GENETICS AND LIVE-STOCK.

Manawatu Standard, Volume LIX, Issue 70, 20 February 1939, Page 5

GENETICS AND LIVE-STOCK.

A recent publication issued by the Department. of Scientific and Industrial _Rcseareb is Util lotin 64, “Genetics and LiveStock 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 stockbreeder and, for its original style and amusing philosophy, to the lay-man 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 remarkably, 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 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 in-breeding, line breeding and back -crossing. There is a long chapter devoted to the mechanism of inheritance, and the mode of transmission of characters from parent to offspring is 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 are rarely observed in New Zealand, but j there is one very good example of split j ears and cleft palate in the pig which is j illustrated in the bulletin. This condition i was observed by Dr Annett, of Matangi, in a strain of Tamworth pigs. Selection and the basis of selection are dealt wilh at considerable length. Selection is made more difficult by the masking , influence of environmental factors, for : though the potential limit of a cow’s pro- , duetivity is determined by her hereditary j make-up, feeding and management, in prac- ] tier, determine her actual production. The 1 value of progeny testing and proven sires is discussed and a fresh emphasis is given to tlie measurement of excellence in animals whether it he for milk, wool or. meat producing qualities. A rather visionary view is introduced with a reference to rerent. 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 t.he microscopic examination ot the skin instead of waiting for years until his progeny have come into production. The bulletin is very well illustrated. There are some forly-sevcn pictures illustrating features that arc discussed by Dr Dry. Most of this material is drawn from domestic live-stock. There is also a useful glossary of technical terms, for though the author has minimised (he use of technicalities it is inevitable tliar such a new science as genetics must introduce new words into the vocabulary of livestock breeders.