Tag: Supplements

Should laminitic horses get a thyroid supplement?

Posted on: June 9, 2012

Kurt’s sides are lumpy despite years of taking thyroid supplements to boost his metabolism.

Editor’s note on June 15, 2015: I wrote this post before reading Juliet Getty’s post on treating the insulin resistant horse. Thyroid supplement may help the laminitic horse lose a little weight, but I think it’s a poor substitute for helping a horse restore balance in its diet and life. Even before I read Getty’s post, I had taken Kurt off thyroid powder because it was making him break out in a drenching sweat. It took me a while to figure out the cause of the sweat. The day I stopped the thyroid powder, the sweat went away. Giving thyroid powder to a laminitic horse may cause unintended consequences. I’m leaving the article up, because the reporting of the research is accurate.

Laminitic horses often are put on the thyroid supplement levothyroxine sodium (commonly sold under the brand name Thyroid-L).

While it can be an effective component for treating the insulin form of laminitis, the reasons for using it have fluctuated over the years.

The thyroid is located in the neck of all mammals. The gland secretes the hormone thyroxine, or T4, and to a lesser extent triiodothyronine, or T3. These hormones predominantly affect metabolism, but they also influence growth, development and body temperature.

The pituitary gland and hypothalamus in the brain also play a role in regulating thyroid levels. The anterior pituitary gland releases thyrotropin, a thyroid stimulating hormone referred to as TSH. The hypothalamus releases thyrotropin releasing hormone, or TRH, which affects thyrotropin.

Low thyroid levels may be the result of problems in the thyroid, hypothalamus or pituitary gland, or all three.

According to Nat Messer, DVM, at an AAEP meeting in December 1998, hypothyroidism is uncommon in horses, but widespread misdiagnosis of thyroid dysfunction results in more than $750,000 worth of thyroid hormone supplement being sold for use in horses annually.

So, why have we been using thyroid supplements for laminitic and foundered horses? There was a time when laminitic horses that were “easy keepers” were presumed to have hypothyroidism because their body condition, particularly regional fat deposits, mirrored that of dogs with hypothyroidism, plus the horses had low or low-normal resting serum T3 and T4 concentrations.

But, in a 2006 proceedings paper for the AAEP, Nicholas Frank, DVM, admitted that scientists had come to realize that low thyroid levels were a consequence rather than a cause of the horse’s metabolic issues and may even be the result of use of phenylbutazone, or bute.

That surprised me. In more than 15 years of treating laminitic horses with bute, I was never told that bute might be lowering my horses’ thyroid levels.

Still, many owners of laminitic horses, including me, have been told to try thyroid supplement because it may help speed up the horse’s metabolism so the horse can lose weight, which hopefully will lower the horse’s risk for having a relapse of laminitis. Losing weight is often a battle for foundered horses because they are too lame to exercise and their food needs drop off dramatically due to the fact that they don’t move much.

I can tell you from personal experience that Thyroid-L doesn’t always help a horse lose weight — my horses got 2 grams of Thyroid-L a day for years, and they both were obese.

Where levothyroxine sodium does appear to help is with controlling insulin levels, though insulin’s role in laminitis was only solidified by research in 2007, so Thyroid-L may have been silently doing some good on the insulin front for years while being prescribed as a weight-loss treatment.

In a study published in 2008 in the American Journal of Veterinary Research, Frank said administration of levothyroxine sodium led to weight loss and increased insulin sensitivity in adult horses with healthy thyroid gland functioning. He also said levothyroxine sodium significantly increased the rate of insulin disposal.

Note that the amount of T3 and T4 in the bloodstream regulates the release of TSH by the pituitary gland, so low levels of T3 and T4, for whatever reason, make the pituitary release more TSH. There is no shortage of studies that talk about the link between a high TSH level and insulin resistance in humans.

In a German study published in 2000 in Clinical Endocrinology, researchers concluded that study subjects with normal thyroid function (euthyroidism) but elevated TSH were more obese, had higher triglycerides and an increased likelihood for metabolic syndrome, also known as insulin resistance syndrome.

The concern with the insulin form of laminitis is how much insulin and glucose is circulating in the horse’s bloodstream. If Chris Pollitt’s Australian research team is correct, elevated insulin levels in a horse can lead to the excess insulin in the blood errantly binding with the wrong receptors in a horse’s feet (insulin-like growth factor 1 receptors, rather than insulin receptors, which don’t appear to exist in horses’ feet), leading to out-of-control hoof growth, not unlike cancer, destroying the structure of the hoof wall, coffin bone and laminae.

If Thyroid L can lead to faster disposal of insulin, that alone might be a reason to add it to the diet of the laminitic horse.

At the same AAEP meeting in 1998, Messer addressed some additional factors that may affect thyroid levels, including nutrition. He said short periods of food deprivation can lower thyroid levels, as can diet composition.

Messer and associates conducted a study at the University of Missouri (published in 1995) in which food was withheld from six adult horses with normal thyroid function for four days. Hormone levels decreased more than 50 percent over that time. When the horses returned to a normal eating schedule, their thyroid levels returned to normal.

In a laminitic horse, thyroid levels might be lowered by bute and food deprivation, which are normal treatments for laminitis, and the resulting elevated TSH levels may increase insulin resistance. Elevated insulin would cause even more damage to the feet than had happened already. Given this scenario, it’s easy to see why owners might see some improvement giving a thyroid supplement to a laminitic horse.

Tricks for giving medicine to laminitic and foundered horses

Posted on: December 19, 2011

Hollow out the end of a carrot with a steak knife to hide your horse’s medicine.

Over 15 years of treating six horses with laminitis, I’ve had to come up with many weird and wonderful ways to give medicine and supplements.

Success often hinges on how bad the medicine or supplement tastes, and some medicines are harder to mask than others.

For example, I gave the supplement LaminaSaver, which is mostly jiaogulan, to Angel on and off for two years to try to stimulate circulation in her feet during the winter. The last few years, winter was really hard on her, and her mobility dropped off with the temperature. But, I gave her this supplement with mixed feelings. Have you ever tasted LaminaSaver? It’s terrible, in my opinion. And the taste stays with you for hours no matter how you try to get rid of it.

I gave it to Angel by buying a juicer, juicing carrots and mixing the powder in with the carrot juice, then squirting the mixture in her mouth with a syringe. The powder tasted better, but it still wasn’t great; at least there was no horrible aftertaste. But, I never was comfortable making her take something that tasted that bad. And the cleanup after each dose was tremendous.

I started giving the horses Quiessence either by hand or in their feed several years ago and kept that up until October 2011; the magnesium was supposed to help control insulin resistance in laminitic horses. Quiessence is made with alfalfa, so the horses always wolfed that down. I never tasted it myself. In fact, I usually only taste things when the horses refuse to eat them. I always wondered about the wisdom of giving them alfalfa, but at least I didn’t have to do much work on that one.

For some medicine, such as bute, it seems better to just get it down without the horse tasting it.

I used to get the apple-flavored powder bute and never had a problem with the horses cleaning it up in their feed. But, I was trying to feed as little as possible, and you need a certain amount of feed to cover it, especially if you’re also mixing in thyroid powder, which I’ve been doing for a long time.

I changed vets and suddenly only had the option of the orange-flavored bute powder. None of my horses would touch it. After getting through one tub by putting the powder in a syringe and squirting into the horses’ mouths (not so easy in the winter when my fingers aren’t working), I changed to bute boluses.

They weren’t orange flavored or scented, and they were cheaper. I didn’t really have a plan how to give them when they arrived. I was thinking about crushing them and given them through a syringe in the same fashion, but I stumbled upon a new trick as I was trying to figure it out.

I took a steak knife and hollowed out the end of a piece of carrot and placed half a bolus of bute inside, and each horse ate his bute as if it wasn’t there.

For a whole gram, I stuck with the half gram-per-carrot ratio and just used two carrot pieces.

This process has worked well for other pills, such as antibiotics.

The only two supplements I’m using now are the Heiro to lower their insulin levels and thyroid powder. As long as there is some feed to cover the thyroid powder, the horses just eat it. I don’t think it has a taste.

The Heiro supplement is chock full of cinnamon. When you open the jar, the whole room smells like cinnamon. The instructions provide ways to make it more palatable for horses, but my horses didn’t have a bad initial reaction. That first day, I held my breath as I put the buckets down, because I was thinking, “This is our only hope to stop this latest bout of laminitis; please don’t let this be a feeding nightmare.” I based that feeling on the fact that we had tried everything else and nothing had stopped bouts of laminitis in progress, and this product was designed to lower insulin levels in laminitic horses, which is what my horses needed. If I could get the supplement in them, I thought it would work.

The horses at first chewed their feed over and over with puzzled looks on their faces because they had never tasted anything like it, but now they pounce on their breakfast, which is when they get the Heiro, and lick their buckets clean. Big relief.

My plea to anyone thinking of making drugs or supplements for laminitic horses in the future is: Please make them taste good or make them in bolus form. Don’t ask my horses to eat anything you wouldn’t want to eat yourself.

How many calories does your laminitic or foundered horse burn exercising?

Posted on: November 6, 2011

Editor’s note on June 15, 2015:

I wrote this post before reading Juliet Getty’s post on treating the insulin resistant horse. I no longer think counting calories is a good way to treat a laminitic horse. However, the included material related to calories is correct.

—–

The National Resource Council’s equine nutrition report, released in 2007, provides information on how much energy horses expend during exercise in addition to giving dietary requirements.

The NRC says that an 1,100 pound horse burns 5,000 calories if it trots for two hours. And the horse burns 2,000 calories if it walks for two hours.

Breaking that down a little bit, a horse trotting for one hour burns 2,500 calories. Trotting for 10 minutes works out to 417 calories. That’s pretty good for 10 minutes of work.

A horse walking for one hour burns 1,000 calories, and a horse walking for 10 minutes burns 167 calories.

By contrast, the average male running for an hour burns about 940 calories or 157 calories in 10 minutes, according to NutriStrategy.

Ten minutes is important in looking at laminitic horses, because some research suggests that 10 minutes of exercise a day is enough to lower a horse’s insulin level.

In 1992, researchers at the School of Veterinary Medicine at Louisiana State University reported that 10 minutes of exercise significantly reduced insulin resistance and helped ponies lose weight in as little as six weeks. The ponies were put on a treadmill and required to walk for one minute, trot for one minute and canter for eight minutes (hard to imagine making a pony canter on a treadmill). This was their only exercise. The rest of the time, they were stalled. The ponies lost a significant amount of weight during this time, changing body shape, losing girth size and seeing more muscle definition. Researchers noted that improved insulin sensitivity was maintained in the six weeks after exercise was stopped.

If your horse burned 417 calories in that 10 minutes, and everything else were kept equal, the horse would burn 2,919 calories a week.

To lose a pound of body fat, a horse must create a deficit of 3,500 calories, either from eating less or exercising more. If the horse burned an additional 2,919 calories a week trotting for 10 minutes every day, the horse would be pretty close to losing that pound.

If your horse needs to lose 200 pounds, 1 pound a week may not sound very helpful, but every diet has to start somewhere.