Vol. 12, Special Issue 7 (2023)

Author(s):
Dr. R Velusamy, G Ponnudurai, N Rani, A Alagesan and B Rubinibala

Abstract:
A study was carried out to investigate the blood protozoan parasites in cross-bred cattle calves in the Namakkal district of Tamil Nadu. Whole blood samples from 20 numbers of cross-bred calves were collected at monthly intervals from the first month of birth to 6 months of age. Haematological studies were carried out by Auto analyzer and DNA was extracted from blood and screened for haemo-parasites using species-specific PCR. The blood smears were also examined microscopically for the presence of haemo-protozoan parasites. The haematological values like PCV, Hb, RBC, and WBC of normal calves were in the range of 23.9 to 35.7%, 6.5 to 13.5 g/dl, 7.8 to 10.6 x 10⁶/µl, and 8.6 to 12.4 x 10³/µl, respectively, whereas in the infected calves, they were 19.1 to 32.5%, 6.9 to 10.5 g/dl, 7.3 to 10.7 x 10⁶/µl, and 7.9 to 11.5 x 10³/µl, respectively. Out of 20 calves screened by PCR, 2 calves were positive for Theileria annulata and 3 calves were positive for Anaplasma marginale, but, none of these calves showed positive for Babesia bigemina infection. No swelling of lymph nodes and changes in mucous membrane was observed and there were no ticks observed on the body during the study period. This study suggests that infected young calves may act as a carrier for haemo-protozoan diseases and may lead to death under stressful conditions such as transportation and vaccination.