Effect of condensed tannins concentrations on protein degradability of red clover, italian ryegrass and their mixtures

Abstract

Growing grasses in a mixture with legumes leads to more profitable production, better quality of forages, an increase in soil biogenicity and fixation of a significant amount of nitrogen. The experiment was established as a two factorial trial by the method of randomized complete block design in three replications. Italian ryegrass – monocrop (IR), red clover – monocrop (RC) and their mixtures – IR:RC (15:5 kg ha-1), IR:RC (15:10 kg ha-1), IR:RC (20:5 kg ha-1) and IR:RC (20:10 kg ha-1) were planted in November 2016, with the first cutting in the spring 2017 – on May the 9th, and the second cutting in the early summer – on June the 22nd. The aim of this study was to investigate the concentrations of phenolic compounds such as condensed tannins in Italian ryegrass, red clover and their mixtures, as well as their concentrations impact on protein degradability in the rumen depends on the seeding rate in the mixtures and harvested in the spring and early summer. Results obtained in this study showed that higher concentrations of non-protein nitrogen and soluble protein in forages harvested in the spring influenced higher rapidly degradable protein concentration in investigated mixtures. The highest rumen undegradable protein was determined in Italian ryegrass monocrop harvested in early summer, and we assume that high condensed tannins concentration influenced the slower protein degradability. Our recommendation for plant breeders is that cultivars with higher content of condensed tannins should be created and introduced in animal nutrition.