Observations on acid-base balance, metabolic, hormonal variables and heartrate in dairy calves from the end of automatic milk feeding to transport by road

The body temperature and heart rate were measured in 38 group-reared dairy calves at 60 days of age immediately and after a 60 minute period of transp ort and on the following day. Blood and saliva samples were also collected at these three points in time. Samples were analysed for cortisol T-4, FT4, T-3, FT3, total protein, albumin, blood urea nitrogen, glucose, lactate, C a, Mg, P and Fe. Statistically significant differences were observed in the mean values of all of these biochemical parameters except those for total protein, glucose and lactate, between the first two sampling points, which persisted, for most biochemical parameters, into the day following transpor t. The significant correlations between most biochemical parameters, and th e sampling points and the starting values indicate that these are highly sp ecific. No such correlations were observed for plasma and saliva cortisol c oncentrations. The large inter-individual variation in plasma cortisol conc entration from 40-150 mol/l after the stress of transport indicates the rea ctional ability of the physiological functional systems and tissue distribu tion of cortisol. The mean concentrations of cortisol in saliva are perfect ly correlated with those in plasma, but the outflow of free cortisol into s aliva appears to be different in calves. Between - animal variation in most of the biochemical parameters indicates that there is a dependency on the development status of calves and therefore that these have to be considered in evaluating the transport conditions fo calves.