The experiment was conducted to study the effects of different levels of additive fat in early lactation and cows were fed northeast hay and corn silage as roughage. Two factors and four levels were used in experimental design, 21 cows were chosen according to ages , parity Jactation period ,milk production and BW. They were random divided into 7 groups of 3. Group A was basic . Group B: the corn oil was added at 1 % of DM of diet. Group C: the corn oil was added at 2.5% of DM of diet. Group D: the corn oil...