EN
The investigation were carried out on two groups of lambs aged 4 months, infested by natural means with coccidia and roundworms. Each group consisted of 15 lambs; in the first group the average intensity of invasion was 6600 coccidia and in the other one 22 700 oocysts. Faeces and blood samples for laboratory tests were taken from the lambs once a month from April to August. The faeces were tested for the presence of oocysts of Eimeria spp. and eggs of roundworms. The blood tests involved haematocryte, the level of haemoglobin, the amount of leucocytes and erythrocytes. In addition, the levels of cholesterol and urea were determined, as well as the activity of asparagine and alanine aminotransferases and alkaline phosphatase. A relationship between the increase of the intensity of coccidia invasion and a decrease of roundworms, mainly Strongyloides papillosus, was found. In group I the intensity of the coccidia invasion ranged in the course of 5 month from 2700 to 13 400 oocysts per 1 g of faeces (opg). The invasion reached its peak in May (13 400 opg) while in other months it was lower and fluctuated from 2700 to 6400 opg. In group II the intensity of the invasion was much higher, ranging from 5700 to 39 400 opg; the highest level of opg occurred in April and May. Generally, haematological and biochemical values in animals of the two groups were similar. The invasion of coccidia and roundworms did not influence the haematological and biochemical indices or clinical symptoms of the animals.