Sue McDonnell, PhD, Certified AAB

Sue M. McDonnell, PhD, is a certified applied animal behaviorist and the founding head of the equine behavior program at the University of Pennsylvania's School of Veterinary Medicine. She is also the author of numerous books and articles about horse behavior and management.

Articles by Sue McDonnell

Follow-Up: Carnivorous Horses

Last October, we shared letters from three readers describing horses killing and/or eating small mammals and birds (see "Carnivous Horses," article #3832 at Read More

Kicking Out at Feeding Time

My gelding is stall kicking. I'm not there at feeding time, but my trainer tells me the stall kicking occurs when it's feeding time. The same thing happened the last two places he lived. She has tried feeding him first, but that didn't help. Read More

Trailer Resistance

I've had my yearling filly all of her life. I trained her from week one to trailer load, and she was fine with getting in and out. However, this was with a four-horse slant load trailer that steps up. Now I need to load her into a two-horse Read More

Foot Work: Training for Hoof Care

My only horse finally lived out his days with me last fall. He died peacefully at the great old age of 32 years. He had been with me through thick and thin for 21 years, and was a sweetheart of a horse. He came to me completely broke and was Read More

Clusters of Aggression Problems

I have an almost 4-year-old Peruvian stallion, born and raised on my farm, living with only his mother and a sister. Because of my inexperience, I treated him as a pet. Since a very young age, he showed a strong will. When I started saddle Read More

Keeping a Stallion With a Foaling Mare, or Mares

We have a mare and stallion together in a pasture. We borrowed a stallion in August just to breed this mare. They have been together since then, and we just had the mare checked for the first time since they were together and found out that Read More

Fly Masks

When I am bringing fly-masked horses in from the field, I feel insecure, as if it's hard to tell what they are doing. I always feel better when fall comes and the masks come off. I've talked to other people who feel the same way. Do you know Read More

Truck Training

I recently had a difficult time trailering my horse to a show. While loading him, we had backed the trailer up to the barn, which resulted in a situation where he became afraid of the truck/trailer by the barn area. After returning from the Read More

Carnivorous Horses

While taking questions from the audience at a one-day behavior program in New Zealand this May, a well-respected horse owner and trainer described behavior she had recently witnessed in a horse involving a scenario I had never heard or thought Read More

Stallion Mounting Behavior

I'm a veterinarian asking this question on behalf of clients who are standing a stallion at stud. The stallion isn't new to breeding or to this farm; he's in his third or fourth breeding season. He normally breeds eagerly, without hesitation Read More

Horse Behavior and Welfare Conference

A recent gathering of equine behavior and welfare specialists in Holar, Northern Iceland, gave scientists from around the world the opportunity to present their work and review the science underpinning management practices on the horse. The Read More

Separating Mare and Foal for Work

A young breeder asked me if she could take a mare from her foal for one hour every day. That young breeder would like to ride the mare; therefore she'll leave the foal in the box. I am not a fan of that. I told her that it would be a Read More

Controlling Cribbing

There is a new 3-year-old gelding in my barn. He cribs and wears a collar; the collar seems awfully tight to me. A respected friend says that the other horses might pick up this habit from this horse. Is that true? And how can I work with Read More

Anti-Social Behavior

I am looking for some guidance on a horse I'd like to buy. He is an ex-racehorse, about eight years old, with no information on his history--not even a name.

The problem is that he kicks at other horses when ridden. He kicks Read More

Overly Social Behavior?

Why does my son's mare seem interested in another mare in a bordering pasture? --via e-mail

Without further information, I can offer explanations for a couple of likely scenarios. If the mare is just buddying up with another mare Read More

Is He Sore, or Misbehaving?

Over the last few months, my horse has changed from a steady, reliable, and willing friend to a miserable grouch. He's an 11-year-old Thoroughbred gelding that I have owned and used just for pleasure since he was seven years old, and I knew Read More

Ground vs. Breeding Mount Semen Collection

We have show pony breeding stallions, and as of last year are doing almost all shipped semen. This year we are seriously thinking about expanding our business to offer semen collection and shipping services for outside stallions, which will Read More

Narrow Doorway Aversion

 My mare has a particular problem with doorways, like stall doorways, small barn doorways, and even to some extent with the round pen gate. Big, wide doors are no problem, but with anything about four feet wide or smaller she will Read More

Foal Urination and Defecation

The first urination in foals typically occurs within the first six hours for females and the first twelve hours for males. Like defecation, the first urination in foals very often occurs soon after the first nursing. Read More

Reactions to Other Species

This might be a bit off the wall, but I hope you can help. We have had horses here at our farm off and on over the years. Since all of the kids moved out and took their horses a couple of years ago, our barn has been empty. Just recently we Read More

How Smart is He? The Thinking Horse

I am writing a paper in my agricultural ethics class on the treatment of horses, and one of my discussions deals with the equality of horses to humans. My roommate and I were debating if horses have the Read More

Stallion Sexual Behavior: When Is He Mature?

How young is too young to breed a colt? We have a coming 2-year-old who acts like he is ready to breed. We don't have any horses to breed to him, but the question came up for discussion last night among a group of guys. This colt was out Read More

More on Panic Attacks

Readers Respond

August's Behavior column (article #914) sparked heated debate about euthanasia for horses with incurable panic attacks. This month we feature two readers' responses and the author's comments.

It was a Read More

Retraining a Rebellious Colt

We recently had a foal who is now one month old. His mother has always been easy to handle in the cross ties or harness (she is a 20-year-old retired Standardbred), but is not a horse which can be caught easily in the pasture, and she isn't Read More

Unpredictable Fear

I have inherited a mare that no one wants because every once in a while she spooks and bolts, big time, without warning. No one has ever been able to figure out for sure what sets her off. But she can go from normal one second to a serious Read More