Is soya milk safe for cats? You shouldn't give your cat cow's milk, but find out whether giving your cat soya milk is safe.
Cat milks have the lactose (a milk sugar) extracted from them. Lactase is the enzyme that digests lactose and the enzyme's activity declines after kittens are weaned.
As a result, some adult cats suffer diarrhoea when fed cow's milk. This effect is often quantity related - the more milk the cat drinks, the more likely signs will be seen.
Soya milk does not contain lactose so it would initially seem like a good choice. Unfortunately, soya has components called anti-nutritional factors which can be difficult for cats to digest.
Stachyose and raffinose are the sugars found in soya milk and although they can be digested by microbes in the gut, they cannot be digested by enzymes the cat produces. As a result, cats fed soya milk will often suffer from flatulence and digestive upset.
Another consideration is that milk is a food, and the more you give the more likely you are to unbalance the diet overall. In the case of soya milk, this would be a significant consideration as cats are obligate carnivores (they need certain nutrients found only in meat) and some nutrients will not be in the form cats require.
Advice given by Vet Susan McKay.