Pregnant and nursing cats are referred to as "queens," though your cat may not feel very royal with a litter of kittens pawing and nursing on her. Mother's milk provides vital nutrients to build up kittens' immune systems and is an important part of their socialization. However, by 8 weeks old, kittens should be weaned and mom's milk production should stop. If not, there are several steps you can take to help stop her milk production.
Extras for Milk Production
As a good parent, you should have provided your little queen with ample cat food and water as she nursed her litter. In the late stages of pregnancy and into the first month of her kittens' lives, a mother cat's nutritional and caloric needs skyrocket; she may end up eating two to four times the amount of food she normally eats. She needs the extra calories and nutrition to produce milk to feed and nourish her kittens.
Enough is Enough
Around 3 or 4 weeks of age, kittens should start experimenting with cat food, learning to eat and drink on their own. They'll still nurse from their mother, which is a good thing, but they should turn increasingly to cat food for the bulk of their diet. Your cat should be helping the process along by pushing her babies away when they attempt to nurse. If she's not, you'll need to lend a helping hand.
Moving Them Along
Moving the weaning process along has two parts to it. Removing the kittens from their mother for an hour or two at a time, several times a day, will give her a break and start them on the road to independence. Putting them in a space with food, water and a litter box of their own gradually will get them used to being away from their mother, allowing them to become less dependent on their mother's presence. At the same time, begin to decrease the queen's food and water intake. Withhold food on the first day of separation and give her half the water she usually drinks. The next day, give her a quarter of what she normally ate before she was pregnant, with half her normal water intake. The third day she can have all the water she likes and you can begin to increase her food intake to what it was before she was pregnant. If she lost weight during her pregnancy, you can increase her food a bit to get back to her prepregnancy weight.
It takes about a week for a queen's milk to dry up after her kittens have been weaned. Sometimes her milk won't dry up, despite the decreased food intake or the fact her kittens aren't turning to her for dinner. Uritca urens is a homeopathic remedy that can help or stop milk production in a nursing cat, depending on the potency and the dose given. Parsley water or tea may help dry up her milk supply. Lemon balm, peppermint and sage also may inhibit the flow of milk. A holistic vet will be able to guide you in the use of herbs and natural supplements to stop your cat's milk production.
If you're waiting to spay your cat because she's still producing milk, talk to your veterinarian. Some vets prefer not to spay a lactating cat because the mammary gland development makes the surgery a bit more difficult, however it can be done. Though your queen likely will take care of the entire nursing and weaning business herself, it's wise to keep an eye on her during this time. Occasionally a nursing mother will have an inflammation in one or several mammary glands, known as mastitis, which is an emergency situation. Some cats may appear healthy, so it's important to check your cat regularly. Symptoms include heat, swelling and pain in affected glands, yellow, thick or bloody milk, and unusual behavior from your mom cat, such as lethargy, refusing to allow her kittens to nurse and depression and loss of appetite. Kittens also may become sick and die.