Bovine theileriosis is one of the most economically important tick-borne haemoprotozoan diseases affecting dairy cattle in tropical and subtropical regions. The disease causes significant production losses owing to decreased milk yield, anaemia, reduced productivity and mortality in severe cases. The present investigation was undertaken to determine the prevalence and clinical profile of bovine theileriosis among clinically affected dairy cattle presented to the Teaching Veterinary Clinical Complex, College of Veterinary Science and Animal Husbandry, Odisha University of Agriculture and Technology, Bhubaneswar. A total of 55 cattle showing clinical signs suggestive of haemoprotozoan infection were examined using Giemsa-stained peripheral blood smears. Microscopic examination revealed Theileria spp. infection in 38 animals (69.09%), whereas 17 animals (30.91%) were negative. The commonly observed clinical manifestations included pyrexia, pale mucous membranes, enlargement of prescapular lymph nodes, anorexia, dyspnoea, salivation, weakness and decreased milk yield. The findings indicate that bovine theileriosis remains an important disease among dairy cattle in coastal Odisha. Microscopic examination of Giemsa-stained blood smears proved to be a rapid, economical and reliable diagnostic tool for field diagnosis of clinical theileriosis. Regular epidemiological surveillance, integrated tick control and early diagnosis are essential to minimize economic losses associated with the disease.

Keywords: Bovine theileriosis, dairy cattle, Giemsa stain, prevalence, Odisha, haemoprotozoan disease.