Fats which are not protected have a depressing effect on rumen cellulolytic microbial activity reducing polyunsaturated fatty acids and increasing saturated fatty acids content in milk fat that are atherogenic, and raise the risk of cardiovascular disease. Bypass fat in rations of the high producing dairy animals is very crucial for enhancing the energy density of the ration. Supplementation of bypass fat had no adverse effect on the rumen fermentation, feed intake and digestibility of nutrients and different blood parameters of the dairy animals. The milk yield is increased along with the improvement in post partum recovery of the body weight and body condition score and reproductive performance of the dairy animals. Choline is a constituent of phospholipid and acts as a methyl donor. It contributes to fat export from the liver via playing a vital role in the synthesis of very low density lipoprotein and consequence metabolism of fat for energy production and increases milk production. Additional study is essential to find out the supplementary effect of the bypass fat on dairy animals fed various types of basal rations as diverse productive levels and stages of lactation.