Lactating Spayed Cat

Question
A friend of mine has had a cat since it was 2 weeks old. He had her spayed in january when it was 6 months old. Now the cat is lactating. Is it normal, even though it was spayed? Or should he be worried?

Answer
Sometimes a little milk production can be considered normal and is nothing to worry about.  But if she's lactating heavily or without stimulation (milk shouldn't be just dripping out), then I would definitely see a vet.  She may have a hormonal imbalance, possibly caused by a pituitary tumor (usually benign) that should be treated.

If the mammary chain is swollen or lumpy at all, I would see the vet, too.  This can indicate abnormal cells which might lead to cancer.  Some vets will remove the entire mammary chain to prevent deadly mammary cancer if the mammary tissue seems abnormal.

And if the discharge from the nipples become thick or discolored, it may be mastitis, which requires antibiotics to treat.

Though uncommon, spayed cats can suffer a false pregnancy, during which time the cat may begin lactating, may even have a fat belly.  Generally these end around the time the cat would've delivered were she really pregnant.