Nutritive value of broad-leaved dock (Rumex obtusifolius L.) and its effect on the quality of grass silages

Abstract

The effect of broad-leaved dock (Rumex obtusifolius L.) on the impaired nutritive value of grassland herbages was studied together with the effect of dock and addition of microbial inoculant on the fermentation process in grass silages. The herbage of broad-leaved dock exhibits low DM content, CP and fibre contents comparable with red clover, yet its NEL concentration is low. Quality of silages made of dock at DM content over 300 g/kg is good but the silages show significantly lower contents of lactic acid (35.9%), acetic acid (70.0%) and higher pH values (4.69 vs. 4.35) as compared with the grass silage. Silages made of dock do not contain butyric acid and exhibit lower rates of proteolysis. The presence of broad-leaved dock in herbage poses a danger of slow wilting and low production of fermentation acids. The addition of lactic acid bacteria (LAB) showed in the studied set of silages and in dock silages by an increased content of lactic acid (+18.9% and +27.0%, resp.) and by a significant reduction of pH value (–0.17 and –0.14, resp.).