SCIENCE IN STOCK BREEDING

Otago Daily Times, Issue 22911, 19 June 1936, Page 10

SCIENCE IN STOCK BREEDING

Dr John Hammond, the great authority on animal physiology of Cambridge University, has published a remarkably informative article on “New Science in Stock-breeding.’’ The last hundred years, he says, have seen a great control by mini over the physical forces of nature, and the motor car, aeroplane, telephone, wirelesa, etc., have resulted. In the next hundred years he thinks we shall sue just as great a control over the animal body and its production. One of the most Interesting observations of Dr Hammond is that of the effect of the season of the year on animal production. It has recently been found, ho says, that it is not ao much the temperature changes as the changes in the length ol the days which are the causes of many seasonal changes. He shows that many animals normally breed in the months of longest daylight hours, and that by lengthening the days by means of electne light they can be made to breed just as well in the days of shortest light. The Hush of milk ‘from dairy cows obtained in the spring may also, he thinks, be due to increased light at that time of the year. The effect of light is thus explained: “The way light acts is prob-

ably by stimulating the email anterior pituitary gland, lying at the base of the brain, to greater action, for, by injecting an extract of the gland we can make the animal breed out of season. Future work will lie in an attempt to find methods to get this gland to work overtime and so increase animal productivity.” Writing of the poor growth of some young animals Dr Hammond says that much of this poor growth of lambs and pigs after birth is due to lack of milk supply in the dam. The growth of the udder during pregnancy had been studied to find out what caused differences in milk yield. Sections through the udder of the heifer in-calf for the first time showed that the growth begins at the twentieth week of pregnancy and continues to the end; this growth of milksecreting tissue replaces fat. Unless, hu says, the mother is fed milk-producing foods during the latter part of pregnancy the udder will not grow to the fullest extent, and the full milk yield after birth will not be obtained, no matter how she is fed after the birth of the young. This statement should be weighed well by dairy farmer readers, for the greatest weakness in Ihe business of dairy farming in New Zealand is failure to feed the cow well, with palatable, easily digested food in the final stage of pregnancy.