EN
The aim of the study was to compare the intensity of fly invasions during the grazing period in two breeds of young cattle. Studies were carried out on 26 2-year old heifers of Polish Red and 25 of Black-and-White Lowland breed. Flies were counted every day, for 6 days in July, on grazing animals between 12-13 pm. within 15 s. at angles in both eyes, on the nose, cheek, neck, side as well as on foreleg and hind leg. Flies particularly attacked the cattle during windless and hot days. The number of insects on the heifers depended both on body region and breed of cattle. House flies, and some species of grazing flies, mostly gathered in the angles of the eyes and nose. A lot of flies occurred also on the heifer’s sides, mainly in the case of Polish Red, and the majority of these flies were Stomoxys type. In heifers of Polish Red breed, the average number of insects in the examined regions was 15.3-27.8% lower than in Black-and-White. The explanation for this phenomenon may be related to the color of coat, which does not heat up as much as in Black-and-White, or the attractiveness of tears and mucus of Polish Red.