September, 1950]
ABSTRACTS
225
was an evidence of past infection. The layout of the fowl houses and pens of the
Egg Laying Tests and the rapidity and direction of spread of the disease therein are
described in detail. The author states that the spread of the disease at time was
very rapid, while at other time as weak or more elapsed with no new pens showing
symptoms of the diseases. Close contact from pen to pen was not a major factor
in the order of the spread of the disease. At one test (place) where there was an
outbreak of the disease, mortality before the egg production returned to normal
was Leghorns 1.1 per cent ; heavy breeds 3.3 per cent. At another test following
vaccination against the disease, the mortality in Leghorns was 5.1 per cent for pullets,
11.1 per cent for hens. The mortality following vaccination in the case of heavy
breeds was relatively low.
In birds affected with Newcastle disease the author studied the laying perfor-
mances and states that a sharp decline in egg production is one typical external
symptom of the disease. In the case of birds in lay there was a drop from a produc-
tion of 74.7 per cent on the day of vaccination to zero 8 days later ; egg production,
however, returned to normal within four to five weeks following a marked drop
in production irrespective of the fact that the infection was of natural origin or by
means of vaccination (perhaps with living mitigated virus). There was considerable
variation between pens in time elapsing before production returned to the level
existing before the infection. The author attributes this to factors inherent in the
stock either of genetic nature or connected with environment earlier in the life of
the fowls.
In India and several other countries especially of the Far East the mortality
following natural infection is usually 98 per cent. Insignificant mortality combined
with considerable economic loss through drop in egg production following vaccina-
tion or natural infection, in the U. S. A., are points of paramount interest to the
Indian poultry keeper. (S.G.I.)
The Nutrition of the New Born Dairy Calf. The Response to a Photolised Milk Diet.
WARNER, R. G. and SUTTON, T. S. (1948) J. Dairy Sci. 31, (11) 976
T HE authors have carried out an experiment to study the effect of feeding
calves with natural milk in which the major portion of the riboflavin has been
destroyed by light. The influence of riboflavin factor upon the absorption of vita-
min A and ascorbic acid by calves and its requirement in the nutrition of them has
also been studied.
Photolised milk was prepared by subjecting the natural milk to the rays of
D. H. 400 Watt mercury vapour lamp. Biological inadequacy of the photolised
milk was verified by a rat growth test.
Four pure bred male Gurnsey calves were used in this experiment. Two calves
A and B were given photolised colostrum while the other two C and R were given
normal colostrum for three days. Following this period of colostrum feeding
all the calves were given twice daily photolised milk (previously heated to 73°C.)
at a rate 10 per cent according to body weight. They were also given vitamin A
oil in Soyalecithen. Calf R in addition to the photolised milk, received 2.99 mg