Moniezia benedeni is a common tapeworm of cattle pastured in coastal and subcoastal regions of Australia. Cattle up to 18 months of age can be infected, but infection is more prevalent in young dairy calves, less so in extensively grazed beef calves.
Moniezia expansa, the common tapeworm of sheep and goats may also infest cattle co-grazed with them but the infection does not persist.
Tapeworms consist of a flat ribbon-like tube of segments (proglottids) often up to 600 cm long with a neck and head (scolex) the size of a pin head, at one end. They attach to the inner surface of the small intestine using the strong, muscular suckers on their heads. Each proglottid is a complete functional unit, including sets of male and female reproductive organs, and thus can fertilise itself or nearby segments as necessary.
Mature terminal segments full of eggs are shed from the tapeworm and pass out of the gut with the dung. They are said to look like grains of cooked rice on the dung pat, although very fresh segments are flat and ribbon-like. The segments disintegrate and release their eggs into the environment. Eggs potentially remain infective for several months.
Figure 1. Pickled intestinal tapeworm, Moniezia benedeni. Image courtesy of Mukund Madhav
Adult tapeworms inhabit the small intestine of cattle.
Figure 2. Adult intestinal tapeworm, Moniezia spp. can often measure several meters in length. Image courtesy of the National Centre for Veterinary Parasitology, ncvetp.org
This is an indirect life cycle with adult stages in cattle and immature stages in a grass mite.
Tapeworm eggs shed in the dung of cattle are ingested by a grass or oribatid mite that lives in moist soil or on pasture. The pre-larval stages develop over the next four to six months into a cysticercoid larvae within the body of the mite.
Cattle become infected when they accidentally eat the tiny mites containing the infective cysticercoid larvae during grazing. Mites are digested in the gut, the larvae are released into the small intestine and grow into adults. The pre-patent period is 37-40 days and tapeworms generally die in three months but may live to six months.
Impact on cattle
Cattle tapeworms are blamed for a range of health problems, but there is no hard evidence for any effects on production or health.
Treating specifically for intestinal tapeworm is unlikely to be beneficial, whether in terms of scouring or weight gains. It is more important to reserve anthelmintics for the less visible, but more important, roundworms such as the barber’s pole worm (Haemonchus placei), small intestinal worms (Cooperia species) and small brown stomach worms (Ostertagia ostertagi and avoid unnecessary treatments which may increase drench resistance in them. .
The broad-spectrum benzimidazoles anthelmintics, namely, albendazole and oxfendazole that are commonly used to control roundworms aid in the removal of tapeworm segments, but will not kill the adult worm.