ANIMAL PARASITES OF SHEEP. 



GENERAL REMARKS. 



In 1782, Goeze, a distiuguisUed German naturalist, wrote : "Among 

 all mammals except the horse, the sheep appears to be most harassed 

 by worms." He thus called attention at that early period to the great 

 abundance of oviue parasites, an abundance which have transmitted 

 their posterity in comparatively undiminished numbers. 



The presentation of all the facts now known concerning these para- 

 sites, their structure, their life histories, the injuries they cause, and 

 the methods of prevention and treatment, together with such new ma- 

 terial as may have been learned concerning them, needs no apology to 

 the sheep owner, for he is alive to the fact that the majority of his losses 

 is due to these parasites. The sheep industry of the United States 

 embraces the product of 42,599,079 sheep, valued at $90,640,369.* De- 

 pendent on these sheep and their products are an army of men aud their 

 families, from the flock-master and his help to the consumers of the flesh 

 and the manufacturers of the fleece. Add to this the value of the plant, 

 which is dependent on the sheep industry in all of its ramifications, aud 

 there results an accumulation of many millions of dollars, a value which, 

 from a business stand-point alone, should cause the Government to 

 foster and to protect it from every source of injury. 



As the whole growth of the industry is dependent on the health and 

 vigor of the sheep, it follows that whatever tends to produce a better 

 condition or ward ofl" threatening disease from them is for the benefit 

 of all interested in and dependent upon the success of the industry. 

 The parasitic diseases — those produced by the animal parasites of 

 sheep — are, if we may judge from observation and the letters of inquiry 

 directed to this Bureau, the chief source of losses, and if in any way this 

 bulletin may result in promoting a better knowledge of these too little 

 known pests, and in teaching facts which will lead to better care and 

 treatment of the flocks as regards hygienic prevention of diseases, the 

 cost and labor laid out upon the work in its various details will be well 

 expended. 



Particular attention has been devoted to illustrating each species of 

 parasite, and, so far as j)ossible, the lesions of the disease produced by 



* United States Department of Agriculture, report on numbers and values of farm 

 animals, January, February, 1889, pp. 5 and 6. 



