Abstract: In this research, the nutritive value parameters of Huayouza 62 forage rape at flowering and early podding stages of crop development were evaluated by chemical analysis and rumen degradation characteristics were determined using three rumen-fistulated Boer goats. The results provide nutritional parameters for feeding forage rape to ruminants. It was found that: 1) The crude protein (CP) of forage rape in the flowering stage was 17.30%, and the total amino acid content was 11.48%, and both values were significantly higher than at the early podding stage (P<0.05). There were no significant (P>0.05) differences between the flowering and early podding crop growth stages in the contents of CP, crude ash (CA), calcium (Ca), total phosphate (TP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). The glucosinolate content in the flowering stage was 10.17 μmol·g^-1 and the tannin content was 0.94%, and these values were higher than those in early podding stage. 2) The rumen degradation rate of dry matter (DM), CP, organic matter (OM), NDF and ADF in the flowering and early podding stages gradually increased with increased digestion time. The CP rumen degradation rate of forage rape in flowering stage was 84.7% at 72 h. The DM rumen degradation rate increased rapidly from 0 to 24 h and stabilized at about 67% after 48 h, while the rumen degradation of NDF and ADF progressed more slowly, with values of 48.22% and 45.78%, respectively, at 72 h. The rumen degradation rate of DM and OM at the early podding stage was lower than at the flowering stage at the same time point from 0 to 72 h. 3) The rapidly soluble component of the various nutrient fractions differed significantly (P<0.05) between the flowering and early podding stage. CP was the nutrient fraction with the highest rapidly soluble values, reaching 64.06% at flowering and 68.81% at early podding, while the effective degradation rates of CP at these two growth stages were 76.50% and 75.13% (P<0.05), respectively. In conclusion, the feeding value of forage rape in both the flowering stage and the early podding stage is very high. The rumen degradation rate of the main nutrients is high, making forage rape suitable as a ruminant feed. Forage rape was more easily digested by goats in the flowering stage, than in the early podding stage.

Key words: forage rape, nutrient composition, rumen degradation rate