354 DISEASES OF CATTLE, SHEEP, GOATS,. ETC. 



ence in the skin of the animal, its secretions, body fluids, character 

 of food, and habits. 



It must be remembered that certain species of lice have, through 

 a long course of evolution, adapted themselves to certain species of 

 animals and that they adhere closely to the habits for which such a 

 long course of evolution has adapted them. 



From a practical standpoint, it is necessary for the stock owner 

 to know to w T hat extent a certain parasite is capable of injuring his 

 stock, the time and mode of its attack, the species of animal it may 

 affect, and the best method to be adopted for its eradication. In 

 the majority of insects acting as parasites a general treatment may be 

 prescribed, but in certain others a knowledge of the complete life 

 history is necessary in order that they may be thoroughly eradicated. 



THE ANIMAL PARASITES OF CATTLE. 



The animal parasites of cattle comprise more than a hundred 

 different species, belonging to various groups of the animal king- 

 dom. Fortunately not all of these parasites occur in this country 

 many are uncommon, and many are comparatively harmless. 

 Some forms, however, occur frequently, and some are of distinct 

 importance to the American stockman on account of the damage 

 for which they are responsible. It is these parasites particularly 

 which will be considered in the present article, and although some 

 forms are discussed which are rare or apparently of little economic 

 importance, most of the minor and unusual parasites and species 

 not found in this country have been neglected. 



Flies.* Of the various species of flies which infest cattle some 

 are injurious on account of the annoyance, pain, and loss of blood 

 due to their bites, and sometimes also on account of diseases or para- 

 sites which are thus transmitted from the blood of diseased animals 

 to the blood of healthy cattle, while others, which in the winged 

 adult state do not bite, are injurious because they live parasitic in 

 cattle during their larval stages. 



Remedies for Flies. There are various remedies to be had, 

 which are more or less efficient in protecting cattle from the attacks 

 of flies. Most of them have to be applied frequently and few, if any, 

 will keep flies away for more than a day or two following their appli- 

 cation. The following mixtures may be made at an average cost of 

 35 to 50 cents per gallon. The numerous propriety fly repellants to 

 be found on the market are usually more expensive, and often less 

 efficient. 



At Minnesota Experiment Station rancid lard, 1 pound, and 

 kerosene, one-half pint, mixed thoroughly until a creamy mass forms, 

 was found to give excellent results as a fly repellant, lasting for two 

 or three days, when rubbed not too thickly over the backs of cows with 

 a cloth or with the bare hand. Similar good results were obtained by 

 applying a mixture of three parts of fish oil and one of kerosene, with 

 a small spray pump. A mixture of two parts of crude cotton-seed oil 



'Further information may be found in a very full report on "Insects Affect- 

 ing Domestic Animals," issued as Bulletin 5, new series, of the Bureau of 

 Entomology, U. S. Dept. Agr. 



