Be prepared for parasite problem when sheep and goats graze on pastures

Mike<metzgerm@msu.edu> Metzger, Michigan State University Extension - May 04, 2011

Sheep and goats are more susceptible to internal parasites than other livestock, due to their grazing behavior and poor immunity.

Internal parasites are a health problem affecting small ruminants. The parasite that causes the most problems to small ruminants is Haemonchus Contortis, better known as the "barber pole" worm. The barber pole worm is a blood-sucking parasite that pierces the lining of the abomasum, causing blood plasma and protein loss to the host. The symptom most commonly associated with barber pole infection is anemia, characterized by pale mucous membranes, especially in the lower eye lid; and "bottle jaw," an accumulation of fluid under the jaw.

The use of clean or safe pastures will help to control parasite problems. A clean or safe pasture is one in which sheep or goats have not grazed for 6 to 12 months. A pasture grazed by cattle and/or horses is also considered safe, since sheep/goats and cattle/horses do not share the same parasites. Pastures that have been renovated or rotated with row crops are clean, as are pastures in which a hay or silage crop has been removed.

In the past, producers relied heavily on anti-parasitic drugs, called "anthelmintics" to control internal parasites in their goat herds. Unfortunately, parasites have become increasingly resistant to many of the anthelmintics. In addition, few anthelmintics are FDA-approved for use in goats. As a result, producers can no longer rely on anthelmintics alone to control parasites in their herds. A more integrated approach will be necessary. You can slow the development of resistance on your farm by not introducing anthelmintics resistance to your farm. New arrivals should be isolated and dewormed with products from at least two families of drugs. Care should be taken not to under dose animals. Combinations of products may slow down resistance. A product should be used on a farm until it is no longer working.

Family	Drug Ingredient	Trade Name	Approved for Sheep	Approved for Goats
Benzimidazoles	fenbendazole	Panacur®	No	Yes
	fenbendazole	Safeguard®	No	Yes
	albendazole	Valbazen®	Yes	No
	oxfendazole	Synanthic®	No	No
Imidazothiazole	levamisole	Prohibit®	Yes	No
	levamisole	Tramisol®	Yes	No
	morantel tartrate	Rumatel®	No	Yes
Macrocyclic lactones	ivermectin	Ivomec®	Yes	No
	moxidectin	Cydectin®	Yes	No
	doramectin	Dectomax®	No	No
Amino acetronitrile derivatives	monepantel	Zolvix®	No	No
Consult with your veterinarian for off-label use concerning: product choice, dosage, animal class, withholding time, mode of administration, use of drugs in combination

There are two tools that producers can use to more effectively control internal parasites: fecal egg counting and FAMACHA©. Fecal egg counts can be used to determine the level of pasture contamination and the need for anthelmintic treatment. FAMACHA© is a system whereby you examine the lower eyelid of the sheep and administer treatment only if signs of anemia are present.

For More information or information on upcoming programs contact Mike Metzger or Richard Ehrhardt.

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