Final answer:
The best substitute for a cow's milk-allergic infant is casein hydrolysate milk formula, as it includes proteins that are less likely to cause an allergic reaction and provides the necessary nutrients for growth.
Step-by-step explanation:
If a 3-month-old bottle-fed infant is allergic to cow's milk, the best substitute to teach the parents to use would be d. Casein hydrolysate milk formula. Unlike cow's milk, goat's milk, or skim milk diluted with water, casein hydrolysate formulas are designed for infants with cow's milk protein allergy, as they contain proteins that are extensively broken down, making them less likely to provoke an allergic reaction. Cow's milk should never be given to an infant due to its unsuitable composition and difficulty of digestion by an infant's immature digestive system. Casein hydrolysate milk formulas also have the nutrients infants need for healthy development and growth.
Antibodies produced in the mother's body are passed to the infant via passive immunity through breast milk, which also contains immunoglobulins to protect the child from bacterial and viral infections. For infants with a lactose intolerance condition, lactose-free options like casein hydrolysate formulas provide a safer alternative to cow's milk.