154 Journal of Ag.. Yic. [lo March. 1912. 



WORMS IX SHEEP. 



By S. S. Cameron, D.V.Sc, iM.R.C.V.S. 



Of the domestic animals that are kept in large numbers to minister 

 to tlie wants of man the sheep is the least subject to attacks of disease. 

 True, the goat, the donkey, the mule, and the cat are much more disease- 

 resistant, but amongst domesticated animals in the economic sense these 

 may be considered a negligible quantity. Sheep are but slightly liable 

 to the ordinary ailments of an inflammatory or sporadic nature, which are 

 of frequent occurrence in horses and cattle, such as colic, pneumonia, 

 pleurisy, enteritis, impaction, or constipation. They are also remarkably 

 immune against germ diseases; and except for anthrax, malignant catarrh, 

 foot and mouth disease, braxy, and one or twO' other contagious diseases 

 of somewhat mild characLcr the ovine species is free from the attack of 

 disease scourges which decimate the equine, bovine, and porcine species 

 respectively, such as glanders, pleuro-pneumonia, and swine fever. 

 Nevertheless sheep, like mortals, have "troubles of their own" 

 in the shape of a truly worrying number of parasitic diseases. 

 Invasion by macroscopic (naked eye) animal parasites such as w^orms — 

 as distingu^hed from microscopic vegetable parasites called bacteria — 

 occurs more frequently in the sheep than in any other domestic animal- 

 and the diseases caused through such invasion, by their untoward effect 

 on growth and fattening and by their frequent fatalities, are a great 

 source of loss to the sheep raiser. These losses are practically perennial 

 in certain districts, but in other localities they are only trouble.some inter- 

 mittently, i.e., during certain seasons. 



Preventive Measures. — Before proceeding to a detailed treatment of 

 the diseases of sheep caused by parasites, it will be well to discuss 

 generally the factors favorable ta parasitism and the measures which can 

 be most advantageously adopted tO' counteract them. Nearly all the 

 harmful worm parasites, and indeed many insect parasites, require moist 

 ground or stagnant water tO' live in while they are in the egg or larval 

 stage. Hence if sheep could be kept to^ country free from stagnant water, 

 marshy ground and boggy spots, the chances of their becoming affected 

 with parasitic diseases would be practically non-existent. This statement 

 is particularly true in regard to such diseases as fluke, lungworm and 

 stomach worm, and, apart from its scientific foundation, is supported by 

 the practical experience that during and after years of drought the pre- 

 valence of fluke and worms in sheep is very much lessened. In England 

 and other closely-settled agricultural countries it has also- been found that 

 along with the reclamation of swamps and marshes and the under-draining 

 of wet lands, parasitic di.seases of animals have declined enormously. 

 This, because the natural harbours in the shape of stagnant water for 

 snails, molluscs, and the like animalculse. in which the parasites have to 

 live during some period of their life history, is done away with. 



Obviously then, to avoid infestation with parasites, sheep should not 

 be grazed on low-lying, damp or marshy land, and for this reason as well 

 as because it also predisposes to foot rot, it is an axiom of the sheep- 

 breeder that such land is not good sheep country. But, equally obviously, 

 in Australia, where the runs are so large, it is next to impossible to confine 

 sheep grazing to dry uplands. On many runs, at all events in some 



