A stallion’s breeding performance can be altered by season, proximity to mares and a mare’s stage of estrus
• Allowing stallions and mares to safely perform natural behaviours in the breeding shed can improve breeding performance
• Teaching your stallions reliable ground handling skills and ensuring staff are trained in appropriate handling techniques creates safer breeding experiences for all parties
• Providing your stallion with regular turnout and healthy socialization opportunities can improve behavior and performance, setting him up for a happy and healthy breeding career