MITIGATING CLIMATE CONDITION EFFECTS WITH OMEGA-3 OR OMEGA-6 SOURCES IN HOLSTEIN DAIRY COW’S RATIONS

Production of healthy milk under climate heat conditions has an enormous challenge in the global dairy industry. The objective of the presented study was to evaluate milk production and nutrients digestibility of Holstein dairy cows during rising temperatures period (spring and summer conditions) in response to feeding omega-3 or omega-6 sources. Fifteen multiparous cows (30 d in milk) were divided into 3 equal groups (5 cows in each) in a complete randomized design according to their milk production, body weights and parity. The first group fed on basal diet and served as control. The second group fed on basal diet supplemented with 10 % Omega-3 sources (Flax seed meal and Flax seed in a ratio of 65: 35 %, respectively on DM basis), meanwhile the third group fed on basal diet supplemented with 8 % Omega-6 sources (equal portions of safflower and sunflower seeds). Data indicated that dry matter intake (DMI) increased (P<0.05) in cows fed Omega-3 or omega-6 by 5.60 and 8.22 %, respectively vs. control. Milk yield increased (P<0.05) with feeding omega-3 and omega-6 sources by 23.61%) 3.60 kg (and 11.48 % (1.75 kg), respectively than those fed control one. The cows in both omega-3 and omega-6 groups produced more (P<0.05) fat corrected milk (FCM), energy corrected milk (ECM), fat %, lactose %, fat yield and lactose yield than the control one. Feeding omega-3 had a positive effect on DM, OM, EE digestibilities, enhancing the nutritive values (TDN and DCP %). However, feeding Omega-6 had no effect on DM, OM and CP digestibilities compared to feeding the control ration. Omega-3 increased (P<0.05) rumen NH3-N concentrations, however TVF’s values decreased. This study, therefore, may be suggested that both omega-3 and omega-6 can be effectively used as acceptable healthy fat sources in dairy cow’s ration during the spring and summer conditions concomitant with positive effect on milk production.