2 BULLETIN 147, U. S. DEPARTMENT OF AGBICULTUEE. 
by a single tick may be relatively small, but the total amount drawn 
by thousands of ticks on one cow can not fail to be injurious. If 
each tick represents but a dram, or a teaspoonful, of blood, a few 
over 1,000 would represent 8 pounds of blood. It is possible that 
each tick absorbs more than a dram of blood. 
But the greatest disturbance created by the tick seems to be, 
not in the amount of blood abstracted, but in the fact that it is the 
carrier of the germ of Texas fever which it transmits to cattle. 1 
When cattle that have never become accustomed to ticks are infested 
they become very sick and usually die. This may occur anywhere, 
either within or without the tick-infested region. Cattle that survive 
the ticks usually remain immune to their worst effects afterward. 
However, as time passes the important fact that no cattle in the 
quarantined area of the South are ever safe from the effects of 
Texas fever, either in its acute or chronic form, becomes more and 
more impressed on those who have to study the affected cattle. 
PLAN OF THE EXPERIMENTAL WORK. 
As the dairy industry is becoming an important branch of southern 
agriculture it was thought desirable to ascertain the effect of the 
tick on the milk production and body weights of dairy cows. Twenty 
grade Jersey cows 2 of about average dairy quality were selected in 
the early part of their lactation periods. They were in fair condition 
of flesh at the beginning, and all had been tick infested at some time. 
The animals being immune to ordinary attacks of tick fever, the 
results should be applicable to the average dairy herd in the tick- 
infested areas. These cows were divided into two groups of 10 ani- 
mals each, the two groups being balanced as nearly as possible in 
regard to milk and butter-fat production, condition of flesh, and 
size. One group was freed from ticks by spraying with "tick dip B," 
an arsenical solution used by the Bureau of Animal Industry in the 
tick-eradication work. Data were taken on only nine cows of this 
group, as one cow received an injury to her udder which stopped 
her milk flow early in the test. The other group was kept tick- 
infested by applying seed ticks at regular intervals. The degree of 
infestation varied with, different animals and with the entire group 
at different times during the course of the experiment. 
The experiment began May 21, 1913, and lasted during a period of 
140 days. The milk of each cow was weighed and a sample taken 
at every milking for a composite fat test at the end of each 10-day 
1 Further details concerning the life history of the cattle tick and the protozoan causing the fever can 
be found in Farmers' Bulletin 258. 
2 The cows and the feed lots used in these experiments were provided by the Anthony Farms Co., 
Anthony, Fla., of which Mr. E. C Beuchler is manager and vice president. 
