508 DISEASES OF CATTLE. 



The inoculation always results on a more or less serious attack of 

 Texas fever. Besides having a fever, there is great diminution of 

 red blood corpuscles, and in about 3 per cent of the cases a fatal ter- 

 mination ; but the proportion of deaths resulting from the inoculation 

 is small when compared with the fatalities among untreated animals 

 taken into infested districts. To this nimiber should be added those 

 animals (less than 7 per cent) that do not receive sufficient immunity 

 by this method and which succumb when exposed to infested pastures. 

 Combining these failures it will be seen that by this method of 

 immunization, instead of a loss of 90 per cent among breeding stock 

 taken South more than 90 per cent can be saved. The animals should 

 be carefully nursed through the attack and their symptoms treated 

 as indicated on page 511. 



Inmiunizing inoculations are now being made by the veterinarians 

 of most of the agricultural experiment stations of the Southern States 

 without cost for the services rendered, a charge being made merely 

 for the actual value of food consumed and attendants' wages. These 

 veterinarians have also issued station bulletins which describe fully 

 the necessary steps to be taken in securing the blood and injecting it 

 into the animals to be immunized, so that the stock owner can follow 

 the instructions with prospects of getting good results. 



This operation is not a difficult one, and excellent results will 

 follow where absolute cleanliness and ordinary care have been used, 

 but undoubtedly the best results will be obtained by those who have 

 thoroughly familiarized themselves with the nature of the disease 

 and are experienced in extracting blood from animals. Two methods 

 are in use and will be described separately. One consists in drawing 

 the blood from the jugular vein of an immune animal and immedi- 

 ately injecting it into the cattle to be immunized. It is compara- 

 tively simple, requires few instruments, and can be satisfactorily 

 carried out where a small number of animals are to be immunized 

 and if a suitable immune animal is close at hand. First, select an 

 inmiune animal which is in good health and which is infested with 

 fever ticks or had them the preceding year. Fasten the animal 

 securely, either by tying, throwing, or by placing in a chute. Clip 

 the hair from a space about 4 inches in diameter over the jugular 

 vein on the upper third of the neck, wash the skin thoroughly with 

 a 5 per cent solution of carbolic acid, and then fasten a strap or rope 

 around the neck below the hairless area and draw it tight in order 

 that the blood in the vein will be stopped, causing distension. With 

 a large hypodermic syringe needle, previously sterilized in a 5 per 

 cent carbolic-acid solution, puncture the vein at a slight angle, di- 

 recting the point forward. When the needle enters the vein the 

 point can be rotated freely in contrast to the restricted movements 

 if still in the tissues, and the blood will either drop or flow from the 



