PSXI-7 Rumen degradation kinetics of chicory forage as a monoculture and in mixture with meadow bromegrass and sainfoin.

Abstract Chicory (Chicorium intybus L.) is an herbaceous, high protein, low-fibre forage species with the potential to improve feed quality for livestock. The objective of this study was to evaluate the rumen degradation kinetics of forage chicory as monoculture, 2, and 3 species mixtures that include meadow bromegrass (Bromus riparius Rehm) and/or sainfoin (Onobrychis viciifolia Scop.). To evaluate the four treatments: (i) chicory (C) (100%); (ii) chicory-grass (CG) (50:50%); iii) chicory-grass-sainfoin (CGS) (50:25:25%); and iv) grass-sainfoin (GS) (50:50%) a replicated (n = 4) random complete block design was implemented. This study used three cannulated beef steers (Average BW = ~950kg), and animal use protocol was approved by the local animal care committee. Dried ground samples of treatment forages were incubated for 0, 4, 8, 12, 24, 48, and 72 h using a gradual all-in/all-out procedure. Residual samples were washed and dried for 144 h. Samples were analyzed for dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF). Effectively degradable fraction (ED) and degradation rate (Kd) were calculated. Data analysis was performed using the mixed procedure of SAS (version 9.4). These data suggest that the addition of chicory into a hay diet will increase (P < 0.001) the effective degradability of DM (EDDM) all treatments containing chicory, C (676.7 g/kg DM), CG (635.6 g/kg DM), CGS (643.5 g/kg DM) all of which were greater than the non-chicory treatment GS (589.0 g/kg DM). Dry matter Kd for the C treatment (0.106%/h) was significantly higher (P < 0.001) than the CG (0.075%/h), CGS (0.073%/h) and GS (0.053%/h) treatment. The effective degradability of CP (EDCP) (P < 0.001) increased for all treatments containing chicory, C (74.90 g/kg DM), CG (61.50 g/kg DM), CGS (64.20 g/kg DM) vs. the non-chicory treatment GS (54.30 g/kg DM). Crude protein Kd values demonstrate that GS (0.095%/h) was lower (P = 0.005) than C (0.192%/h) and CG (0.181%/h), but the CGS treatment (0.131%/h) was not different (P > 0.05) from either the GS treatment or C and CG treatments. Treatments with a higher quantity of chicory, C (158.1 g/kg DM) and CGS (203.1 g/kg DM) have a significantly lower effective degradability of NDF (EDNDF) value (P < 0.001) vs. the high bromegrass treatments CG (230.1 g/kg DM) and GS (253.7 g/kg DM). NDF Kd values demonstrate that the C (0.081%/h) treatment is significantly higher (P < 0.001) than the CG (0.056%/h), CGS (0.053%/h) and GS (0.040%/h). Overall, the results from this study demonstrate that chicory provides improved nutrient and protein content and availability, improving the quality of high-fibre hay diets.