Worm-free sheep

A tropical breed of white hair sheep, St Croix, shows a remarkable immunity to intestinal worms. Within four to six weeks the lambs have developed almost complete resistance. Scientists at the Agricultural Research Service in Beltsville USA, have been comparing St Croix, which comes from the Virgin Islands with the Dorset. In trials St Croix lambs had 99% fewer worms in their fourth stomach than the Dorset lambs kept under the same conditions. They also passed only 0.5% as many worm eggs in the faeces. Researchers have found that the resistance is connected with a large number of immune cells called globule leucocytes, which are found in the fourth stomach. It is thought that these cells prevent the worms from attacking the stomach lining. They might even cause the worms to be expelled from the stomach. Unfortunately when the St Croix are crossed with other breeds the cross-bred lambs do not inherit the resistance. The researchers are now trying to understand how the immune process works. Hopefully this knowledge will make it possible to transfer the resistance to other breeds. Researchers hope that one day it may be possible to transfer this resistance to cattle. Dr R Gamble Helminthic Diseases Laboratory USDA-ARS BARC East Beltsville MD 20705, USA

Bibliographic Details

Main Author:	Technical Centre for Agricultural and Rural Cooperation
Format:	News Item biblioteca
Language:	English
Published:	Technical Centre for Agricultural and Rural Cooperation 1992
Online Access:	https://hdl.handle.net/10568/45727 http://collections.infocollections.org/ukedu/en/d/Jcta38e/
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