Variation in the contents of crude protein fractions of different forage legumes during the spring growth |
| |
| Authors: | S Kirchhof I Eisner M Gierus K‐H Südekum |
| |
| Institution: | 1. Institute of Animal Nutrition and Physiology, University of Kiel, Kiel, Germany;2. Institute of Animal Nutrition, University of Hohenheim, Stuttgart, Germany;3. Grass and Forage Science/Organic Agriculture, Institute of Crop Science and Plant Breeding, University of Kiel, Kiel, Germany |
| |
| Abstract: | The pattern of crude protein (CP) fractions with advancing maturity during a primary spring growth of forage legumes was investigated on freeze‐dried samples of fresh forage using the method of chemical CP fractionation according to the ‘Cornell Net Carbohydrate and Protein System’ (CNCPS). The CP of white clover (WC), red clover (RC), lucerne (LU), birdsfoot trefoil (BT) and Kura clover (KC) was separated into five fractions (A, B1, B2, B3 and C), which are assumed to have different rates and extents of ruminal degradation. Ruminally undegraded dietary CP (RUP) was predicted on the basis of the CP fractions using regression equations that were developed for fresh forage assuming ruminal passage rates of 2, 5 and 8% h?1 (RUP2,5,8). Maturity stage did not affect the soluble CP fractions of the legumes but increased fraction B3 in RC and WC and fraction C of all forages except WC. The estimated RUP values of the legumes increased with advancing maturity. The mean values for RUP5 across all harvest dates for WC, RC, LU, BT and KU were 154, 271, 226, 287 and 212 g kg?1 CP respectively. BT and RC had the highest amount of RUP across all harvest dates and passage rates (159–372 and 134–324 g kg?1 CP respectively). This observation may be related to the advanced stage of vegetation of both species at the harvest dates compared with the other legumes and to condensed tannins in BT and to products of polyphenol oxidase activity in RC. |
| |
| Keywords: | forages legumes crude protein fractions ruminal degradation maturity |
|
|
