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

Abstract

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

Antioxidant Contents in a Mediterranean Population of Plantago lanceolata L. Exploited for Quarry Reclamation Interventions

“…Hamacher et al [ 10 ] found a content of 65 g tannic acid equivalent kg −1 , but they did not report the plant phenological stages; in addition, the environmental conditions were very different to our study. Kapp-Bitter et al [ 31 ], found a content of 89.9 g kg −1 , like our result for Field in July, in fact they harvested the plants during the seed ripening stage.…”

“…No condensed tannins (CT) were detected in the investigated plant organs (leaves, peduncles, inflorescence) and locations. In a study on mature herbs, as a supplement to ruminant diet, CT were not detected in plantain [ 31 ], as in our results. Conversely, a CT content of 3 g kg −1 was found by Hamacher et al [ 10 ], the content being very low respect to other plant species under study as Onobrychis viciifolia (87.6 g kg −1 ).…”

Literature review exploring the options of herbs in grasslands in the Netherlands : Effects on resilience and robustness of cattle and the ability to cope with heat stress

“…Sanguisorba minor is mentioned as a promising plant for methane reduction in dairy (Loza et al, 2021), gaining up to 33% reduction. Also reduction of ruminal ammonia production in cattle is described for this herb when fed to cattle (Kapp-Bitter et al, 2021). Other herbs with a similar effect were Galium verum L., Leontodon hispidus L., Lotus corniculatus L., Onobrychis viciifolia Scop., Plantago lanceolata L. (Kapp-Bitter et al, 2021).…”

“…Also reduction of ruminal ammonia production in cattle is described for this herb when fed to cattle (Kapp-Bitter et al, 2021). Other herbs with a similar effect were Galium verum L., Leontodon hispidus L., Lotus corniculatus L., Onobrychis viciifolia Scop., Plantago lanceolata L. (Kapp-Bitter et al, 2021). Yarrow Achillea millifolium is known for its wound healing properties and a study in rabbits (Jalali et al, 2012) confirmed that an extract of yarrow improved the quality of healing of burn wounds and reduced the amount of pathogens in these wounds.…”

Root exudation of oxalic acid in Lotus corniculatus in response to aluminum toxicity

“…The total annual yields of pastures that contain a greater proportion of legumes are generally higher than grass monocultures (Gultekin et al, 2021). Lotus species are recognized for their tolerance to acid soils and low natural soil fertility (Escaray et al, 2012), and in South America, legumes are currently being more widely adopted as an alternative to improve the quality and quantity of pasture in regions with acid soils (Kapp-Bitter et al, 2021). The objective of this research was to identify the existence of root exudation of organic acid in L. corniculatus germplasms subjected to toxic Al levels and investigate the effect of this mechanism on the Al content in the root tissue and in morphological parameters of plant development.…”