FOR THE FARMER.

Manawatu Standard, Volume LX, Issue 136, 9 May 1940, Page 14

FOR THE FARMER.

INTERNAL PARASITES OF PIGS. (Written for the “Standard.”) The internal parasites which occur in pigs show a wide variation in structure, size, shape, location, and degree of seriousness. Some of these parasites are very simple in structure and so minute that they can be seen only with a high-powered microscope. The minute parasites, known as protozoa, belong to the lowest group of the animal kingdom. Other parasites are worms which have a more or less complex structure. When full-grown, worms are visible to the naked eye, although a number of them are very small and can only be detected ordinarily by a specialist. The worm parasites fall into three distinct groups, namely, flukes, tapeworms, and roundworms, each group having a more or less characteristic shape. Some pig parasites live in various portions of the digestive tractothers occur in the lungs, liver, kidneys, muscles, and various other locations outside of the digestive tract. Wandering young worms penetrate various parts of the body in the course of their migrations. Practically all tissues and cavities of pigs may contain parasites at one time or another. EFFECTS OF INTERNAL PARASITES. Pigs are seriously affected by internal parasites of various kinds, the parasitic infestations of these iood animals frequently reaching a serious stage. Even comparatively light infestations with the large intestinal roundworm, intestinal threadworms, “thornylieads,” or thorn-headed worms, nodular worms, whipworms, kidney worms, and Ringworms may reduce pigs to a state in which they are neither well nor definitely sick; in other words, the pigs become unthrifty. Heavy infestations produce emaciation, diarrhoea, or constipation, and may terminate fatally. The conditions under which pigs are commonly kept in many parts of the Dominion are highly favourable to the spread of parasitism and its associated evils of unthriftiness, stunting, _ weakness, emaciation, and a very high mortality among young pigs. A large, if not the major, part of the mortality among young pigs is due to parasitic infestations acquired early in life, perhaps during the first iew days. Parasites not only devitalise pigs by robbing them of essential feed and inflicting injuries to many vital organs, hut in addition probably render pigs_ more liable to infection with bacteria and other disease producing agents. The migration of developing worms through various organs and tissues results in more or less serious disability'. In mass migrations of worms through the liver, lungs, blood vessels, and in the abdominal and chest cavities, serious consequences arc likely to follow and often do. The most serious effects arc, as a rule, noted in young pigs. You no pigs are not only more susceptible to infestation with internal parasites hut also suffer more severely than older pigs from such infestations Pigs and other young animals of all kinds are special cases and require special care to protect them from an onslaught bv parasites and otliei disease-producing organisms at a period in life when their susceptibility to disease is at its height, and when they still lack the hardiness to cope with disease-producing invaders. J)ue attention to .the protection of pigs early in life, and particularly during the first few weeks after they have been farrowed, will save the owner considerable loss resulting, from lack of condition, stunting, and deaths, and will more than repay the cost of affording protection from onslaughts by parasites. The oft-repeated warning that ail ounce of prevention is worth a pound of cure finds no bettor illustration than in pig-raising operations. A little well-directed energy spent in protecting pigs from the ravages of parasites is not only cheaper hut also far more effective than much of the medication to which many pig-raisers at times resort.'ln addition to actually preventing losses among pigs, control measures against parasites, if carefully and persistently followed, bring about a permanent improvement in swine husbandry by sharply curtailing the source of infection. These sources are the infested pigs, which discharge parasite eggs, and the infested yaids and pastures on which the eggs and larvae thrive. PROTOZOA.

Protozoa are the simplest form of animal life, the individual consisting of an exceedingly minute speck of living matter. Although the largest of the free-living protozoa can he seen by a trained observer with the naked eye, the parasitic forms of these lowly organisms can be seen only with the aid of a microscope. The small size of the parasitic protozga is not an index, however, of their power of doing serious damage. On the contrary, some of the severest diseases that affect human beings, live-stock, and poultry are produced by protozoan parasites. Malaria, amoebic dysentery, and African sleeping sickness arc among the serious diseases, ot /uaukind that produced by protozoa. Some important live-stock and poultry diseases produced by these organisms are tick fever of cattle, dourine and related diseases of equine stock, coccidiosis ol poultry and live-stock, and blackhead of chickens and turkeys. *”'~DYSENTERY-PRODUCING PROTOZOA. Pigs harbour a number of parasitic protozoa, including i-orms cnat aie closely related to, if not identical with, those recurring in human beings. Some parasitic ampebas occurring in the intestine of pigs are practically indistinguishable from those known to produce amoebic dysentery ill man. Other protozoans of the intestines oi pigs, known as balantidia, are apparently identical with forms that occur in persons; in human beings these parasites produce a dysentery known as balantidial dysentery. The dysentery producing protozoa arc conveyed from infested to susceptible animals by microscopic bodies known as cysts. A cyst is a resistant stage in the life cycle of these parasites. The cysts arc discharged with the droppings. Pigs swallow the cysts with contaminated feed and water. Although it has not been determined to what extent the dysenteryproducing protozoa injure pigs, or whether they produce dysentery as a rule, there is some evidence that balantidia are more or less injurious to swine. The possibility of the transmission of these organisms to human beings must he kept in mind. If for no other reason, measures designed to control these parasites in pigs are indicated as a human-health safeguard. The measures to be discussed for the control of coccidiosis are applicable also to the control of dysenteryproducing xirotozoa. —To be continued. Reports from the wheat districts of the Riverina (New South Wales) indicate that mice have increased considerably in recent (weeks, and that in some localities minor 1 plague conditions already prevail.