Fecal crude protein content as an estimate for the digestibility of forage in grazing sheep

Wang, C.J.; Tas, B.M.; Glindemann, T.; Rave, Gerhard; Schmidt, L.; Weißbach, Friedrich; Susenbeth, A.

doi:10.1016/j.anifeedsci.2008.06.005

Cited by 66 publications

(45 citation statements)

References 18 publications

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“…Because herbivores rely on symbiotic gut microbes for digestion, and microbes contain high proportions of nitrogen (N), total faecal nitrogen (TFN) and metabolic faecal nitrogen (MFN, the faecal N not derived from undigested plant N) are proxies for the proportion of microbial matter in faeces; this proportion will be higher on more digestible diets [94], [95]. The principle of using TFN as a proxy for digestibility was experimentally validated in domestic cattle and sheep [19], [96], horses [97] as well as in more limited studies in wild sheep [98], deer [99], antelopes and equids [100], [101] and rodents [102]. In animals that ingest high amounts of plant secondary metabolites such as tannins, higher TFN values will reflect not only digestibility but also the fact that tannins bind protein, render it indigestible, and lead to higher faecal N excretions on lower-quality (i.e., high-tannin) diets [103]; TFN is therefore limited to animals not consuming significant amounts of tannin-containing forage.…”

Section: Characterising Diet Quality and Herbivore Adaptationsmentioning

confidence: 99%

Herbivory and Body Size: Allometries of Diet Quality and Gastrointestinal Physiology, and Implications for Herbivore Ecology and Dinosaur Gigantism

et al. 2013

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Digestive physiology has played a prominent role in explanations for terrestrial herbivore body size evolution and size-driven diversification and niche differentiation. This is based on the association of increasing body mass (BM) with diets of lower quality, and with putative mechanisms by which a higher BM could translate into a higher digestive efficiency. Such concepts, however, often do not match empirical data. Here, we review concepts and data on terrestrial herbivore BM, diet quality, digestive physiology and metabolism, and in doing so give examples for problems in using allometric analyses and extrapolations. A digestive advantage of larger BM is not corroborated by conceptual or empirical approaches. We suggest that explanatory models should shift from physiological to ecological scenarios based on the association of forage quality and biomass availability, and the association between BM and feeding selectivity. These associations mostly (but not exclusively) allow large herbivores to use low quality forage only, whereas they allow small herbivores the use of any forage they can physically manage. Examples of small herbivores able to subsist on lower quality diets are rare but exist. We speculate that this could be explained by evolutionary adaptations to the ecological opportunity of selective feeding in smaller animals, rather than by a physiologic or metabolic necessity linked to BM. For gigantic herbivores such as sauropod dinosaurs, other factors than digestive physiology appear more promising candidates to explain evolutionary drives towards extreme BM.

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Section: Characterising Diet Quality and Herbivore Adaptationsmentioning

confidence: 99%

Herbivory and Body Size: Allometries of Diet Quality and Gastrointestinal Physiology, and Implications for Herbivore Ecology and Dinosaur Gigantism

et al. 2013

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“…OMI was calculated from dOM and total faecal OM output, which was estimated from the TiO 2 concentration in faecal OM, assuming a faecal recovery of TiO 2 of 100% . dOM was estimated from CP (5N 3 6.25) content in faecal OM according to the regression equation of Wang et al (2009). The intake of digestible organic matter (DOMI) was calculated by multiplying OMI by dOM.…”

Section: Study Areamentioning

confidence: 99%

Effect of continuous v. daytime grazing on feed intake and growth of sheep grazing in a semi-arid grassland steppe

Müller

Liu

Wang

et al. 2012

Animal

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In the Inner Mongolian steppe, China, sheep generally graze during daytime and are kept in yards overnight. Hence, nutrients are not returned to the grassland, which might reduce its long-term productivity. Furthermore, the restricted grazing time may limit forage intake and thus the performance of sheep. The aim of this study was therefore to evaluate the impact of continuous 24-h grazing (CG) v. the common daytime grazing (DG) on herbage mass (HM), feed quality, feed organic matter intake (OMI) and live weight gain (LWG) of sheep in the Inner Mongolian steppe. Experiments were carried out from July to September, between 2005 and 2007 on two 2-ha plots per grazing treatment. Each month, the external faecal marker titanium dioxide (TiO 2 ) was orally administered to six sheep per plot on 10 consecutive days. Faecal grab samples were obtained from day 6 to 10 and analysed for CP concentrations to estimate digestibility of organic matter (dOM). Faecal TiO 2 concentrations were used to determine the total faecal output and hence OMI of sheep. Concomitant to faeces collection, HM and quality, as well as LWG of the animals were measured. HM and herbage quality did not differ between treatments. However, as the season progressed, concentrations of NDF, ADF and ADL increased, whereas HM and CP concentrations declined. HM and herbage quality parameters differed between years according to the annual precipitation. dOM was similar in CG (0.577) and DG (0.572) sheep, but it decreased from July (0.583) to September (0.558) and differed between years. Accordingly, the OMI of sheep was similar for both treatments across the entire grazing season and all study years. Although mean LWG differed between months and years, it was identical in CG (101.5 g/day) and DG sheep (101.8 g/day). Additional time on pasture during night does not increase feed intake or animal performance. Positive effects of a nutrient reflux on grassland productivity and herbage quality when animals remained on the plots overnight were not found, most likely because of the fact that sheep crowded together in one corner of the plots during darkness and faecal and urinary excretions were thus not evenly distributed across the entire pasture. Considering the risk of animal theft as well as the importance of sheep manure as fuel, the common penning of sheep at night seems to be an adequate management practice for pastoralists in the Inner Mongolian steppe.

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“…(1) with δ 13 C c = δ 13 C wool −S VW . So far published estimates of the shift for wool for mixed C3/C4 diets are missing as the shift of sheep wool from Männel et al (2007) was established for pure C3 grassland, which exhibits higher digestibility than that in Inner Mongolia (Wang et al, 2009). In principle, such factors could affect S VW .…”

Section: Estimation Of C4 Fractionmentioning

confidence: 99%

Large regional-scale variation in C3/C4 distribution pattern of Inner Mongolia steppe is revealed by grazer wool carbon isotope composition

Auerswald¹,

Wittmer²,

Männel³

et al. 2009

Biogeosciences

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Abstract. This work explored the spatial variation of C3/C4 distribution in the Inner Mongolia, P. R. China, steppe by geostatistical analysis of carbon isotope data of vegetation and sheep wool. Standing community biomass (n=118) and sheep wool (n=146) were sampled in a ∼0.2 Mio km 2 area. Samples from ten consecutive years (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) were obtained. Community biomass samples represented the carbon isotopic composition of standing vegetation on about 1000 m 2 ("community-scale"), whereas the spatio-temporal scale of wool reflected the isotope composition of the entire area grazed by the herd during a 1-yr period (∼5-10 km 2 , "farm-scale"). Pair wise sampling of wool and vegetation revealed a 13 C-enrichment of 2.7±0.7‰ (95% confidence interval) in wool relative to vegetation, but this shift exhibited no apparent relationships with environmental parameters or stocking rate. The proportion of C4 plants in aboveground biomass (P C4 , %) was estimated with a two-member mixing model of 13 C discrimination by C3 and C4 vegetation ( 13 3 and 13 4 , respectively), in accounting for the effects of changing 13 C in atmospheric CO 2 on sample isotope composition, and of altitude and aridity on 13 3 . P C4 averaged 19%, but the variation was enormous: full-scale (0% to 100%) at community-scale, and 0% to 85% at farm-scale. The farm-scale variation of P C4 exhibited a clear regional pattern over a range of ∼250 km. Importantly P C4 was significantly higher above the 22 • C isotherm of the warmest month, which was obtained from annual high-resolution Correspondence to: K. Auerswald (auerswald@wzw.tum.de) maps and averaged over the different sampling years. This is consistent with predictions from C3/C4 crossover temperature of quantum yield or light use efficiency in C3 and C4 plants. Still, temperature gradients accounted for only 10% of the farm-scale variation of P C4 , indicating that additional factors control P C4 on this scale.

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Fecal crude protein content as an estimate for the digestibility of forage in grazing sheep

Cited by 66 publications

References 18 publications

Herbivory and Body Size: Allometries of Diet Quality and Gastrointestinal Physiology, and Implications for Herbivore Ecology and Dinosaur Gigantism

Herbivory and Body Size: Allometries of Diet Quality and Gastrointestinal Physiology, and Implications for Herbivore Ecology and Dinosaur Gigantism

Effect of continuous v. daytime grazing on feed intake and growth of sheep grazing in a semi-arid grassland steppe

Large regional-scale variation in C3/C4 distribution pattern of Inner Mongolia steppe is revealed by grazer wool carbon isotope composition

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