SHEEP BREEDING

New Zealand Herald, Volume LXXI, Issue 21793, 7 May 1934, Page 15

SHEEP BREEDING

FLOCK IMPROVEMENT

SCOPE FOR APPLIED SCIENCE

Id* H.B.T

The development of the sheep in tho direction of maximum production lias been slower than that of any other domesticated animal. In Now Zealand tho rato of progress has been, and still is, below the average for tho rest of the primarily sheep-farming countries of the world, and if we arc to improve our | present position, it is necessary that Ave study and apply tho proved methods that have been successful in improving the productive capacity of our more advanced types of stock. One of the chief obstacles to progress in sheep evolution is tho acceptance of the very general belief that tho sheep is, or should be, a dual-purpose animal. In tho effort to servo both objects—mutton production and wool productiont—wo have fallen between two ideals and have achieved perfection in neither.

The second reason for tardy progress in the evolution of tho sheep is the lack of duplication of modern knowledgo of genetics. Our practical experience with Iniry cows, poultry, pigs and race- ' wos, has conclusively proved that rapid advance in production—in one direction at least —can bo secured by selection of individuals on the basis of their carefully-recorded production performance, and by mating these transmit their parental characteristics to the offspring.

Tho present casual mothods of selecting and mating even stud sheep, combined with the lack of records of tho production of the forebears of each individual, are entirely at variance with tho basic principles of modern scientific breeding Breeding Mistake

The discovery by genoticists that many charaeterictics particularly, those connected with reproduction—aro " self-linked," has enabled the dairyfarmer to increase his milk and butter-fat output quickly and certainly, and tho poultryfarmer his ogg production similarly. Undoubtedly many important characteristics of the sheep are also self-linked. Experiments indicate that both quantity and quality of wool are inherited by the fcmalo progeny from their sire to a much greater extent than from their dam where both are equally prepotent, and that size and conformation aro inherited from the dam more than from the sire. The object of most New Zealand sheepfarmers. to produce a dual-pur-pose sheep by crossing different breeds, has probably done more to delay the evolution of high-producing sheep than any other single factor in our farming methods in tho Dominion. By this practice we have lost both typo and prepotency in our flocks and at tho same time have gained nothing that could not have been secured by selection within the breed.

Evolution o 1 Sheep While such practices as these have definitely delayed tho rapid evolution of the sheep toward greater and more valuable production, it is possible for us in New Zealand even now to achieve a lead with our sheep products. It will be necessary for us to understand and intelligently apply the laws of genetics. Food, or nourishment, in its order of importance consists of air, fodder, sunshine and water. Air is available in abundance everywhere, but in order to be able to utilise this essential " food " to the ' utmost, tho sheep must have that conformation which gives it lung capacity. Grass, or other fodder, varies considerably in quantity and nutritive value 011 different soils and in different localities, and to secure maximum production from the available fodder tho sheep must not only have tho requisite capacity, but in size and inherited predisposition must be adapted to their environment. Sunshine plays a far bigger role in supplying nutriment, to both vegetable and animal life.than the average man realises, and here again the type or breed of sheep must be selected, because of its suitability to tho climate whore it is depastured. Water, though not literally a food, exerts a big influence on both skeleton and wool growth, and both its abundance and mineral content may affect both the type and production of tho sheep. The varying conditions of air, fodder, sunshine and water to bo found throughout the Dominion suggest that a variety of breeds or types arc necessary to fully utilise tho productive capacity of our grazing land

Development of Frame and Flesh Assuming an abundance of suitable food and the capacity to assimilate it, inherited predispositions play the next most important part in production. If the sheep lias inherited from its forebears a tendency to massive bone and great size, all the nutriment which it may absorb in its young life will be diverted to the development of a big frame. Only after this " predisposition" has been satisfied will it commence to lay on condition. If, on the other hand, the breeding of an early-maturing type lias been concentrated upon, the demands of the skeleton will soon bo satisfied, and the food eaten will soon bo diverted to the formation of meat and fat.

During the growing stage, development of tho frame and flesh or condition alternate. Normally a period of three months in the lamb is devoted to growing, or skeleton formation, followed by an equal term when little growth takes place, but during which the youngster puts on flesh and condition. If, because of its predisposition to great size the available food is little more than sufficient for skeleton formation, its flesh formation and energy suffer, while, when mature, it will be unlikely to produce progeny or any quantity of wool. This process follows the natural laws which place survival first, reproduction second and production last.

Mutton and Wool Sheep It. should be obvious that it is easier to produce a " mutton " sheep than a " wool " sheep, because frame and flesh, tho requisites of a mutton type, are the first to benefit from food supplies, whereas the natural increase and wool, are dependent upon any surplus that may ho available. Those breeders and fanners who wish to produce a mutton sheep should concentrate upon selecting light-boned ewes of tho desirable conformation and size, and mate these with prepotent rams having similar characteristics.

The farmer with whoin wool production is the primary consideration lias a more complicated task. Not only must he have in his breeding flock an inherited propensity to develop liheep of Hie correct size and conformation to thrive and reproduce on his available feed, but he must employ all the hereditary influences that aro available, in both rams and ewes, to utilise! surplus food in tho production of both quantity and quality of wool. With him, mutton characteristics must be a secondary consideration, although it is certain that if he secures the correct type, size nnd conformation to suit his country, his stock will not be by any means valueless for fattening..