Ideally, when a queen gives birth, she cleans her kittens, encourages them to nurse, and stays with them almost non-stop for the first week.
Unfortunately, this is not always the case. Abnormal maternal behavior can result from a variety of causes. Abnormal behavior can range from rejection to cannibalism (kronism). To understand what might go wrong, it helps to review and understand what happens in a normal situation.
During pregnancy there is not any specifically associated behavior. When queening is near, nesting behavior is exhibited. Hormones dictate the physiological changes, and they also influence the queen's behavior. The queen will clean the newborns through licking, which simultaneously dries them and stimulates breathing. Later, the licking will stimulate urination and defecation since the newborns won't be able to initiate those actions until they are about 3 weeks old. When the queen wants to move her kittens, she typically will pick them up by the scruff. The dam will prefer to keep the kittens where ever she had them, unless she feels threatened, in which case she will move them to a new location.
Four hormones have an impact on her behavior: estrogen, progesterone, prolactin and oxytocin. Estrogen is largely responsible for the physical (unseen) and behavioral changes associated with estrus. In order for a hormone to have a reaction at the cellular level, there must be receptors on the cell membrane. Without appropriate receptors, the hormone will not trigger the necessary response. The concentration and distribution of estrogen receptors in the brain will determine the response. Once the queen ovulates, the ovaries secrete progesterone to maintain the pregnancy, prepare the uterus to receive and nurture the embryos, stimulate mammary development, and influence maternal behavior. Prolactin is important to mammary development and lactation, and maternal behavior. When birthing is imminent, progesterone levels drop abruptly and prolactin levels increase sharply. Oxytocin influences several activities. It plays a role in mammary development and lactation, the uterine contractions in birthing, and stimulating maternal recognition of her offspring. This recognition is largely due to the scent of her amnionic fluid on them. Both prolactin and oxytocin are stimulated by the dilation of the cervix and passage of the fetus through it and the vagina. Progesterone, prolactin and oxytocin are more effective if certain receptors have been primed by estrogen. This interaction between the hormones is necessary for normal birthing and neonatal care.
Other factors will influence maternal behavior besides, or in addition to, the hormones. The queen's previous experience with pregnancy, delivery and mothering will greatly influence her current behavior. Mothering traits are hereditary, but are seldom used in the selection process when queens and toms are selected for breeding. The sudden presence of the neonate, covered in amniotic fluid, and exhibiting typical newborn behavior also stimulate maternal behavior.
Unwanted maternal behavior ranges from rejection to serious aggression towards the neonates. A good indication of where the problem lies when babies are rejected is whether the dam is rejecting one or two babies, or the whole litter. If it is one or two kittens, the problem is likely with the kittens (hypothermic, hypoglycemic or dehydrated), whereas if it is the whole litter, it is usually the dam who has the problem.
Rejection can escalate to cannibalism, which is called kronism. Queens are more likely to target an injured kitten. Some of the possible reasons include the queen being in pain, the litter being too large, a stressful environment, or overcrowding. Estimates are that over ten percent of pre-weaning deaths are due to kronism.
While cats don't tend to have as much problem with eclampsia as dogs, it occasionally occurs. The cause is low blood levels of unbound calcium. When the calcium levels are borderline and the queen is not yet exhibiting eclampsia symptoms (weakness, fever, seizures), she can show aggression as a direct result of the low ionized blood calcium.
When queens are delivered by caesarian surgery before any kittens have been expelled through the cervix, unapparent maternal behavior can result due to lack of stimulation and therefore release of prolactin and oxytocin. Basically her body isn't recognizing that she gave birth because the process was physically short-cycled.
In summary, good mothering ability is a trait that should not be taken for granted. It results from a multitude of factors working together. Knowing what factors influence maternal behavior can help determine what is contributing to a situation when improved mothering behavior is needed. Likewise, when poor mothering occurs, the breeder needs to record it and monitor the family line in case a higher incidence is evident overall.