Influence of chestnut tannins on in vitro crude protein rumen degradability kinetics of red clover silage

Chestnut tannins in red clover silage reduce rumen dry matter and crude protein degradation. Adding tannins to silage could lead to better nitrogen use efficiency in ruminants

Barriers and levers of enhancing animal welfare in organic and low-input outdoor production: Insights from a supply chain survey

Animal welfare is an essential part of the sustainability of animal production. While low-input farming, such as organic animal production, is often considered animal-friendly, several ways to enhance animal welfare in low-input animal production exist. However, currently there is little information on how farmers and other supply chain actors view different innovations and tools which may influence animal welfare in low-input outdoor and organic production systems. The aim of this study was to examine farmers’ and experts’ reactions to new approaches to pig and poultry production, with special attention to their animal welfare-related measures. The reactions were tested formally in by using a quantitative survey instrument in nine European countries (Finland, UK, France, Denmark, the Netherlands, Belgium, Germany, Italy, Romania). In the survey, respondents’ views on production practices and novel measures were asked. These included aspects such as applicability and advantages and disadvantages of various measures such as avoiding mutilations, using dual-purpose or local breeds, or in-ovo sexing. The data included altogether 218 responses from nine countries. Differences between countries were tested and groups of respondents were identified. The results suggest that supply side stakeholders foresee the welfare benefits and some disadvantages of welfare improving measures proposed to them. However, they also indicate that several measures were considered inapplicable despite their benefits. Inadequate financial provisions to adopt a measure was considered as one of the most important reasons for inapplicability of a measure. This may imply either high costs of implementing measures of low market incentives or perceived low demand for animal-friendly products. Other barriers for adopting welfare-friendly measures included farm-specific factors such as limitations imposed by housing. The respondents indicated a high relative preference for feeding, breeding, shelter from predators and the use of vaccines and anti-parasitic treatments to the provision of enrichments and nesting material to pigs, and to mutilations. Farmers agreed that environmental enrichments are important welfare-improving levers and preferred their use in low-input pig and poultry production. Animal breeding-related measures in pig production were perceived quite favorably by supply side stakeholders. Despite their welfare benefits, farmers in some countries had quite high preference towards maintaining castration and tail docking in pig and beak trimming in broiler production as part of their production method

Comment mieux valoriser les fourrages riches en azote ?

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Les tanins hydrolysables sont-ils des additifs d'ensilage prometteurs pour des systèmes laitiers plus respectueux de l'environnement ?

Today, the livestock sector has to address multiple concerns. Being criticized for its environmental impact and competition for land use, a better efficiency at transforming vegetal proteins into animal proteins while limiting food-feed competition is now one of its main challenges. Several strategies have been identified to improve nitrogen use efficiency (NUE) and reduce environment damage of livestock production; the use of plant secondary compounds such as tannins is one of them. These natural molecules can bind with proteins and protect them against degradation by micro-organisms. Their action can thus help improve nitrogen efficiency and reduce nitrogen losses. Our meta-analysis conducted on 58 experiments showed that tannins are generally ineffective at improving zootechnical performances but a shift in N excretion was observed, urinary N being reduced in favor of faecal N. However, hydrolysable tannins and the effect of tannins addition before ensiling have been little studied to date, unlike condensed tannins. This thesis thus aimed at testing the following hypotheses : i) hydrolysable tannin extracts can reduce proteolysis both in grass-based silage and rumen, ii) hydrolysable tannin extract added before ensiling can improve nitrogen use efficiency in lactating dairy cows. The first experimental results showed that hydrolysable tannin extracts were effective at reducing ammonia-nitrogen content of silages suggesting a reduction of proteolysis. NH3-N proportion was reduced by 12 to 18% with oak tannin and up to 16% with chestnut tannin. Tannins also decreased ruminal nitrogen degradability of grass silage during enzymatic in vitro trial and in an artificial rumen. Proteolysis reduction thanks to oak tannin extract linearly increased with tannin dose in silage. The best dose range for oak and chestnut tannin extracts in silage seems to be around 30 g/kg of dry matter (DM) of forage. From 50g/kg DM, tannins showed a detrimental effect on in vitro organic matter digestibility. The second part of the work revealed that oak tannins extract (added at 26g/kg DM in grass before ensiling) had no effect on nitrogen use efficiency of lactating dairy cows. However, a shift from urine to faecal nitrogen was observed in this trial in presence of oak tannins. This strategy can thus be adopted to decrease the environmental impact of ruminant protein feeding. This experiment also documented the use of the “nitrogen isotopic discrimination” proxy to compare nitrogen use efficiency of two contrasting diets. The results indicated that the proxy would specifically sign the N partitioning at the metabolic level rather than the overall NUE, the latter also being impacted by digestive processes. The greatest interest of tannins would thus lie in their positive impact on environment preservation. The addition of tannin before ensiling seemed pointless in our conditions as compared to direct feeding given that the benefit from protecting proteins in silo did not persist in the rumen. The influence of pH on stability of hydrolysable tannin-protein complexes seems contradictory to literature data on condensed tannins. The specificity of tannin-protein complexes to both tannin and protein structures is a great challenge in the understanding of tannin impacts and the development of tannin applications in ruminant feeding

Comparison of two laboratory-scale ensiling methods to assess effect of reducing sugars

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Que vaut un ensilage de CIPAN fourragère?

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Relay crops: a source of nutritional forage

Spring relay crops can provide complementary forage, especially during periods when traditional forage is lacking. However, little is known about their nutritional value. The Arvalis Plant Institute and INRA each carried out a study on the nutritional qualities of several intercrop species. They found that fresh forage harvested at the vegetative stage was highly nutritional (containing as much as 1.13 French feed units for lactation, 158 g of metabolisable protein [PDIE], and 225 g of rumen degradable protein [PDIN] per kg DM). Silage can be made despite the forage’s low dry matter content and high buffering capacity (Agroscope study). In Wallonia, the quality of intercrop silage is good (0.76 French feed units for lactation, 102 g of metabolisable protein [PDIE], 81 g of rumen degradable protein [PDIN] per kg DM). Many of the study species contained secondary compounds, which can improve livestock health and livestock product quality. They can also reduce negative environmental impacts

Effets des doses des tanins de chêne ou de châtaignier sur le pH, la protéolyse et la digestibilité in vitro d’ensilages en micro-silos

Description of the subject. This short note documents the use of hydrolyzable tannins as silage additives to reduce proteolysis thanks to a laboratory-scale ensiling method. Objectives. To study oak (OTE) and chestnut tannin extract (CTE) dose responses on chemical composition, pH and ammoniacal nitrogen (N-NH3) content of silage. Method. A mixture of cocksfoot, white and red clovers was ensiled in vacuum packs, with OTE or CTE at doses of 0, 10, 30, 50 and 70 g.kg-1 DM. Results. Hydrolyzable tannin extracts decreased N-NH3 content of silage up to 18% (p < 0.05). For the investigated range of doses, OTE induced a linear decrease of N-NH3 content (R² = 0.76) whereas CTE resulted in a quadratic decrease (R² = 0.68). High doses of tannin extracts reduced in vitro organic matter digestibility (OMD) by 3% (p < 0.05). Conclusions. Both tannins reduced proteolysis in silos but highest doses induced a decrease in OMD