December 1948]
ABSTRACT
265
Ralph W. Philliphs, Victor L. Simmons & Ralph G. Scohott. (1943.). Observations on the
normal estrous cycle and breeding season in goats and possibilities of modification of the
breeding season with gonadotropic hormones. Amer. Jour. Vet. Res. 4,360-367.
T HE observations recorded in the paper were made with a view to the production of
milk throughout the year as the breeding season in goats is limited and goats milk only
for five or six months during a lactation.
To achieve this and certain possible means that can be exploited are : (a) Does may be bred at
different times during the breeding season, (b) Select such does that come in estrus out-side the breed-
ing season, (c) To bring about estrus by artificial means such as treatment with gonad stimulating
hormones and, (d) Stimulation of lactation without gestation by use of lactogenic hormones.
Literature has been quoted where extra seasonal breeding in goats have been induced by reduc-
tion of light during the early part of summer and inducing lactation in virgin goats by injections of
stilbestrol.
In Swiss goats ovulation occurs during the months of October, November and December but
may extend to other periods due to domestication ovulation occurs at regular intervals of three
weeks. Whereas in Boer and Angora goats in S. Africa the breeding season is from April to August.
The authors observations were mainly on the duration of breeding season, the length of estrous
cycle and on the possibility of obtaining pregnancies in does outside the breeding season by means
of gonadotropic hormones.
Saanen and Toggenburg does and kids were used in study. The total number observed for estrus
included 32 milking does, 20 dry does, 16 kids born in 1941 and 19 kids born in 1942. The obser-
vations started from 20th October 1941 and lasted up to 13 December 1942. These observations
indicate that most does will come in estrus between the middle of September and middle of December.
A few, during July, August and early September and some in April, May and June.
Estrous cycles were observed in milking and dry does and in the 1941 kids. A considerable
number of estrous cycle fall in about 21 days. Shorter cycles of 12 days or less as well as longer ones
which were multiples of 21 days were also observed. The average length of estrous cycles of 161
observations was 22.8 and 23 days in dry and milking does respectively and 16.6 days in kids.
The results of hormone treatment with P. M. S. (pregnant mare serum) indicate that one injec-
tion of 400 units will bring about estrus in dry does whereas lactating does require 400-600 units
and even then they may not respond as readily as dry does. Of the 15 dry and 4 lactating does which
came in estrus as a result of treatment with P. M. S. only six dry and one lactating doe conceived
and. produced kids though all were bred while in estrus. The number is too small to arrive at a
definite conclusion. A small trial with luteinizing hormone indicated that it may be helpful in
stimulating ovulation at the proper time. [M. K. S.]
Schofield F. W. & Barnum, D. A. (1947). Limitations in the use of Penicillin in the Treatment
and Eradication of Bovine Mastitis. Jour. Amer. Vet. Med. Assn. Cx. 92-96.
PENICILLIN, the wonder drug, which enjoyed a period of unstinted praise as a drug of
great value in the treatment of bacterial diseases in man and animals was found to have
unanticipated limitations when more comprehensive and exacting tests were made with it in certain
diseases. In this article, the authors deal with some of the limitations of penicillin in the treatment
of bovine mastitis. In bovine mastitis it is necessary to determine the nature and type of infection
by bacteriological methods before penicillin therapy is adopted. If the drug is used indiscriminately
it will rapidly bring it into disrepute. In certain infections penicillin will have to be combined with
other methods of treatment.
The authors used penicillin in two outbreaks of acute mastitis due to Streptococcus agalactiae
characterized by sudden onset and rapid spread of the disease terminating in atrophy or fibrosis of