Abstract: In a preliminary version of a study in the Mediterranean region, presented at the last Meeting of ruminant research in Paris, 454 samples of faeces were sampled on 29 farms around Alger. Nearly half were positive on staining for oocytes of cryptosporidium, nearly a quarter for Giardia and a little more than 15% for Eimeria. Combinations of protozoa were observed, especially in the period 25-45 days. The calves from farms on which vaccination against rotovirus, coronavirus and E. coli was practised excreted significantly less cryptosporidium. The three parasites were detected in diarrhoeic and non-diarrhoeic faeces, highlighting the importance of the asymptomatic carrier. The combination of Cryptosporidium and Giardia was significant clinically (Chi-square test of p<0.05).