Effects of Season, Grazing Intensity and Diet Composition on the Radiocaesium Intake by Sheep on Re-Seeded Hill Pasture

Salt, C. A.; Mayes, R. W.; Elston, David A.

doi:10.2307/2404507

Cited by 48 publications

(24 citation statements)

References 27 publications

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“…N-alkane extraction and analysis were carried out as described by Mayes et al (1986), with modifications by Salt et al (1992) and tetratriacontane (C 34 ) was used as an internal standard. The extracted samples were analysed for n-alkanes (C 27 to C 36 ) using a GC (Carlo Erba HRGC Mega 2 series, CE Instruments, Milan, Italy) fitted to a flame-ionising detector, using helium as the carrier gas.…”

Section: Chemical Analysismentioning

confidence: 99%

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Bezabih

Pellikaan

Tolera

et al. 2011

Animal

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Plant cuticular n-alkanes have been successfully used as markers to estimate diet composition and intake of grazing herbivores. However, additional markers may be required under grazing conditions in botanically diverse vegetation. This study was conducted to describe the n-alkane profiles and the carbon isotope enrichment of n-alkanes of common plant species from the Mid Rift Valley rangelands of Ethiopia, and evaluate their potential use as nutritional markers. A total of 23 plant species were collected and analysed for long-chain n-alkanes ranging from heptacosane to hexatriacontane (C 27 to C 36 ), as well as their carbon isotopic ratio ( 13 C/ 12 C). The analysis was conducted by gas chromatography/combustion isotope ratio mass spectrometry following saponification, extraction and purification. The isotopic composition of the n-alkanes is reported in the delta notation (d 13 C) relative to the Vienna Pee Dee Belemnite standard. The dominant n-alkanes in the species were C 31 (mean 6 s.d., 283 6 246 mg/ kg dry matter) and C 33 (149 6 98 mg/kg dry matter). The carbon isotopic enrichment of the n-alkanes ranged from 219.37% to 237.40%. Principal component analysis was used to examine interspecies differences based on n-alkane profiles and the carbon isotopic enrichments of individual n-alkanes. Large variability among the pasture species was observed. The first three principal components explained most of the interspecies variances. Comparison of the principal component scores using orthogonal procrustes rotation indicated that about 0.84 of the interspecies variances explained by the two types of data sets were independent of each other, suggesting that the use of a combination of the two markers can improve diet composition estimations. It was concluded that, while the n-alkane profile of the pasture species remains a useful marker for use in the study region, the d 13 C values of n-alkanes can provide additional information in discriminating diet components of grazing animals.

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Section: Chemical Analysismentioning

confidence: 99%

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Bezabih

Pellikaan

Tolera

et al. 2011

Animal

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“…The DM content of feed offered, feed refused and faeces was determined by forced-air oven drying at 708C for 48 h. Organic matter (OM) was determined as the weight lost upon ashing feeds and faeces at 5508C in a muffle furnace for 24 h. Alkanes and LCOH were extracted from samples using a direct saponification procedure followed by column chromatography (Ali et al, 2004;Dove and Mayes, 2006) and quantified by gas chromatography using a modification (Salt et al, 1992) of the method of Mayes et al (1986) for alkanes and for LCOH, the method of Ali et al (2004) except that LCOH were not derivatised prior to chromatography. Tetracosane (C24 alkane) and tetratriacontane (C34 alkane) were used as internal standards for alkanes and heptacosanol (C27OH) as the internal standard for LCOH.…”

Section: Analytical Proceduresmentioning

confidence: 99%

Using the alkanes and long-chain alcohols of plant cuticular wax to estimate diet composition and the intakes of mixed forages in sheep consuming a known amount of alkane-labelled supplement

Dove

Charmley

2008

Animal

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In a feeding trial with 24 sheep, we used the alkanes, long-chain alcohols (LCOH) or both of these plant wax markers, to estimate the diet composition of animals offered diets comprising alkane-labelled cottonseed meal (CSM) together with up to four forages. The diets used were: Diet 1 subterranean clover (Trifolium subterraneum); Diet 2 subterranean clover 1 phalaris (Phalaris aquatica); Diet 3 subterranean clover, phalaris 1 annual ryegrass (Lolium rigidum); and Diet 4 subterranean clover, phalaris, annual ryegrass 1 wheat straw (Triticum aestivum). Estimates of diet composition were made following correction of faecal alkane or LCOH concentrations for incomplete faecal recovery, using recovery estimates derived from individual animals, mean recoveries for a given dietary treatment or grand mean recoveries. Estimated dietary proportions of CSM and known intakes of CSM were used to estimate forage intake. The LCOH concentrations of the diet components were much higher than their alkane concentrations, especially for phalaris. Multivariate analyses showed that the discriminatory information provided by the LCOH was additional to that provided by the alkanes, and that a combination of (LCOH 1 alkanes) discriminated better between diet components than either class of marker alone. Faecal recoveries of LCOH increased with increasing carbon-chain length; there were no differences in recovery attributable to diet. The most accurate estimates of diet composition were obtained with the combination of (LCOH 1 alkanes). Estimates of diet composition based on LCOH alone were not as good as alkanes alone, due to the high correlation between the LCOH profiles of phalaris and ryegrass. Total grass content of the diet was very accurately estimated using LCOH. Diet composition estimates provided estimates of whole-diet digestibility, which did not differ from the measured values. Trends in the accuracy of forage intake estimates reflected those found with diet composition and almost two-thirds of estimates based on (LCOH 1 alkanes) had lower error than those found with alkanes alone. The results confirm that supplements labelled with plant wax components can be used to estimate forage intake, and also show that the LCOH are useful markers for estimating diet composition. Intakes were also computed using a combination of natural LCOH concentrations in the diet and the daily dose rate of even-chain alkanes administered by intra-ruminal device. Differences between intakes so estimated and the measured intakes were closely related to the difference in faecal recovery between the LCOH/alkane pair used to estimate intake, by an amount close to that expected on theoretical grounds. It is concluded that the use of plant wax LCOH, especially in combination with alkanes, will result in improved estimates of diet composition and intake in grazing animals.

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“…The ground samples were analysed for n-alkane concentrations using gas chromatography, according to the method described in Mayes, Lamb et al (1986) with the modi®cations reported in Salt, Mayes & Elston (1992). The concentrations of all n-alkanes between C 21 and C 35 were determined, with exception of the concentrations of C 22 and C 34 because they were used as internal standards.…”

Section: Composition Of the Dietmentioning

confidence: 99%

Seasonal and spatial variation in the diet of the wild rabbit (Oryctolagus cuniculus L.) in Portugal

Martins¹,

Milne²,

Rego³

2002

Journal of Zoology

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The seasonal and spatial pattern of diet composition of a population of wild rabbits Oryctolagus cuniculus L. occupying a southern Portuguese montado was estimated using the n-alkane technique. The diet was analysed in terms of components that are relevant to habitat management. The dietary categories considered were gum cistus leaves and¯owers, cork oak and holm oak seedlings and acorns, cereals, olive tree regrowth and grass-forb species. The objectives were to assess the changes in diet across seasons in relation to the reproductive cycle of the rabbits, and to relate these changes to herbaceous biomass availability and to habitat structure, in terms of density of scrub cover and accessibility to arable crops. The results demonstrated that the diet was dominated by grass-forbs, and cereals when they were available. Browse was an important component of the diet and became more important in a year of low herbaceous biomass availability and in areas dominated by dense scrub. A similar phenomenon was observed in relation to consumption of acorns in winter. Seasonal and spatial variation in diet composition suggested a strategy aimed at maintaining a high quality diet. This was supported by the observed high dry matter digestibility of the diet during most of the year. The relevance of growing arable crops and providing fodder, as a means of increasing the carrying capacity of montados for rabbits and protecting the natural regeneration of trees, is discussed.

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Effects of Season, Grazing Intensity and Diet Composition on the Radiocaesium Intake by Sheep on Re-Seeded Hill Pasture

Cited by 48 publications

References 27 publications

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Using the alkanes and long-chain alcohols of plant cuticular wax to estimate diet composition and the intakes of mixed forages in sheep consuming a known amount of alkane-labelled supplement

Seasonal and spatial variation in the diet of the wild rabbit (Oryctolagus cuniculus L.) in Portugal

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