INFLUENCE OF CORN CONDENSED DISTILLERS SOLUBLES (CCDS) ON RATION DIGESTIBILITY. NITROGEN/ENERGY UTILIZATION AND RUMEN FLUID CHARACTERISTICS OF LACTATING DAIRY COWS

Résumé

Digestion and Balance trials were conducted with 18 lactating dairy cows in their 7-8 weeks of lactation using 7 day total collection to determine nitrogen and energy balance and digestibility of ration nutrients by lactating dairy cows fed three levels (0.8 and 16%) of corn condensed distillers solubles (CCDS). Cows were fed treatment rations for 4 weeks before collection. Following digestion and balance trials, rumen fluid samples were collected esophagially before feeding and 3 hours after feeding to determine the influence of CCDS on rumen pH, ammonia nitrogen and volatile fatty acids. Corn condensed distilers solubles significantly (P<0.05) improved the digestibility of the neutral detergent fiber and ether extract but depressed the digestibility of the ash. Apparent nitrogen retention was significantly (P <0.05) lower for animals on 8% CCDS ration. There were no significant differences in energy utilization among groups. Corn condensed distilers soluble did not significantly affect rumen pH, but depressed rumen ammonia nitrogen. On molar percentage basis, animals on the 8% CCDS ration had significantly (P< 0.05) higher acetate in the rumen 3 hours after feeding. Other VFA remained relatively unaffected by treatments.