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This past year we did S.T.E.M. week as one of our Hooked on Horsessm themes for summer camp. For Science day, we focused on genetics. Why genetics if we are not a breeding facility?

As a horse owner, and especially since we only use one breed at our facility, I felt it is important that our riders understand that the horse they may choose when they are ready to purchase their first horse, needs to be vetted beyond the typical vet check. They need to look at their horse’s genetics and what may possibly be lurking.

As the ability to isolate genes and track diseases improves so is the possibility of being able to determine the future health of a horse. Since we only have Haflinger horses on our facility, I will discuss their potential diseases. Bear in mind that these and others are present in many other horse breeds.

Equine Polysaccharide Storage Myopathy (EPSM, PSSM, EPSSM)

EPSM is a metabolic disorder. Horses are unable to keep their muscles working properly on what we consider “normal” horse diets. The symptoms include tying up, or weakness in the hind limbs. Some owners feel their horse is lazy because part way through the ride or lesson the horse slows down and has a hard time moving. This is because the horse cannot store, and therefore get muscle energy from carbohydrates.

This disorder is across all breeds of horses. Research shows that about two-thirds of draft type horses and one-third of light horse breeds are susceptible to EPSM. Often the best built, best temperament, best performing horses are diagnosed with it. This is a hereditary disorder that we may be inadvertently breeding into our stock.

It is treatable with proper diet. The horse is fed fat in the form of oil instead of the carbohydrates froun in grain. Any pelleted food is high in fat and does not contain carbohydrates. If not treated, this disorder may result in death.

In 2007 we were stunned when a horse that we felt was healthy succumbed to this disease within 48 hours. Once it was identified as her cause of death, we had the rest of our herd of 10 horses tested for the disorder. At that time the only way to test was by performing a muscle biopsy. The results showed that four of our horses also had this disease. There is now a DNA test that can be done using the hair root from the horse’s tail to determine if the horse has this disorder.

Squamous cell carcinoma

This form of eye cancer is the second most common type of tumor in horses and the most frequent eye tumor. The tumor typically develops in non-pigmented areas of the skin and the eye. It is frequently found in Appaloosas and color-dilute breeds such as Belgians and Haflingers.

Early symptoms are a reddening, roughening or ulcerating area. Treatment involves surgically removing the tumor through one of many means. Chemotherapy may also be an option. If left untreated the tumor can spread behind the eye, into the sinuses, and ultimately the brain.

Once treated, the horse needs to wear an ultra-protective fly mask during the peak sunlight hours since exposure to the sun’s ultra-violet rays can trigger this disease.

In 2014 a tumor appeared in one of our horse’s eye. We had it removed and, because we did not use the horse for our program, we sold him with full disclosure. This spring we discovered a smaller tumor in the eye of two of our horses. We had the tumor removed and treated both horses with chemo for one month. We keep fly masks on both horses during the day. To date, both are doing well.

The interesting aspect was that these horses were all full brother/sisters. All three of them developed squamous cell carcinoma in the right eye. Coincidence or hereditary?

The University of California, Davis has recently developed a DNA test to determine if a horse is susceptible to squamous cell carcinoma. We will definitely be taking advantage of this test and, should any other horses show susceptibility, they will also be sporting fly masks all year round.

Seeing that both of these diseases, along with many others, are hereditary, we can’t help but urge breeders to have their horses tested, then, decide whether breeding the horse is the right thing to do.

EPSM only requires ONE of the parents to have the disorder to pass it on to an offspring. With squamous cell carcinoma, breeding horses even if one is heterozygote (R/N), risks producing horses that can be affected with this disease.

For us, we already test any horse that we acquire for EPSM. The test for squamous cell carcinoma will now be added to the vet check list.

Linda Watson-Call is the owner and head riding instructor at Pretty Pony Pastures. Visit the website for details on all the lessons and activities at this facility.

Horses eating hay

Keep your horse well fed during the winter.

It’s almost here again and we look into the barn and wonder if we have enough hay to last our animals.

How do you figure out how much hay you need? Do you track how many bales you used from year to year? What if you increase or decrease your herd? Did you switch your hay supplier? Are the bales heavier or (gasp!) lighter than the previous years?

Depending on the age and activity level of your horse, he will consume between 1.5% and 2.5% of his weight in hay/grain.

For the sake of simplicity, let’s say our horse weighs 1,000 pounds and is lightly worked, even in the winter. So, that horse would eat about 2% of his weight or 20 pounds of hay/grain every day. If your hay bales average 40 pounds, you would feed this horse a ½ bale of hay a day. We are making the assumption that the horse is not getting any grain. The amount of hay would, of course, be decreased based on the amount of grain fed daily.

Now the question is, is your horse on hay all year or do you pasture you horse during the warmer months. This is critical in figuring out how much hay you will need.

If you feed hay all year, and you feed a half bale a day, you would need 183 bales of hay per horse. However, this does not take into account cold winters nor other factors like wind chill or the winter coat your horse may or may not have.

Using 400 as a base temperature, we would add about one pound of hay for every 10 degrees below this base temperature. So at 300, you may want to add one or two pounds of hay, depending on the winter coat. But, if it’s raining, you may need to add three to six pounds of hay and if the wind is at 10 to 15 miles per hour, you might want to think about adding 10 to 14 pounds of hay!

So now, how do you figure out how much hay you really need?

Since we have determined that a 1,000 pound horse would need 183 bales of hay if the horse was not on pasture, we now need to calculate how many days of cold our region has. Again, to make the math simple, let’s say we could have 100 days of temps at or below 300. Of those days, 30 would be at or below 00.

Coat 70 days at 300 – 00 30 days below 00 Total pounds
Heavy 70 x 3 pounds = 210 pounds 30 x 8 pounds = 240 pounds 450 pounds = 11.25 bales
Light 70 x 6 pounds = 420 pounds 30 x 14 pounds = 420 pounds 840 pounds = 21 bales

If your horses are stalled and out of the elements, you may be able to give them less hay, but, always do a check of your horse’s weight during the harsh winter months. Winter coat can be deceiving, so feel for your horse’s ribs as well as a visual inspection to see how he is wintering.

Linda Watson is the owner and head riding instructor at Pretty Pony Pastures. Visit the website for details on all the lessons and activities at this facility.


You have to wonder which is worse, the deep snow or the gusting winds that are bringing the temperature below 00 and the wind chill into the -30s. We can bundle up, but what about our fur kids – the horses.

With over ten years’ experience, you would think I wouldn’t worry any more. But I do. Even though I know that our horses have enough to eat and warm water to drink and shelter. I still can’t help being concerned even though I know how the metabolism of the horse works.

Eating_Hay_1re

Good feed

Hay is the best feed for horses, especially during the cold winter months. When the hay is digested in the hindgut, it ferments and keeps the horse warm. Increase hay as the temperature drops below freezing. Consult your vet to determine the optimal amount of hay for your horse. Older horses and working horses may require more hay than easy keepers or pasture ornaments. If you can keep hay in front of your horse at all times, that would be perfect. But some horses would gorge themselves, so this is not a wise choice.

Plenty of water

Even in the winter the horse needs a good source of palatable water to prevent colic. Water heaters work good in large tanks and heated buckets work in stalls. If the water is too warm, your horse may not drink it. Also make sure the heater is grounded. Your horse will refuse to drink if it gets a shock from the water bucket.

Nature’s insulation

Most horses put on a thick coat for the winter. But did you ever wonder if it is thick enough? Do you ever shiver and get goose bumps? So do horses. Shivering – not excessively – can help boost the metabolism and help warm the horse up. More effective is piloerection. When you get goose bumps, your skin contracts and little bumps appear causing your hair to stand on end. The same thing happens with the horse, but, this fluffs their coat. They can actually control how “fluffy” their coat gets and the air space between the hair helps to insulate them against the cold. A healthy horse will have a “blanket of snow” on their backs and not be wet at all.

Moving the blood

But what about their hooves, ears, muzzle? The horse has a capillary system that can direct the blood to and from different parts of the body. So, in the summer, the thermoregulatory system directs the blood away from the organs and toward the skin to relieve the body of heat. It also directs the blood in a way to cool the hooves, ears, and muzzle. In the winter, the opposite happens and the blood warms these areas.

Knowing all of this, I will still check on the horses regularly, making sure they have a good supply of hay and a filled, warm water trough. Then go back to the house for a cup of hot chocolate, since my body could learn something from the horse’s metabolism.