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

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. What should I do so that she'll sleep more? Read More

Using the Twitch Properly

Can you explain in your column how a twitch works and your recommendations for how to use it most effectively? Read More

Spooking on Trail

I have a 17-year-old Arabian mare. When trail riding, she looks for every opportunity to jump, spook, or take off, especially now that my other horse, her companion, no longer accompanies her. The companion is 30 years old, and due to a recent Read More

Water Crossing

How can I get my horse to cross through water when I'm riding him on trail? He refuses to even get his feet wet. 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

Taming an Aggressive Foal

We recently were blessed with a healthy filly. However, the breeder we bought the mare from had her due date wrong. She came five weeks before we were expecting her. She was born in the pasture with another mare present. Th Read More


In any of the equine behavior literature that I have read, I am unable to find any description of the sleeping behavior we see in our retired broodmare (17 years old). She has functioned as the watch horse in the small herd she was from, and she Read More

Blind and Restless

My horse is 95% blind, and when he's not eating or sleeping he walks in circles. What can I do to stop this behavior? Read More

Don't Leave Me Alone!

Why do some horses not like having their buddies taken out of their pen when they have to stay in? Read More

Get a Vet!

When I ride my 24-year-old Arabian mare Western, she tends to want to pick up the pace and wants to look around. How can I get her to slow down and stay focused? She gets stiff and starts to limp on her left hind leg when I am riding her. Anothe Read More

Play Invitation

We have been struggling with a very particular behavior problem with a young colt. From birth, he's been a strong and athletic rascal, and has been "full of himself," with the usual colt behavior tendencies. We have dealt successfully with all Read More

Foals and Geldings

My 12-year-old daughter's 9-year-old Welsh Pony gelding (named Taffy) was moved to a new stable about eight weeks ago. Six weeks after the move, Taffy was introduced to the mares and allowed to graze and socialize with them. Since four of the 16 Read More

Handling a Hostile Broodmare

My mare just had a colt today and I have a concern about it because she is 13 years old and not broken. She had been broken three times prior to me getting her, and she won't come near anyone. My question is: How will I be able to mess with the Read More

Bereavement Leave?

I'm worried about my horses' dependency on one another and any future bereavement of the horse left behind. Read More

Hauling Training

I'd like recommendations for safe hauling for weanlings. What's the easiest way to proceed for happy hauling? Read More

Sudden-Onset Headshaking

My pony started tossing his head and cribbing at about the same time. The head tossing has increased to the point of not being able to ride him. He has had his teeth floated and has been checked by a vet for common problems. He has never had Read More

Fear of Cows

What can I do to help my horse overcome his fear of cows? I'd really like to resolve this rather than sell him. Read More

Abusive Training for Stud Colts

I hope you are not offended by this question, and that you will find time to answer it if you know anything about it or maybe could refer me to someone else who might have heard of this fairly unusual advice. My boyfriend was afraid to write Read More

Tail Rubbing

One of our mares rubs her butt on everything, all the time. It messes up the top of her tail, and she always has these big scratch marks across her butt.

We can't seem to get her to stop it. We have dewormed her regularly and Read More