Effect of transportation and relocation in post-weaning anoestrous primiparous sows.

The object of this investigation was to study the clinical and endocrine responses to transportation and relocation in 8 post-weaning anoestrous sows. They had been anoestrous for at least 24 days after weaning before transportation/relocation was performed. Laparoscopy, performed at the beginning of the experiment, revealed that the ovaries contained many follicles (less than or equal to 6 mm in diameter), but no corpora lutea. Blood samples, taken before and after transportation/relocation, showed that LH activity was low at the beginning of the experiment and increased after transportation/relocation in the majority of the sows. Peripheral plasma concentrations of of oestradiol-17 beta increased 1-4 days after transportation/relocation in 6 out of 8 sows which was followed by oestrus and ovulation. Progesterone concentrations were also below the practical detection limit until the end of oestrus. This study has demonstrated that a change in environment by transportation and relocation can induce oestrus by increasing the LH activity in post-weaning anoestrous sows.