Dr. Murai Éva szerk.: Parasitologia Hungarica 21. (Budapest, 1988)

sive grazing favour the development of pasture parasitoses, including gastrointestinal helminthoses of cattle. So-called gastrointestinal helminthoses

, caused by nematodes belonging to the family Trichostrongylidae and to the genera Bunostomum and Chabertia, occur all over the world (BORGSTEEDE, 1977). Literature data indicate that in some cases this helminthosis has considerable economic importance. For that very reason it is surprising that the parasite fauna of cattle is poorly known in Hungary. In the neighbouring countries also rather few investigations have been aimed at better knowledge of the bovine parasite fauna (Table 1). A planned and economical control of bovine gastrointestinal helminthoses requires detailed knowledge of the gastrointestinal helminth fauna of cattle, prevalence of the different helminth species, epizootiology of these parasitoses and their effect on productivity. Last but not least, the means of efficient control should be available. Our first objective was to collect data on the prevalence of gastrointestinal helminthoses in cattle by slaughter-house examinations and coprological surveys in cattle herds. MATERIALS AND METHODS 1. Survey of the prevalence of gastrointestinal helminths in slaughter cattle a) Helminths parasitizing the abomasum and small intestine Samples from abomasal and small intestinal contents of grazed cattle slaughtered or emergency slaughtered at abattoirs or in slaughter-houses of five counties (Borsod-Abaúj-Zemplén, Csongrád, Nógrád, Tolna and Veszprém) of Hungary were regularly obtained and examined. Sampling took place as follows: the abomasum was ligated, removed, slit open along the greater curvature, and its contents were emptied into a plastics bucket. Subsequently the entire contents of the abomasum were washed into the bucket with a mild jet of water directed at the mucosa. Finally, the abomasal contents were made up to 2 litres with tapwater. During thorough mixing two 200 ml samples (occasionally, for technical reasons, only one 200 ml sample) were taken with a wide-necked sampling dish and preserved with formalin. Small-intestinal contents were sampled by collecting the entire contents of a 8-m long intestinal segment starting at the pylorus. This included the entire duodenum and the proximal jejunum. The small intestine was isolated by ligation at both ends and peeled off the mesenterium. The isolated intestinal segment was slit open, its contents were emptied and washed into a bucket similarly as the abomasal contents. The mucosa was carefully washed with a jet of water to make sure that the entire contents were collected. Subsequently the contents were made up to 2 litres: if the small intestinal contents had become too thin, they were sedimented for about 5 minutes, then the supernatant fluid was decanted, and total volume was adjusted to 2 litres. After thorough shaking two (or in some cases one) 200 ml samples were taken and preserved with formalin. From abomasal and small-intestinal samples worms were collected, counted, and their species and sex were identified under a stereomicroscope (SKRJABIN and SIHOBALOVA, 19 52; YAMAGUTI, 1959; HOLLÓ and KÁVAI, 1970). Total worm counts were calculated by multiplying the worm counts of the sample. A total of 58 samples taken from previously grazed cattle (mostly 3 to 14 years old cows) were examined. b) Sedimentation of the abomasal contents and enzyme digestion study of the abomasal mucosa for helminths and their larvae Worms inhabiting the lumen of the abomasum were isolated by the method described above. The only difference was that 2x100 ml samples were taken from the 2-litre contents. The conventional (sedimentation) procedure is not suitable for demonstrating larvae parasitizing the wall of the abomasum: first they have to be released from the tissues by enzyme digestion or by some other method. Of methods available for this purpose (HERLICH, 1956;