Date of Award


Document Type

Honors Thesis


Environmental Studies

First Advisor

Carol Loeffler




Infestation with the gastrointestinal nematode Haemonchus contortus in small ruminants, such as sheep and goats, can cause farmers severe economic losses and endanger animal welfare. Adult H. contortus attach to the stomach of a sheep and feed on their blood. Eggs are secreted in the animal's feces, hatch on pasture, and are ingested by the sheep while grazing. Chemical anthelmintics are commonly used to treat H. contortus, but the parasite is becoming resistant to these drugs at an alarming rate. This research investigates alternative methods for managing H. contortus in two parts. The first part tested a natural dewormer developed by the company Fertrell on ten sheep at the Dickinson College Farm. This experiment used FAMACHA and McMaster's methods to determine responses in anemia and H. contortus loads in the animals' feces. The second part investigated the effectiveness of alternative prevention methods in existing literature. The experimental results indicated that the natural dewormer has potential for being effective – the longevity of the effect, however, is uncertain. More research is necessary. The literature review found that selective treatment, pasture rotation, and nutrition supplementation are important and effective ways to increase sheep resistance to and resilience against H. contortus and suggests areas for future research.