Tapeworm and Roundworm Parasites of Cattle

THE TAPEWORM and roundworm parasites reported to affect cattle tliroughoiit the world comprise over 70 different species. Although some species occur infrequently and others are comparatively harmless to their bovine hosts, some exact a heavy annual toll from the beef and dairy industries. Losses are due to deaths from gross parasitism, lowered vitality and resultant poor growth and performance, and condemnation, in the course of meat inspection, of carcasses or edible parts as a result of invasion by parasites. Members of these two groups of parasites—tapeworms and roundworms—vary considerably in their location, structure, and harmfulness. The cestodes, or tapeworms, of cattle are found as adults in the intestine and as larval forms in the muscles, liver, lungs, and other viscera. The adults are elongated, flattened worms consisting of a head and a chain of segments, each having both male and female reproductive organs, and terminal segments containing mature egg*s. The larval forms, commonly referred to as bladder worms because they resemble a bladder in shape, are intermediate asexual stages of tapeworms that live as adults in the intestines of man and other animals. The bladder worms vary in diameter from one-fourth inch in the case of the beef bladder \^ovm.. {Cysticercus hovis) to as much as 6 inches in the case of the hydatid cysts {EcMnococcus granulosus),