EN
Studies were carried out from January to December on a herd of primitive Polish horses consisting of a 17-year-old stallion, 8 mares (1-17-years-old) and 7 foals born in April, May and August. Recent excrement was examined by a flotation method according to Fulleborn and McMaster. Only an invasion of toothed strongyles occurred throughout the year in the stallion, its intensity fluctuating between 300 eggs/g of excrement (February) and 1300 in October. In mares, besides a permanent invasion of strongyles, eggs of Parascaris Equorum and tapeworms occurred in some months. The greatest number of eggs of strongyles in mares’ excrement was found in July (2700 epg) and November (1400 epg), and the lowest in February (200 epg). The eggs of Parascaris Equorum were detected in June in a one-year as well as a 17-year-old mare and in August in a 14-year-old one, while tapeworm eggs were found in a one-year-old mare in May and October and in a 17-year-old one in May and June. In the excrement of foals born in April, eggs of strongyles as well as Parascaris Equorum appeared in June. 100% of the foals were infected with toothed strongyles since September. The eggs of Parascaris occurred in June and July in the excrement of a 3-month-old foal and in September in all foals born in April and May. The tapeworm invasion was noted in one foal in September and in the second one in November. The intensity of toothed strongyles invasion in foals fluctuated between 30 epg (June) and 300 epg (July, November, December). The intensity of Parascaris Equorum and tapeworms was 20-300 epg and 20-60 epg respectively. The presence of a large number of toothed strongyles eggs and a considerably lesser presence of Parascaris as well as tapeworms in the excrement of the examined animals is connected with the environment where the primitive Polish horses have continually lived for over 50 years. It was also noticed that the intensity of invasion depends on sex, age and period of investigations.