FACTORS LEADING TO EXCESSIVE WASTAGE IN THE PIG INDUSTRY.

New Zealand Journal of Agriculture, Volume 53, Issue 3, 21 September 1936, Page 150

FACTORS LEADING TO EXCESSIVE WASTAGE IN THE PIG INDUSTRY.

D. Marshall,

Veterinarian, Hamilton.

Consideration of slaughtering and inspection figures over the past season emphasizes the loss through condemnation of pig-carcasses or their rejection for export, which represents a serious loss to the farmers and to the country. It is, however, only a portion of the wastage in the industry. Mortality at Birth. Mr. H. M. Peirson, Recording Officer of the Waikato Pig Recording and Research Association, in his annual report states that “ A mortality of 22 per cent, had to be recorded between birth and weaning. The greatest percentage of deaths has been recorded as ‘ born dead,’ which is not actually the case. Had some one been in attendance at the time of farrowing, the death-rate would have been reduced very considerably, as in many cases the pigs born (alive) died of suffocation.” This is in recorded herds where the Recording Officer is advocating the value of management, and attention at farrowing, and where owners take more than average interest in their pigs. The loss at this period may well be greater over all herds.

Some of the farm loss through pigs being born prematurely, or imperfectly developed, or dead, is undoubtedly due to defective feeding of the pregnant sow. Successful breeders have shown that the supposed danger of sows being “ too fat at farrowing ” does not arise if the sow is active and healthy. As in the case of other stock, pigs provide evidence that better feeding of the pregnant mother results in heavier young being born. On the other hand, pregnant sows underfed, either through lack of green feed in dry autumn periods, or poor-quality herbage and no supplement, such as meat-meal and roots or milk, during the winter, are more liable to the above losses. Loss after Weaning. Further wastage occurs between eight and twelve weeks. This appears to be one of the most susceptible periods of the pig's life. It follows directly on weaning, and unless the creep system or other method has been developed to make the change from mother’s milk less of a shock, and unless care and conditions at this stage are good, the pig suffers from the change in diet, it has frequently to contend with older pigs at feeding, and is exposed to the hazards of. overcrowding and dirt. Even if the pig survives this period, under bad conditions it may contract some infection which, while not fatal, renders its carcass at a later stage unexportable or even unfit for consumption. . Fawcett, in a statistical survey of the position for 1934, estimated by a comparison of the number of pigs that should have been available for slaughter with those actually put through that there was a discrepancy of 125,000, or, in other words, a death-rate of 125,000 pigs. Bacillus suijestifer infection is an important bacterial factor in the mortality at the eight to twelve weeks’ period and will be dealt with later. Causes of Condemnation and Rejection. The following are the chief causes of condemnation and rejection : tuberculosis, pleurisy, peritonitis, septic wounds, faulty castration, arthritis, nephritis, bruises, and skin-lesions. It should be emphasized that, with the possible exception of tuberculosis, all are the results of defective management and are to that extent preventable. Mcllwaine, in this Journal, October, 1935, writes, “ There is no doubt whatever that if greater attention is paid to the cardinal matters — improved housing, feeding, and improved conditions — alarming mortality in young pigs would be reduced to reasonable proportions.” To quote again H. M. Peirson, “ The more pig-recording is extended the more definite has it become that management is the biggest factor in successful pig-keeping . . . It is still unsatisfactory to find that the pig is the first animal to be neglected on the farm. At haymaking and holiday-time the weights of many litters shows a considerable decline.” What are the reasons for this ? One might suggest failure to recognize the extent of loss and the value of housing and hygiene, overwork, and lack of sufficient time to attend to pigs, or a method of pig-farming not suited to the soil type and locality. Success in pig-farming is usually under one of the following conditions : Locality highly suitable with dry subsoil, sunny aspect and abundant natural shelter, plant big enough to employ one or more men the whole time, or else the owner or one of his staff keenly interested in pigs and able to take the time necessary to attend to them.

Tuberculosis

The most common source of tuberculosis is undoubtedly infected skim-milk. Other ways of infection are grazing after infective cows, association with other pigs in an advanced stage of the disease, or with tuberculous poultry, or possibly from a diseased mother. Bad housing, sanitation, and management cannot themselves cause the disease, but may be responsible for its spread and for its more rapid development in any pig once infected. Visible signs of the presence of tuberculosis in the pig are not common. Detection of every possibly infectious cow in the herd is not easy without the use. of the tuberculin test. Infections from this source could be lessened, however, were farmers to familiarize themselves with the suspicious signs, and to promptly report to their Inspector of Stock any cows showing these. They are — (1) Tuberculosis of the lungs : Loss of condition and chronic cough, the cough being manifested after exertion. (2) Tuberculosis of the throat-glands with peculiar carriage of head, abnormal “ roar ” in breathing, or swelling at throat. (3) Swelling of any superficial lymphatic gland, the three chief being below ear, front of shoulder, and fold of flank. (4) Tuberculous mammitis : Gradual increase in size and hardness of one quarter of the udder without previous acute inflammatory stage of ordinary mammitis. Pleurisy. Pleurisy is inflammation of the normally smooth and thin membrane lining the inside of the chest and also covering the lungs. The condition found in slaughtered animals is usually a thickening of the membrane as a result of a previous acute attack of pleurisy. If thickened, the membrane must be stripped off, and the British authorities will not accept carcasses from which' the pleura has been removed. Cases condemned are those in which the inflammation is still in the acute and fevered stage or septic fluid is present in the chest. Practically all cases of pleurisv are associated with some degree of pneumonia, the symptoms of which we recognize in the piggery. Numerous specimens of lung from pigs found with pleurisy in slaughterhouses have been examined at the Veterinary Laboratory at ■Wallaceville, and in a large percentage Pasteurella organisms, believed to cause swine plague or infectious pneumonia, have been found. Pasteurellosis, therefore, becomes of importance not only on account of the mortality it causes, but also because of ill effects (in the form of a thickened pleural membrane) left behind in recovered cases. -According to one authority, the infection is more widely spread than the disease, suggesting that certain pigs may carry the infection without suffering. Factors lowering vitality and rendering pigs susceptible thus become of importance, and these are poor housing, lack of shelter to runs, dirt, and overcrowding. Pasteurellosis may be introduced into a piggery by purchased pigs, hence the importance of isolating these for ten days. Symptoms are cough, discharge from nose, watering of eyes, together with hurried jerky breathing. Condition may be lost, and deaths

occur ; occasionally pigs over a fairly wide age-range and up to the heavy porker are affected. The trouble should be treated by isolating affected pigs, feeding light laxative diet including molasses and cod-liver oil, teaspoonful daily, in milk. ' It is advisable to spray houses and bedding with creasote and oil. During the past season regular reports have been made by the Meat Inspectors on all lines of pigs in which the percentage of tuberculosis or pleurisy has been ' unduly high. These have been referred by the District Superintendent to the Inspector of Stock in - the district concerned so that conditions on the farm could be noted and advice given if necessary. The following are extracts from reports of Mr. E. A. McKinlay, Inspector of Stock, for Hamilton on some of the many farms visited, pleurisy up to 16 per cent, to 20 per cent, having been found in pigs raised on them : (1) Stores had been run in the open without houses for a time during a period of wet, cold weather. (2) Conditions very bad, poor draughty houses, pigs sleeping mostly in the open under trees. (3) One small house, many sleep in the open. (4) Unsatisfactory, no house or shelter. (5) House raised on piles and draughty, piggery exposed. (6) Heavy wet land, houses draughty, runs small and dirty. In other instances conditions were good, but pigs had been bought at sales and seeds of disease already sown. It has been felt that feeding is an important factor in disease-control, particularly more complete feeding of the younger pigs, sufficient starchy foods in winter, and mineral supply. However, amongst those pig-farming successfully there is a wide diversity in feeding, including skim alone, whey and meat-meal, maize and roots, extensive grazing, and sty-feeding. The above reports suggest that poor housing and lack of shelter are two of the most important factors leading to excessive pleurisy. Pigs can be reared free from pleurisy. A recent experiment at Ruakura, carried out by the Fields Division to test certain feedingmethods, concerned thirty pigs. These were raised to the eight-weeks stage on a standard milk-meal ration and thereafter run in different lots under different conditions of feed and management. Housing mostly was not elaborate, but draught-proof and floored. Paddocks or pens were reasonably sheltered and clean — for pigs for the first time twelve months previously. Feeding was of various types after eight weeks, but milk and meal were fed at regular hours and in measured amounts. No cases of pleurisy were found on slaughter. In a second instance, out of 120 pigs put through, only three were found to have pleurisy. The owner here was an enthusiast and a great believer in good housing and the value of bedding, which was changed daily and sometimes twice daily. The three, pleurisy cases were believed to be three pigs which refused to sleep inside. PREVENTION OF PLEURISY. Prevention of pleurisy therefore appears to depend on attention to the following points : Housing. — The house must be tight-walled to be free from draughts, but ventilated below the roof, and have wooden floor ; felt or wood beneath an iron roof keeps it warmer in winter and cooler in summer. Designs for houses are readily available. Provision of a concreted yard in front of the house is useful, particularly in wet country, as

pigs may be confined to the house and yard during very wet weather. Proper provision of. drainage from the yard is essential to keep surroundings clean. Shelter. — For the runs where the pen . system is followed shelter is perhaps even more important for pigs than for other classes of stock. Outbreaks of disease and in pigs under record a. marked check in rate-of-weight increase have been frequently observed during spells of cold southerly weather where housing and feeding were satisfactory, but runs badly exposed to bleak winds. Shelter may take the form of artificial barricades of wood, iron, or scrub on windward side, of runs or suitably close live hedges. Pampas requires fencing till established, but when mature makes a dense mass which is almost a substitute for a house. Other points are cleanliness, avoidance of overcrowding, regular feeding, adjustment of amount of food to rate of growth, change of run where necessary, and the various other points summed up under the term “ good management. Peritonitis. Peritonitis is inflammation of the membrane lining the bellycavity, and covering the intestines and other abdominal organs. As seen at the works, it resembles pleurisy in that many cases show only the thickening of the membrane resulting from a previous acute attack, but “stripping” is necessary. The percentage of peritonitis was higher than usual last autumn, probably as a result of the wet summer. In the field it is frequently found associated with Salmonella suipestifer infection, and.preventive measures will be dealt with under that head. It may follow post-castration infection. Nephritis. Nephritis is inflammation of the kidneys, acute or chronic. Bacterial infections, including suipestifer, have played a part. Arthritis. Arthritis, an inflammation of a joint, frequently the stifle, with excess discoloured synovia present, is also in many cases due to an infection, suipestifer having been found in some. A percentage of cases may be set up by bruising of the joint, possibly through climbing up on to feeding platforms. Salmonella Suipestifer Infection. Infection by Salmonella suipestifer is thus apparently an important factor in the production of the three previously named lesions, but it is also one of the chief causes of mortality in young pigs. In suckers it is one cause of scours, if houses are contaminated and conditions dirty. In older pigs pneumonia is often present, evidenced by jerky breathing and loss of condition. Bowel-lesions are also common, either with pneumonia or independently, varying from small ulcers to extensive thickening—-the so-called necrotic enteritis. The symptoms of this are usually chronic scour, marked loss of condition, pigs becoming skinny. Peritonitis is nearly always found in such cases. Deaths from a very acute infection may occur before the above signs develop, dead pigs often showing blue discoloration of belly and thighs

blue belly”)- The feature of suipestifer infection is the periodic occurrence of deaths, and the presence of odd, skinny unthrifty pigs showing the above symptoms. It is largely a dirt-disease, and infection becomes active where resistance is lowered. PREVENTION AND CONTROL. Prevention and control are in the direction of greater cleanliness, . especially at feeding-places, change of runs if the ones in use are old and contaminated, and avoidance of overcrowding, which is a potent cause of spread. The obviously unthrifty pig which is merely distributing infection should be destroyed. Thoroughly clean out all milk-containers, add some lime, and for a period a daily amount of a chlorine disinfectant say, a teaspoonful per 40 gallons. Feed a little whole milk to smaller pigs cod-liver oil is useful. Access to good grazing often helps. Give necessary attention to housing. Small doses of sulphate of iron solution to suckers will check scouring. Faulty Castration. Castration is a surgical operation, incision being made into clean, healthy tissue, and healing should be rapid and uneventful. Occurrence of large tumour-like swellings points to infection. Castration should be carried out at an early age, and Waikato Recording Association pigs are usually castrated at three weeks old. It is essential that pigs should be clean when operated on, and imperative that for ten days afterwards they should be kept strictly clean, either confined to a clean house or preferably in a clean grass run, with clean house and feeding-space available. Do not apply strong antiseptics on or in wound, and rather use an antiseptic on skin before operation, preferably tincture of iodine. Septic Wounds. Septic wounds are the result of infection by dirt organisms of any wound or scratch. They may occur on any part of the body or limbs ; about joints they may cause severe lameness. The infection may attack gums and lips of suckers. Many respond to treatment by first scrubbing the sore well to remove dead tissue, and then dusting with tartar emetic. Repeat in a week. If in the mouth, swab with iodine. Overcrowding at feeding-places, quarrelsome pigs, excess barbed wire all tend to cause wounds, and filth harbours the infection. One may see such cases occasionally where pigs have quite a clean range on grass but come into some filthy pen for milk. Summary. Much of the loss due to the presence of tuberculosis in pig-carcasses could be prevented by more prompt detection and elimination of the dangerous cow in the dairy herd. Condemnations and rejections for pleurisy, peritonitis, faulty castrations, and septic woulds could be lessened, and pig-mortality on the farm reduced, by attention to the following matters : Good draughtproof housing, with sufficient accommodation for all pigs and bedding in cold seasons ; clean runs and feeding-places ; correct feeding, particularly of the pregnant sow, and of the litter and weaner, along the

lines developed by recording clubs ; adequate shelter for pens or runs ; avoidance of overcrowding either in houses, in runs, or at feeding-places ; temporary isolation of all newly bought pigs. Good management comprises all the above matters, and also .includes that little measure of interest in the pigs and attention to detail without which the best of plants may fail.