Selection of Breeding Sows within the Herd

New Zealand Journal of Agriculture, Volume 84, Issue 4, 15 April 1952, Page 281

Selection of Breeding Sows within the Herd

THE normal practice on New Zealand * dairy farms for replacement of breeding sows is to save gilts for breeding from the pigs in the fattening pens. This article by A. Longwill, Superintendent of the Pig Industry, Department of Agriculture, Wellington, deals with the main points in making this selection. MOST pig producers who breed their own pigs replace sows by selecting likely looking gilts from the baconer pens. Provided the existing breeding stock are sufficiently good and a good purebred boar has been used, there is much to be said for this method of herd replenishment. There are, however, a number of points to be watched if successful results are to be expected. The essential qualities wanted in sows are prolificacy, good milking ability, and good mothering temperament. The progeny must be rapid growers and efficient converters of their food into meat, and the carcasses produced must be of the type to yield the maximum of high-value cuts. The farmer who has studied the breeding of his dairy herd and methods of testing and selecting for improved performance will realise that effective methods of selection cannot be based on guesswork or even observation combined with memory, valuable as is the latter. Testing of breeding stock and careful recording of performance, if properly employed, will play a bigger part in the improvement of the general standard of performance of the breeding herds in New Zealand than any other factor. Performance Tests Methods of testing performance in pigs available include litter recording and carcass testing, the latter taken in conjunction with rate of growth. The operation of these schemes and their importance in pig improvement were described in the December 1951 issue of the “Journal”. Though these schemes, if used intelligently, can be of assistance to the pig raiser within his own

herd, considerable development, particularly of testing for efficiency of food conversion and for carcass quality under standard environmental conditions, will have to take place before the schemes can be of very great value in improving the herds of New Zealand. This is because, nationally, herds can be improved chiefly through boar selection, and it is only when the progeny of various boars can be compared under uniform conditions that a logical method of boar selection can be followed. Meantime the home breeder by recording the performance of all the sows in a herd and their progeny to pork or bacon weight can use these tests to select replacement gilts. A minimum

standard of performance of 9 piglets born and 8 reared with litter-recording weights of 1001 b. at 3 weeks and 3001 b. at 8 weeks should be set and adhered to rigidly. If this standard cannot be achieved, the existing breeding stock or the management of them is at fault and this must be remedied first. It is not a sufficient criterion for selection that a sow should have put up one litter record of this standard. A sow if reasonably well managed should show that she is capable of producing up to this standard regularly and over a long breeding life. • The additional tests of efficiency of food conversion and final carcass quality should be superimposed on the initial litter recording to give a complete picture on which to base selection. To test efficiency of feed conversion strictly it would be necessary to record carefully every pound of feed used and the gains made, but for practical purposes at the moment rate .of gain can be taken as a rough guide on the farm. Rate of gain and carcass quality can be recorded • through the carcass-quality evaluation scheme. Representative pigs from individual litters could also be entered in carcass competitions, when the full carcass score can be obtained.

Lifetime-performance Records The keen breeder, particularly the pedigree breeder, could well go to the extent of keeping a lifetime-perform-ance record for each sow in his herd. Copies of a form suitable for recording this data may be obtained from the Department of Agriculture.

The standards set for growth rate and carcass quality must be kept together. It is possible, for instance, to increase the carcass score at baconer weights, provided time is taken to restrict feeding, in pigs which normally would be too short and fat to make ideal baconers. To be worthy of selec- , tion for breeding, a sow’s progeny should make 1501 b. baconer carcasses in . 200 days or less and at the same time should achieve an average carcass score. of 70 per cent, with as little variation as possible. Because of the seasonal nature of feed supplies in New Zealand, some latitude in interpreting . such standards is necessary. The minimum carcass score of 70 should be set rigidly, however, and latitude down to a growth rate of ,701 b. carcass gain per day allowed only if growth has been over a period when food supplies were inadequate. Again, a test of one litter is insufficient and it should be possible to test one litter from each sow every year under reasonably favourable feed- . supply conditions.

A more satisfactory test for New Zealand conditions would be to aim for a 901 b. dressed porker in 20 weeks (140 days) with a minimum carcass score of 70. If this growth rate and carcass score is obtained, it should be possible, with careful finishing, to obtain a fairly good baconer carcass from the same strain of pigs. Breeders interested mainly in baconer production would pay special attention to individual carcass measurements, such as of length and backfat, to ensure that the pigs they selected were breeding the right type for baconer production. ■ Cnmnlo+a Por-nrrlinn v -' om P ieTe becoming Those not able to undertake complete recording could use a selection technique based on the ability of pigs to grow efficiently and to produce generally good-type carcasses. The standard for growth rate could be 1501 b. liveweight in 22 weeks (154 days) and that for carcass type could be set from grading results on the

hooks coupled with an assessment of the animals on the hoof. It would be a step forward if in the', selection of gilts to be used for breeding home breeders added the growthrate criterion (1501 b. in 22 weeks) to the usual visual appraisal for carcass type, teat placement, feet and legs, etc.. The ability to convert- food rapidly and efficiently into meat is largely an inherited characteristic. The use of gilts which have shown that they have this trait and are from sows which have passed other tests outlined in this article should offer scope for . improvement in the efficiency of New Zealand’s breeding stock. The runt of the litter and the last pigs in the fattening house at the end of the season should not be the material from which future breeding stock is selected. Management of Selected Gilts Final selection should be made when gilts are between 22 weeks and the baconer stage. Gilts selected should be run out on pasture and fed to maintain growth rate without production of too much fat. Mating should take placeat about 8 months, depending on the times of other farrowings and the overall fitting of pigs to the seasonal food supply. Gilts being selected from the fattening pens now should be grown on for mating in July and August to farrow in November and December, Pigs from litters born in May and Juneshould be selected, on the criteria described, for mating in January and February to farrow at 1 year. May toJune is probably the best time to bring new gilts into the herd. As pigmeat prices are sufficiently attractive and the need and scope for increased production are clear, there should be no hesitation about increasing sow herds. Some indication of how this can be done most effectively from the existing stock on the farm has been given here; further assistance may be obtained from officers of district pig councils and from the Department of Agriculture.

Ruakura Farmers' Conference Week

AN opportunity for farmers to keep abreast of research work into farming problems is again given by the annual Ruakura Farmers’ Conference Week, which is to be held at Hamilton this year from Tuesday, 13 May, to Friday, 16 May, inclusive. The chairman of the conference will be C. P. McMeekan, Superintendent of the Department of Agriculture Animal Research Station, Ruakura, in cooperation with the Waikato Farmers’ Educational Committee. The programme is well planned and comprehensive. It deals specifically as it has done in previous years with problems of sheep and dairy farmers, and a large part of the time will be devoted to a section for all farmers. The opening day, 13 May,, is set aside for the sheep farming section and- will begin with a paper by Dr. McMeekan on the work at Ruakura. Other subjects are “Improvement of Pastures on Sheep Farms”, “Pulpy Kidney in Lambs, Sleepy Sickness and Milk Fever in Ewes”, “Dipping and Drenching”, “The Place of Galloway Cattle on Hill Country”, and

“Diseases of Beef Cattle”. An open forum will be held at the end of the day, when A. Rowlands, F. C. Johnstone, and Dr. McMeekan for the meat industry, the producer, and the research worker respectively will discuss “How Beef Output Can be Increased”. v The section for all farmers extends over two days, Wednesday and Thursday, 14 and 15 May, and covers a wide range of subjects. It will begin with a field day at Ruakura and will continue with papers such as “North African Phosphate Can be Dangerous to Stock”, “Eucalypts on the Farm”, and “Avoidable Losses in the Meat Industry”. On the last day of the conference Friday, 16 May, problems of dairy farmers will be dealt with. Dr. McMeekan will give an address on the work at Ruakura and other subjects will be artificial insemination, lifting production in low-producing herds, the eradication of tuberculosis in dairy herds, cleaning the milking machine, and recent developments in providing an efficient testing and servicing organisation for milking machines.

Bands from Wild Ducks Wanted DRAINAGE of swamplands in recent years has reduced steadily areas where duckscan breed in New Zealand. Many farmersmaintain artificial duck ponds, but under thechanged conditions these are not much use to ducks unless they are fringed with dense marsh vegetation. There are signs that farmers areappreciating increasingly the need for thepresence of native swamp plants about theseholes if they are to keep duck on their properties. By banding of ducks the Wildlife Division of the Department of Internal Affairs is obtaining knowledge of how the birds react to changed conditions. The shooting season for game l starts on 3 May, and the Secretary for Internal Affairs asks farmers to return any bands takenfrom ducks they shoot to the Controller, Wildlife Division. Returns of bands in former years have been* good. As before, each person returning a band will be given the history of the bird. Some loss of bands occurs through delay in posting them to the Wildlife Division, so the Department asks that they be returned promptly.