How to Handle 8 Stallion Behavior Problems

How to Handle 8 Stallion Behavior Problems

Learn how to handle eight troublesome behaviors and teach your breeding stallion manner with tips from Dr. Sue McDonnell.

stallion teasing mare in breeding stocks (Photo courtesy of Dr. Sue McDonnell)

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By Abigail Boatwright

In a perfect world, a stallion walks into the breeding shed, drops, stands calmly for preparation, travels politely over to the mare, and while he might vocalize with excitement, he still takes care of business in an organized, safe manner – either on the mounting dummy or with the mare – then dismounts and follows his handler back to his stall.

But what do you do when your stallion acts like a ruffian – striking, biting and exhibiting other problematic behavior? How can you encourage a more amenable demeanor?

Dr. Sue McDonnell is an adjunct professor and the founding head of the Havemeyer Equine Behavior Program at the University of Pennsylvania School of Veterinary Medicine New Bolton Center, and she advised us on handling undesirable stallion behaviors. Not surprisingly, a calm handler is key to keeping a stallion calm and well-mannered in the breeding barn.

Many of a stallion’s behaviors that are completely natural to him can be dangerous to human handlers. Use these tips to manage his behaviors without stifling his libido.

Nipping and Biting the Handler

The scenario: At any point during the interaction with a stallion, he reaches around and nips or bites the handler.

Why he does it: Dr. McDonnell says this typically represents either “playful inter-male aggression” that is often play initiation attempts, or “displaced aggression” in response to inherent frustration to being handled.

“It’s called a ‘thwarted goal’ situation, where the animal has all this forward momentum, but he can’t really move forward on his own terms, so the frustration gets vented in nipping or biting,” Dr. McDonnell says.

How to handle it: Dr. McDonnell says the best option is to first try positioning the handler so arms are less accessible targets and then to totally ignore the nipping so there’s no reaction at all.

“I’ve had horses that were dangerously nippy, and you give them to another stallion handler who can totally avoid and/or ignore the nips, and within a few minutes, it stops,” Dr. McDonnell says. “But if you try to fight with the stallion over it, in most cases, regardless of the cause, you’ll typically accelerate the behavior rather than reduce it.”

Practical tips: The handler should gear up with whatever it takes to keep calm – a heavy jacket to protect arms and shoulders, for example.

“For some stallions, just stand like a tree – be nonreactive,” advises Dr. McDonnell. “Reacting to their behavior will accelerate it.”

If the handler can’t keep from responding when the stallion tries to nip, or if the bites are more serious, Dr. McDonnell recommends trying a soft grazing muzzle on the stallion during these interactions.

“You’ll be less likely to get hurt – you can get bonked with the muzzle, but the stallion can’t get in a good bite,” Dr. McDonnell says. “And for some novice horses, putting the muzzle on, taking away the tools, and they’ll just stop doing it.”

Another strategy is changing up the restraint. If the chain is looped around the nose, for example, Dr. McDonnell says try threading it through the mouth gently, like a bit, with loose tension, to give the horse something to use his tongue to play with rather than nipping. Horses are individuals in what works best, but it is worth trying different halter and lead arrangements.

Aggressively Biting the Mare

The scenario: During the teasing portion of the breeding process, or while he’s mounted, the stallion responds too aggressively toward the mare by biting her.

Why he does it: During the teasing phase, the stallion might bite at the mare for a few reasons: It can be frustration with the restraint on the stallion or the mare might not be at liberty to respond that she is ready with the appropriate signals to the stallion.

How to handle it: Keep the stallion at enough of a distance, and with the lead at a length that when he goes to dart at the mare, he’ll correct himself.

“Only give him so much latitude that he can poke, poke, poke, but doesn’t actually reach her, and many will stop trying.” Dr. McDonnell says. “Some stallions just lunge though, and you can’t effectively keep them checked that way.”

For a stallion with an extreme problem with biting the mare during teasing, Dr. McDonnell’s team takes the mare out of the picture altogether and trains the stallion to respond to estrus mare urine instead. McDonnell calls it “suboptimal stimulus.” 

“We do that quite a bit for stallions with all sorts of exuberant behavior,” Dr. McDonnell says. “You can do that for semen collection, and even during the preparation for live cover. Then you just have to get them to the mare safely.”

Practical tips: You can employ the muzzle in this situation, as well.

“In the same way as with the horse biting people, if the stallion isn’t actually able to grasp on, he sometimes will stop doing it,” Dr. McDonnell says.


The scenario: During the time leading up to actually mounting the mare, a stallion might strike out at the mare with a foreleg.

Why he does it: “Striking is a normal pre-copulatory response for horses living under natural conditions, but it’s only ever a strike threat – it occurs when the stallion is positioned such that the strike would not contact the mare,” Dr. McDonnell says. “It’s usually when he goes nose to nose, either parallel, off to one side, or at angle, he’ll do this little reflexive action. It’s an aggressive threat, but my interpretation is that he’s just testing to see if the mare is really in estrus.” 

A mare truly in estrus, ready for mating, will either quietly tolerate the strike threat or might even “break down” in response, but a mare that isn’t totally ready will typically respond negatively.

This behavior, thought natural, can be dangerous for a couple of reasons. If the handler is in the way, injuries could occur. If the stallion is positioned close to the breeding stocks or some other stationary object, he could hit his leg, or push the handler into it.

“If he was at liberty, he would position himself to where he wouldn’t hit anything,” Dr. McDonnell says. “It’s just an ‘Are you really ready?’ gesture.”

How to handle it: If your stallion tends to do this, Dr. McDonnell recommends keeping him away from the head of the mare. Although the face-to-face meeting is typically the first encounter at liberty, she says most stallions can respond for breeding without that interaction.

Practical tips: Be sure the handler is at the stallion’s shoulder to avoid being in the path of a potential strike. And give the horse plenty of room away from stationary objects, should he try to strike.

Kicking During Prep

The scenario: Some stallions kick out in response to having their penises cleaned prior to either breeding a mare or semen collection.

Why he does it: Dr. McDonnell says this response most frequently occurs with inexperienced stallions naturally unused to the sensations of the cleaning process.

How to handle it: For a novice stallion, Dr. McDonnell says the handler’s response is critical for shaping the stallion’s behavior in future encounters. The handler should have his hip pressed close to the stallion’s shoulder facing the rear, then push his shoulder against the stallion’s abdomen during the washing process.

“That’s the safest place for the handler,” Dr. McDonnell says. “Keep your knees out of the way so that if he cow kicks you, it won’t clip your knees. And then just calmly commit to what you’re doing.”

Once in position, do your best to ignore the kicking behavior should it occur.

“If he just kicks, kicks, kicks with no response, sooner or later he’s going to stop kicking and settle down,” Dr. McDonnell says. “After a couple of sessions with no reaction from the handler, he’ll usually come in and just stand there to be washed.”

Practical tips: Dr. McDonnell advises handlers to wear a helmet, a safety vest and safety shoes for this work, and particularly for a horse that has a tendency
to kick.

“Our record is held by a veterinarian named Dr. Regina Turner, who didn’t flinch and proceeded calmly through 30-something kicks,” Dr. McDonnell says. “The horse stood quietly ever after. That’s our Hoffman Center record.”

Be fair to the horse, and make the experience as comfortable as possible for him.

“Some stallions seem genuinely more sensitive. The tendency may be to rush, and with that often, without even realizing it, we accidentally make it more uncomfortable for the horse. Proceed with nice, warm water and a touch that seems most soothing to the horse,” Dr. McDonnell says.

Avoid having a handler at the horse’s head trying to discipline the horse while another handler is washing the penis.

“That makes it even more complicated,” Dr. McDonnell says.


The scenario: As the handler is leading the stallion toward the mare or breeding shed, the horse rears.

Why he does it: Dr. McDonnell says rearing is not a normal pre-copulatory behavior, adding that it is often provoked by checking the horse’s forward momentum, particular with sharp pressure at the mouth or poll, whether deliberate or accidental.

How to handle it: Avoid trying to tug the horse down with the lead.

“Rearing is actually an inter-male aggressive behavior in horses,” Dr. McDonnell says. “So by responding, the handler gets into the game with him. The horse goes up in the air, you jerk on him, he comes down, and the pressure on the chain pops him right back up. It’s a handler training issue as much as a horse training issue.”

When the horse is in a situation where he might rear, use a long lead with him, and as the horse rears, let out on the length of the lead so there is no tension on the horse, and then gently guide him to come down in the opposite direction from which you’re going – the key point, because usually you’re headed toward the mare.

“It takes a while to learn the 1-2-3 timing, but as the horse goes up, just 1) release the tension on the lead so as not to put any pressure on the poll or mouth, 2) while stepping aside into a safe spot, and almost simultaneously 3) gently and respectfully directing the stallion to come down facing away from the mare or dummy mount,” Dr. McDonnell says. “On two legs, a stallion has little lateral stability, so guiding him to land takes less effort than you might expect. After two or three replicates of that, many stallions appear to figure out that rearing gets them going in the wrong direction.”

Practical tips: Make sure you don’t allow the stallion to escape from you – which is why the long lead is so important. If rearing frees him from the handler so he can get to the mare or the dummy mount, the handler is inadvertently reinforcing that behavior.

When the horse is in a situation where you expect he might rear, use a long lead with him, and as the horse rears, let out on the length of the lead so that there is no tension on the horse, and then gently guide him to come down in the opposite direction from which you’re going.

Rushing Ahead

The scenario: During the breeding process, a stallion  might mount the mare or dummy too soon or too vigorously – whether before everything is in place or before the mare is in position or simply just too forcefully.

Why he does it: If rushing has led to breeding before, Dr. McDonnell says, stallions can behave as if they think that’s what they are supposed to do to get the job done.

How to handle it: Reduce the stimulation. For example, for semen collection, try without using a live stimulus mare. Or prepare the stallion outside of the breeding area. Skilled specialist stallion handlers might use specific retraining aids, for example a judiciously applied gum chain, not to be used as punishment, but to distract and calm the stallion enough so that he can learn to follow the handler’s pace.

Similarly, sometimes blinkers or blinders can subdue a rushing stallion so he can learn he does not have to rush. Of course, it is important to accustom the horse/handler team to use of these aids in a safe, nonsexual environment before trying them in the breeding situation.

Dr. McDonnell says in a semen collection situation, the center’s team sometimes turns to using alternate methods, such as ground semen collection, which doesn’t require a mounting dummy at all. 

Ground Collection

If you’ve got a stallion that hurries to breed, is aging or has issues with the mounting process, Dr. Sue McDonnell says ground collection might be a better option.

“The horse is held in crossties or by a handler, stimulated with estrus mare urine to get an erection, and an artificial vagina is put on the penis as the horse is standing on the ground,” Dr. McDonnell says. “A single person can do it, if you’re organized. When we first started doing it, it seemed like a wild and crazy way to go about it, but we’ve been doing it pretty regularly, and it’s a nice workaround for semen collection.”

For more information on this technique and others, type into a search engine “Penn Equine Behavior Lab.”


The scenario: As the handler is leading the stallion toward the mare or breeding shed, the stallion barges ahead and pushes past the handler.

Why he does it: This is usually because the stallion is anticipating getting to the mare.

How to handle it: Work with the horse away from breeding conditions to teach him basic ground commands of forward, stop and back. When you’re preparing for breeding, you can treat the situation like you do if the horse rears. As you approach the mare, as long as he stays with you, even if prancing and vocalizing, keep progressing. If he starts to get ahead of you, calmly turn and walk him in the opposite direction.

“You can push back on the shoulder – not aggressively – or just turn the horse the other direction,” Dr. McDonnell says. “Most stallions quickly learn that if they rush ahead of you, they end up going further away from the goal.”

Practical tips: Some handlers will carry a small stick, to keep something rigid between them and the stallion. Dr. McDonnell says that for horses and handlers, this stick can be a physical reminder for the horse to keep space between himself and the handler. Again, care should be taken not to use this as a weapon of punishment. And the goal is to use this as a temporary training aid with the expectation that once the horse learns, it will no longer be needed.

Threatening to Kick the Mare

The scenario: If the stallion senses the mare is not completely ready to stand for breeding, or there’s a hitch in the breeding process, the stallion might whirl around and kick out toward the mare or dummy.

Why he does it: Under natural conditions, this is a common behavior, a threat gesture, says Dr. McDonnell. It is always a kick threat toward the mare, without actual contact, as if to say, “Well, have it your way, then!”

In an indoor situation, where the horse is not at liberty to deliver only a threat, it’s extremely unsafe for all involved. The stallion will approach the mare and ask if she’s ready to breed, and if she’s not, he might spin around and kick out in her direction. It’s a reflexive action with the spin as the two go butt to butt.

If the stallion mounts the mare or dummy but is not able to ejaculate for some reason, he might try the same reflexive threat gesture toward the dummy mount.

How to handle it: Particularly for a teasing mare, or a mounting dummy, make sure you’re always ready to direct the stallion away rather than turn him around where his hindquarters face the mare or dummy.

Practical tips: In a stallion’s basic ground handling skills, using the same restraint you plan to use for breeding, teach him to back away with gentle guiding pressure on the shoulder or even or voice command. It will surprise many handlers how valuable this simple skill can be in the breeding situation.

Training Breeding Stallions

During any undesirable behaviors while teasing and preparing a stallion, work to redirect the stallion’s focus back to the mare. Dr. McDonnell says it’s better for the stallion to focus on the mare versus the handler. 

“A lot of handlers philosophically focus on wanting the horse to pay attention to them, but it is often less problematic and safer if the horse primarily focuses on the mare, not you,” Dr. McDonnell says. “It’s a different mindset for some handlers.”

Physically disciplining your horse is the one thing that Dr. McDonnell says is completely unhelpful with handling a stallion’s undesirable behaviors.

“Unless you’re going to be really serious, to the point of being inhumane, you’re only accelerating the problem,” Dr. McDonnell says. “And if you have a horse that is delicate with its sexual response, as many are, you really risk suppressing the response you need.”

Establishing a trusting relationship is more effective, safer and more efficient, Dr. McDonnell says.

“Be really calm, relaxed and quiet,” Dr. McDonnell says. “Try to be an invisible partner for the stallion. Be soft and nonconfrontational.”

About the Source: Dr. Sue McDonnell

Dr. Sue McDonnell is an adjunct professor of reproductive behavior at the New Bolton Center at the University of Pennsylvania School of Veterinary Medicine, where she is the founding head of the university's equine behavior program. She is a certified applied animal behaviorist (CAAB) of the Animal Behavior Society. And she is the author of two introductory books on horse behavior: "Understanding Horse Behavior" and "Understanding Your Horse's Behavior." She has also written a catalog of horse behavior, "The Equid Ethogram, a Practical Field Guide to Horse Behavior."