Megafat is a concentrated source of energy for dairy cows during first half of lactation. It is a source of protected rumen indegradable long chained fatty acids that does not affect the micorbial fermentation in rumen and total degradability of feed components. The index of digestability of Megafat is 80-90%. It does not affect the pH of rumen as well as digestion of fiber. It increases the flow of fatty acids into the small intestine, what increases the total available energy level for lactation. It contains chemical bonds that are degradated when exposed to pH less than 3. This is the reason why MegaFat cannot be degradated in rumen, but first in abomasum.