October 31, 2003 | By: Aimee D. Heald

Did you know a female worm can produce up to 5,000 eggs a day? That’s a pretty overwhelming statistic for goat owners who are trying to reduce internal and external parasites in their herds.

“Eggs are passed in the fecal pellets,” said Patty Scharko, Extension ruminant veterinarian for the University of Kentucky College of Agriculture. “The eggs need a warm, moist environment to molt to the infective larval stage.”

Scharko said it takes about three weeks, even less time in warmer weather, for eggs to become infective larvae that goats can consume while grazing on grass. 

Some goat owners who submitted goats to the UK Animal Disease and Diagnostic Lab over the past few months said they had dewormed their goats and thought the goats may have been resistant to the dewormer.

“We did have weather conditions this year that allowed the Haemonchus worm to thrive,” Scharko said. “So, exposure time needs to be ruled out before dewormer resistance is investigated. Yes, there can be resistance to dewormers in goats; the most common resistance is to ivermectin products. Also, the dewormers were given to goats at the cattle dosage rate in many cases, and goats require a higher dosage than cattle.”

Scharko recommends that goat owners stay away from injectable dewormers. 

Perhaps the most important thing goat owners can do to lessen parasite problems is to keep the goats browsing and not grazing (grazing meaning less than about four inches). Scharko said one pasture for year-round grazing is not good.

“We should rotate goats to different pastures to keep them browsing and not grazing,” she said. “The rule of thumb is one doe and her offspring per grazeable acre. Wooded areas allow for more animals per acre.”

Some easy steps can help owners protect their goats from parasites. Scharko said to weigh goats and deworm at the correct dosage for that animal.

“Work with your local veterinarian to determine if your goats are resistant to the product you’re using,” she said. “This can be done by taking fecal samples from the goats at deworming and then again seven to 10 days later.”

There are four classes of dewormers and goat owners should make sure when they change products that they choose a new dewormer from a different class of drugs. 

Scharko said to consider treating goats 10 to 14 days after a major rain, especially after a drought period and if they have had problems in the past.


Writer: Aimee D. Heald 859-257-4736, ext. 267
Source: Patty Scharko 859-253-0571