Bloody Discharge From Puppy. Bloody discharge in dogs can be due to various problems, but it is a distinct symptom of open pyometra. Vaginal discharge is also a normal finding in the immediate postpartum (after birth) period.
At that late stage, dog kidney dialysis will be one of your few options. You may continue to see bloody discharge for the next couple of days. A dark green to black discharge is often present for several days, and traces of discharge may persist for up to 3 weeks.