Diseases in the Pig

New Zealand Journal of Agriculture, Volume 60, Issue 1, 15 January 1940, Page 1

Diseases in the Pig

Conditions Affecting Arthritis, Paralysis And Trembles

D. MARSHALL,

District Superintendent, Livestock Division, Wellington.

ARTHRITIS A RTHRITIS is inflammation of a ARTHRITIS is inflammation of a IX joint. This disease is ,of considerable practical importance in the swine industry. At the meat works the percentage of pigs rejected for this cause varies from £ to 1 per cent, in different works. In the field, however, it is responsible for considerable mortality in young pigs, and some unthriftiness.

Causes There are various causes, and more than one factor may be concerned in any particular case. They may be grouped under the headings of infection, mineral deficiency (or imbalance,) injury, and poisoning. Infection In New Zealand infection is undoubtedly the most common and most important direct cause. Germs of various types may be found present, commonly streptococci of some kind. In countries where swine erysipelas is

common this organism is a frequent cause. Rarely, the bacillus of tuberculosis may localise in or ' about a joint and set up a tuberculous arthritis. Skin ulcers in the vicinity of a joint frequently invade the joint cavity. Defects in Diet Defects in the mineral elements in the diet, or an improper proportion of these elements, may also be a cause. In the United States, where grains, particularly maize, form a large percentage of the diet, there is likely to be an excess of phosphorus in proportion to the lime present. Under such conditions there may occur a type of

stiffness, and lameness, with some enlargement of the ends of long bones, , at the joints. The condition may be put down to rheumatism. Under the reverse condition, with excess lime in proportion to the phosphates fed, similar conditions may occur. It is very doubtful whether this type of arthritis is at all common in New Zealand, largely . because milk forms a big portion of the feed for most pigs. Certainly, in addition to the correct supply of minerals, there is necessary either a sufficient, supply of vitamin D in the feed or adequate exposure to sunlight for proper bone formation. The above condition has been noted once or twice in pigs wholly confined to houses for long periods. With regular or periodic exposure to sunlight, and a mixed diet, including milk and grazing, the complaint is most unlikely. Injury Instances have occurred of an undue number of arthritis cases among pigs

which were known to have run over defective floors and gratings, with the opportunity for the foot or leg to slip through and the limb to be bruised or wrenched. Other cases are caused where a considerable number of pigs, running together, attempt to scurry through narrow gateways to feeding places or in and out of houses. The remedies for such conditions are ob-vious-sound floors, wider gateways, and fewer pigs run together. Zinc Poisoning

Zinc poisoning has already ‘ been dealt with in the “Journal” in July,

1936, by Messrs. Grimmett and Mclntosh, who described the first authenticated cases, in April, 1937, by Messrs. Grimmett, Mclntosh, Wall, and Hopkirk, who described experimental zinc poisoning in pigs, and in the August and November issues, 1939. Briefly, zinc poisoning is likely to occur only where a considerable length of new galvanised piping is used to convey skim milk or butter milk. The acid of the souring milk dissolves the zinc from the inside of the pipe. Unthriftiness and deaths occur, and a fairly constant finding was a type of

arthritis with sponginess of ends of bones and loosening of cartilage. Since the occurrence of the condition was confirmed, odd cases of lameness have been detected in pigs in new layouts, where new piping was in use, and the pigs have recovered where the use of the piping was discontinued. Most Common Type The type of arthritis most commonly met in New Zealand in the living animal comes under the first heading, and can be described as acute bacterial arthritis or polyarthritis. This condition may be seen in small pigs from ten days to a month old. Arthritis of this kind in the young animal is seen in other species—in foals under the name of joint-ill or navelill, in calves, and in lambsand there is still difference of opinion as to the method of infection, whether through the navel after birth or from the mother before birth, and also as to the influence of the proper feeding of the dam. While the majority of cases occur in insanitary conditions, pigs may be affected when kept in wellbedded houses. Symptoms Lameness or stiffness may be noticed in the small pig. This is frequently put down at this stage to injury by the mother. Later, swelling occurs of one or more joints, hock, knee, stifle, in that order. The pigs lie about, are unwilling to move, and show pain on handling. Deaths occur from poisoning of the system. On being opened, the affected joints may be found distended with a turbid discoloured fluid instead of the normal clear synovia. Treatment Beyond keeping the little pigs warm and comfortable little in the way of treatment can be applied, and it is doubtful whether any treatment is justified except in mild cases. Mr. C. E. Ballenger, Experimentalist at Ruakura, has had instances of pigs which apparently recovered from an attack in the sucker period only to be rejected for arthritis at bacon weight, indicating that damage to the joint persisted. Prevention Prevention becomes of chief importance. Strict cleanliness of everything about the farrowing pen is essential, and small pigs should be kept from

roaming into dirty cowsheds, drains, manure piles, etc. Where a succession of cases occurs in permanent farrowing houses, they should not be used for a time, and sows should be farrowed in fresh quarters. This has sometimes resulted in cessation of the cases. Correct diet, including sufficient protein, such as meat-meal, green-feed-grazing, and some mineral supply, should be supplied to the sow during pregnancy. The addition of iodine to the sow’s feed has been tried, but little influence on arthritis was noticed. PARALYSIS Paralysis denotes inability, complete or partial, to use certain muscles because of interference with the nerve supply. In the conditions referred to here the muscles concerned are chiefly those of the limbs, more particularly the hind-quarters, though to some extent all muscles are involved. There is imperfect control of the hind legs, resulting in a staggery gait, or perhaps in the hind legs being trailed on the ground. Paralysis is seen in fracture of spine, in tuberculosis of spine, and in vitamin A deficiency. Fracture of the spine occurs mostly in mature pigs, such as sows, as a result of fighting or accidents. Sows which have just weaned a litter appear to be more liable to fracture because of the removal of portion of the mineral matters from the bones during pregnancy and lactation. The resulting paralysis appears suddenly. The animal appears perfectly healthy, but is unable to raise its hind-quarters from the ground. Treatment is not justified. A waiting policy may be adopted for a day or two, but if the diagnosis of fracture is reasonably certain the animal should be slaughtered. T überculosis Tuberculosis of the spine is a rare cause of paralysis, but cases have been seen, again usually in mature pigs. The onset of the paralysis is more gradual. Diagnosis of the actual cause cannot be made with certainty during life, but a positive reaction to the tuberculin test would provide some confirmation. Paralysis from vitamin A deficiency is the most common type. In Austra-

lia a very comprehensive report on the conditions was given by Seddon and Frazer in 1927, although the cause was not then known. More recent work in the U.S.A, and at Cambridge has shown conclusively that deficiency of vitamin A is a cause. It has been noted more or less regularly in New Zealand. Here we meet it under conditions of feeding where this deficiency is very likely to occur, namely a skim milk diet without any supplement or green feed or grazing of any kind. It is probably a tribute to the improvement in the type of feeding and to the wider adoption of a sound open-air system with regular access to a good quality grazing that cases of this kind are becoming fewer. Symptoms Seen Affected pigs may be from three to six months old. Frequently they are in good condition. The first sign is unsteadiness on the hind-quarters and a tendency to sag to one side and for the pig to tumble over if it turns quickly. Later, the power of the hind legs is lost to such an extent that the animal is unable to stand on them and adopts a sitting attitude or trails the hind limbs. The voice becomes shriller, and the pigs are somewhat more nervous. A post-mortem examination may show nothing amiss, although the large (sciatic) nerves supplying the hind limbs may be found microscopically to be degenerated. Treatment consists in supplying vitaman A, which can be done readily by giving fresh green feed, cod-liver oil, or whole milk. Where nerve damage is extensive, recovery does not always follow. Prevention is along the same lines. TREMBLES This very apt name is given to a condition perhaps more properly termed chorea, or shivering, which is fairly frequently seen in small pigs. The whole body is constantly agitated by a jerking and twitching of the muscles, which may be so severe as to prevent the animal from standing up. One or two pigs, or perhaps the whole litter, may be affected, in varying degrees. Various writers have discussed this condition, and speculated as to its cause, and while there is a tendency to ascribe it to some hereditary factor,

this is by no means established. In the writer’s experience there was in one case a suggestion of an hereditary factor, all the sows farrowing to one boar showing a percentage of cases in their litters, while litters by another boar and farrowing about ths same time were unaffected. In other cases, however, sows which had affected litters were again bred to the same boar and had normal litters. A sow affected as a sucker was bred, and litters were not affected. More Data Needed Further information over numbers of cases is required before any preventive measures can be advised. Where affected piglets are able to suckle, they should be kept, as the tendency in all cases is to gradual disappearance of the condition. Usually, all signs of it are lost by weaning time. Occasionally, little pigs are so badly affected at birth that .they are unable to suck or even to stand up.

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