Dogs are not intolerant to milk, and in fact no young mammal is intolerant until a good time after weaning. You did not say what age your puppies were or when they were separated from their mother. If they have been orphaned or separated from their mother at an early age, it is imperative that they are fed the correct food at regular intervals if they are to remain healthy.

Young puppies should be bottle fed a milk formula designed specifically for puppies (readily available from pet shops), and they should always be fed while on their stomach, as if they are feeding from their mother. You should not feed the puppies cow’s milk because it is not of high enough nutrition. Puppies need to be fed every 2 hours for the first 3 or 4 days, lengthening to 3 or 4 hour intervals later in the first week. By the second week, the puppies should be able to endure a longer stretch overnight of about 6 or 7 hours.

By the third week of life, bottle feeding should be supplemented with high-grade puppy food blended with the same milk formula you are using for bottle feeding, provided three or four times a day. The consistency of such solids should be similar to what you would feed a baby. Oatmeal is an adequate temporary replacement if good quality puppy food is not available.

In week 4, bottle feeding can be reduced, and the blended puppy food can be fed four or five times a day. By the age of about 42 days (6 weeks), puppies can be fed only the puppy food with milk formula blend you have previously been feeding. They will require up to 10 feedings per day for a further two or three weeks, at which point they should be transitioned to more solid foods and less meals.