A problem of parasites

Sheep and goat have long been plagued by parasites, resulting in production losses to the detriment of farmers’ income. Aggravating this concern are reports that parasites are gaining resistance to major anthelmintics or drugs.

To address the problem, the scientific community together with the sheep and goat raisers decided to look for other control strategies less dependent on the use of anthelmintics, one of which is identifying sheep breeds resistant to endoparasites.

Researchers focused on genetic variations of the indigenous or native and exotic sheep breeds particularly the St. Croix, Katahdin and Rambouillet Merino in terms of their resistance to gastrointestinal nematode parasites. The study shows that native ewes have low parasitic load comparable to that of the Katahdin and St. Croix while the Rambouillet Merino had significantly higher fecal egg count.

Evaluation using 176 lambs produced from eight rams across four lambing seasons, revealed that St. Croix lambs had significantly lower transformed fecal egg count at weaning (the time when the animal is not dependent on the mother’s milk) compared to the other breeds. The same group of lambs had lower fecal egg count at eight months old.

With the indication of parasitic resistance among St. Croix and Katahdin sheep, the study recommends their use in breeding.

The researchers said that other methods of endoparasite control include rapid rotational grazing, complete confinement, and supplementation of forage and tree shrubs.

Dr. Mario Suba of Central Luzon State University and Dr. Andrew T. Orais of the Department of Agriculture- Regional Field Unit 8 (DA-RFU 8) conducted the research. – Jerosalem A. Marquez, S&T Media Service