The short answer: No.
The long answer: Most adult cats cannot drink cow milk because their stomachs don’t have the necessary enzyme to break down the sugar (lactose) found in it. Though kittens have lactase in their system, it is also not enough to handle the lactose levels found in cow milk.
Cats who drink this type of milk may end up having digestive upset, which may manifest as diarrhea, bloating, intestinal cramps, gas, and vomiting. Regular drinking of cow milk may also cause weight gain and obesity in your cat.
What to do if your cat accidentally drinks cow milk: A tablespoon of milk should not create adverse effects in your cat. However, if she drinks a saucer of milk in one sitting, it’s similar to a person eating one whole 12-inch pizza—unhealthy and unnecessary. Keep a close eye on your cat and call your veterinarian immediately if she displays any of the aforementioned symptoms within 24 hours.
In summary: Your cat will not receive any substantial nutritional benefits if she drinks cow milk. As long as she is given complete and balanced food appropriate for her age, size, and activities, she will not need to drink this dairy treat.
However, if you feel that your cat needs to drink milk, consult with your veterinarian first to discover the kinds of milk she is allowed to have and how much you’re allowed to give her. There are commercially sold kitten glop (liquid meal replacement for kittens) made with cow milk that have been modified to provide complete and balanced nutrients.