Mature herbs as supplements to ruminant diets: effects on in vitro ruminal fermentation and ammonia production

Context High concentrations of crude protein in ruminant diets may lead to excessive production ruminal ammonia, which stress the animal’s metabolism and impact nitrogen efficiency. This become a problem zero-concentrate feeding systems when pasture grass is rich protein. Polyphenols such as tannins protect part dietary from degradation thus inhibit ammonia formation. Aims The present study screened mature herbs for their potential mitigate formation cattle, provided supplement forage diet. Methods Thirty-five temperate-climate, herbaceous meadow plant species (including three legumes) that appear biodiverse natural sown pastures were investigated effects on production. Aboveground material was harvested during ripening seeds analysed nutrient phenol concentrations. Net energy absorbable at duodenum calculated. Incubations (24 h) with cattle rumen fluid following vitro Hohenheim Gas Test protocol performed compare test plants gas replaced one-third basal mixture consisting 57% Lolium perenne L. 43% Medicago sativa (air-dry-matter basis). Results compared those obtained alone. Key results According regression analysis, concentration after incubation negatively related total extractable phenols feed mixtures, whereas relationship weakly positive In 23 19 diets, respectively, (indicating organic matter digestibility) medium 24 h significantly lower than containing Galium verum L., Leontodon hispidus Lotus corniculatus Onobrychis viciifolia Scop., Plantago lanceolata Sanguisorba minor Scop. Scabiosa columbaria maintained estimated digestibility while same time lowering Conclusions Seven screening 35 proved have utilisation without impairing fermentation. Implications These are particular interest supplements dairy cows grazing protein-rich pastures.