Checking Eyelids New Tool For Shepherds, Goat Producers Battling ‘Barber-Pole’ Parasite

By Jane Fyksen, Crops Editor
Thursday, February 14, 2008 1:25 PM CST

Susan McClanahan

Parasites n especially Haemonchus contortus n are causing dramatic financial losses for sheep flocks and goat herds worldwide. Wisconsin is no exception. Not only is Haemonchus (alias “barber-pole worm” for its red-and-white-striped appearance) “the most important and devastating parasite in sheep and goats,” it’s also resistant to many dewormers, reports University of Minnesota Veterinarian Susan McClanahan.

McClanahan, an assistant clinical professor of small ruminants and beef cattle at the University of Minnesota Large Animal Hospital, spoke last weekend at the Indianhead Sheep Breeders Association annual Shepherd’s Clinic in Rice Lake. The northwest Wisconsin conference drew roughly 200 producers and additional youth.

To prevent further resistance, frequent deworming (not evidence-based) is no longer recommended practice. Knowing parasite resistance to traditional dewormers is “quickly becoming a significant problem, now more than ever, we need to make informed decisions before using any dewormer in sheep and goats,” contends McClanahan. One useful tool to help producers make “informed decisions” about Haemonchus in their flocks or herds is FAMACHA, a trademarked parasite monitoring system that relies on the color of inside of the lower eyelid. FAMACHA is named after its South African inventor Dr. Francois “Faffa” Malan (i.e. FAffa MAlan CHArt).

FAMACHA specifically targets Haemonchus, which McClanahan says is the cause of a lot of poor performance n even sudden deaths n in sheep and goats in the Upper Midwest. The primary impact of this parasite is anemia and loss of blood and protein from the intestinal tracts. Small ruminants with severe infestations often have very pale “conjunctiva” (tissue surrounding the eyes). “Bottle jaw” (edema that manifests on the lower jaw from loss of body protein) is another sign. Although there are other causes of anemia and bottle jaw (like Johne’s disease and chronic poor nutrition), Haemonchus is the most common. This vet says she sees lots of down sheep and goats that are anemic due to heavy loads of this parasite. As noted, Haemonchus is responsible for sudden deaths, too.

She thinks some sheep are genetically more prone to this parasite. Boer goats, she notes, “don’t tolerate parasite loads as well.” In a given flock or herd, there’s a minority of individuals that are shedding the majority of the eggs. Using FAMACHA and keeping records about necessary deworming can help producers detect n and cull n animals that are costing them money. They’ll also greatly reduce pasture contamination by these heavy-egg-shedders.

McClanahan says that in sheep carrying a load of Haemonchus in the abomasums (fourth stomach), shepherds can look at the internal color of the lower eyelid to determine just how bad off they are.

“Two things I can’t emphasize enough with sheep,” stresses this veterinarian, “are hands-on body condition (scoring) and pulling down the lower eyelid to look at the color (of the mucous membrane). You can look in the mouth to assess anemia, too, but many sheep have pigment in the mouth.”

By the time a ewe gets a parasite load severe enough that she’s thin, has bottle jaw and white mucous membranes around the eye, “you can’t pull those animals back,” says McClanahan, advising producers to cull them. They’re shedding billions of eggs and contaminating the rest of the flock.

Always examine the lower eyelids of individuals that “lag behind” the rest of the flock.

Late-gestation ewes, particularly those carrying quads, are stressed and “very susceptible” to running into trouble from a parasite load. Severe weather n like lately when it’s been 20-below - can also cause problems for heavily parasitized ewes. She sees a significant number of dead sheep and goats in July, too, due to heat stress, coupled with Haemonchus.

McClanahan says she gets “tired of seeing dead animals with Haemonchus.” Admitting there’s some controversy about FAMACHA in that it only is useful on this one parasite, she counters, “It’s the one that kills them n the one that has resistance.”

Getting trained in FAMACHA and routinely comparing eyelids to the chart n coupled with hands-on body-condition scoring n the number of dewormings can be reduced (compared to traditional deworming practices in the industry). Not only will that prevent dewormer resistance in your flock but, of course, save time and money, too. FAMACHA is especially useful in organic operations that can’t use traditional anthelmintics.

The eye chart features a scale of 1 through 5, with 1 being healthy red conjunctiva (i.e. no anemia) and 5 the worst (i.e. white conjunctiva and severe anemia). In between are: 2 n red/pink, 3 n pink, and 4 n pink/white. Treat animals in categories 4 and 5, and “if in doubt,” score into the paler category, she notes of those individuals you can’t quite figure out 100 percent.

Use the chart as a guide to determine which animals to treat, she says. As noted, make sure you record your findings on all animals. In addition, you may also want to make pasture management changes based on flock data. Since lambs and kids, weanlings, pregnant ewes and does and ones in poor body condition are most vulnerable, you may decide to treat those more aggressively with dewormer. Cull those that need treatment more often or are chronic poor-doers, since they may be the 20 to 30 percent of the flock or herd that’s harboring the most parasites. Resistance to parasites is moderately heritable, she notes.

McClanahan suggests producers contact their UW-Extension agent and request access to training from the UW. The chart is also on the Internet, she notes, by searching FAMACHA. Email FAMACHA@vet.uga.edu (University of Georgia).

Always use the chart against the sheep’s eyes; don’t go from memory. Examine them in the sunlight; check both eyes. Couple FAMACHA with putting your hands on the backs of your sheep to detect body condition. (Wool can fool producers sometimes, hiding overly thin ewes.) Monitor your flock or herd once a month if possible, but especially during late-gestation. Use FAMACHA in June in order to deworm if necessary before the heat of the summer hits. Another good time is going into winter.

If nobody scores 4 or 5, you can figure the flock is “safe,” but to be sure, reexamine two weeks later in the Haemonchus “season,” when it’s wet and warm in the spring, summer and early fall. In dry and cool times of the year, every four to six weeks may be sufficient. If over 10 percent of the flock is 4 or 5, consider treating all the 3s as well. Changing pastures, as noted, is crucial to managing this parasite. However, don’t treat your animals and then move them right away or they’ll contaminate the new pasture. Deworm, wait 10 days and then move them. It also helps to clean up pastures by alternating sheep or goats with cattle or horses (that’ll ingest larvae on the pasture).

McClanahan reminds producers that ewe condition can impact the entire life of her offspring as well. If she’s in poor condition, the quality of her colostrum won’t be as good. She’s apt to produce less milk. The impact on her lambs can be long-lasting, from average daily gain, even their reproduction.

Although llamas and alpacas, elk and deer are also impacted by Haemonchus, FAMACHA is also appropriate for use with sheep and goats, says McClanahan.

Asked about diatomaceous earth as an alternative dewormer, McClanahan replied that she’s been to many farms relying on diatomaceous earth and seen “heavy loads of parasites.” She doesn’t think it’s effective. Asked about garlic, she noted that the properties of garlic aren’t effective against parasites per se, although they may help the immune system of the sheep in general.

She advocated “smart drenching,” taking into account the nature of the parasite, pasture management, time of year, deworming history and the flock’s parasite load. Making an informed decision before deworming will maximize the effectiveness of treatments while decreasing the possibility of drug resistance. Sheep and goats that don’t respond to deworming strategies should be culled.

Moxidectin (Cydectin) is the newest dewormer approved for sheep. Although very effective, McClanahan says producers must use this product judiciously and not on a “routine, wide-scale basis,” to preserve its efficacy. Use moxidectin only in clinically ill animals and stick to your goal of preventing Haemonchus resistance, she directs.

As noted, many UW-Extension agents and vets are trained in FAMACHA. It takes about two hours and once completed, you’ll be able to buy the laminated card at a cost of around $12.

“But remember,” McClanahan concludes, “FAMACHA is only part of a total worm control program and not a replacement. Producers must make every effort to control parasites through management strategies such as rotational grazing, resting pastures and monitoring fecal egg counts.”

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