Feeding red osier dogwood (Cornus sericea) to beef heifers fed a high-grain diet affected feed intake and total tract digestibility

Abstract

Red osier dogwood (ROD; Cornus sericea) is an abundant native shrub plant across North America and it is rich in bioactive compounds with total phenolic concentration up to 220 g/kg dry matter (DM) depending on the season. The phenolics include anthocyanins, gallic acid, ellagic acid, quercetin, and cyanin, which have both antioxidant and antimicrobial properties. The objective of this study was to determine the effect of increasing substitution of ROD for barley silage in a high-grain diet on DM intake, ruminal pH and fermentation, digestibility in the total digestive tract, blood metabolites and acute phase response in beef heifers. Five ruminally cannulated Angus heifers (averaged body weight of 660 ± 40.8 kg; initial age of 18 months) were used in a 5 × 5 Latin square design with 21-d periods including 14 d for adaptation to new diets and 7 d for data collection. Treatments were a control diet containing 150 g/kg barley silage and 850 g/kg barley concentrate mix (DM basis), the control diet substituted with 30, 70 or 100 g/kg of ROD for equal proportions of barley silage, respectively, and the control diet supplemented with antibiotics (330 mg monensin + 110 mg tylosin/heifer/d). Apparent digestibility was determined using Cr2O3 as external marker by sampling feces from the rectum. Intake of DM quadratically (P < 0.02) increased with increasing the substitution of silage for ROD. Mean ruminal pH were not affected by diets, and no effects of diets on total volatile fatty acid (VFA) concentration were observed. However, ruminal NH3-N concentration linearly (P < 0.01) decreased with increasing ROD feeding. Digestibility of DM linearly (P < 0.04) increased with increasing dietary ROD. Increasing ROD feeding also linearly increased plasma concentration of haptoglobin (P < 0.01) and concentration of serum amyloid A (P < 0.06). Compared with antibiotic group, feeding ROD resulted in greater (P < 0.01) intake and digestibility of DM, and greater (P < 0.05) VFA concentration. These results indicate greater feed value of ROD versus barley silage in high-grain diets. Feeding ROD potentially improves immune status and antioxidant activity in finishing beef heifers. Beef cattle fed ROD performed better or at least equal to antibiotics currently used in beef cattle rations and it could be used as a natural alternative for beef cattle production.