146 Phenothiazine—A Remarkably Efficient Anthelmintic
Cattle
Experiment No. 10.—Concerned an outbreak of parasitic gastritis among
seven Jersey calves in which two had just died at the time that the outbreak
came to our notice. Egg counts made on samples of faeces collected from two
dead calves on September 3rd gave a count of 3,900 and 1,500 eggs per gramme
respectively, counts that are considered to be high for cattle. Post-mortem
examination showed the presence of a pure infestation of Ostertagia ostertagi,
8,200 being recovered from the fourth stomach of one calf and 20,200 from the
other.
Three of the five remaining calves were then treated with 25, 35 and 45
grammes of phenothiazine powder respectively, and the other two kept as
controls. On September 13th the three treated calves were found to have
improved in condition and to have recovered from the diarrhoea ; one of the
two controls, however, looked distinctly worse than on the previous occasion
and so was given a dose of 30 grammes of phenothiazine. This animal died on
September 20th, presumably having been beyond the hope of recovery at the
time that treatment was given : post-mortem examination revealed the pre-
sence of only 200 O. ostertagi in the stomach and 600 in the small intestine.
The remainder of the animals ultimately made a good recovery.
This observation appears to indicate the efficiency of 25 to 40 gramme doses
of phenothiazine against O. ostertagi in calves.
Experiment No. 11.—Was carried out by W. J. Ironside of the Midland
Agricultural College on six cattle which had previously received treatment with
copper sulphate and nicotine sulphate.
The three treated cattle varied considerably in size but all received the
same dose of 70 grammes of phenothiazine, as a result of which they were all
very seriously upset and refused food for several days. One of the three,
which was in a weak state at the time of dosing, became so ill that it was ex-
pected to die ; but all ultimately made a good recovery.
The egg count per gramme of faeces in the treated cattle was reduced
during the three weeks observational period from 800, 100 and 1,200 to 200, 0,
and 0, respectively, whereas among the three controls the successive counts
were 300, 1,300 and 700, respectively, at the first examination, and 400, 1,000
and 900 at the second.
TOLERANCE OF CATTLE.—The suggestion of susceptibility to toxic action
given in experiment 11 led to our carrying out one or two direct observations
on this point, and on October 26th a dose of 1,000 grammes was given in the
form of a drench to a 14-weeks-old calf, it being anticipated that the tolerance
of cattle might approach that of sheep. Within an hour the calf lay down and
would not rise ; on the following day it was found to be lying on its side,the
temperature having risen to 102.4°, at which point it remained. Great
muscular weakness was noted on October 28th and 29th, on October 30th
respiration was observed to be rapid, the pulse was weak, and death occurred
during the afternoon.
Post-mortem examination showed extensive ulceration of the mucous
membrane at the pyloric end of the stomach, and slight inflammation through-
out the whole length of the bowel lining. The liver and lungs were congested ;
the kidneys appeared to be normal, Petechial haemorrhages were seen under