Abnormal maternal behavior can be classified into two forms. It is either excessive maternal behavior in the absence of newborns or deficient maternal behavior in the presence of dog's own newborns.
The mothering feelings are the result of powerful hormones, such as progesterone, released from the ovaries, and prolactin, released from the anterior pituitary gland. This hormonal drive is so powerful that some non-pregnant bitches engage in the nesting behavior during what is called a false pregnancy. In such cases, non-pregnant bitches will lactate (produce milk) and some will gather stuffed toys into a designated nesting area to fulfill a basic biological need.
No genetic basis has been identified in dogs for these behavioral problems but a breed tendency in Jack Russell terriers indicates that a genetic component may be involved.
Common symptoms associated with deficient and excessive maternal behaviors include
Inadequate Maternal Behavior
Abandons her own newborn pups (most common after caesarean section)
Does not allow her offspring to nurse
Insufficient cleaning of the young
Inadequate retrieval of the young
Failure to stimulate elimination
Attacking and/or killing some or all of the newborn, especially if it has a different odor or appearance
If disturbed by people or other animals, may redirect her aggression to her young
Excessive Maternal Behavior
Un-bred mother may attempt to nurse unfamiliar pups
Guarding of inanimate objects such as stuffed animals
An increase in the size of mammary glands