This chapter deals with the health of the calf from birth to weaning, that is until approximately six weeks old.
Current UK figures give a national calf mortality of approximately 5% of live births, and it is disappointing that this has remained unchanged for the past 20 years. In North America, the mortality rate from birth to weaning is even higher, at 8.5%, with scour accounting for over 50% of the total losses.
Taking the 1998 UK value of a calf at £150, this means a loss of £750 per annum to the average 100 cow dairy herd. If there are four million calves born each year, it represents a national annual loss of £30 million.There are many reasons why the young calf is particularly susceptible to disease. Its defence mechanisms are not fully developed, it will be going through the transition from passive to active immunity, it may have several changes of diet, and on top of all this it has an additional route by which infection may enter the body, that is through the navel. As many of the diseases of young calves are the result of failures of proper housing, feeding and colostrum intake, these factors will be discussed in some detail before specific health problems are dealt with.