ABSTRACTS
71
noticed directly due to extra colostrum feeding. The amount of colostrum received
by each calf, the blood plasma vitamin A and carotene level and the gain in body
weight are all tabulated. It was found that calves receiving more than 200 lb. of
colostrum maintained higher levels of vitamin A in the blood plasma and made
greater cumulative weight gains than those received less than 200 lb. During this
experiment over 4000 lb. of surplus colostrum was used in feeding the calves in group
I and thus same quantity of marketable milk was saved. It is estimated that even
if half the surplus colostrum from the 26 million dairy cows in the U.S.A. is utilized
in calf raising it will save 650 million lb. of marketable milk. The surplus colostrum
can also be frozen and stored wherever it is possible and used when required. Thus
the economic importance of using all colostrum in raising calves has been fully
demonstrated by these experiments. [M.K.S.]
Breeding chickens for resistance to caecal coccidiosis. PALAFOX, A. L.,
ALICATA, J. E. and KAXTMAN, L. (1949). World's Poult. Sci. J. 5, 2, 84-87
T HE authors started breeding work with the foundation stocks comprising
White Leghorn hens having the highest rate of survival in progeny against
caecal Coccidiosis and a susceptible line of the same breed having the lowest rate of
survival of progeny. In breeding of these two lines revealed that the dams selected
for high resistance to Caecal Coccidiosis transmitted high resistance to their F 1
progeny. Similarly dams selected for low resistance transmitted only low resis-
tance to their progeny. Resistance or susceptibility in the F 1 progeny was tested
experimentally at four weeks of age by inoculating with approximately 120,000
sporulated oocysts of Eimerla tenella. However, in the resistant line the individual
variation of the degree of resistance in the progeny of resistant dams mated to
the same sire was considerable indeed.
In another attempt reciprocal matings between the resistant and susceptible
lines showed that neither line was homozygous for the character. Further selection
amongst resitant birds was therefore indicated to obtain homozygosity.
In the F 2 progeny of the resistant line increased resistance was demonstrated
whereas in the unselected control lot it was intermediate between the resistant and
susceptible lines. It is suggested, therefore, that resitance to Caecal Coccidiosis is
dependent, at least in part, on inherited multiple factors.
Coccidiosis amongst rearing stock in specialised farms in India is all too common.
From the foregoing results it seems breeding chickens for natural resistance to Cocci-
diosis is a profitable line of approach to the problem of solving poultry mortality.
[S.G.I.]
The Galactopoietic effect of Iodinated Casein: Dose Response Relationships during
Prolonged Treatment. LEECH, F. B. (1950). J. Endocrinology, 7, 42-53
F IFTYNINE cows were fed daily with iodinated casein in different dosage
levels of 15, 20, 25 g. for 28 weeks from 3 months after calving except
in cows which become dry before time. The increase in milk yield lasted for a
period of 8 weeks after which the response to the two lower doses quickly disappeared.
The response of the group receiving 25 g. of iodinated casein was maintained at a