Abstract: The digestive system of newborn calves is not fully developed, especially the rumen and reticulum. During this period,calf nutrition mainly relies on reed and intestinal absorption,which is similar to the single stomach animals. Liquid diet has become the ideal diet for calf lactation stage. Acidified milk refers to cow's milk(including waste milk and abnormal milk) or calf milk replacer as raw material,adding acidity regulator to keeping the pH value of milk between 4.0 and 4.5,which reduces the number of bacteria in milk,thus reducing the diarrhea rate of calves,improving the digestion and absorption capacity of nutrients,and allowing longer storage and saving labor costs. In this paper,studies on the effects of feeding acidified milk on growth performance,intestinal flora structure and immune function of calves in recent 10 years were reviewed.

Key words: acidified milk, growth performance, intestinal microbiome, immune function