Mobile Veterinary Services, LLC

The Scoop On Fecal Egg Counts October 4th, 2010

QUESTION: 

I have read a lot on Fecal Egg Counts over the past few months.  Could you discuss the appropriate use of counts here in Colorado?

 

ANSWER:

In the last Ask a Vet, we discussed rotational deworming and its application here in Colorado.  Fecal Egg Counts (FEC’s) are a tool that we use to help us direct rotational deworming.  A FEC is a test the counts the actual number of parasite eggs within the horses’ manure.  This is done by submitting a small sample of manure to your veterinarian.  Your veterinarian then runs a floatation test on the sample and counts the number of parasite eggs that are present in that sample, reported as eggs per gram of feces.  The ideal time to run the test is about 3 months after the last dose of dewormer was given, which allows an appropriate timeframe for parasite eggs to reappear.  This gives you the baseline amount of parasites that your horse has present without interference from any deworming drugs.

 

At this point, each horse within a herd can be ranked in regards to the amount of parasite eggs that they are shedding.  This ranking is dependent upon each horse’s individual natural immunity to internal parasites.  The extended timeframe since the last deworming gives us insight into the immune system of the horse and its ability to naturally fight off parasites, rather than the efficacy of the last dewormer used. 

 

We will generalize and place each horse into a broad category of parasite shedding.  If, a horse is found to be a “low” shedder, then it is possible that the horse can be dewormed less frequently (once every 6 months).  These horses have a higher natural immunity to parasites, and are less likely to accumulate a large number of parasites within their system.  Many horses fall in the “moderate” shedder category.  Normal deworming for these horses would be considered quarterly rotational deworming (previously discussed here), where the horse is dewormed about every 3 months.  The “high” shedders are the problem horses.  These are often older or immune compromised horses, which are unable to fight of parasites.  These horses should be dewormed more frequently (up to 5 or 6 times a year). 

 

The second part of the Fecal Egg Count is the egg reduction test.  After the “baseline” is established, a second test sample is taken 10 to 14 days after deworming.  This sample allows us to determine if there is a drug resistance problem within your herd.  If the dewormer that you gave is effective, then a horse should have a significant (>90%) reduction in the number of eggs seen within the manure.  If there is less than 90% reduction in the number of eggs, then the dewormer that you used lacks efficacy or you have resistant parasites to that dewormer present in your horse.  In combination with appropriate rotational deworming, Fecal Egg Counts can help guide parasite control for your horse, and potentially save you some money on deworming products.  More importantly, FEC testing can help you to more closely monitor you horses’ health, and potentially help save you money in the long run.

Rotational Deworming… What’s the Right Choice? September 14th, 2010

QUESTION: 

Can you please discuss “appropriate” rotational deworming?

Due to the influx of deworming questions, we will tackle them in 2- 3 parts over the next few months.

 

ANSWER:   

Standing in the feed store, there are dozens of packages of dewormers, and the age old question of, “which one do I use now?” goes through every horse owners mind.  The answer to this question is not always a simple one.  To appropriately deworm your horse through the year, a rotational deworming program is essential. 

            Here in Colorado, we usually recommend quarterly rotational deworming.  Some herds may require more frequent or less frequent deworming, depending on fecal egg counts. (To be discussed here at a later date). 

Rotational deworming is exactly what it sounds like, rotating through different chemical classes of drugs throughout a year’s timeframe.  Though the name brand might be different, the active ingredient is the important part to rotate.  The idea behind rotating the chemical classes is to reduce the chance of a parasite developing resistance to a type of drug (much like antibiotic resistance).

            To begin rotational deworming this fall on an adult horse our recommendation is using an avermectin product.  There are dozens of avermectin products on each shelf, with various name brands (to name a few – Equell, Equimectrin, Ivercare, Rotectin, Zimectrin, and Horse Health Ivermectin and Quest Gel).  Avermectins have a very broad base of activity, but there are a few types of worms that are not killed.

            In the winter quarter, we usually recommend, for an adult horse a benzimidazole product.  When you’re at the counter, the easy way to remember is that you are looking for an active ingredient that ends with “azole.”  A few name brands in this class are Safe-Guard, Panacur, and Anthelcide EQ. 

            In the spring quarter (usually about the time you see us for spring shots), we rotate back to an avermectin product, but usually include praziquantel.  The praziquantel is effective against tapeworms.  The name brands in this class are Equimax, Zimectrin Gold, and Quest Plus.

            To come full circle and cover a full year, in the summer MVS likes to use a pyrantel salt based dewormer.  Some name brands in that class are Strongid Paste, Rotectin P, Pyrantel Pamoate paste and Liqui- Care P.

As another alternative to quarterly deworming, there is the option of daily deworming (feeding a small amount of dewormer every day).  Using one of these products, you still need to “rotate” and 2 times a year give a paste dewormer.  Our recommendations for these horses on daily dewormers are to use an avermectin once a year, and then a benzimidazole about 6 months later. 

            With appropriate rotation of deworming products, your horse should maintain a minimal parasite load. 

            Look for the next post regarding Fecal Egg Counts to round out your deworming knowledge.

 

 

In Summary:

MVS Rotational Deworming Recommendations (Quarterly Deworming Schedule):

 

-         Fall:  Avermectin (Ivermectin or Moxidectin)

-         Winter:  Benzimidazoles (Fenbendazole or Oxibendazole)

-         Sping: Praziquantel w/ Avermectin

-         Summer:  Pyrantel Pamoate

 

Horse Rabies In Colorado May 3rd, 2010

QUESTION:
I have heard on the news over the last week or so about a couple of cases of Rabies in horses here in Colorado. Should we be vaccinating the horses for Rabies?

ANSWER:
The short answer is yes, here at MVS, we are currently recommending rabies vaccines for all of our equine patients.
There are many different “variants” of rabies, but here in Colorado we are concerned about only two. Bat rabies is carried in insectivorous bats (they eat only insects) here in Colorado and there is a low incidence of exposure and therefore transmission of the disease. Skunk (or terrestrial) rabies is carried by skunks and has a higher chance of exposing domestic pets and horses. Here in Colorado we have always had an incidence of bat rabies (though never reported in horses before 2009). Since 2008 there have been an increasing number of cases of skunk rabies reported. This has also led to a small increase in the number of domestic animals that have been exposed and tested positive for rabies, including a small number of horses. Since 2009, El Paso, Adams, and Douglas counties have each reported a case of rabies in a horse.

For a small cost each year, a horse can be protected from this 100% fatal disease. The vaccine is effective at protecting the horses, and is also quite safe. For a disease like rabies, where there are very serious public health ramifications to you and your family, the rabies vaccine is a great idea. Although the risk of exposure is still small, a properly vaccinated horse is the only horse that will survive infection with rabies.

As a note, we spoke with the state veterinarian today, and they confirmed that a horse has to be vaccinated by a licensed veterinarian to be considered protected from the disease. Therefore, in the event of a suspected rabies exposure, if your horse was not vaccinated by a veterinarian, they will be considered unvaccinated by the State of Colorado!