The aim of the present studyis determination of probable correlation between parasitemia rate and hemolysis in cattle infected with Anaplasma marginale. Two groups including 10 uninfected cattle and 20 infected cattle were selected. Based on parasitemia rates, the infected animals were divided into 3 subgroups (<10%, 10-20% and 20-30%). PCV, Hb, RBC count, MCV, MCH, MCHC, MCF, LDH, SOD and serum haptoglobin were measured in all animals. The results showed significant difference (p<0.05) between hematological factors of infected and uninfected animals except for haptoglobin.
Negative correlations (p<0. 05) were observed among parasitemia, RBC count, Hb and PCV. Positive correlations (p<0. 05) were observed among parasitemia rate, MCF and LDH. SOD activity had negative correlation with parasitemia rate in cattle with parasitemia, being lower than 10%, but no significant correlation (p>0. 05) was observed between SOD activity and parasitemia rate in cattle with 10-20 and 20-30% parasitemia rate. There was no significant correlation between parasitemia rate and serum haptoglobin. In addition to autoimmune mechanisms in anemia, there is lower activity of SOD and higher RBC fragility only in cattle with parasitemia rate being lower than 10% and not for cattle with higher parasitemia rate. The exact mechanisms of anemia in bovine anaplasmosis are unclear and further investigations are needed to clarify this point.