Serum cortisol levels in camels (Camelus dromedarius) during the reproductive cycle.

1. Cortisol concentrations were measured in sexually mature female camels (N = 18), two newborn camels and one adult male. 2. The study revealed a significant difference in the amounts of cortisol in pluriparous mated camels (N = 7) during the breeding season before (8.0 +/- 1.3 ng/ml) and immediately after mating, 45.0 +/- 11.9 ng/ml (P less than 0.01). 3. At the start of parturition (N = 7), the maternal serum cortisol level rose suddenly from the basal value, 11.4 +/- 1.3 ng/ml, 3 days pre partum, to 45.3 +/- 5.0 ng/ml (P less than 0.005). 4. Immediately after birth, serum levels of cortisol in the newborn camels were 35.9 ng/ml and 37.0 ng/ml, respectively; in the dams, the concentrations of serum cortisol were 60.0 and 57.0 ng/ml, respectively. 5. In the female camels (N = 2) in seasonal anoestrus the amount of serum cortisol did not exceed 8 ng/ml. 6. During the breeding season the level of serum cortisol in the male was 1.15 ng/ml; 10 min post coitus the serum cortisol level rose to 9.92 ng/ml.