Controlling Internal Parasites in Sheep and Goats
If you've raised sheep or goats, you've doubtless seen symptoms of internal parasites. In our own sheep, these symptoms include diarrhea, general lethargy, anemia, and bottle jaw. If you've been in the business of raising sheep and goats for any length of time, you'll also know that dewormer resistance (that is, parasites that develop resistance to specific dewormers) is an increasingly difficult challenge. Thanks to a great webinar put on by the American Sheep Industry's Let's Grow Committee, I recently discovered a new resource for managing internal parasites in small ruminants. The American Consortium for Small Ruminant Parasite Control has an outstanding website - check it out at www.wormx.info!
We've long used the FAMACHA(c) system to identify anemic animals in our flock - anemia is a symptom of infection with Haemonchus contortus (barber pole worm). By using the FAMACHA(c) system, we can target infected animals only with our deworming treatments. According to Dr. Ray Kaplan of the University of Georgia College of Veterinary Medicine, proper use of the FAMACHA(c) system "will significantly slow the development of resistance to dewormers which is becomign an extremely important concern in small ruminant production." Click here for more information on the FAMACHA(c) system.
The FAMACAH(c) system, however, doesn't tell the whole story about parasitic infection. Fecal egg counts can be used to more closely monitor the level of parasitism in your herd or flock. We've not done this systematically with our sheep, but I think we'll start! Here's more information.
At one time, our veterinarian recommended rotating deworming products to reduce the likelihood of developing resistance. Today, rotation will not prevent resistance from worsening. Instead, experts now recommend that dewormers be used together at the same time in combination. Another article by Dr. Kaplan indicates that using combinations of dewormers gives each drug an additive effect, which means fewer resitant worms survive the treatment. Click here to read the full article. Be sure to read the "Precautions and issues to consider" section!
Finally, someone told me when we first started raising sheep that chicory contained a compound that was helpful in controlling internal parasites. It turns out that there may be something to this! An experiment conducted in Ohio in 2009-2010 investigated non-traditional forages (including chicory) as a strategy for reducing parasite burden in lambs. The researchers found that lambs grazed chicory showed statistically lower fecal egg counts. They acknowledge that "grazing forage chicory is not an effective parasite control strategy in and of itself," but that it might have potential as one tool within a multi-tool approach. Click here for more information on chicory. It may be worth seeking funding for conducting a similar trial in California - contact me if you're interested in researching this topic!
Finally, here a few more helpful links:
Sheep Agriculture (with links to ASI webinars)
US Lamb Resource Center: great information on managing lambs