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

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

One-Horse Property?

I am in the process of relocating from Indiana to Pennsylvania. I planned to move my retired 21-year-old Quarter Horse gelding as soon as I could find a property with enough space to keep him at home. I was shocked to hear my realtor in Read More

Mare Savages Foal

Mares which unpredictably savage a foal in this manner typically savage again if given the opportunity, either with a surviving target foal or with subsequent foals. Read More

Physical or Psychological?

A little over two years ago, we acquired a lovely Irish Draught mare, Colleen, from neighbors who were retiring and selling their place. This mare had been their family pleasure horse for many years. After their kids outgrew her, Colleen Read More

Enjoying Veterinary Visits

In our referral equine behavior practice, we frequently rehabilitate horses perceived to be uncooperative with one or more veterinary procedures such as injections, nasogastric tubing, genital examination, etc. We have found that straightforward Read More

Rushing Out of Trailers

One of our horses has a problem with unloading from a trailer. He bolts out of the back as soon as we start to open the back gate, often before we can undo the butt bar. He has done this since we got him over a year ago. He loads and rides Read More

Water Temperature and Drinking Behavior

A few years ago I read an article describing research done at New Bolton Center on drinking behavior. It said that the research showed that in winter, horses prefer to drink warm water rather than ice cold water, and as a result veterinarian Read More

Bizarre Behavior

We have a new problem with our old family pony. Pokey is a Shetland gelding that we have had since our first of five daughters was five years old. We figured he was about 10 years old in 1978 when we got him, so he is now just over 30. Pokey Read More

Foal Eats Manure

One quick question. What about our foals that eat manure? Why do they do it? I find it completely disgusting. My little filly paws and chows down mouthfuls of fresh, warm poop.


Till Death Do Us Part

How do horses perceive a dead horse? Do they know the deceased is not coming back? Read More

Rolling Along

Dear Dr. McDonnell,

Almost every time I let my horses out of the stalls after feeding them, they roll in the dirt, dust, o Read More