Physiological and blood biochemical responses to submaximal treadmill exercise in Canaan dogs before, during and after training.

Physiological haematological and blood biochemical parameters were studied in Canaan dogs (n = 8) as possible indices of fitness. These parameters were then used to distinguish between fit and unfit dogs and to monitor the changes in these parameters during training and detraining periods. Fitness was defined as the ability to run for one hour on a motorised treadmill (speed 8.65 km h-1, inclination 10 degrees) while maintaining rectal temperature and heart rate below 41 degrees C and 250 beats min-1 respectively. Fit dogs showed consistently lower values of heart rate and rectal temperature during exercise and recovery, and significantly lower increases for post exercise plasma creatine kinase activity and plasma lactate concentration. Significantly higher values for haemoglobin concentration were found immediately post exercise. There were no significant differences between fit and unfit dogs for post exercise plasma concentrations of aspartate aminotransferase, white blood cell count or total protein, although the unfit dogs showed a tendency towards higher values. Similarly, unfit dogs tended to have lower values for plasma glucose concentration, haematocrit and red cell count. Values for heart rate and rectal temperature during exercise differed significantly between various dogs until numbers fell, due to the inability of certain dogs to complete the exercise test. Dogs were consistent according to whether their values lay above or below the mean value for all dogs. These differences disappeared after 8 weeks of training. Fitness deteriorated after 3 to 5 weeks of detraining. According to these results, heart rate and rectal temperature appear to be the most suitable and sensitive indicators of fitness in tracking dogs. The haematological and blood biochemical parameters tested were found to be of limited use. It is suggested that apparent inherent superiority of dogs should be accounted for in prospective breeding programmes.