The zinc sulphate turbidity test was used to establish the total immunoglobulin levels of calves from birth to 4 months of age. Colostral immunity fell rapidly and the lowest levels were found in the third and fourth week of life. During the fifth week there was a significant increase. 25% of animals were hypogammaglobulinaemic in the first week of life. This ratio increased to 50% in the third week of life. At the age of two months the lowest immunoglobulin levels almost vanished. These findings are discussed as basic information for the appropriate management of calf agglomerations. Animals should be agglomerated only after the first months of life. When this is not possible, the pens for large agglomerations should have individual housing for the newly admitted calves. The importance of appropriate epizootological measures to reduce infections are pointed out.