The relationship between trace elements status and health in calves

This paper reviews the present knowledge on the relationship between selected trace element nutrition of cows or calves and the health in calves. Trace elements deficiencies can lead to specific diseases relating to specific nutritional functions: myopathy for selenium, goitre or thyroid dysfunction for iodine, anaemia for iron. Insufficient status of copper. zinc and mainly selenium can lead to a decrease of defences, mediated in the newborn calves by a low transfer of immunoglobulin from the colostrum, and in older calves by a depressed acquisition of immunity. These effects on immunity have more often been demonstrated experimentally on biological markers of immune defences than on the incidence of diseases. However, large scale survey can evidence an increased risk of diseases, mainly diarrhoea, in calves from herds with poor trace element status. As a consequence, deficiencies must be avoided, particularly in late pregnancy cows, by meeting recommended allowances without imbalances, and checking the nutritional status of animals when the dietary supply is uncertain.