1715
Production performance parameters of early lactation Iranian Holstein cows fed diets containing high levels of palmitic acid or ca-salt of unsaturated fatty acids
Fat supplements can improve energy balance, feed efficiency, and the yields of milk and milk fat. However, the effects of different FA profiles have not yet been adequately studied. The aim of this study was to evaluate the milk fatty acid profile in early lactating dairy cows supplemented with protected unsaturated fatty acids sources and prilled source of palm fatty acids. Twenty four multiparous Iranian Holstein cows were assigned to diets with different fatty acid profiles and supplemented through 30 days prior to expect calving date to 50 days in milk. Dietary treatments consisted of (1) Prilled Pam fatty acids (PO) [Energizer RP10 ®, 2 & 2.25 % DM in pre- and postpartum, respectively]; (2) Ca-salts of sunflower oil (SO) [Persia Fat®- SO]; (3) Ca-salts of fish oil (FO) [Persia Fat®- FO] and (4) equal amounts of Persia Fat®- FO & Persia Fat®- SO. Calcium salts were supplemented as 2.2 and 2.5% of dietary DM in pre- and postpartum period, respectively Milk yield and the dry matter intake were measured daily throughout the experimental period. The milk samples were obtained weekly (2 consecutive days, 3 daily milking, Individual milk samples were analyzed for fat, true protein, and lactose concentration by mid-infrared spectroscopy by the Iranian Dairy Herd Improvement Association. Yields of 3.5% FCM, ECM, and milk components were calculated using milk yield and component concentrations for each milking. Data were analyzed using PROC MIXED of SAS 9.1 according with repeated measures in time function. Milk and milk component yields were greater with Persia Fat® than with palmitic fatty acid prill. However feed efficiency was not statistically different (1.84 kg FCM/kg DMI vs. 1.89, 1.88 and .86, for treatments 1 to 4, respectively). Cows fed Persia Fat® had greater DMI than those fed Palm oil fatty acids ® (20.17 kg DM vs. 23.56, 22.25 and 22.53, for treatments 1 to 4, respectively). Milk protein concentration was higher for PO compared with Persia Fat® (3.27 % vs. 3.14, 3.12 and 3.08, for treatments 1 to 4, respectively), but Persia Fat® fed cows produced more milk protein per day. Based on results we conclude that different fatty acids have different digestibilities, absorption and/or differing biological effects post absorption.
Keywords: PUFA, Palmitic acid, FCM