Wednesday, April 21, 2010

COW: Pinworms

Here is an under the tail view of a horse I encountered earlier this week. When I first looked under the tail, a large female pinworm (Oxyuris equi) was sticking its head out of the anus, looking for a nice place to deposit some eggs. By the time I had my camera in hand, she had already done the deed. The yellow creamy looking stuff is what she left behind (no pun intended).

We do not often seen pinworm infections because they are usually easily killed by most conventional dewormers. The interesting thing about this case was that this horse has just been treated with ivermectin two weeks prior. So either the worms were resistant to ivermectin or she became reinfected immediately after treatment. Resistance of pinworms to dewormers has become an emerging concern over the past several years. However, a study done just last year looking at just that, was unable to support any pattern of increasing resistance. That study showed that pyrantel was 91% effective and ivermectin was 96% effective at killing pinworms in horses.

The primary presenting complaint in horses with pinworm infections is tail itching or rubbing. The itching is caused by the eggs being deposited around the anus. There are other things that can cause tail rubbing as well, so an itchy tail does always mean there are pinworms present.

Pinworm eggs do not show up very well on regular fecal exams. If we suspect a pinworm infection we have to use a more creative approach to finding the eggs. One technique that really works well is to dab some scotch tape around the anus and then look at it (the tape that is) under a microscope, specifically looking for the eggs. The scotch tape on this horse showed an overwhelming large presence of eggs.

Treatment usually is fairly straightforward since most dewormers do a pretty good job at killing these pests. It is best to treat all the other horses at the same time, since if one horse has it, their pasture mates are also likely infected as well. Contamination of the environment, especially with heavy and long standing infections can be a concern as well. Occasionally, the more challenging cases, such as this one, require more creative means of treatment. It is best to talk to your veterinarian about the possibility of pinworms if your horse seems to be rubbing his/her tail excessively.

Thursday, April 15, 2010


Preventicare Colic Assistance Program (March 1, 1997 - April 14, 2010)

This week marked the passing of a staple health maintenance program for the horse. Preventicare is survived by its parent company Pfizer Animal Health, its cousins Quest and Quest Plus gel and Strongid C 2X. It is preceded in death by the recent passing of Equell Paste and Equimax Paste. Cause of death was suicide. In 2009 the program was changed to require online registration and assessed a $50 enrollment fee. The pulling of that trigger resulted in the program being maintained on life support for the past year. It quietly slipped away on April 14, 2010. The program marked a significant shift in equine health care that encouraged teaming with your veterinarian to address a comprehensive approach to the maintenance of your horse’s health, including spring and fall vaccinations, spring and fall health maintenance exams, dental care, parasite control and discussion of nutrition. This package appeared to greatly reduce the risk for a colic episode in your horse. Participating horses were eligible for up to $5,000 of insurance toward a colic that required surgery to correct. The program required the use of Strongid C2X daily dewormer. Prior to its suicide, it had entered into a depression due in part to the increasing concerns of parasite resistance and the annual cost for maintaining a horse on the daily dewormer, especially when cheaper generics had become available. Details of a memorial service have not yet been finalized. Internment to take place at Pfizer corporate headquarters. In lieu of flowers, annual health maintenance exams of your horses are suggested.

Tuesday, April 6, 2010

“I need a Jukebox with a ??? song…”

I walked into a barn this morning and someone had left the radio playing for the horses. It seems a lot of people think horses like to listen to music while they are away. That got me wondering what type of music do horses like the most? As far as I know, no one has ever done a scientific study to answer this perplexing question, though it sounds like the makings of a good PhD thesis. Since we don’t have science to answer the question, we are left to clinical impressions—which can be dangerous.

Here is what I have observed:
o Quarter Horses, Paints and most stock type breeds prefer Country music.
o Arabians prefer Rock or Classic Rock
o Dressage horses prefer Classical music

So far, I haven’t found any horses that prefer to listen to talk radio.

Friday, April 2, 2010

COW (Case of the Week): Long in the Tooth

Here are before and after pictures of an interesting dental case I saw today. This is just one example of some of the different kind of surprises we sometimes find in the mouths of horses. Sorry the pictures are not all that great. This 11 yr. Quarter Horse gelding was in excellent body condition without any history of difficulty eating. He was fairly new to the current owner, but they had noticed a change in temperament over the past couple of months. Time will tell if fixing this tooth fixes the behavioral issue, but my bet is that it will.

My assumption is that this horse has never had any dental work, given the extent to which the third premolar is so overgrown. As you are probably aware, horses continue to erupt new tooth throughout their lifetime. They wear their teeth at approximately the same rate they erupt. However, when the opposing tooth is missing, as was the situation with this case, the tooth continues to grow and given a sufficient amount of time, it begins to resemble a tree trunk. The lower third premolar (second tooth back on the bottom) was missing. As a result the second lower premolar had drifted back a little bit, so you can also see a slight hook forming on the upper second premolar. There is also a fairly deep cut in the cheek caused by this severely overgrown tooth.

It is not wise to correct these severely overgrown teeth in all at one time. The reason being, that if you are overaggressive with correction, it is possible to enter the pulp chamber of the tooth. Thus it is best to do the reduction in two or three stages, giving sufficient time in between reductions to allow the pulp chamber to recede a bit before the next reduction. In 6 months we will further reduce this overgrowth.

The only reason we looked in this horse’s mouth was as part of his regular health maintenance exam. We routinely do health maintenance exams free of charge with spring and fall vaccinations. It is often said that more things are missed in veterinary medicine for not looking then for not knowing. This case is a good demonstration of the value of routine oral exams.