The Parasite Problem in Small Ruminants & Camelids

Raising sheep, goats, llamas and alpacas in Virginia can be interesting, rewarding, and challenging. Many of these animals produce high quality fleece, milk, and meat for Virginia farmers, and provide a unique farming and 4-H experience. There are several major difficulties to raising these animals in this region, however, and from a veterinary standpoint the most frustrating has to be parasite control. These four species share some common parasitic worms and protozoa (kind of like big bacteria) which cause widespread sickness and death loss year round, but particularly in early summer and fall. The "Big Four" parasitic killers in this area are: a blood-sucking worm called Haemonchus contortus or barber-pole worm; the protozoan disease Coccidiosis which causes severe diarrhea in young animals by damaging the intestinal walls; the meningeal worm Paralaphastrongylus which has paralyzed and killed so many llamas that most owners treat for it prophylactically every month (it also affects the other small ruminants); and an emerging worm called Nematodirus which has been hiding in the shadows for a long time and is now causing problems because of some of our traditional deworming practices.

The purpose of this article is to raise your awareness of these sneaky killers, and to suggest some control measures. An in-depth discussion of parasite control will literally fill chapters of books, and every farm is different, so please consult with one of our veterinarians for specific recommendations for your farm. This will probably require a farm visit and fecal sampling.

Virginia\'s climate is well suited to the long-term survival of these worms. Our winters are not cold enough to kill them, our summers are not dry enough to kill them, and our methods of raising livestock promote very large parasite populations. Additionally, we have leaned heavily on deworming drugs like fenbendazole, levamisole, and ivermectin for the past 50 years to maximize survival rates. This may have painted us into a corner because animals that "should" have died from worms lived, and passed on their less parasite-resistant genes.

As I suggested earlier, we bring a lot of this on ourselves. The number one cause of heavy worm loads and multiple parasite deaths on a single farm in my opinion is overstocking pastures. It sneaks up on us because when we first brought the animals in, we only had a few of them, and the pasture was uncontaminated. "We had no worm problem!" people say, "We\'ve never lost an animal to worms in all the years (3-5 usually) we\'ve been raising livestock! Why are they dying now?!" Because over the years, we bred the animals that we like so much, or we adopted a few more every year, and maybe all those plans to sell the offspring every year…didn\'t exactly pan out. And now we\'ve got 30 critters (or more) on 10 acres (or less) and every time they take a bite of grass they\'re getting a mouthful of parasite larvae too! This happens especially quickly with sheep and goat breeders since they commonly have 2-3 babies per female per year. Camelid owners have this phenomenon develop more slowly because of the slower reproductive cycle and the fact that their animals use dung piles, so the manure and larvae don\'t spread all over the place as quickly. But llama and alpaca owners beware if you have sheep and goats also or if you use a harrow to spread out those dung piles all over your nice clean pasture…You will be much better served to take a scoop and wheelbarrow and clean up those dung areas every two weeks.

Some parasite control basics:

Don\'t get overstocked. There are no magic number of animals per acre formulae because, again, every farm and herd is different. It will take some trial and error and common sense to find the right number for your farm. The grass will probably support more animals than is safe from a parasite control standpoint. If the grass is grazed down to Astroturf you are extremely overstocked. I have exactly one goat herd with no worm problem. About 30-40 does go out on 300 acres after milking every day.

Encourage browsers (goats) to browse brush instead of grazing grass (manure doesn\'t stick to bushes very well). Make sure your local bushes aren\'t toxic, like Mountain Laurel, Azalea, Rhododendron, or Japanese Yew.

For Coccidiosis, feed a coccidiostat such as Corid to young animals during stressful periods such as weaning, extended bad weather, moving to a new farm, etc. Keep them in clean, dry conditions. It\'s easier to prevent coccidiosis than to treat it.

For meningeal worm: deworm llamas, alpacas, and valuable breeding animals of other species monthly with injectable ivermectin product. BIG DOWNSIDE: this will make the ivermectin class of drugs almost useless against gastrointestinal parasites such as H. contortus and Nematodirus, worms that are also resistant to the other classes of drugs and starting to kill more camelids. So the question arises: is the loss of an occasional animal to meningeal worm worth reducing the other parasites\' resistance to ivermectin? For sheep and goat herds, my opinion is definitely yes. Because of the higher individual value of llamas and alpacas it is a more difficult call in these herds.

If you have deer on your farm (who doesn\'t?), you will have meningeal worm and the current standard recommendation is for llamas and alpacas to be injected with ivermectin monthly. Meningeal worm will not develop resistance because it does not reproduce in domestic livestock. Use periodic fecal sampling to keep a finger on your parasite loads. Sample 10 animals in small herds, or 10% of the herd on larger operations. Samples are best taken directly from the rectum with a well lubricated, latex glove. Gently gather at least 4-5 fecal pellets, then invert the glove, tie it off, and write the animal\'s i.d. on it with a Sharpie pen. Key times are late spring/early summer, early fall, and lambing/kidding time. Take samples to a state lab. Request a McMaster\'s fecal floatation, it will cost more and they will probably have to send it out, but it gives much more specific information than the "light, moderate, heavy" reported on the standard fecal float. The McMaster\'s test determines the exact # of parasite eggs/gram feces and can be used to monitor the effectiveness of deworming agents by taking a second sample from the same animals one week after deworming and determining the percentage reduction in egg counts. When using deworming drugs for stomach and intestinal worms, use an oral drench, not injectable or pour-on. Ivermectin is the most effective in sheep and goats. It\'s less effective in camelids due to its excessive use against meningeal worm. Fenbendazole (Panacur, Safeguard), albendazole Valbazen (not in pregnant animals during the first trimester), and levamisole may also help. Use a drenching gun to get that drug well over the back of the tongue. Accurately measure the animal\'s weight, or if not possible for every animal, accurately weigh the largest animal in the group and dose all of them at that weight. It is better to slightly overdose than to underdose; these drugs are not that toxic. Doses are not usually on the bottle for goats, llamas, or alpacas; we have to use these drugs "off label." As a rule of thumb, for GOATS use 1.5-2x the labeled sheep dose. I generally use the sheep dose for camelids, or if using the equine products Panacur or Safeguard, use double the horse dose on a per lb. basis. In herds with resistance problems (you are deworming, animals are still weak or dying), consult a vet to make sure there is not another problem such as copper toxicity (this may be as simple as taking a freshly dead animal or nearly dead animal to the state lab for necropsy). Some things we may try include utilizing different classes of drugs at the same time, management changes, targeted deworming, grazing alternative species, etc.

Accept the fact that if you plan to raise these animals in this area, you will eventually have an animal get sick and possibly die from parasites no matter how careful you are. If you raise a large number of animals on limited acreage, you will eventually see significant morbidity and death loss.