Why Does Dog Lip Discolor Mother Dog's Lips Chapped From Cleaning Puppies~ Looking For Online References?

Mother dog's lips chapped from cleaning puppies~ looking for online references? - why does dog lip discolor

A lip "red" is cleaning her puppies, then that is normal, as explained to me thinking about my veterinarian and expert mentors, I have a family, to his potential. I would like an article online that explains why the lips of a dog fades find the mother of the mother to constantly clean their babies.

Anyone who saw this? Thank you!