Condensed tannins concentration of selected prairie legume forages as affected by phenological stages during two consecutive growth seasons in western Canada

Abstract

SummaryApproximately 4.9 to 5.0 M ha of cultivated marginal land in Western Canada is environmentally unsustainable and would benefit from conversion to permanent cover from current annual cropping. Since 2001, re-establishment of native grasslands into marginal cropland has been successfully accomplished using conventional seeding technology and a productive and sustainable pasture grazing system has been achieved. The current native grasslands are providing high quality forage for yearling grazing livestock, consistent biomass production (1100 kg of DM ha -1 ) and vegetative cover, acceptable average daily gains (0.4 to 0.8 kg d -1 ), improved biodiversity and additional environmental benefits to soil and water.

Effects of purple prairie clover (Dalea purpurea Vent.) on feed intake, nutrient digestibility and faecal shedding of Escherichia coli O157:H7 in lambs

“…Furthermore, the CT in the PPC was about 47 g/kg DM, but only trace amounts of CT were detected in the orts. The CT concentration in stems of PPC is lower than that of the leaves ranging from 10 to 16.8 g/kg DM (Jin et al, 2012;Li et al, 2014). If portions of PPC and Alf were consumed to a similar extent, there would be detectable amount of CT in the orts.…”

“…In addition, only traces CT were detected from orts that consisted of stem only (data not shown). It has been shown that majority of CT in PPC is in flower and leaves (Jin et al, 2012;Li et al, 2014) which were ingested by the animals. Accordingly, CT concentrations estimated in ingested diet (35-36 g/kg DM) was numerically higher than that estimated for diet offered (29 g/kg DM).…”

“…The CT concentration of PPC in this study (47 g/kg DM) was lower than that reported by others (89.8 g/kg DM, Jin et al, 2012;63.3 g/kg DM, Li et al, 2014), possibly due to differences in growth conditions among these studies. The PPC used in the current study was grown under irrigation at Lethbridge, AB, whilst that reported by Jin et al (2012) and Li et al (2014) was grown on dryland at Swift Current, SK. It has been shown that dry weather promotes the accumulation of CT in plants (Ushio and Adams, 2011;Li et al, 2014).…”

“…The PPC used in the current study was grown under irrigation at Lethbridge, AB, whilst that reported by Jin et al (2012) and Li et al (2014) was grown on dryland at Swift Current, SK. It has been shown that dry weather promotes the accumulation of CT in plants (Ushio and Adams, 2011;Li et al, 2014). In addition, only traces CT were detected from orts that consisted of stem only (data not shown).…”

“…is widely distributed across North American Grasslands and is considered an important palatable component of prairie hay (Posler et al, 1993;Schellenberg and Banerjee, 2002). Purple prairie clover has been shown to possess high CT concentrations (up to 94 g/kg DM) throughout the year (Berard et al, 2011;Jin et al, 2012;Li et al, 2014). In vitro studies showed that among tannins isolated from forages common to western Canada, only PPC CT possessed strong anti-E. coli O157:H7 and anti-generic E. coli activity (Wang et al, 2013a), a toxicity that was linked to disruption of the bacterial cell membrane (Liu et al, 2013).…”