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.
Tjugosju gyltor av svensk Yorkshire-ras transporterades 12 km till kliniken. Blodprov togs på 8 gyltor (grupp A) i samband med transporten, hos de övriga 19 gyltorna (grupp B) togs ej blodprov då. Efter transporten undersöktes gyltorna med laparoskopi och venkatetrar opererades in. Blodprov togs 3 gånger per dag och brunstkontroll gjordes 2 gånger per dag. Efter en vecka upprepades laparoskopiundersökningen.
Tjugo gyltor (74 %) visade brunst inom en vecka, i medeltal 5,4 dagar (4–7,5 dagar) efter transporten. Förhöjda östradiol-17βnivåer sågs hos dessa gyltorna ca 2 dygn efter transporten. Kortisolnivån var signifikant högre (p < 0.001) dag 1 (transportdagen) än dag 2 och markant högre nivåer av kortisol sågs dag 1 och 2 hos de gyltor som ej visade brunst (2 gyltor) i jämförelse med de gyltor där brunst inducerades med hjälp av transporten. Skillnaden var signifikant dag 2 (p < 0.05). CBG nivån var signifikant sänkt (p < 0.001) dag 2 hos alla 8 gyltorna. Under dag 3 till dag 8 var det ingen skillnad i kortisol nivån mellan dagarna (grupperna A och B, 27 gyltor) och ingen skillnad sågs i kortisol och CBG nivåene mellan gyltor som visade brunst (20 st) och gyltor som ej visade brunst (7 st). En hypotes framfördes att en högre nivå av kortisol dag 1 och 2 hämnade inträdandet av brunst hos gyltor som ej visade brunst efter transport.