蒙牛乳业全年净利润15.5亿元人民币，预估34.6亿元人民币。

Group 1 - The core point of the article is that Mengniu Dairy's net profit for the year is 1.55 billion RMB, which is significantly lower than the estimated 3.46 billion RMB [1] Group 2 - The reported net profit of 1.55 billion RMB indicates a substantial deviation from market expectations, highlighting potential challenges faced by the company [1] - The estimated profit of 3.46 billion RMB suggests that analysts had anticipated a much stronger performance from Mengniu Dairy [1]