TICK-RESISTANT CATTLE. 
We have interested ourselves in the question of tick resistance of cattle, and 
have endeavoured to collect: all the information that we could regarding the 
condition. With this end in view we have visited a number of farms where 
resistant stock were to be found, and have given special attention to the animals 
which at present form, or previously formed, part of Mr. Hull’s herd. We have 
inspected them on many occasions during 1915-18, while during the present year 
(1918) one of us accepted the offer of hospitality from Mr. and Mrs. Hull in 
order to make a detailed study of the cattle for a prolonged period (January, 
February, March and June), when all the engorged ticks to be seen on resistant 
animals were carefully collected, most of the cattle being examined both morning 
and afternoon, whilst the non-milkers were usually inspected once daily. 
The following is the result of our thorough collecting from a number of 
resistant cows during a period of 27 consecutive days in the height of the tick 
season (January and February, 1918):—Cow No. 1, nil; No. 2, 3; No. 4, 33° 
No. 5, 2; No. 6, 0; No. 7, 4; No. 8, 13; No. 9, 0; No. 10, 30; No. 11, 16; No. 
12, 0; No. 13, 1. Nine were taken from No. 14 in twelve days, and 64 from No. 
15 in 27 days. The last animal is regarded by Mr. Hull as a non-resistant cow. 
Nos. 7, 9, 14, and 15 are young animals. Excluding No. 10, only thirteen 
fully-matured ticks were removed from nine cows during the whole period, and 
even if we include No. 10, then the total is only 27. It may be urged that these 
figures only prove that ticks were extremely scarce on the property at the time, 
but that such was not the case was shown by the occurrence of fairly heavy 
infestation of a number of control heifers from another district, which were then 
being depastured with Mr. Hull’s herd. No stronger evidence need be brought 
forward to prove the presence of a very marked tick resistance in these animals. 
Many others were carefully, but not so systematically, examined, and most of 
these showed the presence of resistance, ; 
We have placed ourselves in communication, as far as possible, with those 
who have had any experience with Mr. Hull’s stock, and have taken the oppor- 
tunity to examine many of them elsewhere. 
In practically all eases, the animals retained their resistance even when moved 
to other districts, provided that they maintained fair or good condition, and, as 
a consequence, did not require any treatment to prevent tick worry—in other 
words, under conditions of natural infestation, our observations have led us te 
agree with Mr. Hull’s contentions numbered in this report as Nos. 1, 2, and 3. 
It may be urged that departmental findings in regard to the two selected cows 
are exactly the opposite to our own. We have, as already stated, had Mr. Hull’s 
animals under intermittent observation for three years and a half, and under the 
closest observation for a period greater than the normal parasitic period of the 
cattle tick. Mr. Pound’s findings are, no doubt, correct when the animals were 
subjected to abnormal circumstances, e.g., poverty of condition, intense artificial 
infestation, &c. When these same two animals were allowed their freedom under 
conditions which permitted only natural infestation, the published evidence 
associated with the names of Messrs. Corser and Walker, M.L.A., Chambers, Bates, 
and Butcher has satisfied us that Mr. Hull’s claims were correct in regard to 
these two animals also. One of them, Clover, just before death became heavily 
infested, but this is only what one might expect, as, with old age, comes a 
lowering of condition and a lessening of resistance to any disease, including 
tick invasion. 
Those who are interested in the matter are invited to peruse a somewhat 
lengthy communication on “ A tick resistant condition*in cattle” which is being 
published in the Proceedings of the Royal Society of Queensland (1918, p. 219). 
This article deals with tick worry; habituation of cattle to tick infestation; tick 
poison; tick resistance; conditions affecting such resistance; and the transmissi- 
bility of the peculiarity. All the evidence that we have been able to collect is 
there summarized. ; : 
_ We have carried out a series of observations with engorged ticks from resistant 
animals with a view to testing the fertility. We found that from the eggs laid 
by such ticks, the percentage from which larve were obtained was. considerably 
smaller than in the case of ticks.from control animals. The percentage of those 
whose eggs did not develop into larve was the same in both cases, whereas the 
percentage of partial fertility was much greater, and of practically complete 
59 
