Exploring alterations in hematological and biochemical parameters, enzyme activities and serum cortisol in Besnoitia besnoiti naturally infected dairy cattle.

BACKGROUND: Besnoitia besnoiti is an Apicomplexan protozoa causative of bovine besnoitiosis, a chronic and debilitating disease of cattle, with a variety of pathological findings that could alter some laboratory parameters. A study was conducted in a bovine besnoitiosis endemically infected dairy herd located in Italy characterized by high intra-herd seroprevalence and cattle with clinical signs of the disease. In the study, alterations in laboratory parameters, i.e. hematological and biochemical parameters, enzyme activities and serum cortisol levels, in Besnoitia besnoiti naturally infected cows were investigated in depth.
METHODS: Laboratory parameters in 107 cows, of which 61 were seronegative and 46 were seropositive to B. besnoiti, including 27 with clinical signs of bovine besnoitiosis, were compared. Generalized linear models were used to evaluate the effect of Besnoitia infection on the considered laboratory parameters.
RESULTS: Hematological analyses revealed that B. besnoiti infection determined a significant alteration to the leukocyte differential, with a higher percentage of granulocytes and a lower percentage of lymphocytes in seropositive and clinically affected animals (Mann-Whitney U-test, P = 0.022); erythrocyte and platelet counts did not show any difference between the considered groups of cows. Biochemistry tests evidenced that the parasite infection influenced serum protein values in seropositive cows and glutamate dehydrogenase values in clinically affected animals. No or only slight differences were revealed for all of the other biochemical and enzyme activity parameters in B. besnoiti-infected animals. In addition, despite the lack of statistical significance, seropositive and clinically affected cows evidenced higher concentrations of serum cortisol values compared to seronegative animals.
CONCLUSIONS: Although physiological, pathological and farm-related factors could have influenced the results in investigated animals, further studies involving more animals from different farms would be advisable to infer the role of B. besnoiti on these alterations, since laboratory parameters could help veterinarians in the diagnosis of bovine besnoitiosis in cattle.