Researches are investigating whether naturally occurring plant compounds could provide a sustainable way to control internal parasites in sheep. Their findings, published in Frontiers in Veterinary Science, highlight the potential of plant-based alternatives to conventional parasite treatments.
The study was led by Tumen Wuliji, professor of animal science with Lincoln University Cooperative Research, whose interest in natural parasite management grew from research conducted at LU’s certified organic Alan T. Busby Farm. His work focuses on improving animal health within organic sheep production systems.
The research explored bioactive compounds found in various plants that are commonly present in pasture forage.
“The goal was to find ways to help control parasites in small ruminants by studying bioactive compounds found in different plants, which can be components of pasture forage,” Wuliji said.
Bioactive compounds are natural plant substances that can affect biological functions. In this study, researchers examined whether these compounds could eliminate parasite larvae before they develop into adult worms capable of producing thousands of eggs that spread through sheep manure.
The team tested water-based extracts from 24 plant species, including forage crops, herbs and common weeds. Laboratory experiments, led by recent MU Ph.D. graduate Chao Ke under Wuliji’s supervision, measured parasite survival after 12, 24 and 48 hours of exposure.
The results showed stronger parasite control as both extract concentration and exposure time increased. At the highest concentrations, extracts from goatweed, spurge weed, goosefoot, velvetleaf and tall boneset achieved at least 90% larval mortality after 48 hours.
Wuliji noted that the effectiveness of tall boneset and velvetleaf against sheep parasites has received little previous attention.
The findings establish a foundation for future feeding trials to determine whether these plant-based treatments remain effective in live animals.
“Whether this result actually happens when you feed animals, that is another matter to be verified,” Wuliji said.
Future studies will evaluate these promising plants in grazing systems and feed supplements, with the goal of providing sheep producers with more sustainable parasite-management options while supporting long-term flock health.