A USEFUL MANUAL

Wairarapa Times-Age, 21 February 1939, Page 8

A USEFUL MANUAL

“GENETICS AND LIVE-STOCK PRODUCTION.” VITAL FACTORS IN SELECTION AND BREEDING. A recent publication issued by the Department of Scientific and Industrial Research is Bulletin 64 “Genetics and Live Stock Production,” which has been prepared by Dr F. W. Dry of Massey Agricultural College. Dr Dry has handled a difficult subject for practical presentation with considerable skill and the result has been a book full of interest to the stock-breeder and, for its original style and amusing philosophy, to the layman as well. The bulletin, however, is not light reading. As the author warns in the introductory pages, “Genetics calls for the centred focus required in algebra rather than the receptivity of the student of the novel. It is a field of thought not to be entered by casual perambulation.” The first chapter of the bulletin defines the science of genetics and discusses the value of this comparatively new science in assisting the live-stock breeder. The part that genetics has played in the development of new strains of pasture and forage plants has been remarkable, but progress in the realm of animal breeding has been much slower due to the greater complexity of the factors defining the characteristics of an animal. Nevertheless, genetics has much to offer the animal husbandman, not only in the provision of new concepts in animal breeding but also in presenting justification for such long established practices in live stock breeding as inbreeding, line breeding and backcrossing.. There is a long chapter devoted to the mechanism of inheritance and the mode of transmission of characters from parent to offspring in concisely and clearly described. An explanation is given of such freaks of nature as throwbacks. A variety of lethal factors resulting in the death of progeny at birth or some time prior to birth are also described. Fortunately lethal factors ai-e rarely observed in New Zealand, but there-is one very good example of split ears and cleft palate in the pig which is illustrated in the bulletin. This condition was observed by Dr Annett of Matangi in a strain of Tamworth pigs. Selection and the basis of selection are dealt with at considerable length. Selection is made more difficult by the masking influence of environmental factors, for though the potential limit of a cow’s productivity is determined by her hereditary ipake-up, feeding and management, in practice, determine her actual production. The value of progeny testing and proven sires is discussed and a fresh emphasis is given to the measurement of excellence in animals whether it be for milk, wool or meat producing qualities. A rather visionary view is introduced with a reference to some recent Russian work which reports a high correlation between the abundance of sweat glands and milk yield. It is a possibility that one may be able to judge the innate" dairy worth of a sire merely by the microscopic examination of the skin instead of waiting for years until his progeny have come into production.

The bulletin is very well illustrated. There are some forty-seven pictures illustrating features that are discussed by Dr Dry. Most of this material is drawn from domestic livestock. There is also a useful glossary of technical terms, for though the author has minimised the use of technicalities it is inevitable that such a new science as genetics must introduce new words into the vocabulary of live-stock breeders.

The bulletin is published at a price of 2s 6d net.