Black cherry tree leaves can be troublesome to deal with for horse owners: these leaves don't always pose a risk to horses, but are particularly dangerous when wilted.
Black cherries are members of the Prunus family, which also include peach, plum, chokecherry, and fire cherry trees. Leaves of these trees contain cyanogenic glycosides, which convert to cyanide when the leaves wilt. Ingestion of wilted leaves can lead to cyanide poisoning in animals that ingest it, reports The Horse.
Native to Central America, North America, and Mexico, dead, dried or crumbling cherry tree leaves don't pose as much of a threat to horses, but wilted leaves can be lethal if ingested in high enough doses. Horses that are fed well will rarely ingest wilted leaves if they have access to adequate forage, which may include supplementation of free-choice hay in the fall when grass is sparse.
Some horses, if inquisitive, may eat the leaves to try them, even if offered adequate hay. Luckily, a few mouthfuls shouldn't hurt – a 1,200-pound dairy cow must ingest between 1.2 and 4.8 pounds of wilted leaves to receive a lethal dose.
Of greater concern than ingestion is the possibility of trees harboring the Eastern tent caterpillar; these trees are the favored food source of the insects. Eastern tent caterpillars pose a great risk to pregnant mares: if ingested, they can cause early- and late-term fetal losses, late-term foal losses, and weak foals. It is recommended that any black cherry trees near pregnant mare fields be removed.
If you're unsure whether black cherry or any other toxic plants may exist near equine pastures, contact a local extension agent or botanist to be sure exactly which types of trees you have. A toxicologist, often found at veterinary diagnostic labs, can assist in determining whether the trees are poisonous.
For many decades, horses have developed habits that frustrate the people managing them. From cribbing to stall weaving to pawing, owners have swapped explanations, old wives' tales, and supposed remedies for these behaviors, which are often lumped together in a category called “stable vices.”
Dr. Katherine Houpt, professor emeritus in behavior medicine at the Cornell University College of Veterinary Medicine, says that has a lot to do with the way we've traditionally thought about those habits. And that our way of thinking about them is wrong.
Houpt is a founder of the American College of Veterinary Behaviorists, which is a certifying body for veterinarians who get specialty training in the connection between an animal's behavior and its health. The organization was launched in 1976 as there became an increased interest in the subject by veterinarians and researchers.
In a recent edition of Cornell's Equine Seminar series, Houpt gave a rundown of what we know about the most common undesired behaviors in horses.
First of all, Houpt said it's no longer appropriate to call this group of behaviors “vices,” as that seems to confer responsibility on the animal for having a bad habit. It's more appropriate to call these stereotypic behaviors, or even more accurately, repetitive, functionless behaviors.
Here are some takeaways:
–Almost all stereotypic behavior is a reflection of some kind of stress or pain the horse is experiencing. Houpt said that when you look at the way domesticated horses are managed, it's no wonder. Studies of feral horses find they spend 60% of their time eating, 25% resting while standing, 9% walking around foraging, and 7% lying down.
A stabled horse allocates their time very differently, and unless they have free choice hay (which many do not) will probably not be grazing as much. Even if they have free choice hay, they won't be walking around to find it, and the high-concentrate meals more commonly fed to stabled horses result in a different environment for the GI tract than a forage-centric diet.
Then there's stabling. Stalls are often constructed based on what's most convenient for the people running the barn (or what's most affordable) but often won't take into account horses' social needs. Horses are used to not just seeing each other, but also being able to touch. They're also used to being able to escape a testy neighbor. Stalls with poor visibility to other horses can inhibit all of that, which triggers stress. Some horses find situations like this more stressful than others.
–Houpt has noticed breed differences in stereotypic behaviors. Arabians are more likely to be stall walkers, while Thoroughbreds and Warmbloods (who have considerable Thoroughbred genes) are more likely to be cribbers. No one has isolated which genes are responsible for these behaviors, but Houpt suspects the genetic link may come along with some other trait that is selected for, which would account for how the behavior keeps getting passed along.
–Some types of stereotypic behavior are unintentionally rewarded by humans. A horse who paws at feed time, for example, will do it until they're fed. Since they're eventually fed, they may associate the two activities.
“The natural reason that horses paw is to get to food, usually when it's covered in snow or dirt, so it's not surprising that it often occurs around feeding time,” she said.
Withholding food to make the horse “wait” or to try to generate “patience” isn't likely to work. Operant conditioning learning theory has demonstrated that an infrequent or longer-awaited reward only makes the association between a behavior and the reward deeper.
–Stall kicking (kicking the wall inside a stall) probably has to do with the horse's feelings about their neighbor – either a demonstration of aggression or self-defense. Swapping stalls may help.
–Houpt doesn't have a lot of hope for stall toys remedying a stereotypic problem, but they also won't hurt to try. Mirrors can relieve social anxiety in some animals, but some horses will attack them (so opt for plastic if you want to try one). Chew toys may be good for horses who chew wood. Food-dispensing toys can be effective, as they simulate grazing, but Houpt has also had research horses who lost interest when they became difficult to use.
–Cribbing and wood chewing are two different issues. Cribbing involves the horse sucking air into their esophagus while bracing their teeth on a wood surface. Wood chewing involves the actual ingestion of wood.
Wood chewing is thought to be connected to diet, as it's more commonly seen during late winter, when horses may have less access to roughage in the pasture. One study suggested it could also be related to a lack of exercise.
–Horses do not appear to be very likely to learn to crib by watching another horse do it.
“There is this old horse trainer's fable that horses learn to crib from other horses and there is no evidence of that,” said Houpt. “When we surveyed horses in our cribbing study, we asked how many of you have had cribbers and non-cribbers at the same time and how many horses started to crib after the cribber join your barn? And of 118 cribbers who lived with other horses, only 12 other horses began to crib. So that's less than 10%. I don't think it's a big risk.”
–If you catch a horse cribbing early enough in the process, any number of solutions, including cribbing collars, will probably stop the behavior. Once it becomes established, it's much harder to stop.
–There are two ways to address most of these unwanted behaviors – by dealing with the symptom or dealing with the problem.
Houpt has known there to be a range of physical barriers that can prevent a horse from engaging in an undesired behavior. Besides cribbing collars, there are surgeries that supposedly prevent horses from being able to crib (though she says these are not usually long-term solutions and come along with serious welfare concerns); you could replace soft bedding with a hard floor for horses who paw; people will modify stall fronts to reduce a horse's ability to weave out an open-front door.
All of these things have questionable effectiveness, and Houpt says the horse will still be triggered by whatever is stressful to them.
The better bet is to reduce stress by increasing roughage, increasing turnout time, changing social groups, improving visibility of other horses in stalls and paddocks, or some combination therein.
–Stereotypic behaviors do need to be addressed, Houpt said. Cribbing can damage walls and fences and cause harm to a horse's teeth. Stall kicking or pawing can create injuries. Stall walking makes a horse go through more bedding material and can overstress limbs and joints if the stall is small.
The behaviors probably do help a horse with their stress.
“Don't let it being a coping strategy mean that you don't have to do anything to make the horse's life better,” said Houpt. “But yes, I'm sure that's probably the reason many of these persist because it does help the horse deal with whatever is stressing them.”
Dana Stead, longtime Southern California track veterinarian, is resigning his position after 14 years, reports the Daily Racing Form.
“I put in my 14 years here and I'm looking to do some other things,” Stead told DRF. “I haven't made any final decisions [about next steps]. I'm talking to some people.”
Stead, a 42-year-old native of Glendale, wrote in a letter to regulatory officials that while “track management has gone above and beyond to create a team of veterinarians dedicated to protecting our equine and human athletes,” the job has “come at much sacrifice to my personal happiness and that is why I decided to make a change.”
Among the factors influencing Stead's decision are the rash of fatalities during the 2019 Winter/Spring meet at Santa Anita, “frivolous litigation,” and watching “my esteemed colleagues be labeled criminals by the profession we serve.”
Question: What are your recommendations for exercising horses during the winter months? Do you have any tips for cooling them off?
Response: Continuing to exercise your horse throughout the winter months can help keep them in shape and healthy if you have a safe space to do so. Reduced activity in the winter can lead to stocking up, loss of muscle condition, and weight gain.
Bitter cold, snow depth, and ice are just a few challenges we face in Minnesota when it comes to exercising horses outside during winter.
Before working your horse, check for and remove compacted snow and ice (snow balls) from their hooves.
When riding in the snow, be mindful of snow depth and your horse's fitness. Deep, heavy, or wet snow can stress tendons and lead to injury. Additionally, riding in these conditions is hard work and may not be appropriate for an unfit horse.
Never ride or work your horse on ice.
What if you have poor footing for exercise and no access to an indoor arena? Most horses handle having the winter off very well. If you want to encourage your horse to move during turnout, try placing hay in multiple spots around their lot. Hand walking is also a good option for horses that tend to stand by the hay feeder all day or are stocked up.
If you are fortunate enough to have a safe space to work your horse over winter, make sure you take time to properly cool them off following exercise. Thick winter hair coats can leave horses wet and steamy after a ride. Turning out a wet horse or leaving them stand in a cold barn can lead to illness. Use a cooler to help wick away moisture from your horse and allow their coat to dry. Alternatively, if you regularly work your horse, consider trace clipping them. Trace clipping will allow your horse to stay cooler during exercise and shorten the time it takes them to cool after exercise. Clipped horses will require a blanket during turnout to help keep them warm.
