Vol. 9, Special Issue 2, Part C (2025)

Livestock is an integral part of the agricultural production system in the Indian economy and the socio-economic development of millions of rural households. Diarrhoea is a leading cause of death in calves under six months old, resulting in significant economic losses to the cattle industry. Various pathogens, including bacteria, viruses, protozoa, and intestinal parasites, can cause diarrhoea in calves. Among these, Cryptosporidium species are widely recognized as the most common pathogens responsible for diarrhoea in calves, surpassing other enteric infections like rotavirus, bovine coronavirus, and enterotoxigenic Escherichia coli. These species exhibit a distinct age-related distribution in bovine hosts, with Cryptosporidium parvum (C. parvum) being the most prevalent in pre-weaned calves (1-3 months old) across various countries. In contrast, C. bovis and C. ryanae are more commonly found in calves aged 3 to 11 months. Additionally, C. parvum infection is considered a significant zoonotic risk, as it often causes watery diarrhoea in newborn calves and can be easily transmitted to humans. Hematological analyses are essential tools for diagnosing diseases, making medical decisions, and providing valuable insights during the diagnostic process. By comparing the test results from affected animals with the normal reference values of healthy animals, these analyses help in identifying abnormalities and guiding appropriate treatment strategies. Several parameters are recognized or suggested as useful indicators of a calf's susceptibility to illness or death. Among these are the total red blood cell count (tRBC), hemoglobin (Hb) levels, and packed cell volume (PCV), which are commonly used to assess the animal's health status.