Milk fatty acid composition of dairy cows fed green whole-plant buckwheat, phacelia or chicory in their vegetative and reproductive stage

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 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.

The links between supplementary tannin levels and conjugated linoleic acid (CLA) formation in ruminants: A systematic review and meta-analysis

A systematic review and meta-analysis were conducted to predict and identify ways to increase conjugated linoleic acid (CLA) formation in ruminant-derived products to treat human health issues with dietary tannins. The objective was to compare and confirm the effects of dietary tannins on CLA formation by analyzing in vitro and/or in vivo studies. We reported the results of the meta-analysis based on numerical data from 38 selected publications consisting of 3712 treatments. Generally, via multiple pathways, the CLA formation increased when dietary tannins increased. Concurrently, dietary tannins increased Δ⁹ desaturation and the CLA indices in milk and meat (P < 0.05 and P < 0.001, with average R² values of 0.23 and 0.44, respectively), but they did not change the rumen fermentation characteristics, including total volatile fatty acids (mmol/L) and their acid components. In vitro observations may accurately predict in vivo results. Unfortunately, there was no relationship between in vitro observations and in vivo results (R² < 0.10), indicating that it is difficult to predict CLA formation in vivo considering in vitro observations. According to the statistical meta-analysis results regarding animal aspects, the ranges of tannin levels required for CLA formation in vitro and in vivo were approximately 0.1–20 g/kg dry matter (DM) (P < 0.001) and 2.1–80 g/kg DM (P < 0.001), respectively. In conclusion, the in vivo method was more suitable for the direct observation of fatty acid transformation than the in vitro method.

Cover crops as alternative forages for ruminants: nutritive characteristics, in vitro digestibility, methane and ammonia production

Context The use of cover crops provides agronomic and environmental benefits in crop–livestock systems. They can also constitute alternative forage resources for ruminants, particularly when climatic conditions limit grass supply. However, information on the nutritive value of these crops remains scarce. Aims The objective of the present study was to assess the fresh forage potential of several plant species (sainfoin, buckwheat, phacelia, berseem clover, crimson clover and vetch) commonly used as cover crops and harvested at two phenological stages, namely, vegetative stage (VS) and flowering stage (FS). Methods Chemical composition and fermentation parameters after in vitro ruminal incubation of the plant species were measured and compared with those of lucerne. Key results Chemical composition and in vitro organic-matter digestibility varied both with species (P &lt; 0.001) and stage (P &lt; 0.001). Crude protein concentration (g/kg dry matter) varied at VS from 212 (sainfoin) to 151 (phacelia), and at FS from 187 (vetch) to 88 (phacelia). The in vitro organic-matter digestibility at VS varied from 0.91 (buckwheat) to 0.82 (lucerne), and at FS from 0.81 (vetch) to 0.74 (lucerne). Buckwheat and sainfoin had the greatest concentrations of condensed tannins and total phenolic compounds. The incubation of phacelia, sainfoin and buckwheat resulted in a lower production of volatile fatty acids than did incubation with the other plant species. Methane production was lower at both stages for phacelia (–26%), buckwheat (–12%), sainfoin (–14%) and berseem clover (–13%) than it was for lucerne. Ammonia production expressed as total N proportion was significantly lower for sainfoin and buckwheat than for the other plant species. The reductions in methane and ammonia appeared to be linked to certain phenolic compounds for buckwheat and to condensed tannins for sainfoin. Conclusions The present study showed that these cover crop species hold nutritive characteristics as good as lucerne, indicating that they could be suitable for ruminant nutrition. Moreover, buckwheat and sainfoin have potential beneficial effects on methane and ammonia production. Implications These results constitute a first step towards a recommendation to farmers to use cover crops as forage.

Grazing on Upland Pastures Part-Time Instead of Full-Time Affects the Feeding Behavior of Dairy Cows and Has Consequences on Milk Fatty Acid Profiles

Simple Summary

Transhumance of dairy cows to upland pastures during summer is a tradition in mountain farming systems. Different management systems are practiced in the upland depending on topography and available infrastructures. This study aimed to assess the effects of two traditionally practiced upland pasture management systems (full-time grazing and part-time grazing) on feeding behavior and milk yield and quality. Cows with access to pasture for only 6 h per day had different feeding behaviors than cows on pasture 24 h per day; their milk yields, however, were similar. Although protein and casein contents were higher in the milk of cows with full-time access to pasture, milk coagulation properties did not differ between the two systems. The differences found in milk fatty acid profiles suggest that cows with part-time access to pasture mobilized more body fat reserves to counterbalance the energy expenditures required during fasting periods and for walking back and forth between the barn and the pastures.

Abstract

Different grazing management systems are practiced on upland dairy farms during summer, depending on topography, local traditions, and infrastructure. The present experiment compared two distinct management systems with respect to feeding behavior and milk-related properties. Two similar groups of eight Valdostana Red Pied cows originating from two farms were followed during three grazing events in summer on three upland grazing sites. Cows in the full-time grazing group were kept exclusively on pasture and milked twice daily in a mobile milking parlor. Cows in the part-time grazing group had access to pasture for 4 h and 2 h after their morning and evening milkings, respectively. The part-time grazing cows differed markedly in their feeding behavior; they exhibited shorter daily ingestion times and longer durations of ingestion and idling bouts than full-time grazing cows. Part-time grazing cows had lower milk protein and casein contents, but milk yield and milk coagulation properties did not differ from the full-time grazing cows. As a result of the fasting periods in the barn, part-time grazing cows synthesized less fatty acids de novo and mobilized body fat reserves, as evidenced by the higher proportion of oleic acid in their milk fat.

Antioxidant properties, phenolic and mineral composition of germinated chia, golden flax, evening primrose, phacelia and fenugreek

Seeds and sprouts are of considerable interest due to their numerous pro-health benefits. The aim of this study was to investigate the effect of germination on the mineral composition (performed by flame absorption atomic spectroscopy), total phenolic content, antioxidant activity, as well as phenolic profiles (before and after alkaline hydrolysis by high-performance liquid chromatography) of chia, golden flax, evening primrose, phacelia and fenugreek seeds. Generally, significant (p < 0.05) changes in the individual minerals composition of the seeds, improvement of their antioxidant properties, as well as increase in levels of individual phenolic compounds was found after seeds germination. Alkaline hydrolysis allowed to release free forms of phenolics and to confirm (chromatographically) their significantly higher amounts when compared to the nonhydrolyzed fraction. Gallic, protocatechuic, caffeic, p-coumaric, ferulic and sinapic acids, as well as quercetin and kaempferol were identified in analyzed seeds and sprouts. Sprouts exhibited better nutritional values than their un-germinated forms.