Effect of prill fat supplementation on hormones, milk production and energy metabolites during mid lactation in crossbred cows

Materials and Methods The ability of the dairy cows to increase daily energy intake depends on the net energy density of the diet. The daily Dry Matter Intake (DMI) is highly regulated by animal nutrient requirements, metabolic states, and the type and temporal absorption of fuels. Fat supplements from different sources, its form and type has different hypophagic effects [1]. Previous reports indicate that feeding of fatty acid (FA) supplements including calcium salts of palm FA linearly decreases DMI with increasing dietary concentration, whereas hydrogenated FA had no effect on DMI [2,3]. However, dietary fat feeding induces decrease in milk protein concentration in animals. Milk yield changes in by pass fat cows could be due to the changes in ruminal fermentation, endocrine signaling, or mammary nutrient metabolism [4]. A linear decrease in milk crude protein (CP) yield with abomasal unsaturated fatty acid (FA) infusion [2] and a decrease in milk casein yield with C18 unsaturated FA infusion compared with saturated FA [4] indicated that FA profile has an important role in fat-stimulated decreased milk protein. The maintenance of lactation of dairy cows depends on the balanced feeding during postpartum period. It has been found that hydrogenated palm oil triglyceride provide a better energy supply for high-yielding dairy cows in negative energy balance than calcium soaps of palm oil fatty acids around calving [4]. Prill fat is a non-hydrogenated vegetable oil and contains more than 85% palmitic acid with high melting point. Due to this reason it does not melt at low pH, by pass rumen degradation and is digested in small intestine by lipase enzyme. Prill fat is prepared by liquefying mixture of fatty acid by spraying it under pressure into a cooled atmosphere. prill fat remain inert in the rumen and resist hydrolysis and association with the bacterial cells of feed particles. Thus total supplemented energy in diet of a lactating animal is available for the productive processes. Considering the importance of prill fat as an energy source in diet of lactating animals, the present experiment was conducted to find out the effect of prill fat supplementation on plasma hormones and milk production in crossbred cows so that this technology, if proved beneficial, could be used to augment lactation under field and farm conditions.