The test choose dairy cows from different areas of Inner Mongolia,360 Hostein cows from Hohhot and BayanNour;90 Hostein cows and 90 Simmental cows from Tongliao;90 Hostein cows and 90 Sanhe cows from HulunBuir.In order to compare and study the content and difference of protein,fat, lactose,dry matter, casein and amino acid in milk which from different areas、feeding mode、season、breed、fetal time、lactation period,to analyze the effect on contents of amino acid in milk and variational regulation on amin...