Observations on suckler calves separated from their dams, exposed to transport stress and temporary isolation at differing ages: The effect of dam vocalisation by audio-playback on biochemical parameters and clinical signs

Thirty-one suckler calves, 18 male and 13 females, were separated from thei r dams and transported for 90 to 120 minutes with and without the audio pre sentation of their dams' vocalisation. Body temperature, biochemical blood components, saliva cortisol and heart rate measurements were made before an d after the isolated transport and the audio-visual playback of the respons es of the isolated calves and of the remaining calves. After a period of so me days, all calves were treated in the same way except that non-transporte d calves were exposed to audio recordings of the responses of their dams. A gain, body temperature, saliva cortisol and heart rate were determined. Cha nges in clinical and bio-chemical values exhibited considerable inter-anima l variation and there was a strong dependence on the initial values before separation and transport. These changes became more uniform and stronger wi th age. Characteristic heart rate values indicated an enhancement of excita tion, the periods of comparative rest during separation, transport and isol ation and the effect of age. Calves 15 days of age had significantly reduce d heart rates when they were exposed to the dams vocalisations. Mean plasma cortisol levels were significantly different between those after being sub jected to separation, transport and isolation and calves which were not. Me an initial saliva cortisol levels were similar for all ages, but were signi ficantly different after separation transport and isolation. Cortisol level s were greater in younger calves. Exposure to the dams' vocalisation to cal ves in isolation resulted in reduced cortisol levels after separation, tran sport and isolation, but mean differences were not significant. Altered rea ctivity of the calves from the viewpoint of development quality, social bon ding and of adaptation to social partners is discussed.