Letters: 08/03

Insulin Resistance
I must tell you that I recently referred to your October 2002 issue regarding insulin resistance.

My 12-year-old mare became lame in the left front, which turned out to be laminitis. We tested her for Cushing’s and everything else because her dam was diagnosed with Cushing’s about the same age. The Cushing’s test came back negative, which surprised us. All of the blood work was normal, except insulin, which came back at 1194.

My vet found it peculiar that only one foot showed laminitis. We consulted with a specialist who agreed that it was unusual to see only one lame foot. However, given her blood work, there was no question that treating the high insulin should resolve the laminitis issue. So the cause is also the cure: diet and exercise.

It was helpful to have your information, as I was well prepared for the consultation with the specialist.

-Karen Bertrand


Ivermectin And Ticks
In your June 2003 issue, there is a suggestion that “the oral administration of ivermectin at doses at or below those used for deworming” has been shown to kill attached ticks on dogs, etc., and “one treatment can also reduce the number of feeding ticks.” You conclude that using ivermectin to deworm your horse “may also be helping avoid ticks.”

Does this refer to the typical periodic ivermectin worming, or to more frequent use’ I use a daily wormer, with ivermectin twice a year.

-Catherine Gabriels
New York

In species where the anti-tick effects of ivermectin have been studied, it’s been looked at both with low-dose daily administration (20 to 50 mcg/kg/day) or with the usual one-time dosing also used for intestinal parasites (200 mcg/kg). The intermittent purge dosing, such as we use in horses, provides tick control for about 14 days.

We weren’t suggesting you rely solely on ivermectin for tick control in horses, since the efficacy, duration of activity and susceptible species haven’t been looked at specifically for horses. We simply thought it was important to know that this drug’s assistance in tick control could also be an added benefit for your horse when you deworm with ivermectin. However, oral pyrantel tartrate (daily dewormer) has no activity against ticks to our knowledge.


Back Issues Pay Off
Am I ever happy that I keep my Horse Journal back issues.

I recently purchased a new mare who is susceptible to girth galls. She is fine-coated and has scar tissue in the “elbow” area. A liberal application of Corona ointment and a fleece girth cover cleared up the problem, but I was looking for a long-term solution. Your November 2000 issue featured the Balding cinch for western tack available from Bontrager’s Leather Shop. I contacted Bontrager’s and received a quote by return mail. I ordered the cinch, and it was sent to me right away.

I especially liked the fact that I could order a specific size, as I needed a 24-inch cinch, which is just not readily available except in string girths. The cinch is well-made and completely avoids the sensitive area on my mare. Thank you for finding this source. The product certainly lived up to your recommendation.

-Anne Barnett
New Jersey


Clover Experience
I hope your July article, “Facts about Clover” will spread the word about the potential toxicity of clover. Several years ago I purchased “The Horse Owner’s Field Guide to Toxic Plants” (by Sandra M. Burger, published by Breakthrough, 800-824-5000, www.booksonhorses.com). I found lots of surprises in this book, including the information about clover.

After reading the book, I called our state veterinarian, who confirmed the symptoms and effects of red and white clover. A light bulb went on over my head. Some past problems with my horses that couldn’t be explained by me or my veterinarian now made sense: sunburned noses and founder.

I’ve told everyone I can about this, but clover is so traditionally accepted as a favorite food for horses that my words were almost always met with disbelief. Friends with horses that slobbered all summer long made light of it and discounted the notion of any plant toxicity.

Surprisingly, not many veterinarians know of clover toxicity and possible resulting liver problems or take it seriously. My farrier looked at me with doubt when I told him, but when he surveyed his clients he found that his client’s horses with the worst feet were on clover.

Before I buy a horse I always have their blood checked for liver problems. I haven’t fed clover to my horses in about seven years. And in seven years I haven’t had another sunburned nose, founder, or any other unexplained maladies.

-Polly McNichol

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