From The Real Food Channel Cow's milk and infant apnea

Higher risk of SIDS?

Nature provides the perfect food for babies: a mother's milk. But if mom is drinking the milk of another species, particularly cow's milk, can compounds designed for the baby cow affect her baby? Dr. Greger looks at a case of a baby whose apnea (stopping breathing) occurred only after his breastfeeding mother drank cow's milk. The opiate-like effects of the casomorphin in cow's milk may have a depressive effect on the respiratory center of infants and lead to "milk apnea," in which babies temporarily stop breathing and are placed at risk for sudden infant death syndrome (crib death). 

The Link!