author(s)
Harish Rohila, Amar Shroha and Rakesh Kumar

abstract
RPF (Rumen Protected Fat)/ bypass fat in the rations of the high producing dairy animals is very crucial for enhancing the energy density of ration. Rumen Protected Fat means that resists lipolysis and bio hydrogenation in rumen by rumen microorganisms, but gets digested in lower digestive tract. Most of the animals in developing countries including India are fed on agriculture by-products and low quality crop residues, which have got inherent low nutritive value and digestibility. The shortage of feed resources coupled with their poor nutritive value. Hence, during early lactation, dairy animals are often forced to draw on body reserves to satisfy energy requirements (negative energy balance); this leads to substantial loss in body weight. Cereal grains and fats plays an important role as source of energy in the ration but due to use of cereals for human consumption and monogastric animals the alternate source of energy in dairy ration is supplemental fat/RPF (Rumen Protected Fat)/ bypass fat. And inclusion of unprotected fat in dairy ration is limited to 3% of dry matter (DM) intake, beyond which digestibility of DM and fibre are reduced. So, diets containing rumen protected fat often stimulate energy intake, improved efficiency of utilization of energy without adversely affecting the DM intake and improved body condition in dairy animals.