Abstract:

To evaluate the nutritional quality and rumen degradation characteristics of different oat forages， 17 oat varieties planted in Guinan County， Qinghai Province were selected to determine their conventional nutritional components， in vitro fermentation parameters and gas production， then the forage quality evaluation index was calculated. Principal component analysis and the subordinate function method were used for multivariate evaluation. The results showed that dry matter （DM） content was 24.44%-32.91% fresh weight （FW）， with variety Monica the highest. Ether extract levels were from 1.60%-4.03% DM， with Qinghai 444 the highest. Crude protein content ranged from 4.35%-6.23% DM， with Qinghai 444 the highest. Ash content was 4.58%-6.51% DM， with Qinghai 444 the highest. Water soluble carbohydrates content was 3.49%-12.61% DM， with Qingtian No.2 the highest. The levels of neutral detergent fiber and acid detergent fiber were 45.56%-62.31% DM and 23.75%-_{32.38% DM， respectively， and were highest in variety Bayan No.6. Relative feed value and relative feed quality ranged from 95.06-143.74 and 118.32-213.25， respectively， and were highest for Tianyan No.1. GI ranged from 6.34-11.91 MJ·d^-1， with the highest value in Qinghai 444. The pH range was 6.58-7.07， with Hanma the highest； NH3-N content ranged from 9.65-15.87 mg·dL^-1， and Qinghai 444 was the highest. The dry matter degradation rate ranged from 63.01%-76.47%， and Qinghai 444 was the highest. The cumulative in vitro gas production of different oat varieties at different time points differed， with a range of 56.59-105.28 mL in 72 hours， and the highest in variety Haymaker. Based on the principal component analysis and membership function， the comprehensive scores of the 17 oat varieties ranked as follows： Qinghai 444>Tianyan No.1>Qingtian No.1>Tianyan No.3>Qingtian No.2>Sweet oat>Baler>Monica>Haymaker>Baiyan No.7>Hanma>Youmu No.1>Magnum>Forage plus>Titan>Everleaf 126>Bayan No.6. Therefore， Qinghai 444 is the oat variety with the best nutritional quality and potential feeding value and can be recommended for planting in high-altitude and cold regions.}

Key words: oat, nutritional value, rumen degradation characteristics, principal component analysis, membership function