Spring brings sunshine . . . and sweet itch

Sweet itchIf you have never had a horse that suffered from Sweet Itch, consider yourself lucky. According to an article posted on www.thehorse.com, as many as 60% of horses in Queensland, Australia, are affected; more than 21% of horses in Israel; 26% of horses on the northwest coast of North America; and nearly 5% of horses in Japan.

Sweet Itch is an allergic reaction to the saliva from the bite of midges — also called no-see-ums or gnats. The midges travel down the long hairs of the forelock, mane and tail to reach the skin and bite.

Horses that are allergic to the bites have a hypersensitivity reaction — an acute allergic reaction — which sets off a cycle of itching and scratching. In extreme cases the horses suffer so severely that they drop to the ground to roll and scratch themselves or destroy fencing by rubbing on it. Most horses simply end up with sores and hair loss, mostly along their mane and tail and spend a lot of time scratching, swishing their tails and biting at themselves.

Preventative Measures

  • No see ‘ums congregate in wet areas like water troughs and ponds. Try to keep tanks clean or add a filter to keep the water moving.
  • Keep your horse inside during from about 4pm to 8am when midges are at their worst
  • Put bug screens on stable windows
  • Hang insect-repellent strips in the stable and braid fly repellent tags into your horse’s mane and tail.
  • Put fans in the barn, as gnats cannot fly against a strong air current
  • Use an effective insect repellent daily
  • Keep your horse in a fly sheet with a neck guard and a fly mask.
  • Consider adding garlic to your horse’s feed (but be careful because too much garlic can cause anemia)


According to a study conducted by the University of Guelph Equine Research Center (ERC) feeding flaxseed (linseed) can relieve the symptoms of sweet-itch.

Flaxseed has long been recognized as a superior vegetable source of omega-3 fatty acids to treat many atopic (allergies likely to be hereditary) skin diseases in dogs. But while it is commonly fed to horses to improve the hair coat, the exact effect of these omega-3 fatty acids on the equine dermis (skin) is unknown.

In the ERC’s double-blind study, six Icelandic horses with a history of sweet-itch (confirmed by a skin test with Culicoides extract) were fed ground flaxseed, or an equivalent amount of bran meal as a control, for 42 days. On Days 0, 21, and 42, the horses were injected with Culicoides extract, saline (as a negative control), and histamine (as a positive control, guaranteed to trigger a skin reaction), and the resulting reactions were assessed over a period of 18 hours. Samples of skin, blood, and hair were also taken to provide a fatty acid profile.

Horses on the flax seed supplement showed significantly smaller skin test reactions to Culicoides serum after 42 days, indicating a less severe allergic response. Researcher Wendy Pearson O’Neill, MSc, also noted a reduction in the long-chain saturated fatty acids in the analyzed hair, which she says is an indication of changes in secretions from the skin. “By altering the fatty acids in the skin secretions, it’s possible that certain populations of dermal microflora were affected, changing their ability to metabolize compounds such as histidine and trans-urocanic acid, which are involved in immune function,” she explained. “This would reduce the overall immune response to Culicoides injection.”

Feeding flax seed is simple — studies have shown that you can feed it whole. I personally feed a cup and a half per day. You can see my previous post on it — Flax Seed: How and why to feed it to find out the other health benefits to feeding flax.

Sweet Itch Information & Resources

Cure closer for sweet itch in horses

Treating sweet itch gnat allergy

A guide to sweet itch in horses by Global Herbs


The cost of adding fat to your horse’s diet

Adding fat to your horse’s diet is one of the quickest and least expensive ways to add calories. If you are already meeting your horse’s nutritional needs, you don’t necessarily want to feed more grain. Certainly, that’s been the case with Freedom. He is a bit of a “hard keeper” but if I feed him too much complete feed, he gets too hot to focus.

Oil is messy to feed. For many years I assiduously avoided it for that reason, preferring to feed rice bran. However, when you have a horse that is thriving on the calories provided by two cups of oil per day, it quickly becomes advantageous to find the least expensive source for fat. Over the winter, when feeding oil was a non-issue because it froze in the barn, I asked my husband to prepare a cost per calorie comparison to determine which fat source offers the biggest bang for the buck. I had just bought a bag of rice bran and was amazed by how much it cost.

Keep in mind that this comparison is only to evaluate cost per calorie. At a later date I’m planning to write about the reasons why you might — or might not — choose  particular fat source based on other issues.

Here’s what he compared: Soybean oil vs. corn oil vs. rice bran vs. flax seed.

Here’s a caveat. We belong to Costco. Price clubs like Costco allow you to purchase vast quantities of products such as oil at low prices. To benefit from the price comparison that’s detailed here, you need to have a bulk source of oil. I’ve been feeding soybean oil although I also feed half a cup of flax seed per day.  For Rice Bran I used the Triple Crown rice bran available from my feed store.

Update on feeding flax seed

After I wrote, Flax Seed: How and why to feed it, I got an excellent question from a reader.
Anne wrote, “Could you tell me your source for the ‘current research’ on feeding flax seed whole. I would like to read how this research was done and by whom.”

I do keep track of my sources for articles, but when I looked back at my notes, I found that I had quoted the “current research” statement from this article,  Understanding Horse Nutrition: Flax Seed which does not publish a source. Typical internet, right? Someone says something unverified and then it’s plastered across the web as the gospel truth. However, I’d also discussed this with a vet and a nutritionist and know several people besides myself who feed whole flax seed (I know, plural anecdotes do not equal data).

I circled back and got this answer from the nutritionist.

There is very little research on digestibility of flax in equines at all, of any kind, it’s nearly all been done on cattle or humans.

But,  for what it’s worth, here’s my opinion. the Omega 3s in flax are VERY sensitive to light and air, once ground it loses the Omega 3s very fast. Stabilizing (usually a heat treatment) does not preserve the Omega 3s it only stops the cyanide production.

So the best way to get the O3s into the horse is to feed freshly ground flax, but if you can’t do that then feed whole flax they can digest around 50% of it and they get more O3s that way.

Remember horses have good teeth (unlike cattle) and an acid environment in the stomach (unlike cattle) both of those act to split the seed coat and allow access to the seed for digestion.

That’s why you don’t see a difference whether you feed whole flax or ground flax.

I have 40 horses on flax no way could I grind for all of those.

So there you have it. Just remember that if you choose to grind flax seed daily it’s very important that you clean the grinder thoroughly. The flax that remains in the grinder quickly goes rancid and will contaminate the next batch.

As for me, I will continue to feed the whole seeds. I like the convenience and the price. Heck, I’ll just feed slightly more so that they get their full dose of Omega 3s.

Flax Seed: How and why to feed it

These beautiful blue flowers are the signature of the flax plant.
These beautiful blue flowers are the signature of the flax plant.

I’ve been feeding my horses flax seed (also called linseed) for about a decade. I started with HorseTech’s fabulous products, first with Glanzen, their hoof & coat supplement, then moving onto one with glucosomine in it. I found that feeding a flax-seed based supplement improved their coats so that they glowed. I also liked the fact that flax seed adds Omega 3 fatty acids to the diet — the only other natural source of Omega 3s in a horse’s diet typically is fresh grass, something my horse doesn’t get enough of!

These days I feed flax as part of my horse’s overall diet. I feed it separately now mostly because when I had two horses, they had different needs: it was easier for me to customize their nutritional packages by buying individual components than finished products. Now I’m used to “building” my own supplements.

There are several benefits associated with Omega 3 fatty acids:

  • It can help reduce inflammation which may help horses with joint stiffness or arthritis.
  • It helps improve coat quality adding shine and softness.
  • It improves digestion.
  • It boosts the immune system and can help regulate thyroid function.
  • It can help reduce the chance of laminitis.

In humans, Omega 3 fatty acids improve heart health and can reduce the chance of blood clots forming in the veins, thereby reducing the chance of strokes. There have been no comparable equine studies, but hey, it can’t hurt!

Horses are able to extract the nutrients from whole flax seeds.
Horses are able to extract the nutrients from whole flax seeds.

How do you feed it?

If you do a Google search on feeding flax seed you’ll see that there are several recommended ways to feed it: ground, boiled, soaked — anything except whole seeds. Lots of sites tell you that whole seeds can’t be digested. However, that appears to be a myth. Current research shows that horses can masticate flax seeds just fine and that the nutrients were extracted from the seed hulls even if you see a few whole seeds in your manure pile.

I’ve been feeding whole flax now for about a year. Previously, I fed ground flax seed. I haven’t seen any changes in my horses so far and it’s far easier to feed it and store it. I’ve also read that there’s another benefit to feeding whole seeds: when they are eaten they form a coating in the digestive tract that helps keep the gut moving effectively.

Probably the most popular way to feed flax is ground. When you buy commercially ground flax seed it is stabilized. That’s an important point: if you grind it yourself, you need to grind it fresh for each meal. The nutrients in flax seed start to degrade very quickly if they are not stabilized and when they are exposed to heat, light or oxygen. Ground flax also goes rancid quickly so you should be very careful about cleaning the grinder very well as the remnants can contaminate new batches. Refrigeration can help extend its shelf life a few days, but you’ll still see a loss in nutrients.

People who boil or soak their flax seed often do so because they believe that otherwise the flax might contain harmful levels of cyanide, which is toxic. In truth, while the seeds do contain the two components necessary to create cyanide, they are in different parts of the seed. Ironically, it’s the contact with water that brings the two components together and causes the formation of cyanide. Soaking is actually the most dangerous way to feed flax.

Boiling isn’t a good idea because while it changes the cyanide to a gas form, removing it from the flax, it also destroys the fatty acids which is why you feed flax!

Another consideration

While cyanide shouldn’t be a concern, if you feed flax seed keep in mind that it’s calcium/phosphorous ratio is not balanced appropriately for horses. Since it is high in phosphorous you should feed either a calcium supplement or a feed high in calcium (such as alfalfa) to balance your ration.

Generally nutritionists recommend feeding 4-8 oz of flax seed per day which makes it a very low cost supplement with many nutritional benefits.