2 females mating?

Question
We have 2 female GPs (sisters) about 1.5 years old. Just recently one has started pursuing the other with mating behavior. I know females do this with females. Our questions: why now after a year and a half? how long does this go on (how often in heat and for how long)? any danger in keeping them together during this? Thanks for your help.

Answer
Hi Kay

I doubt very much the behaviour will last more than a few weeks and it also very doubtful any more serious problem may develop.

It may be something even very small has changed in their environment to cause one pig to restablish her dominance.

Andy