Wheat pasture bloat dynamics, in vitro ruminal gas production, and potential bloat mitigation with condensed tannins1

Abstract

The aim of this study was to determine the effect of winter wheat (Triticum aestivum L.) forage growth stage, forage allowance, time of day, and commercial condensed tannins (CT) on steer bloat dynamics and in vitro ruminal gas production. Twenty-six crossbreed steers (Angus x Hereford x Salers; average initial BW = 194 +/- 26 kg) were used. Wheat forage allowances were either 18 kg (high forage allowance) and 6 kg (low forage allowance) of DM/(100 kg BW.d). In each bloat observation period, fresh wheat forage samples were hand-clipped to ground level in all study pastures for nutrient and in vitro ruminal gas production analyses. In vitro ruminal gas accumulation was measured at 0, 1, 2, 3, 4, 5, 6, and 12 h. Commercial CT was added at 0, 10, 15, and 20 mg of CT/g of DM. Bloat was scored once per week on two consecutive days at 0800 and 1500 during the vegetative stage and once every 2 wk during the reproductive stage of wheat development. Mean bloat score was calculated for each steer by time of day, stage of plant growth, and forage allowance. Bloat was detected in 65.8% of the observation periods. Average bloat scores were four and 2.5 times greater (P < 0.05) in cattle grazing at a high forage allowance than at a low forage allowance in the vegetative and reproductive growth phases of wheat, respectively. Rate of gas production was greater (P < 0.001) in the vegetative stage than in the reproductive stage. Steer bloat score was positively correlated with forage CP (r = 0.22; P < 0.05) and IVDMD (r = 0.32; P < 0.05). Rate of ruminal gas production was positively correlated (P < 0.01) to forage CP (r = 0.48), NPN (r = 0.40), soluble protein (r = 0.32), and IVDMD (r = 0.47). Conversely, negative correlations were found for forage DM (r = -0.20; P < 0.05), insoluble protein (r = -0.40), NDF (r = -0.69), and forage height (r = -0.49; P < 0.01) on the rate of ruminal gas production. Addition of CT at levels greater than 10 mg of CT/g of DM decreased (P < 0.05) the rate of in vitro ruminal gas and methane gas production after 5 h of incubation. Wheat pasture bloat is a complex disorder that varies across an array of forage and environmental conditions. Condensed tannins have the potential to decrease bloat by altering ruminal gas production and soluble protein digestibility from wheat forage.

Use of ‘natural’ products as alternatives to antibiotic feed additives in ruminant production

“…Severity of bloat legumes is thus lowered in the presence of CTs since gas formation and microbial protein degradation are both decreased (Jones and Lyttleton, 1971;Waghorn and Jones 1989;Min et al, 2003Min et al, , 2005. Tannins can also destabilise the structure of plant protein foams by altering surfactant forces in the ruminal liquid phase (Tanner et al, 1995).…”

In vivo and in situ measurements of the digestive characteristics of sainfoin in comparison with lucerne fed to sheep as fresh forages at two growth stages and as hay

“…This rapid degradation has two major effects: (1) a large portion of the ammonia produced is absorbed and converted into urea, which is then excreted in the urine, resulting in poor nitrogen (N) use efficiency by the rumen microorganisms and (2) some of the soluble proteins released in the rumen can form foams, which, if allowed to persist, may cause bloat (Jones et al, 1973;Min et al, 2005).…”

The role of condensed tannins in ruminant animal production: advances, limitations and future directions

“…The effects of CT from various forage legumes on RDP are well studied, but the relationship is blurred by inconsistent experimental methodologies. In general, inclusion of dietary CT shifts the site of N metabolism and absorption by reducing both the rate and extent of ruminal protein degradation (Coblentz and Grabber, 2013) and NH 3 concentrations (McNabb et al, 1996;Min et al, 2005;Agle et al, 2010), increasing postruminal amino acid flow (Waghorn et al, 1994b). Results from our research team (Naumann et al, 2014c) suggested that we can use a screening tool to predict the potential of structurally diverse mixtures of CT to bind protein based on the concentration of protein-precipitable polyphenols ( Figure 5).…”