The effect of transportation/relocation on cortisol, CBG and induction of puberty in gilts with delayed puberty.

Twenty-seven Swedish purebred Yorkshire gilts were transported 12 km to the clinic. In 8 gilts (Group A), blood samples were drawn in connection with transportation, while in the remaining 19 gilts (Group B) no samples were drawn at this time. After transportation the gilts were examined by laparoscopy and catheterized. Blood samples were then drawn 3 times and oestrus detection was performed twice daily. After 1 week the laparoscopy was repeated. Twenty gilts (74 %) showed oestrus within 1 week, on average 5.4 days (4–7.5 days) after transportation. Elevated oestradiol-17β levels were seen in those gilts approximately 2 days after transportation. The Cortisol level was significantly higher (p < 0.001) on day 1 (the day of transportation) than on day 2 and a markedly higher level of Cortisol was seen on days 1 and 2 in the gilts which did not show oestrus (2 gilts), compared with the gilts in which oestrus was induced (6 gilts) by transportation. The difference was significant on day 2 (p < 0.05). The CBG level was significantly decreased (p < 0.001) on day 2 for all 8 gilts. During day 3 to day 8 there was no difference in the Cortisol level between days (groups A and B, 27 gilts), and no differences were seen in the levels of Cortisol and CBG between gilts showing (20 gilts) and not showing oestrus (7 gilts). The hypothesis propounded that the higher levels of Cortisol on days 1 and 2 inhibited induction of oestrus in those gilts which did not show oestrus after transportation.