TRANSPORT-INDUCED STRESS RESPONSES IN FED AND FASTED DONKEYS

Plasma endocrine and metabolic responses to transport for 30 minutes a nd four hours were investigated in six fed donkeys. Ln the unstressed animals there was a pulsatile secretion of cortisol at two-hour interv als, from minima of 51.4 +/- 17.6 nmol litre(-1) to maxima of 160.0 +/ - 11.0 nmol litre(-1), but during transport this pulsatility was lost and the animals' stress response was characterised by steady high conc entrations of 110 to 220 nmol litre(-1). The cortisol concentration de creased after the journey and remained at a minimum until the restorat ion of pulsatile secretion 8.5 to 10.5 hours later. The transport-indu ced adrenocortical response did not produce any significant changes in the plasma concentrations of triglycerides, cholesterol, glucose, tot al protein, albumin, globulin or urea. The donkeys' responses to trans port for four hours were also investigated after they had been deprive d of food for one or three days. Food deprivation alone increased plas ma cortisol and triglyceride concentrations, and decreased glucose and insulin concentrations, and transport consistently, and feeding after the journey sometimes, accentuated their adrenocortical function; the changes in cortisol concentrations as a result of the journey tended to be lower than in the fed animals. Transport had no effect upon the triglyceride response to either period of fasting. Hyperglycaemia was induced by transport in four of the six donkeys fasted for one day and in all of them after three days of fasting.