106 BULLETIN 1369, U. S. DEPARTMENT OF AGRICULTURE 
projecting grubs were pulled out; the cysts under these were small | 
and the animal had improved noticeably in condition of flesh. At — 
this time more than one-half of the holes were healed. When the 
grubs are punctured before they are extracted the cattle are wor- 
ried much less than when extraction by the usual method is prac- 
ticed. Schottler (S7) states that in Germany a crochet needle has 
been used for puncturing and extracting grubs, but that this method 
had been found to be undesirable because the juice from the grubs 
may cause nettle fever. 
COST OF TREATMENT OR EXTRACTION OF GRUBS 
To gain information on the expense of treating cattle for grubs, 
records were kept on the time required in applying the different 
treatments, the quantity of the material used, and its cost. 
It was found that for cattle of the island breeds hand extraction 
was the most economical. The time consumed in extraction varied 
considerably with the breed and with the local conditions under 
which the work was done, as well as with the experience of the 
operator. The rate of extraction per hour ranged from 388 grubs 
in Holsteins to 191 in a dairy herd of mixed breeds. It appears 
that with the average herd of Jerseys or mixed breeds, not Holsteins. 
the grubs can be extracted caretully and thoroughly at the rate of 
about 125 per hour. Naturally the degree of infestation affects the 
rate, as in very light infestations much time is occupied in going 
from one animal to another and in very heavy infestations more 
care is necessary to avoid missing some grubs. 
In tests in which the backs of the cattle were thoroughly moistened 
with soap solution the average number of larve extracted per hour 
was 119, and where normal salt solution was applied prior to 
the extraction the grubs were removed at the rate of 100 per hour. 
These tests therefore seem to indicate that the wetting of the backs 
of the cattle in the case of island or mixed breeds, not Holsteins, 
tends to retard the rate of extraction. 
In tests of the method of extracting the grubs after puncturing 
them and expelling the contents, the average number of grubs re- 
moved per hour was slightly over 88. This work was done without 
special forceps, which if used would have hastened the work. AI- 
though this rate of extraction is considerably slower than that of 
the hand extraction in Jersey or mixed herds it is decidedly more 
rapid than hand extraction in Holsteins. 
The rate of treatment when injecting the cysts with a hypodermic 
syringe ran about 170 grubs per hour. The time consumed in in- — 
jecting the material by means of an oil can varied considerably, 
ranging from 74 to 240 grubs per hour. The very slow record 
mentioned was probably due to the fact that a large number of 
the grubs had dropped, and it was necessary to examine each cyst 
to determine if the larva was still present. Under good conditions 
in a dairy it is thought that by the oil-can injection method 225 
grubs per hour might be readily treated. 
The application of such general treatments as dusts and washes 
is considerably more rapid than the individual treatment of grubs. 
The thoroughness with which either of these methods must be car- 
ried out, however, causes more time to be consumed in the treat- 
