Validating the n-alkane technique for determining herbage dry matter intake in sheep offered perennial ryegrass harvested at varying growth stages and seasons

McGovern, Fiona; Garry, B.; Creighton, P.; Galvin, N.; Hennessy, Deirdre; Kennedy, E.; McHugh, N.; O’Donovan, M.; Beecher, Marion

doi:10.1016/j.anifeedsci.2021.115025

Cited by 2 publications

(2 citation statements)

References 24 publications

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“…DMI was estimated on hoggets (summer and autumn), lactating (10 wk postpartum), and dry (18 wk postpartum) ewes, grazing a predominantly perennial ryegrass-based sward using the n -alkane technique as described by Mayes et al (1986) and validated under Irish conditions for grazing sheep by McGovern et al (2021) . Briefly, each animal was administered an n -alkane bolus containing 132 mg of C 32 -alkane ( n -dotriacontane) in the morning for 11 consecutive days.…”

Section: Methodsmentioning

confidence: 99%

Methane output across life stages in sheep, how it differs from lambs to adult ewes using portable accumulation chambers

Connor,

McHugh,

Dunne

et al. 2024

Journal of Animal Science

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Methane (CH4) produced from enteric fermentation is a potent greenhouse gas produced by ruminant animals. Multiple measurements are required across life stages to develop an understanding of how CH4 output changes throughout the animal’s lifetime. The objectives of the current study were to estimate CH4 output across life stages in sheep and to investigate the relationship between CH4 output and dry matter intake (DMI). Data were generated on a total of 266 female Suffolk and Texel animals. Methane and carbon dioxide (CO2) output, estimated using portable accumulation chambers, and DMI, estimated using the n-alkane technique outdoors and using individual penning indoors, were quantified across the animal’s life stage; as lambs (< 12 months), nulliparous hoggets (12 to 24 months) and ewes (primiparous or greater; > 24 months). Ewes were further classified as pregnant, lactating and dry (non-pregnant and non-lactating). Multiple measurements were taken within and across life stages on the same animals. A linear mixed model was used to determine if CH4 and CO2 output differed across life stages and using a separate linear mixed model the factors associated with CH4 output within each life stage were also investigated. Methane, CO2 output and DMI differed by life stage (P<0.05), with lactating ewes producing the greatest amount of CH4 (25.99 g CH4/day) and CO2 (1711.6 g CO2/day), while also having the highest DMI (2.18 kg dry matter/day). Methane output differed by live-weight of the animals across all life stages (P<0.001). As ewe body condition score increased CH4 output declined (P<0.05). Correlations between CH4 output measured across life stages ranged from 0.26 (SE 0.08; lambs and lactating ewes) to 0.59 (SE 0.06; hoggets and pregnant ewes), while correlations between CO2 output measured across life stages ranged from 0.12 (SE 0.06; lambs and hoggets) to 0.65 (SE 0.06; hoggets and lactating ewes). Dry matter intake was moderately correlated with CH4 (0.44; SE 0.04) and CO2 output (0.59; SE 0.03). Results from this study provide estimates of CH4 output across life stages in a pasture-based sheep production system and offer valuable information for the national inventory and the marginal abatement cost curve on the optimum time to target mitigation strategies.

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Section: Methodsmentioning

confidence: 99%

Methane output across life stages in sheep, how it differs from lambs to adult ewes using portable accumulation chambers

Connor,

McHugh,

Dunne

et al. 2024

Journal of Animal Science

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“…Measuring the dry matter intake (DMI) of grazing animals is a challenging task, but one that is crucial for evaluating the feed conversion efficiency of individual animals. Although various methods have been reported for estimating the DMI of different ruminants [1], the n-alkane technique is the most accurate for individual animals [2,3]. Due to the widespread presence of epicuticular wax on the adaxial surface of grass species and the quasi-indigestibility of long-chain alkanes present in the wax, the possibility of estimating herbage intake in ruminants using dosed C32 and natural C33 n-alkanes was demonstrated over three decades ago [4].…”

Section: Introductionmentioning

confidence: 99%

A Simplified Alkane Analysis Method for the Determination of Herbage Intake by Dairy Cows

et al. 2022

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An accurate dry matter intake (DMI) measurement method is of great importance for determining the performance of dairy cows. While n-alkane technique is commonly used to estimate the DMI of ruminants, the protocols used to measure alkanes are complex, time consuming and low throughput. Herein we present a simplified and miniaturised protocol that combines a smaller sample matrix (60 mg of faeces or herbage), a shorter (3 h) saponification step and a direct purification of the crude extract by filtration through silica powder or mixing with silica powder prior to GC-FID analysis. In addition to a much higher throughput compared with the existing methods, by skipping the commercial SPE columns and reducing the organic solvent volume, our miniaturised protocol should significantly reduce the sample processing cost and is thus suitable for alkane determination for large-scale experiments.

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Validating the n-alkane technique for determining herbage dry matter intake in sheep offered perennial ryegrass harvested at varying growth stages and seasons

Cited by 2 publications

References 24 publications

Methane output across life stages in sheep, how it differs from lambs to adult ewes using portable accumulation chambers

Methane output across life stages in sheep, how it differs from lambs to adult ewes using portable accumulation chambers

A Simplified Alkane Analysis Method for the Determination of Herbage Intake by Dairy Cows

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