The present work describes the clinical and laboratory examination as well as the treatment of a 7-year-old local dairy breed cow presented with reduced appetite, decreasing milk yield and striking yellowish discoloured skin and mucosa. The laboratory examination revealed a high degree regenerative anaemia and hyperbilirubinaemia. The bovine haemotrophic mycoplasma species Mycoplasma wenyonii and 'Candidatus Mycoplasma haemobos' were detected in the blood by PCR. Treatment with oxytetracycline rapidly improved the general condition, and milk production was increased. In a follow-up study, blood samples of all 23 animals from the same herd were examined. Fifteen cows were found to be infected with both haemoplasma species, three animals were only infected with 'Candidatus Mycoplasma haemobos' and one animal only with Mycoplasma wenyonii. Two out of three tested calves were positive for 'Candidatus Mycoplasma haemobos'. Except for the above described anaemic cow, all other animals were clinically healthy.