tie out of heat

Question
Hi,  I have 2 female dogs that I use for breeding and one male that is not yet ready.
My female in question had a litter of pups in Dec then my other female went into heat early and we bred her as well in March.  Shortly after those pups were born my original female went into heat again which we skipped in May.  Now she is producing milk, which is normal for her to do at this point even though she is not pregnant, but this morning she and the male (intact) tied together for 15 mins.  She is not swollen or bleeding, no signs at all of a heat.  I don't know anything about split heats,  or  could she just want pups so bad because the other one has pups that she would breed when she is not ready?  I didn't think it was possible to tie when not in heat.

Answer
Hi Kelly

Animals, unlike humans, breed for procreation not recreation.  So that means a female can only be bred when she's in season not because "she wants pups so bad".  

A Tie is a natural phenomenon of dog breeding in which the bulbus glandis of the male's penis swells inside the bitch's vagina.  It's the male that swells causing the tie.

How old is your female in question?  Some older females don't bleed as heavily.  Or if there is a discharge, is there a possibility that she could have an infection?  That will confuse the male into thinking she's ready to be bred.