Mother cats need sufficient nutrition to support milk production during lactation. Here are some foods and supplements that can help mother cats produce milk:

High-protein foods: Chicken, fish, eggs, etc. These foods are rich in protein, which helps to increase the quantity and quality of breast milk.
Wet food: contains a high moisture content, which helps maintain the mother cat's water intake, thereby promoting milk production.
Dairy products (small amount): unsweetened yogurt or cheese, which are rich in calcium and protein, and are very important for the mother cat's milk production and the growth and development of kittens.
Omega-3 fatty acids: Fish oil supplements or foods containing Omega-3 fatty acids, such as salmon and tuna, can help improve the quality and quantity of breast milk.
Calcium and other minerals: Adequate amounts of cooked bone broth or calcium supplements are recommended, as calcium is essential for milk production.
Specialized lactation cat food: High-calorie, high-protein cat food specially designed for lactating mother cats to meet their nutritional needs during lactation.