Control Parasitic Worms In Sheep With FAMACHA

FAMACHA can help you control worms in a sheep flock without overusing medication, and free certification courses ensure you're scoring your animals right.

by Jana Wilson
PHOTO: Maria Sbytova/Adobe Stock

If you’re a seasoned sheep owner (or even if you are new), you’re probably no stranger to the issue of worms. Worm infestations are a common concern among sheep farmers, often leading to health problems for the flock. One particularly troublesome parasite is the barber pole worm, notorious for its ability to attach to the stomach wall, causing bleeding and feeding off the blood. Consequently, long-term and severe infestations with this worm can result in anemia in your sheep. Sometimes you’ll see with barber’s pole worm infection a state that is called “bottle jaw,” which is a fluid swelling beneath the jaw.  

This is where the FAMACHA score comes into play as a valuable tool in managing worms in your sheep and your overall flock health. Developed in South Africa and introduced to the United States by the American Consortium for Small Ruminant Parasite Control (ACSRP), the FAMACHA score involves assessing the mucosal tissue, primarily the lower eyelid, to gauge the level of anemia in your sheep. The scoring system ranges from 1 to 5, with 1 representing the healthiest, pinkest eyelids and 5 indicating severe paleness, signaling anemia. 

So, why is understanding and utilizing the FAMACHA score crucial in managing infestations of worms in your sheep? Let’s delve into the details. 

The Logic Behind FAMACHA Score-Based Treatment 

The ACSRP recommends treating only those sheep falling within the 3 to 5 range on the FAMACHA scale. Surprisingly, this means that you shouldn’t treat the sheep with pink lower eyelids. But why? The answer lies in the potential for drug resistance to worming medications. 

Some worms can develop resistance to certain types of wormers. If you administer wormer medication to all your sheep indiscriminately, you may kill the worms that aren’t resistant while leaving the drug-resistant ones unaffected. Consequently, these drug-resistant worms can continue to reproduce, potentially leading to the creation of “super worms,” a situation you definitely want to avoid. 

However, by selectively treating only the sheep that genuinely require deworming, you allow the coexistence of both resistant and non-resistant worms in your flock. Over time, these worms interbreed, diluting the gene pool with worms that are more susceptible to the worm medicine. The ACSRP refers to this concept as “parasite refugia,” and it substantially increases your chances of effectively managing worm infestations in the future. 

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Reducing Medication Usage 

One of the most significant advantages of monitoring your flock’s FAMACHA score is the potential to reduce your reliance on wormer medications.

Surprisingly, it’s estimated that approximately 70 to 80 percent of infections occur in just 20 to 30 percent of the animals. This information can inform your future breeding decisions, allowing you to selectively breed animals with greater resistance to worm infestations. 

Special Considerations for Lambs and Nursing Ewes 

It’s essential to note that recently weaned lambs and nursing ewes are particularly susceptible to worm infestations. Given their vulnerability, it’s advisable to err on the side of caution when in doubt. If you have any reservations about a lamb’s health, it’s best to go ahead and deworm it to prevent potential complications. 

FAMACHA Certification & Resources 

If you are really interested in using the FAMACHA score, the University of Rhode Island offers an online FAMACHA certification class. While the course is free, it does require some effort on your part, such as creating a video demonstrating the proper techniques for testing one or more animals. This certification can be a valuable asset in managing your flock’s health effectively. 

Additionally, the ACSRP’s website is a fantastic resource for sheep owners, covering a wide range of topics related to parasite control and flock health. It’s a valuable resource to bookmark and return to whenever you have questions or concerns about your sheep’s well-being. 

The FAMACHA score is a powerful tool in your arsenal for managing your flock’s health and combating worms in your sheep. My plan is to work on this course over the fall and become certified by November or December. 

By using this scoring system wisely, you can reduce the need for medication, prevent the proliferation of drug-resistant worms, and make informed breeding decisions for a healthier and more resilient flock.  

Your sheep will thank you for it!


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