Nutrient requirements of beef cattle

The Statistics of Canada

Flavonoids are secondary metabolites involved in several aspects of plant development and defence. They colour fruits and flowers, favouring seed and pollen dispersal, and contribute to plant adaptation to environmental conditions such as cold or UV stresses, and pathogen attacks. Because they affect the quality of flowers (for horticulture), fruits and vegetables, and their derivatives (colour, aroma, stringency, etc.), flavonoids have a high economic value. Furthermore, these compounds possess pharmaceutical properties extremely attractive for human health. Thanks to easily detectable mutant phenotypes, such as modification of petal pigmentation and seeds exhibiting transparent testa, the enzymes involved in the flavonoid biosynthetic pathway have been characterized in several plant species. Conserved features as well as specific differences have been described. Regulation of structural gene expression appears tightly organized in a spatial and temporal way during plant development, and is orchestrated by a ternary complex involving transcription factors from the R2R3-MYB, basic helix-loop-helix (bHLH), and WD40 classes. This MYB-bHLH-WD40 (MBW) complex regulates the genes that encode enzymes specifically involved in the late steps of the pathway leading to the biosynthesis of anthocyanins and condensed tannins. Although several genes encoding transcription factors from these three families have been identified, many gaps remain in our understanding of the regulation of this biosynthetic pathway, especially about the respective roles of bHLH and WD40 proteins. A better knowledge of the regulatory mechanisms of the flavonoid pathway is likely to favour the development of new biotechnological tools for the generation of value-added plants with optimized flavonoid content.

/pdf/recent-advances-in-the-transcriptional-regulation-of-the-38kdsk8jcj.pdf

Recent advances in the transcriptional regulation of the flavonoid biosynthetic pathway

This paper examines the nutritional and veterinary effects of tannins on ruminants and makes some comparisons with non-ruminants. Tannin chemistry per se is not covered and readers are referred to several excellent reviews instead: (a) Okuda T et al. Heterocycles 30:1195-1218 (1990); (b) Ferreira D and Slade D. Nat Prod Rep 19:517-541 (2002); (c) Yoshida T et al. In Studies in Natural Product Chemistry. Elsevier Science, Amsterdam, pp. 395-453 (2000); (d) Khanbabaee K and van Ree T. Nat Prod Rep 18:641-649 (2001); (e) Okuda et al. Phytochemistvy 55:513-529 (2000). The effects of tannins on rumen micro-organisms are also not reviewed, as these have been addressed by others: (a) McSweeney CS et al. Anim Feed Sci Technol 91:83-93 (2001); (b) Smith AH and Mackie RI. Appl Environ Microbiol 70:1104-1115 (2004). This paper deals first with the nutritional effects of tannins in animal feeds, their qualitative and quantitative diversity, and the implications of tannin-protein complexation. It then summarises the known physiological and harmful effects and discusses the equivocal evidence of the bioavailability of tannins. Issues concerning tannin metabolism and systemic effects are also considered. Opportunities are presented on how to treat feeds with high tannin contents, and some lesser-known but successful feeding strategies are highlighted. Recent research has explored the use of tannins for preventing animal deaths from bloat, for reducing intestinal parasites and for lowering gaseous ammonia and methane emissions. Finally, several tannin assays and a hypothesis are discussed that merit further investigation in order to assess their suitability for predicting animal responses. The aim is to provoke discussion and spur readers into new approaches. An attempt is made to synthesise the emerging information for relating tannin structures with their activities. Although many plants with high levels of tannins produce negative effects and require treatments, others are very useful animal feeds. Our ability to predict whether tannin-containing feeds confer positive or negative effects will depend on interdisciplinary research between animal nutritionists and plant chemists. The elucidation of tannin structure-activity relationships presents exciting opportunities for future feeding strategies that will benefit ruminants and the environment within the contexts of extensive, semi-intensive and some intensive agricultural systems. (c) 2006 Society of Chemical Industry

Unravelling the conundrum of tannins in animal nutrition and health

The goal of this review was to analyze published data related to mitigation of enteric methane (CH 4 ) emissions from ruminant animals to document the most effective and sustainable strategies. Increas- ing forage digestibility and digestible forage intake was one of the major recommended CH 4 mitigation practices. Although responses vary, CH 4 emissions can be reduced when corn silage replaces grass silage in the diet. Feeding legume silages could also lower CH 4 emissions compared to grass silage due to their lower fiber concentration. Dietary lipids can be effec- tive in reducing CH 4 emissions, but their applicabil- ity will depend on effects on feed intake, fiber digest- ibility, production, and milk composition. Inclusion of concentrate feeds in the diet of ruminants will likely decrease CH 4 emission intensity (Ei; CH 4 per unit animal product), particularly when inclusion is above 40% of dietary dry matter and rumen function is not impaired. Supplementation of diets containing medium to poor quality forages with small amounts of concen- trate feed will typically decrease CH 4 Ei. Nitrates show promise as CH 4 mitigation agents, but more studies are needed to fully understand their impact on whole-farm greenhouse gas emissions, animal productivity, and animal health. Through their effect on feed efficiency and rumen stoichiometry, ionophores are likely to have a moderate CH 4 mitigating effect in ruminants fed high-grain or mixed grain-forage diets. Tannins may also reduce CH 4 emissions although in some situations intake and milk production may be compromised. Some direct-fed microbials, such as yeast-based products, might have a moderate CH 4 -mitigating effect through increasing animal productivity and feed efficiency, but the effect is likely to be inconsistent. Vaccines against rumen archaea may offer mitigation opportunities in the future although the extent of CH 4 reduction is like- ly to be small and adaptation by ruminal microbes and persistence of the effect is unknown. Overall, improv- ing forage quality and the overall efficiency of dietary nutrient use is an effective way of decreasing CH 4 Ei. Several feed supplements have a potential to reduce CH 4 emission from ruminants although their long-term effect has not been well established and some are toxic or may not be economically feasible.

/pdf/special-topics-mitigation-of-methane-and-nitrous-oxide-3picl514fh.pdf

Special topics--Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options.

Condensed tannins (CT) are polyphenolic secondary plant products that are widespread in the plant kingdom. By definition, CT bind to protein and are regarded as "antinutritional" compounds which re...

A review of the effects of forage condensed tannins on ruminal fermentation and bloat in grazing cattle

Fenugreek (Trigonella foenum-graecum L.) is extensively used as a spice in India and the Mediterranean region and is known to possess a number of medicinal properties. Steroidal sapogenins and mucilaginous fibers present in the seed and leaves of this legume plant contribute to anti-diabetic and hypocholesterolaemic properties attributed to the plant. In recent years selected genotypes of this species have formed a niche crop that produces high yields of bloat-free forage that can increase both beef and milk production in semiarid regions of western Canada. Fenugreek genotypes tested in western Canada have demonstrated genetic variability for biomass production and nutraceutical properties indicating that there is much potential for enhancing the properties desired by agricultural and nutraceutical industries in this region. This paper reviews the history, culture and documented medicinal, agronomic and environmental value of fenugreek as well as discusses future potential of this crop for use in semiarid regions of North America.

Fenugreek, an Alternative Crop for Semiarid Regions of North America

Mixtures of steroidal sapogenins isolated from the seed and combined aerial parts (foliage) of fenugreek (cultivar Amber) have been examined by capillary column gas chromatography with mass spectral and flame ionization detectors. Diosgenin [(25R)-spirost-5-en-3β-ol] was the major component in seed and foliage extracts hydrolyzed with hydrochloric acid. Yamogenin also appeared to be present. Tigogenin, neotigogenin, smilagenin, and sarsasapogenin were identified in the extracts. Dihydroxy steroidal sapogenins, tentatively identified as yuccagenin, gitogenin, and neogitogenin, were detected as minor components in hydrolyzed extracts from seed. A gas chromatographic method based on the use of an internal standard and a column of HP-5MS was developed to determine diosgenin in Amber fenugreek. Expressed on a dry weight basis, mean levels of diosgenin in seed were 0.54%. In field-grown foliage sampled during a season at 9, 15, and 19 weeks postseeding, diosgenin levels were 0.16, 0.07, and 0.07%, respectively....

Analysis of Steroidal Sapogenins from Amber Fenugreek (Trigonella foenum-graecum) by Capillary Gas Chromatography and Combined Gas Chromatography/Mass Spectrometry†

Legume forage is the most economical source of nutrients for ruminants. Sainfoin (Onobrychis viciifolia Scop.) is high nutritive forage growing worldwide and possesses polyphenolics including condensed tannins (CT) that contribute to some of its superior nutritional properties such as improved protein utilization, bloat-free, and anthelmintic characteristics. This review attempts to capture the latest research in characterizing the impact of polyphenolics on the feeding value of sainfoin with an emphasis on CT. Sainfoin contains a diverse array of polyphenolics and its CT content declines as the plant matures, with an increase in the degree of polymerization and a decreasing proportion of prodelphinidins, resulting in a reduction in biological activity. This forage is best to be utilized between bud to flowering stage to balance the biological activity of CT and biomass yield. Incorporation of sainfoin into alfalfa (Medicago sativa L.) pasture has been effective in reducing alfalfa pasture bloat due to the presence of CT. New sainfoin populations suitable for survival in high-performance grazing systems have been developed and have demonstrated superior anti bloat activity due to the increased grazing persistence. Fresh sainfoin is the best feed for cattle for maximum effect of CT, but if it needs to be preserved then hay would be better than silage in terms of preservation of the biological activity of CT. Although greater CT content is desirable for this forage in terms of antibloat and antiparasitic activity, sainfoin with CT concentration at about 50 g kg⁻¹ dry matter (DM) offer the best feed value.

Condensed Tannins in Sainfoin: Composition, Concentration, and Effects on Nutritive and Feeding Value of Sainfoin Forage

Wood ash is considered a waste product that accumulates from the burning of wood waste for energy production. Field studies were conducted on acidic Boralf and Eutrochrept soils and in the greenhouse using material from the surface of these soils in randomized complete block designs to evaluate the effectiveness of wood ash as a liming material for improving crop production. For the greenhouse study, soil was treated with the equivalent of 0 to 200 t ha -1 (w/w) wood ash. Barley (Hordeum vulgare L.) yielded up to 50% more dry matter in this study. Based on these findings, a 3-yr field study was done to determine the effect of single applications of 6,12.5, and 25 t ha -1 wood ash to Boralf soils in central Alberta. Significant increases in barley dry matter and grain yield and oil seed yields of canola (Brassica rapa L.) were observed when soil was supplemented with 12.5 or 25 t ha -1 along with N fertilizer. Increases of 72 and 50% in barley dry matter and grain yield were observed while canola oilseed yield increased 124% due to wood ash application. Applications up to 25 t ha -1 did not have a deleterious effect on biomass or seed production in barley or canola crops. Results show that land application of wood ash increased pH and nutrient content of acid soils while having a beneficial effect on crop production. Land application of wood ash can provide timber companies with a viable alternative to landfill disposal.

Surya Acharya

Papers

A review of the effects of forage condensed tannins on ruminal fermentation and bloat in grazing cattle

Fenugreek, an Alternative Crop for Semiarid Regions of North America

Analysis of Steroidal Sapogenins from Amber Fenugreek (Trigonella foenum-graecum) by Capillary Gas Chromatography and Combined Gas Chromatography/Mass Spectrometry†

Condensed Tannins in Sainfoin: Composition, Concentration, and Effects on Nutritive and Feeding Value of Sainfoin Forage

Barley Biomass and Grain Yield and Canola Seed Yield Response to Land Application of Wood Ash