Cortisol concentrations in the perinatal and weaning periods of alpacas

Cortisol concentrations were determined during the perinatal and weaning pe riods in alpacas. Fifty males and 50 females were chosen at random (25 at e ach period) for blood collection on day of parturition, 3 and 5 days after birth. For the weaning period, blood samples were collected 2 days before, on the day of weaning (0), and at days 3 and 5 after weaning, Cortisol was determined using an ELISA protocol validated for the alpaca. There was no d ifference (P < 0.05) in cortisol concentrations in both periods, perinatal and weaning between male and female crias. Cortisol was elevated at day of parturition (125.8 ng/ml) and then decreased to 27.2 ng/ml at 3 days after birth (P < 0.05), Conversely, cortisol was 32.5 ng/ml 7 days before weaning and then increased at day 3 to 64.7 ng/ml (P < 0.05), but then decreased t o 29.4 ng/ml at day 5 after weaning, Cortisol is elevated in new-born alpac as and then decreases at the third and fifth after birth. Concentrations of cortisol are also increased after weaning and then decreased 5 days after weaning. (C) 2001 Elsevier Science B,V. All rights reserved.