ABSTRACTS
The composition and properties of goats milk
G. M. TROUT (1941). Bull. Mich. agric. Exp.
Sta., 23, 254-64
FOURTY samples of bulk milk from individual goats
and from herds on analysis gave an average fat percen-
tage of 3.91±0.75 and total solids 13.00±1.04. The
fat percentage of the milk varied widely between the
breeds. Fat was determined by Babcock method, total
solids by the Majonnier method and the S. N. F. was
calculated from the values obtained for fat and total
solids. Nubian milk was rich in fat (4.41), Steanen milk
slightly less (4.18) and Toggenberg milk least (3.54).
The ash content of 17 samples of goat's milk showed an
average 0.923 per cent, with a range from 0.872 to 0.972
percent. The ash content was slightly higher than that
of cows milk. The ash content of breed milk varied
slightly with the fat. Specific gravity determinations
of 17 samples gave a mean of 1.0337, with a range from
1.032 to 1.035. The titrable acidity of 39 samples of fresh
milk brought to the laboratory packed in ice well below
50°F., ranged from 0.12 to 0.275 per cent with an average
of 0.199 per cent. This is contrary to the opinion that
goat's milk is alkaline in reaction when compared with
cow's milk. The pH of the goat's milk (19 samples)
ranged from 6.33 to 6.52 which is a lower figure when
compared to cow's milk. The average flavour score
of 40 samples was 21.75 which is to be recognized as
good flavour. Of the above 19 samples scored 23 and
above having no flavour criticism. Of the off flavours
present, those of 'feed' were noted in 10 samples.
[C. P. A.]
A simple differential medium for mastitis testing
J. G. DAVIS (1941). Dairy Indust. 6, 38
THIS new medium, Brom-cresol purple chalk agar,
suggested for mastitis work has the following compo-
sition :—
Peptone (1) . . . . .
Lactose (2) . . . . .
Yeastrol (3) . . . . .
Lemco (4) . . . . .
Precipated chalk (5) . . . . .
Agar . . . . .
Separated milk
.
.
.
.
.
Brom-cresol purple (0.04 per cent aq. sol.)
Tap water
.
.
.
.
.
3 gm.
5 „
3 „
3 „
10 „
15 „
10 ml.
50 ml.
1000 ml.
Peptone, lemco, yeastrol and agar are dissolved in
water by heating and filtered hot. The pH of the me-
dium is adjusted to 6.8 with Bromthymol blue using
a Hellige comparator. Lactose, milk, chalk and Brom-
cresol purple solution are added and filled in sterile test-
tubes with constant shaking and then sterilized at 15
lb. pressure by momentary autoclaving. The remark-
able feature of this medium is that the acid forming
colonies dissolve the chalk forming zones. In the freshly
drawn samples of milk from the cows suspected to be
suffering from mastitis, when plated on this medium,
the zones formed are generally due to Streptococcus agala-
ctiae, the causative organism of mastitis. In normal
aged samples the acid-producing types will form zones
by dissolving the chalk.
N. R.—
(1) Any peptone may be used.
(2) Dextrose may be substituted to detect those orga-
nisms fermenting dextrose but not lactose.
(3) The yeast autolysates on the market are roughly
of equal growth promoting value.
(4) Any reliable meat extract may be used.
(5) The precipated chalk should be sterilized in dry
condition for three days at 200ºC. [E. V. S.]
The control of parasitism in sheep with pheno-
thiazine in a salt lick. J. W. BRITTON R. F.
MILLER and H. S. CAMERON. Cornell Vet. 32,
400-406
OBSERVATIONS were made on Ladino clover pastures in
California, on which approximately 250,000 lambs are
annually fed. The stomach worms, Ostertagia and Trin-
chostrongylus, constitute a source of great menace in these
lambs. In the past, anthelmintics such as tetrachlor-
ethylene and a mixture of copper and nicotine sulphates
were used. These medications are not, however, very
effective, for, as Gordon has estimated, about 12 per cent
of the lambs fail to respond to the drugs, because of the
failure of the oesophageal reflex to operate in time to
direct the drug into the abomasum. Furthermore, the
labour involved is very costly, and the starving of lambs
overnight and for several hours after treatment retards the
rate of growth. Mass administration of anthelmintics has
not so far been attended with success due to the toxicity
of the agents employed. The authors used a mixture of
phenothiazine and half-ground salt in the proportion
of 1:15 and made it accessible to lambs as the only
salt lick. The results of the experiments showed that
the mass administration of this mixture was nontoxic
and very effective when given over a period of 78 days.
The total dose necessary for the effect was approximately
half the minimum single therapeutic dose. This com-
bined with the ease of administration and the elimi-
nation of the preliminary starvation period reduces the
cost of the treatment considerably. Repeated small
doses administered in this manner maintain a continual
small concentration of the drug in the alimentary canal.
This at first might, retard or inhibit the development
of eggs, later inhibit the egg production, and finally prove
lethal to partially paralyzed worms. When a single
therapeutic dose is administered, roughly half of the drug
is absorbed and excreted in the urine. In the case of
repeated small doses little, if any, is absorbed from the
intestinal treat and this explains why only half the total
amount of the therapeutic dose of the drug is required
in this case. The lambs on the medicated salt mixture
consumed on an average slightly over 22 grams of pheno-
thiazine per head during the period of 78 days. There
were no toxic symptoms or staining of the wool and the
fæcal cultures indicated that the lambs were free from
parasites. The method appears to offer great possibilities
[G. D. B.]
Immunization against bovine trypanosomiasis
H. E. HORNBY (1941). Trans. R. Soc. trop.
Med. Hyg., 35, 165-76
THE author has critically reviewed the work of Schilling
(1936) on the immunization of African bovines against
trypanosomiasis. Schilling's contentions were as follows:
(1) young animals possess a considerable resistance
against trypanosomes transmissible by tsetse flies, and
(2)this resistance is enhanced to full immunity by minimal
infection or by preventive vaccine treatment. The
author had the opportunity to follow in detail the
fate of the experimental herd of Schilling and he found
that when this herd was transferred to well-known tsetse
belt the animals developed the disease. It was observed
that of all the animals vaccinated or otherwise treated by
Schilling in 1934 only one out of 38 was alive at the close
of the experiment (21st January 1941). Schilling conti-
nued his observations from June 1934 to July 1938 and
he came to the following conclusions which were based on
the evidence of survival at the end of this period:—three
out of twelve control calves, four out of nine vaccinated
199