Whinny, Author at Springhill Equine Veterinary Clinic

Poisonous plants… a few to start

Sep 28, 2011 | Uncategorized

This week, as Dr. King was working on landscaping at the clinic, there was a lot of discussion about plants that can make us animals sick. Many times horses don’t eat toxic plants, until there is no choice between these plants and not eating; however, I decided it was worth talking about some of the most important plant species that can affect horses. The best prevention for toxicity from wild-growing plants is to know how to identify them, and walk your pasture on a regular basis to identify and remove them. Major trees/plants to be aware of include yew, red maple, cherry, oak, and ornamental flowers. These should never be planted where your horse (or other animals) can access them.

Florida or Japanese yew can kill your horse quietly in a matter of minutes – it is common to find the dead animal next to the yew. Animals will show nervousness, trembling, ataxia, and collapse will occur as the poison slows the heart to a stop. Only 6 to 8 oz. will kill a large animal, and all species are susceptible to poisonings (including you people!). Do not plant this anywhere your animals may gain access to, or in a place where clippings may be thrown over the fence to your animals.

Yew

Red Maple

Red maple ingestion causes hemoglobin, the molecule in red blood cells that carries oxygen to the body, to change into methemoglobin, a less efficient form, for reasons unknown. This also results in rupture of the red cells, called hemolytic anemia. This effect is specific to horses. Wilted or dried leaves are the most dangerous (the toxin concentrates as leaves get ready for autumn). Fresh leaves do not appear to cause a problem. Signs of toxicity include dehydration, depression, and change in gum color (blue to brown, also yellow or “icteric”). Increases in heart rate and respiratory rate are mild, but the urine will become dark red to brown. Death generally occurs 1-5 days following ingestion of a lethal dose.

Black, wild, and laurel cherry trees contain cyanide, which turns the horses’ gums red. This is a result of a decline in oxygen utilization. Symptoms usually onset 30 minutes to an hour of ingestion. The most toxic parts of the plant are the leaves and the seeds. One laurelcherry berry can kill a horse, and all animals are susceptible to cyanide toxicity. There are many other species of plants that produce cyanide compounds, including elderberry, heavenly bamboo, hydrangeas, and various clovers.

Laurelcherry flowers

Oak leaves and acorns contain tannins, the substance that makes the Santa Fe River red. The redder the leaf, the higher the tannins. Tannins cause kidney damage, making it difficult to form urine and regulate water and electrolytes. Clinical signs include colic, depression, frequent or no urination, constipation and/or bloody diarrhea. “Oak bud poisoning” occurs when weather damages most available forages, and the budding oaks and acorns are most of what’s left. In 1985, oak bud poisoning killed over 1,000 cattle in Sacramento, CA when snowfall left nothing but oak leaves to eat. Cattle and sheep seem most susceptible, while horses, goats and chickens are occasionally affected. Pigs seem to be resistant. All species of oak should be considered dangerous.

If it is an ornamental plant, has waxy leaves, seed “pods” of some kind, or berries, it probably isn’t something your horse should be eating. Most notable pods to stay away from include Crotalaria species, a yellow-flowered plant commonly referred to as “rattlebox.” Ingestion of rattlebox can result in liver failure in the horse. Common signs with chronic toxicity are icterus, and signs of forebrain disease such as a change in attitude with depression, circling, and head pressing.

Rattlebox

Another dangerous plant tip… don’t ever use black walnut shavings for your horses’ bedding. It will result in laminitis with even limited exposure.

Thanks for visiting my counter, may your litterbox be clean and food bowl full!

Poisonous Plants….More to stay away from

Sep 24, 2011 | Ailments, Pests, Uncategorized

I got started on poisonous plants last week and couldn’t get the doctors to stop so this week I am going to cover a few more, concentrating more on weeds than decorative plants. A couple of items I learned from the docs this week: most poisonous weeds like fence lines because they don’t get mowed there, low soil pH can promote weed growth and most horses will only eat poisonous plants if there is nothing else available or it is baled in to hay.

Deadly Nightshade

This is a very common plant seen on fence lines. A very small amount of nightshade can be deadly! Nightshade acts on a very specific portion of the nervous system leading to colic-like symptoms, dilated pupils, disorientation and loss of muscle control. Keeping fence lines sprayed with herbicides on a regular basis or manual removal are the only ways to control this weed. Don’t forget to check pastures occasionally, especially around trees, for additional plants. Treatment is a drug called physostigmine or pilocarpine.

Bracken Fern

These ferns are commonly seen in wooded areas. The most common way horses eat these ferns is if they are turned out in damp wood areas with limited roughage. Symptoms are usually slow to present with the most common sign being weight loss. Other symptoms include a decreased appetite, in-coordination and a characteristic wide leg, arched back stance. The toxic portion of bracken fern causes a Vitamin B1 deficiency. Treatment with Vitamin B1 is very effective if signs are caught early.

Lantana

Many plants we use to attract butterflies are also poisonous to our horses. Lantana is one of these. Just like many other poisonous plants, horses will avoid them if given enough roughage. Here at the office we keep our butterfly attracting plants outside the fence or away from horse areas to minimize risk of ingestion. Lantana will grow wild in fields and along driveways and fence lines. Horses do have to eat a large volume of lantana to cause toxicity. Symptoms of large volume ingestion begin with photosensitization (sunburn on white markings), decrease appetite followed by yellowing of the skin and colic symptoms. If horses eat small amounts over prolonged periods symptoms may begin with a bloody diarrhea, listlessness, colic symptoms and sores on the gums and tongue. Treatment is only supportive, such as fluids, and often unsuccessful.

Milkweed

Milkweed is another common butterfly garden plant. Unlike lantana, milkweed usually doesn’t grow well as a wild plant. However, it can escape from gardens to grow in protected areas such as against barn walls, pump houses or the like. Also unlike lantana, very small quantities can cause toxic signs with 1 pound capable of causing severe symptoms in a 1000 pound horse. Symptoms include profuse salivation, colic symptoms and seizures. Treatment can only be started within a few hours after eating and is often unsuccessful. Prevention is the best treatment for milkweed. Milkweed is also very poisonous to other pets like dogs and cats so be very careful with this plant!!

Many horses are naturally curious. Unfortunately much like your 2 year old child, they explore with their mouths!! Frequently walking your pastures on the lookout for poisonous plants is key to control. Look for a seminar on poisonous plants in 2012 from Springhill Equine. It will be held at the office so even us office cats can learn all about what plants to avoid.

Thanks for visiting my counter! May your litterbox be clean and your food bowl full. Tony

Tony’s Don’ts

Sep 10, 2011 | Ailments, Feed, Leg issues, Pests

Tony here. I heard a lot of talk around the office about veterinary don’ts this Labor Day weekend. Recently I’ve thought of topics that I would like to add to your list of Veterinary Don’ts.

While the logic may sound a bit backwards, don’t give antibiotics to your horse if you suspect he has a foot abscess.

An abscess in the foot requires coaxing. Although it makes sense to treat infection with antibiotics, it really just needs a way out. Soaking the foot with salts, and drawing salves like ichthammol, that bring in moisture (water follows salt) softens the hoof horn, so the abscess can break through. Your farrier or the vets “digs” with the hoof knife around the sole of the foot where the horse is painful and/or the surface is irregular to give the infected tract an exit. If your horse has to be on antibiotics for more severe complications or another medical condition, that is a matter to discuss with the doctors. Antibiotics simply slow the maturation of the abscess, delaying healing.

On that matter… be careful not to overuse antibiotics in general. Antibiotic resistance, as seen with the emergence of MRSA, is an ever-pressing issue in medical treatment. It is important to avoid unnecessary antibiotic use, while treating your horse appropriately for their condition. I am no microbiologist (I prefer rodent-ologist), but I can tell you that the art of what the bug is and what antibiotic kills (or doesn’t kill) it is a complicated process. If the docs prescribe you antibiotics, keep using them until the prescription is gone (which should be after the symptoms resolve completely). If you’ve run out of your prescription, and you don’t think the infection is completely resolved, let us know. We always recommend a culture if we suspect a serious infection –this will give us a sensitivity profile of the microbe to a variety of antibiotics, telling us what will work. We will start treating with an effective antibiotic as soon as possible. In the meantime, help us have a bacterial population with sensitivity to the things we have that kill them. Don’t change antibiotics, or repeatedly start and stop unless necessary. And don’t keep giving your antibiotics if your horse develops diarrhea or colicky signs, call Dr. King or Dr. Lacher instead.

We animals can be pretty good at sensing what is and isn’t good for us, but sometimes we just can’t resist eating what will make us really, really sick (like those silly dogs and their chocolate). Horses have the added pressure of sensing their environment with trimmed sensory whiskers.

As a result, don’t forget to check your alfalfa thoroughly for blister beetles.

Blister beetles can result in a painful death for your horse. They live in hay. Blister beetles can be toxic dead or alive. There are 2500+ species of blister beetle worldwide, but it is the three-stripe blister beetle shown below that can be toxic to a horse with ingestion of only a dozen insects. A defensive chemical called cantharadin results in blisters when the insect is crushed against the skin, hence the name. The beetles cause severe intestinal wall inflammation, and can result in kidney failure and death in about 72 hours. Poisonings occur in horses, sheep and cattle. Double check through each flake of hay to make sure there aren’t any beetles. Hay qualities that are considered more risky for infestation with blister beetles include later cuttings, southern sources, and the presence of more blooms or weeds. Buy first cut hay to avoid infestation.

If your horse ingests a toxic level of blister beetles, he will begin to show signs of colic, straining to urinate, and frequent progressing to no urination. Call immediately if you discover your horse has ingested these buggers.

Thanks for visiting my counter, may your litterbox be clean and food bowl full!

Feeding the Senior Horse

Aug 7, 2011 | Feed

This week I saw quite a few older horses come in to the clinic and overheard a lot of information about feeding them so I thought I would compile it all in my blog. I also thought this would go well with the informative Cushing’s Disease newsletter just posted by Dr. King.

To start with I learned that most older horses fall in to two categories when it comes to feeding: easy keepers (like me) and hard keepers. Both horses require careful feeding to make sure they stay healthy.

Easy keepers are the horse that looks at a blade of grass and gains 50 pounds. The biggest problem seen in these horses is laminitis due to insulin resistance. This is not a problem exclusive to older horses but does tend to get worse with age. I think most of us can relate to the ease of weight gain as we get older. Calorie control is the name of the game here. Most commercial diets will have recommended weights to be fed on a daily basis. If controlling calories means going below the lowest recommended weight, your horse is not getting the vitamins and minerals he needs. Therefore for the easiest keepers my doctors recommend feeding a ration balancer. Ration balancers contain the protein, vitamin and minerals your horse needs with no added calories. These are fed in small weights of ½ to 1 pound per day.

The next big source of calories is pasture, especially in the summer. Dr. Lacher told a client that the Bahia grass seed heads are full of protein and starch! This means quality time with the lawn mower to keep those seed heads at bay. If that isn’t enough for your horse a grazing muzzle can be used to further decrease grass consumption. The most interesting thing I heard the doctors saying this week involved the light/dark metabolism of grass. They said grass (and all plants) changes metabolism around sunrise and sunset which causes a buildup of starches. By keeping your horse off the pasture during these times you can decrease another source of starches.

Now for the hard keepers. The first thing Dr. King and Dr. Lacher do for hard keeper is a good dental exam. This involves sedation, a full mouth speculum and a bright light. On one horse this week they found an infected tooth that was sending bacteria into the horse’s bloodstream and making it painful to chew. They removed the tooth and will now watch the horse over the next month to see if she gains back her lost weight. The next thing recommended was testing for Cushings disease. If your horse comes back positive for Cushings disease medication can help with weight loss. No matter what the cause of weight loss, Senior diets are recommended to put weight back on. Senior diets are pre-cooked to make it easier for your horse to digest. In fact these diets don’t need to be chewed at all! As long as your horse is able to get the pelleted feed swallowed it will be digested. To help your older horse swallow Senior, water can be added to make it a mash.

If more calories are needed fat is a calorie dense, safe addition. Horses are very fat tolerant. One pound of fat for every 1000 pounds of body weight can be added daily. Fat comes in two main forms: vegetable oils and prilled (powdered) fats. This should be gradually added over 7 to 10 days to minimize diarrhea. The nice thing about fat is it doesn’t add much in the way of volume. This means your horse who is low man on the totem pole can eat the same volume of grain but get more calories from it.

Another way to add calories is with high quality roughage. Alfalfa and peanut hay can be fed free choice very safely and will add loads of calories. For our senior patients with poor teeth this can be done with soaked alfalfa pellets or cubes.

Sometimes weight loss is secondary to behavior changes. Older horses can move down the chain of command due to lameness or other chronic pain problems. If you are feeding your horse in a group situation you may need to change your setup to allow the old guy to eat alone.

I hope my summary of all I heard from the front counter helps you feed your older horse. If you have any questions, please contact the office and I will make sure Dr. King or Dr. Lacher get right back with you!

May your litterbox be clean and your food bowl full…Tony, the Official Springhill Equine Office Cat

Equine Cushing’s Disease

Aug 1, 2011 | Uncategorized

Equine Cushing’s disease, also referred to as Equine Pituitary Pars Intermedia Dysfunction (PPID) or hyperadrenocorticism, is one of the most common endocrine diseases of horses. It is most commonly seen in horses older than 15 years of age. There are many recognized syndromes of hyperadrenocorticism in people, dogs, and other species that are commonly referred to as “Cushing’s disease,” but the problem can vary as to the organ source and underlying endocrine dysfunction that results in indistinguishable symptoms. In the horse, it is generally a more consistent underlying process, but the specific cause (or pathophysiology) remains largely unknown.

The pituitary gland is a normal part of the typical mammalian brain, sitting at the base of the brain just above the two optic nerves (one from each eye). There are three lobes in the pituitary gland – one of which is the “pars intermedia.” For reasons unknown, the cells in this region begin to increase in size, increase in number, and/or change into a benign tumor – called an adenoma. This underlying change seems to be the primary contributor to Cushing’s disease in the horse, which is different from, say, a dog, who may develop Cushing’s due to a problem in the pituitary gland or the adrenal gland. The pituitary gland, in both species, regulates the adrenal glands’ production of cortisol (commonly known as adrenaline). It is primarily the effects of cortisol that result in the symptoms seen with PPID.

Symptoms of PPID can vary based on the stage of the disease and specific proteins that are being overproduced by the horse’s pituitary gland. The average age is 20 years, but horses 7 years or older can develop the disease. Ponies and Morgans have a high incidence of the disease. The most commonly recognized sign of PPID in horses is a long, curly hair coat with abnormal shedding patterns. Another common sign is excessive drinking (considered >25-30L (8-10 gallons) in the normal horse) and/or urination. Bulging eyes, abnormally located fat deposits, inappropriate lactation, muscle atrophy, and/or weight loss may also be seen. Related problems that can occur in horses with PPID include laminitis, fertility problems, chronic infections or recurrent hoof abscesses, and blindness. Blindness in horses may occur when growth of the pituitary gland results in compression of the optic nerves.

There is more than one way to diagnose Cushing’s disease in your horse. The “gold standard” test is called the Dexamethasone Suppression Test – it is considered the most reliable. The horse is given an injection of dexamethasone, a type of steroid. Then a blood sample is taken approximately 18-20 hours later. If the horse is not able to reduce his own level of cortisol in response to the steroid we injected (“doesn’t suppress”), he is considered positive for Equine PPID. This test can be performed with the horse in-hospital overnight, or with two farm call visits. The other test for Equine Cushing’s is a baseline ACTH measurement (a hormone that is produced by the normal and abnormal pituitary). If, at rest, the ACTH is above a certain level, it can be presumed that the excess production is a result of PPID. These are the two most reliable and commonly performed diagnostic tests for Equine PPID.

While treatment of PPID is not curative, it can significantly improve your horse’s quality of life, ability to fight off infections, and potentially fertility in older broodmares. The most effective treatment for Equine PPID is pergolide powder, given by mouth as a top-dress to feed or via syringe once daily. Sometimes the initial dose of pergolide must be adjusted to fit your horse’s disease severity and response – repeating the above diagnostic tests once your horse is started on pergolide treatment can help determine if the given dose is appropriate. Pergolide treatment costs about $80 per month, and is given for the remainder of the horse’s lifetime. While expensive, it may reduce your horse’s future discomfort, and your future medical expenses related to management of laminitis, chronic infections, or infertility. Other treatment options include cyproheptadine, which is generally less expensive, but seems to show less consistent benefits than what has been seen in studies when compared with pergolide. It has been used in combination with pergolide for the purpose of improving its efficacy. Other important aspects of treatment and management of PPID in horses include a good preventative medicine program (vaccines, deworming, dentals), clipping of the long hair coat in summer, management of infections with antibiotics, corrective farriery for laminitis and hoof abscesses, and maintaining a good body condition with an appropriate feeding schedule.

If you suspect your horse may be affected with Equine PPID, and are interested in diagnostic testing and/or treatment, please contact the office to schedule an appointment. For any further questions about this newsletter, feel free to contact Dr. Lacher or Dr. King by phone or email.