116
ABSTRACTS
disease had appeared in them would reduce mortality, (3) the reaction from vaccina-
tion in young chicks is in the way of lowered feed intake for two to three days
from the 3rd or 4th day after vaccination and some respiratory sounds which
symptoms disappear by the 10th day and (4) there is a drop in egg production
which starts from the 5th or 6th day and returns to normal in two weeks. (Re-
garding parental immunity which is said to last four weeks and on which the
authors have stressed so much it is to be noted here that the experience of workers
in this country seems to be contrary. The propagation of either the virulent
virus or the Mukteswar vaccine strain virus in embryonating eggs from immune
parents always kill the embryos. If there is any so called parental immunity
this should not happen. Again day and week old chicks from immune parents
do not show any appreciable resistance to an artificial infection with virulent
virus. (M. K. S.)
The relation between the Month of Calving and Yearly Butterfat Production.
MOHAMED M. OLOITFA AND JONES,I. R. (1948). J. Dairy. Sci., 31, 1029-31
I N this article the authors have studied the data of 2690 head of first-calf
heifers (consisting of 1881 Jerseys, 358 Guernseys, 301 Holstein Friesians
and 150 Ayrshires) to determine, if any relation between the month of calving
and yearly butterfat production existed in Western Oregon (U. S. A.)—a region
with an average temperature of 52° F. and a monthly mean range from a height
of 65° F. in July, to 38° F. in December, and with an average rainfall of 42 in. a
year. The butterfat records consulted for the collection of the data covered a
period from 1910—1946. The study was considered to be of interest, in view
of the fact, that differences in yearly milk production between cows freshening
in the different months of the year, and also an effect on their butterfat produc-
tion, in various parts of the U. S. A., were found to exist by other workers. The
first table of the article Shows a month wise average yearly butterfat production
of the 2690 head of heifers, split up in five groups under study. The second one
shows the analysis of the variations of the butterfat records. The authors con-
cluded that under Western Oregon conditions, the part of the year, in which a
cow freshens had no influence on her butterfat production. One of the groups
however, showed some significant difference, which was considered by the
authors to be of doubtful value. [T. A.]
Mineral Metabolism Studies in Dairy Cattle. Effects of Mineral Supplementation
of the Perpartal Diet upon the Composition of the Blood of Cows and their
Calves at Parturition. J. THOMAS REID, GEORGE M. WARD AND R. LAWRENCE
SALSBURY (1948). J. Nutr., 36, 75-87
F OUR groups of cows were fed the following mineral supplements in the con-
centrate feed during the last two months of gestation. Group I containing
12 cows, basal concentrate feed (commercial dry cow and fitting ration); group
II containing 9 cows basal concentrate feed plus 2.5 per cent of calcium car-
bonate ; group III having 14 animals basal concentrate feed plus 3.0 per cent of
calcite flour; group IV 14 animals, basal concentrate feed plus 3.0 per cent of
mico (composition of calcite and mico is given in the original article).