The reasons why dogs have lumps in their breasts after giving birth:

1. Milk engorgement. If a puppy has just been given birth and a lump appears in the breast after the puppy is weaned, it may be caused by Breast engorgement causes swelling and even lumps in the breasts.

2. Mastitis. If the dog suddenly develops a hard lump in the breast area after giving birth and nursing for a period of time, it may also be mastitis.

How to deal with hard lumps in the dog's breasts after giving birth:

1. First apply a hot towel to the lumps and breasts of the dog for about 10-20 minutes every day. And massage the dog to make the hard lumps smaller.

2. Inject anti-inflammatory injections or take anti-inflammatory drugs to the dog.

3. Help the dog express the excess milk. If you don’t pay attention to the problem of lumps in your dog’s breasts, your dog may suffer from mastitis.