Protein and carbohydrate profiles of a diploid and a tetraploid red clover cultivar

Red clover (Trifolium pratense L.) is characterized by high dry matter (DM) yield and a high nutritive value. It has a higher concentration of soluble carbohydrate than lucerne and its protein is less degradable in the rumen than lucerne protein. The aim of this study was to quantify the main crude protein (CP) and carbohydrate (CHO) fractions of a tetraploid (4n, cv K-32) and a diploid (2n, cv K-39) red clover cultivar harvested at three stages of development in the spring growth. Results showed that the cultivar and stage of development had a large impact on chemical composition and the protein and carbohydrate fractions determined by the Cornell Net Carbohydrate and Protein System (CNCPS). The rapidly degradable protein fraction (PA) was significantly higher in the tetraploid (272 to 287 g kg-1 CP with advancing plant development) than in the diploid red clover cultivar (214 to 268 g kg-1 CP). Rumen degradable carbohydrate concentration was not affected by cultivar but it was significantly influenced by the stage of development. The concentration of rumen degradable protein decreased from 726 to 655 g kg-1 CP with advancing plant development in the diploid red clover cultivar. In conclusion, the tetraploid red clover cultivar was higher in CP, its protein was more rapidly degradable, and it was characterized by lower concentrations of lignin and unavailable carbohydrate fractions than the diploid cultivar.