Ok here goes, Pups now 9 days old feed well and gaining weight, the problem we keep encoutering is one of her back breasts keeps getting encroged, it has happened 3 times now today being the third the first two times I managed to get the pups to feed from it this time they are reluctant to do so :( I am worried about mastitis setting in as it looks a little red, we are at the vets tomorrow for her staples out. How often to I need to put a hot compress on it ? and if the pups feed from it during the night will it be ok???

If it gets infected the pups won't feed from it, but otherwise it will be OK.  You need to apply compresses so that the breast softens enough for them to feed.  If they don't want to then you need to milk the gland,a and the colour will tell you if it is infected.

My Jozi had Mastitis in one breast when pups were 10 days old, it was her third and last litter.  It was Boxing day but I had to take her in as it was not reducing, she needed very strong Antibiotics and the pups carried on gaining , though a little less for that week, but once the AB's had done their work she carried on rearing without issue.

Mastitis can be an emergency and is very painful will result in a temperature and she could loose her milk without prompt treatment.

thanks for your replay, the breast is not as red as i first thought, could have been th compress that made it look worse, it is still firm so another compress is due i think, one pup has latched on for a while so will try again after the compress.

it is infected, i used a compress at milked it myself (half the size now), one half of the nipple was normal milk the other very thick  and yellowy :( . I have phoned the vet who asked allsorts  of question, is she eating drinking etc which she is.The pups are ok too, I am taking her first thing unless she gets worse. I am worried about the pups now the one that tried to feed from it :( also about her loosing her milk, this has only flared up today so where have I gone wrong :(

Mastitis can flare up very quickly, as it did for my girl on Boxing Day and entailed a very expensive out of hours vet visit ;(

Could be something as simple as picking up pathogens from the ground while peeing in the garden, as those who curtsy low may touch the ground with their boobs.