PSXIII-21 Nutrient intake ruminal and apparent total tract digestibility and nitrogen utilization in finishing cattle fed increasing amounts of grape pomace.

摘要

Although it can be available for use in finishing cattle diets, there is still limited information on the effects of feeding grape pomace (GP) in place of barley grain on nutrient supply. Therefore, our objective was to determine the effects of feeding 0, 15, or 30% GP (DM basis) on nutrient intake, ruminal and apparent total tract nutrient digestibility, and nitrogen (N) excretion in beef cattle. Six ruminally-cannulated heifers (mean initial BW ± SD, 714 ± 50.7 kg) were used in a replicated 3 × 3 Latin square with 21-d periods (14 d for adaptation). Heifers were fed finishing diets containing 0, 15, or 30% GP (DM basis); GP partially replaced barley grain. Dry matter intake was measured daily. Ruminal fluid was collected (d 15) to determine fermentation characteristics. Feces and urine were collected (d 19 to 21) to measure apparent total tract nutrient digestibility and N excretion. Blood samples were collected 3 h post-feeding on d 21. Data was analyzed using PROC MIXED in SAS. Although it had no effect ( = 0.27) on DMI, increasing the amount of GP in the diet increased ( < 0.01) NDF and ADF intake. Apparent total tract DM, NDF, and ADF digestibility were lower ( < 0.01) in heifers fed the 30 than 0 and 15% GP diets. Although there was no diet effect ( ≥ 0.11) on the VFA profile, rumen NH -N tended to be greater ( = 0.07), and BUN was greater ( = 0.04) for heifers fed the 30 than 0 and 15% GP diets. However, there was no treatment effect ( ≥ 0.33) on microbial N supply, urine N and urea-N excretion. In summary, feeding an increasing amount of GP in finishing diets reduced apparent total tract DM, NDF, and ADF digestion and did not improve N utilization.