BREEDING OF PIGS

Taranaki Daily News, 13 April 1935, Page 24 (Supplement)

BREEDING OF PIGS

requirements of trade CONFORMITY OF THE CARCASS. London, March 9. Mr. J. Hammond, F.R.S, (of the School of Agriculture, Cambridge), was one of the speakers at the conference at Harpenden on the production of pigs for bacon. He spoke on carcass quality and breeding from it. Breeders, he said, would do well first to find out what are the weak spots in their pigs from the grading reports of factories, from the reports of the local Pig Recording Society, or from the score cards of the carcass tests carried out by various societies and shows. Having found out these defects, they should get a boar which was particularly good m these respects. Before condemning the had stock, the feeding and management should be examined to see if they were right, such as getting quick growth in the young stock, making good gains for food fed, in putting on lean meat rather than fat, and feeding sufficient' proteins and accessory food factors. If these were not right, then no matter how well bred the pigs were they would' have no chance or showing what they could do, and buying good stock would not help to put things ri The body proportions and composition of a pig did not remain constant, but changed as the pig grew up. In the pork type they changed quickly so that they were right, i.e., with small proportion of head and bone and a high proportion of loin and lean meat, with just the right amount of fat-half an inch over the loin for the London trade at 701 b carcass weight (951 b live weight). In the bacon type these same proportions were not attained until the weight was 1501 b carcass weight (2001 b live weight). The proportions required by the consumer were the same for both pork and bacon pigs, but the weight at which the two types arrived at those proportions differed, the one being early maturing and the other late maturing. Within any one breed; therefore, the type could be changed by selection, as had been done with the Poland-China in the United States, although for commercial purposes this result could be acquired quicker by crossing with an appropriate breed. TRADE REQUIREMENTS.

The speaker went on to describe the various requirements in the carcass. The back part, he said, forms a good measure of the fatness of the carcass generally, and nowadays the public do not require very fat meat. The fat is always thickest over the shoulder and * for requirements to-day the fat here should measure one inch and a-half or less. In the young pig the shoulders are well developed and the loin poorly developed as compared with a mature animal, and the fat is much thicker at the shoulders than at the loin in a young pig. The difference in ratio between these two parts generally narrows as the pig grows up. Thus, a back fat gradually tapering from the shoulder to loin is a sign of a carcass which has not yet attained its full maturity and fatness. Such carcasses are required for bacon production. Since the pork types are small, short, blocky, and early maturing, they usually carry more back fat at 2001 b live weight than do the longer, larger and liter maturing bacon types, and by lengthening the pig the chances of getting too thick back fat are reduced. On the same feed gilts usually grade better than hog pigs as regards back fat measurement. A thick streak (over Ilin) can be obtained In two ways:—(l) By fattening to a high degree, and (2) by developing the thickness of the muscle or lean meat. It is the latter which is required by th® public, and hence under the pig marketing scheme a pig only gets into grade A when b >th the streak is thick and the back fat is thin. It is this development of the thickness of lean meat without getting too much fat in our pigs which is the main problem in pig production to-day.

RAPID GROWTH. y

In the young pig bone growth reaches its maximum first, then muscle, while later fat makes ■ its maximum growth. This forms one of the reasons for weigh-* ing the young pigs (under Pig Recording Society schemes) at eight weeks old, for it is at just after this time that the lean meat is developing and pigs which grow well then will grade better than those whose growth is checked at this stage. This rapid growth in the young pig is, in addition to the feed factors, involved, a breed character both as regards the young pig itself and also with respect to the milking qualities of the sow, for young pigs will not make rapid growth unless the dam has a plentiful supply of milk

At birth the ham is nearly all bone, and as the pig grows up the bone becomes proportionately smaller, and thd meat is “let down” to the hocks. A good ham is one in which these age changes are well developed. Width of the buttock is a characteristic which requires to be improved very much in our pigs, 1 as It adds much to the appearance of the gammon when the side is hung up. I Apart from the fact that the pig which is long for its weight will generally be less fat than one which is short for its weight, length is required in order to get a large proportion of back cuts as compared with belly cuts, for the former are higher priced than the latter.

QUESTION OF DEPTH.

One requires a pig with well-sprung ribs, rather than a deep, flat-sided one. The depth of the pig increases in proportion to its length as the pig grows up, anH this increase in depth/is associated with increase in the fat of the carcass. One requires .to breed the type of pig which at bacon weight (2001 b live) has only just begun to deepen, but which has not gone so far as the pork type does at this weight. It is the proportions of the body at the weight at which the pig is to be killed, and not the adult proportions, that matter. The may be deep in proportion to length provided her offspring are not too deep in proportion to length at 2001 b live weight. The shoulder is a low-pnced part of the carcass as compared with the and, consequently, should be reduced as far as possible. There is a natural tend, eney in pigs following their wild boar ancestors to become heavy in the Shoulders and light in the lom, and this fault will tend to creep in unless continuous selection is made 'against it. Pure breeding is the only method by which Pigs can be improved pennmwntlv. No pure breed is absolutely perfect yet, and it is for the breeders to discover all the weak spots in their animals and put them right. In so far as they do this they will reduce the need for cross