Ask the Equine Vet: Holiday Hazards

Author: Sallie S. Hyman, VMD, DACVIM, CVA

The holiday season is upon us. For many people, this means the fun and creativity of decorating the house for each holiday. And for many, it also means decorating the barn, or at least their own horse’s stall. While getting our equine friends into the holiday spirit may seem like a good idea, it must be done very carefully so that the holiday fun does not turn into a holiday emergency. Many dangers lurk in what may seem like innocent decorations.

Fall Holidays:

Fall signals the harvest and Halloween. Pumpkins, mums and dried corn stalks are commonly used to decorate around the barn and arenas, especially at barn entrances and on jump standards.

Chrysanthemum

Chrysanthemums are a favorite fall flower for the garden. By Digigalos, via Wikimedia Commons

Chrysanthemums, sometimes called mums or chrysanths, are flowering plants of the genus Chrysanthemum in the family Asteraceae. Mums are traditional fall flowers and come in a variety of colors. All parts of chrysanthemum plants are potentially toxic to dogs, cats, horses and other mammals. Ingesting the plant can cause vomiting, diarrhea, excessive salivating, rashes or a lack of coordination. How a specific animal reacts to the plant varies, depending on the animal, its size, the amount it consumed and the chrysanthemum species. Horses can experience GI discomfort if they eat a large amount of mums. It is best to avoid letting them munch on the flowers. If they do happen to get into them, monitor their comfort closely and let your veterinarian know in case more severe signs develop.

Corn stalks make great fall decorations, but care should be used when horses are around. A problem that can occur from a horse trying to eat a corn stalk or the corn cob on it is choke. Often, in their haste to eat something that they know they shouldn’t, horses will inadequately chew the cob or stalk and it will become lodged in the esophagus. Signs of choke include drooling, coughing, feed material coming out of the mouth and nose, and occasionally a “gagging” like response. This is a medical emergency and you should contact your veterinarian immediately to relieve the choke and prevent complications. It is highly unlikely that a horse would become ill from ingesting just a bite or two swiped from a decoration, but all horses should be discouraged from eating corn stalks and any corn that is on them. Corn and the stalks can contain a mold called Fusarium, especially if was grown during a particularly wet season or there was a lot of insect damage. Fusarium produces the mycotoxin fumonisin that causes the deadly neurological disease known as Equine Leukoencehalomalacia, commonly referred to as moldy corn disease. White matter is the brain is affected and produces signs of incoordination, weakness, loss of appetite, and eventually death. Signs can take a week to several months to appear. Once signs appear, there are no treatments that can reverse them. Horses should not be fed corn or corn stalks as a feed supplement unless they have been tested for fumonisins.

Pumpkin display

A typical Fall display featuring pumpkins and cornstalks.

Chocolate: Halloween means treats. We humans love our chocolate and often have bowls of chocolate goodies around the barn. Although a yummy treat, chocolate contains substances that can be toxic to our horses. The toxic substances in chocolate are theobromine and caffeine. Theobromine and caffeine are mild stimulants, bronchodilators, and vasodilators. It is unlikely that a horse would be able to find enough chocolate to consume to induce toxicity, but it is conceivably possible in a mini or small pony. The greater danger is the possibility of having a positive drug screen in a competition horse. Because of the widespread distribution of caffeine, the FEI has removed caffeine from its list of prohibited substances and some regulatory authorities allow a low threshold in plasma and urine samples. However, other jurisdictions have a zero tolerance to caffeine in swab samples. An oral dose of caffeine can be detected for up to ten days. Don’t be tempted to share your Halloween bounty with your horse. It has been shown that the feeding of 10 M&M’s® with peanuts would produce a detectable concentration of theobromine and caffeine in the horse’s urine for 48 hours.

Pumpkins are abundant this time of year and can make a good treat for your horse. They can be fed cooked or raw. Just make sure that the pumpkin is cut into manageable sized pieces to prevent choke. Avoid feeding whole pumpkins of any size. A greedy horse may try to swallow a small one whole.

Winter Holidays:

Traditional Christmas decorations include many hazards. A little knowledge, planning and common sense can keep your horse safe.

A lovely Poinsetta, a common Christmas flower. By KENPEI (KENPEI's photo) [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC-BY-SA-2.1-jp (http://creativecommons.org/licenses/by-sa/2.1/jp/deed.en)], via Wikimedia Commons

A lovely Poinsetta, a common Christmas flower. By KENPEI (KENPEI’s photo), via Wikimedia Commons

Poinsettia are one of the hallmarks of the winter holiday season. They come in many beautiful colors and add a festive look. Well, rest assured, poinsettia are safe! This plant has developed an undue bad reputation for being toxic. The milky white sap found in poinsettias contains chemicals called diterpenoid euphorbol esters and saponin-like detergents. Mild signs of vomiting, drooling, or rarely, diarrhea may be seen. If the milky sap is exposed to skin, dermal irritation (including redness, swelling, and itchiness) may develop. Rarely, eye exposure can result in a mild conjunctivitis (“pink eye” secondary to inflammation). Signs are self-limiting and generally don’t require medical treatment unless severe.

Other holiday plants, however, can be quite toxic. Mistletoe and holly can be toxic to horses. The berries are most toxic, but all parts or the plant contain toxins. In addition, the pointed leaves can cause injury. The plants contain several toxins that cause symptoms of colic, difficulty breathing, slow heart rate and collapse, erratic behavior, tremors and seizures. It is best to avoid hanging holly or mistletoe where your horse might be able to reach it.

Breyer Holiday 2014 Horse

The Breyer Holiday Horse is outfitted in holly and mistletoe, which looks lovely, but is a dangerous decoration for your real horse.

Some smaller ornamental Christmas trees may be of the genus Taxus, commonly referred to as Yew. This evergreen shrub has fleshy red seed coverings. All parts of the yew plant, both fresh and dried, are extremely toxic to horses. The plant contains taxine, a toxin that affects cardiac activity. Consumption of as little as 1-10 g/kg of body weight for ruminants and 0.5-2 g/kg for horses is lethal. This means that, for a 454-kg (1,000-lb) horse, as little as 227 g (0.5 lb) of yew needles could be fatal. Sudden death, often within 2-3 hours of ingestion, is the most common observation with yew poisoning. Animals are often found dead next to yew bushes or clippings. Prior to death, muscle trembling, loss of coordination, nervousness, difficulty breathing, slow heart rate, vomiting, diarrhea and convulsions may be observed. There is no antidote for yew poisoning, only supportive treatment.

Christmas decorations such as ornaments, tinsel/garland, and lights should also be placed with care. Curious horses will try to eat ornaments that might look like yummy fruit to them. These can result in choke or an intestinal foreign body that can result in colic. The same goes for stockings with carrots or other horse treats. Your horse may decide it is easier to eat the whole stocking than to pull out the treats.

Christmas lights should be carefully inspected to ensure that they are not a fire hazard and should be placed so that horses cannot pull on them or the extension cords. Both lights and garland should be carefully secured so that horses cannot get tangled up in them.

The holidays should be a time of fun and festivities. With a little knowledge and common sense, you can make the holidays happy for you and your horse. Stick to safe Horse Treats this holiday season!

Registered 2014 Equestrian Collections

Information in this article is for educational purposes only and is not a substitute for evaluation by an equine professional.  In particular, all horse owners should seek advice  and treatment from a licensed veterinarian for their horses’ medical care.