338 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



the possibility of the blood clotting in the syringe, but with practice 

 and promptness this can be easily overcome. 



The second method is better suited for the inoculation of a large 

 number of cattle or where the immune animal is at a distance from 

 the cattle to be immunized. 



The preliminary steps the clipping of the hair, disinfection 

 of the skin, placing the rope around the neck to distend the jugular 

 vein, and restraining the animal are the same as for the first 

 method. In puncturing the vein it is advisable to use a small trocar 

 and canula after sterilization in a 5 per cent carbolic-acid solution, 

 and, when the vein has been entered, to draw out the trocar, allow- 

 ing the blood to flow through the canula into a perfectly clean and 

 sterile vessel. After sufficient blood has been drawn for the animals 

 to be injected, a clean stick, previously sterilized by boiling in water, 

 is placed in the vessel containing the blood and the latter is stirred 

 for ten minutes or so or until the fibrin in the blood is whipped out. 

 The remaining blood, known as defibrinated blood, is then inocu- 

 lated under the disinfected skin of the animals to be immunized, as 

 in the first method. This blood should be used as early as possible 

 after drawing, to prevent it from becoming contaminated and de- 

 composed. The place where this injection is made is immaterial, but 

 for convenience a point just behind the shoulder is usually chosen. 

 The dose and number of injections vary with the individual ani- 

 mals. As a rule, it may be stated that 1 cubic centimeter should be 

 injected into an old animal coming into the infested district, 2 cubic 

 centimeters for a 2-year-old, and 3 cubic centimeters for an animal 9 

 to 15 months old. It will be observed that, unlike the usual custom 

 of applying a treatment, the older animals take less than the young 

 ones owing to their greater susceptibility to the disease. Where an 

 animal has reacted well to a first injection and shows a very high 

 temperature, great reduction of red blood cells, or other symptoms 

 indicative of reaction, it will not be necessary to repeat the injec- 

 tion, but in those cases where the reaction is slight, a second injec- 

 tion should follow after an interval of forty days, and, if need be, a 

 third injection after a similar lapse of time, always increasing the 

 size of dose 50 per cent. A thermometer, to indicate the course and 

 severity of the disease, is indispensable in this work. Usually, after 

 three to ten days, sometimes longer, the inoculated animals show a 

 mild type of Texas fever, which runs a course of from six to eight 

 days and is followed in about thirty days after the injection with a 

 second attack of a milder character than the first. After forty days, 

 when the animal has entirely recovered from the inoculation, a sec- 

 ond injection may be given to increase its immunity. In some cases 

 a very severe type of fever follows the first inoculation, requiring 

 careful nursing and treatment, as suggested above. A second, milder 

 attack follows usually in about thirty to forty days, after which the 

 animal need have no further inoculations. It is advisable to prevent 

 any ticks from getting on the cattle until sixty days after their in- 

 oculation or until they have fully recovered, at which time a few 

 ticks may be placed upon them in order to re-enforce their immunity. 



