Colostrum intake by dairy calves

Aims. To determine which clinical parameters could be used to identify calv es with low serum immunoglobulin levels and to examine the influence of cow and calf behaviour on colostrum intake. Methods. Blood samples were taken from 74 dairy calves after they were sepa rated from their dams, and analysed for serum gamma glutamyltransferase (GG T) activity. Physical and behavioural measurements were taken for 57 of the se calves at this time. The behaviour of 21 dairy cows and their calves was observed between birth and the time the calves were separated when a blood sample was taken from 17 of them and analysed for GGT. Results. Low serum GGT activities (below 200 U/1 GGT), indicating low serum immunoglobulin levels, were found in 45% of the group of 74 calves. The ca lves which had not received colostrum were not easy to distinguish from tho se that had on the basis of physical or behavioural features. The amount of time that the 21 calves spent with their dams before being separated range d from 1.2 to 24.9 hours. Thirty-three per cent of these calves had not suc ked within this time. Of the calves that did suck, 79% did so within 6 hour s of birth. Conclusions. About one half of New Zealand dairy calves may not receive col ostrum from their darns even when they are together for up to 24 hours. Mos t calves that are going to suck of their own accord will do so within 6 hou rs of birth. Clinical significance. Dairy calves should be removed from the ir dams after 6 hours and fed colostrum to guarantee that they receive suff icient immunoglobulins.