In the feeding of infants,' cows' milk is the best and most common substitute for human milk. In the feeding of delicate infants, however, considerable difficulty is often experienced from its use. The ideal substitute for mothers' milk has not been found, and most of the clinical effort has been directed towards the modification of cows' milk for infants.
Comparatively little research has been done on the difference in the digestibility and food value of milks from different cows for the infant. It is a well-known fact that the curd of cows' milk forms in a tough mass which varies considerably from the soft flaky curd obtained from human milk. That there is a wide variation in the toughness of the curd obtained from the milk of different cows is not generally known. Variation in the toughness of the curd of milk from different cows has been given very little attention in the field of research.
Hill, R. L., "Bulletin No. 207 - The Physical Cure Character of Milk and its Relationship to the Digestability and Food Value of Milk for Infants" (1928). UAES Bulletins. Paper 180.