I have just taken Bianca to the vet, thinking that she had a crusty white/yellow discharge around the nipples and concerned about ovarian cysts (particularly given that this little piggy is a rumblestrutter extraordinaire). But apparently it is not that at all but toughenings of the skin around the nipples. The vet hasn't this seen before in guinea pigs and so is sending photos to other vets and will get back to me. He isn't concerned, just puzzled and needing to check. Does anyone have experience of this? (We noticed it a month or so ago, but there was so little to see then that I just opted for a 'monitoring' approach! Apart from this, Bianca appears to be her usual healthy, rumblestrutty self.)