Review on Common Infectious Diseases of Neonatal Calves

Neonatal calf mortality is one of the important problems of calf rearing in dairy farms worldwide. A successful dairy farm operation requires that a large percentage of cows wean a live healthy calf every year. However, in many developing countries, a large number of calves die during the early neonatal life, this causing heavy economic loss. This is due to several infectious (bacterial, viral, and protozoal) and non-infectious factors (management around birth, colostrum management, calf housing, feeding system, hygiene, and pathogens) play an important role in calf rearing. This paper aims to review major infectious causes of neonatal calf mortality. Numerous studies have been conducted in the past from many parts of the world using both retrospective and prospective data sources to document the major causes of calf mortality. Of the infectious diseases of calves, neonatal diarrhea is a matter of major concern, and multiple etiological agents from viruses (Bovine rotavirus, Bovine coronavirus, Bovine viral diarrhea virus) from bacteria (Salmonella spp, Escherichia-coli, and Clostridium perfringens) from protozoal (Cryptosporidium-parvum) have been identified as major causes of neonatal calf mortality. Among the infectious agents, rotavirus and E. coli are mainly involved in the causation of neonatal calf diarrhea which leads to high mortality and morbidity in young calves. E. coli mainly plays its role up to the second week of life whereas, rotavirus up to the third week. Generally, early calf mortality leading to economic losses due to the cost of treatment, prophylaxis, increased susceptibility to other infections, reduced growth rates, and death of calves. Keywords: Calf Mortality; Infectious Diseases; Diarrhea