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

Sexual Misbehavior Vaccine?

I am looking into ways to settle down a colt that is showing full-blown sexual interest already at a 1 1/2 years of age. He's just too much for us to handle, but we are not ready to geld him. If you try to correct him when he's all excited, he Read More

Cribbing Weanling

I have a client with a foal that was weaned a few days ago, and it has started cribbing. Within only a few hours after it was separated from the mare, it was seen doing something funny that the owners now appreciate was cribbing. Once they Read More

Pony Girthing/Mounting Issues

My 11-year-old daughter is having trouble with her pony nipping at her when she is girthing him, and when she goes to mount without an assistant. He also smacks his tail and pins his ears, almost looking like he might cow-kick at her sometimes. Read More

Semen Collecting from a Blind Stallion

We have a Standardbred stallion that had a minor neurologic episode a few months ago that was never really figured out. He has recovered slowly back to normal, except that he has gone completely blind. He does well at pasture and you would hardl Read More


I'm studying for an MSc in Equine Science and am researching equine behavior. Having studied scientific literature, including your catalog of horse behavior (The Equid Ethogram, A Practical Field Guide to Horse Behavior), I cannot find any Read More

Keeping Horses in Harems

I am a veterinarian in Atlanta with a special interest in behavior. I also own and raise Arabian horses. I have a 2 1/2-year-old stallion, and I would like to keep him in a harem situation. He is now pastured with another gelding and is quite Read More

Kicking Problems

My horse constantly kicks his stall, and in the pasture he's very rough with other horses, biting and kicking them. How can I stop this behavior?          Jess; Boulder, Colo.

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Deliberate Abuse?

I hope you remember me from psychology graduate school back in the early '80s. Time flies. Anyway, I still have horses and enjoy your contributions on behavior to The Horse magazine and web site. Sometimes I wish I had gone into horse or dog Read More

Transportation Trio: Kicking and Pawing

Why would my horse kick the lorry (van or truck) and paw at the floor, both with company or when alone? Read More

Transportation Trio: Runny Nose and Cough

Every time we trailer our horse, he arrives with a cough and runny nose. Our vet has suggested that he is sensitive to the dust from bedding in the trailer or bits of hay from the hay net bouncing around in front of his nose. It has been Read More

Transportation Trio: Loading Trick

I found an amateur video clip in our tack room and nobody knows where it came from. It shows an amazing demonstration of loading two horses on a trailer. The horses, without a lead or halter, went right into the trailer, one after the other, whe Read More

Eating Poop

Our first foal is 10 days old and has already been spotted eating manure. We have accepted the fact that eating manure is normal foal behavior and are trying to ignore it. A quick question: When should he get over this behavior? via e-mail Read More

Barn Aversion

 Our elderly Connemara gelding was unfortunately exposed in his stable to multiple bee stings on more than one occasion over a period of two weeks before the problem was figured out and fixed. He used to be very calm and content in the stable, Read More

A Stallion as a Problem Breeder

We purchased a stallion for breeding at nine years of age. He had bred before, but curiously had very few offspring for his impeccable credentials. He was a lovely stallion, very well-behaved, and a perfect gentleman to work around. When we Read More

Finding a Stallion Handler

We have expanded our semen collection/shipping facility, so we can now keep up to eight stallions in residence and accommodate local stallions trailering in just for semen collection as needed through the season. In the past we have depended upo Read More

Is My Horse Psychotic?

I bought my gelding as a stallion from a local sulky racetrack a year ago (where he never got out of his stall except for training). He had just turned three and was very excitable, so we had him gelded. After several months, he seemed to calm Read More

Foals of Non-Milking Mares

I have a gorgeous palomino Quarter Horse mare that I would like to breed, but I have a problem. She ran into barbed wire as a yearling and she cannot produce milk as a result of that accident. The man who owned her before bred her twice, and he Read More

History of the Horse

There are many scientists who have studied and theorized about how man and horses came to be together. Read More

Stallion Washing Aversion

My husband and I run a business of shipping semen from a few stallions that we board. We have some started ourselves, and some have started elsewhere. Most of them do really well with our simple collection routine. We bring them to the breeding Read More

Men vs. Women Handlers

Your answer to the question about the fellow with the peculiar method of "dominating stallions" (December 2003, led to a very long Read More

Breeding Your Stallion On Cue

Our stallion has a great pedigree, and we have kept him intact hoping he could eventually become a breeding stallion. We’ve put a lot of effort into getting him to show well enough to be worth breeding. He has always done really well except for Read More

General Social Organization of Equids

Editor's Note: This excerpt is from The Equid Ethogram--A Practical Field Guide to Horse Behavior by Sue McDonnell, PhD. The book is available from Read More

Sleeping Patterns

I think my 11-year-old mare isn't getting enough sleep. My mother and I have seen her start to fall asleep in her paddock and in her stall during the day. Her eyes begin to close, her lower lip hangs loose, and her head slowly lowers. When it Read More

Using the Twitch Properly

I attended a short course on horse behavior at New Bolton Center where you explained how a twitch works and your recommendations for how to use it most effectively. It seemed to make so much sense why sometimes it works and sometimes it doesn't, Read More

Breaking A Young Horse

My husband and I recently broke my 3-year-old mare to ride. The first few times she rode like a dream, then she caught on to the idea that when we catch her, she has to work, and she has gotten a bad attitude. Her new antics include bucking. I'v Read More