Parasites are a significant threat to all small ruminants, especially in this geographic region. Recommendations can vary from farm to farm, and most certainly, from region to region. We encourage all of our clients to work with us to tailor protocols that are specific to their herds. The instructions provided here should only be used as a reference after we have examined your animals and established herd protocols.
Because we are forced to use either ivermectin or doramectin on a regular basis, we have to assume that all of the more common gastrointestinal parasites are resistant to these two drugs. Although you are probably using only one of them, remember that they are in the same family, so resistance to one means resistance to both. The typical gastrointestinal parasites (Strongyle species, Nematodirus, Trichuris, etc.) are constantly exposed to the ivermectin or doramectin levels in the bodies of treated animals. They quickly become resistant, and this usually means that they are able to help the entire parasite population on a farm to become resistant.
To prevent problems from other nematode type parasites (Trichuris species (aka whipworms) and Strongyle species including Haemonchus contortus and Nematodirus), we recommend deworming your animals every six months with Panacur (fenbendazole). Panacur for large animals may be obtained in two forms, liquid and paste. Already, we have seen a small number of farms with fenbendazole resistance. This drug has a high margin of safety and is safe in young and pregnant animals. It is better that an animal gets a little more per pound of body weight than a little less. This is not true for every drug, but it is the case for Panacur. If you have a scale, use it! The best times of the year to treat the herd with Panacur are in the fall after several hard frosts and in the spring once animals are out on pasture, though there may be other times when individual animals may require treatment.
Monthly herd surveillance is very important in keeping parasites from becoming a problem in your herd. This can be accomplished by regularly body condition scoring all of your animals, looking for bottle jaws, and watching for diarrhea. We are happy to discuss this or show you how to manage your herd; just ask! You need to feel through their fiber to determine if they are fat, thin or just right. When you are doing this, we recommend that you also look at their conjunctiva. This is the underside of each animal’s eyelid (not the white part of the eye, but the part of the eyelid that you would see if you flipped it inside out)! It should be red or dark pink. If it is light pink or white, this indicates the animal has some degree of anemia. Anemia means that an animal has a lower concentration of red blood cells in its blood which is sometimes an indication of internal parasites.
To assist with this process, we can provide you with instructions and a special card called a FAMACHA card. This shows a color scale ranging from red to pink to white with indications for when to be concerned. It is better to have the card in hand to compare to the conjunctiva, as lighting conditions can alter how pink the conjunctiva appear. FAMACHA cards and the system are copyrighted and available only through veterinarians who obtain them through the University of Georgia. We are more than happy to bring them to your farm and demonstrate how they can be used as an assessment tool on your farms.
In general, parasites follow the 80:20 rule. 80 percent of the problems seem to affect only 20 percent of the animals. Picking out thin and anemic animals is one way that you can help find that 20 percent on your farm. Another very useful way is by routinely submitting feces from at least 20 percent of the animals for fecal flotation. Generally, I recommend finding the thin animals and choosing them, but it is also good to check one or two animals in each of your groups or pens even if they all appear in good body condition. Pooled fecals (scooping feces from the ground or manure piles) is NOT generally recommended. It is hard to make specific treatment decisions with the results of a pooled fecal sample. Ideally, checking fecal samples once per season, or four times annually, is recommended. Of course, any time an animal is found to be thin, weak, inappetant or anemic, we hope that you will contact us! If you are already following the general deworming guidelines, we don’t advise you to treat such animals without at least a conversation with us. We have a few other dewormers in our arsenal (though not many), and a careful evaluation of the situation is needed to determine what specific treatment would be best.