176 ANNUAL RErORT OF THE Off. l)oo. 



Dr. Leonard Pearson aud the writer discovered about this time 

 that it was important if one wanted to obtain success in increasing 

 the resistance of cattle against tuberculosis, to keep the animals 

 during and for not less than six months following the last vaccina- 

 tion in a manner in which there would be no i)ossible chance of infec- 

 tion. Jt appears that the normal resistance of an animal is lowered 

 during the period of vaccination. 



During the year 1904 there were thirty-two calves vaccinated with 

 vaccine prepared after the method above outlined. The number of 

 doses given was three, the first consisting of 2^ cc, the second of 

 4^cc., and the third 7| cc. After the third vaccination was completed 

 these calves were turned to past:ure and contracted lung worms 

 (strongylus micrurus or plubmonalis) and twelve of them died from 

 the same. There are six of these animals in the herd at the present 

 time and the remaining number have either been sold as milch cows 

 or slaughtered for beef, owing to the fact that they did not produce 

 a sulTicient number of pounds of milk yearly to warrant keeping them 

 in the herd, it has been the policy of this farm to have a standard 

 number of pounds of milk for each breed and if the animal falls be- 

 low this standard during a period of Inctation it is disposed of to the 

 butcher. 



In 1905 there were forty-two calves vacccinated, each animal re- 

 ceiving four vaccinations; the initial dose being 1 cc, the second dose 

 2^ cc, the third dose 5 cc, and the fourth dose 7^ cc Six of these 

 animals are in the herd at the present time. The others have been 

 disposed of either for beef or sold to other parties for dairy pur- 

 poses. 



For the year 1906 the records show that thirty-eight animals were 

 vaccinated receiving three vaccinations, the dosage consisting of 

 one, three and five cc. respectively and extending over a period from 

 May 14 until September 5th. Of the number vaccinated during this 

 year there are six remaining in the herd. 



Twenty-two animals were vaccinated in the year 1907, the majority 

 of which received four vaccinations, over a period from October 2.3, 

 1907 to March 23, 1908. The doses consisted of 1 cc, 2^ cc, 4 cc and 

 6 cc Two of these animals received but three vaccinations and 

 three animals received but two vaccinations. Of the twenty-two ani- 

 mals vaccinated there are eight in the milking herd. 



During the years 1908 and 1909 there were fifty animals vaccinated, 

 forty-one of which were given ten vaccinations, covering a period 

 of approximately one year's time. The increased number of vacci- 

 nations were given in order that another experiment could be started 

 to determine whether the milk of animals hyper-immunized had any 

 protective value against tuberculosis. This experiment is under pro- 

 gress at the present time and the results will be published at a later 

 date. The remaining nine animals vaccinated during the two years 

 above mentioned, received four vaccinations covering a period of six 

 months. All of these animals are still members of the herd except 

 five which have either been sold or slaughtered for meat purposes. 



Only one-half of these animals have given birth to their first calf 

 and are members of the milking herd, though they are kept in a 

 separate stable some distance from the main barn, owing to the fact 

 that they have not lost their sensitiveness to tuberculin and will react 



