Parasite Control for Herd Health

— Written By Laura Oliver

Image of sheep

The heat is ramping up and small ruminants, like sheep and goats, throughout the county are gaining access to the lush green pasture they have missed all winter. While this access can mean improved nutrition and lower feed input cost for local farmers, it also means increased exposure to parasites. Parasites are one of the biggest health concerns for small ruminant producers in the southeast. At their worst, parasites cause disease and death; but even in small numbers, these creatures can cause nutrition and efficiency issues, reduce weight gain, decrease successful pregnancies, and ultimately have a detrimental impact on the owner’s bottom line. Controlling parasites, especially internal parasites like stomach worms, should be one of the primary concerns for producers in Martin County. Unfortunately, many parasites are drug resistant, so producers must consider more creative solutions including integrated approaches to parasite control.

Image of a goat

In order to fully understand how to control parasites, producers must first understand the worm life cycle. Adult worms produce eggs that are passed through the digestive system and out in manure. These eggs hatch and go through several developmental stages before infecting a new host. This means that during the warmer months of the year, huge numbers of larvae can build up in a pasture. These worms need grass, moisture, and warmth for development, all of which are plentiful in NC pastures. These worms can also go through an arrested development stage to keep the worm alive through the winter when the eggs would not survive in pasture.

Using this information, producers can use the following techniques to control parasites and reduce the need for frequent deworming treatments. First, animals should be checked regularly. Some parasites exhibit scouring in animals to alert you to a problem, but the deadliest parasites cause anemia and no scouring. This anemia can be observed in mucous membrane like those around the eye. If this area is pale, it can alert you to a problem.

Image of anaemia

Next, nutrition is critical to the health and resiliency of your animals. Research shows that animals who are on a diet high in protein, minerals, and energy are more resistant to the adverse effects of parasites and can help the animal develop an immune response to parasites. In addition, some animals will be more likely to have better immune response like adult bucks, does, and ewes. Kids, lambs, and lactating or pregnant females are more at risk for infection. Deworming efforts should be concentrated on the animals that need it most, and those animals that are consistently infected should be considered for culling as there is a genetic component to parasite resistance. Do your research on the drugs you choose to keep from developing parasite resistance and quarantine new animals for several days before commingling them with your herd to avoid introducing drug resistance to your herd.

If you would like more information on parasite control or any other livestock or horticulture questions, contact Laura Oliver, Martin County Extension Director, 789-4370.

The information in this article was sourced from “Small Ruminant Parasites,” 2018 by Dr. Chelsey Ahrens and Dr. Heidi Ward, University of Arkansas Division of Agriculture.