Estimates of repeatability and heritability of methane production in sheep using portable accumulation chambers

Goopy, John P; Robinson, Dorothy L; Woodgate, Reg; Donaldson, A; Oddy, Hutton; Vercoe, P E; Hegarty, Roger

doi:10.1071/AN13370

Author(s)

Goopy, John P

Robinson, Dorothy L

Woodgate, Reg

Donaldson, A

Oddy, Hutton

Vercoe, P E

Hegarty, Roger

Publication Date

2016

Abstract

This study was designed to screen a large number of sheep to identify individuals with high and low methane (CH4) production, and to estimate repeatability and heritability of CH₄ emissions in sheep, utilising portable accumulation chambers (PAC) designed for in-field use. Mature ewes (n = 710) selected from a research flock with known sires had their CH₄ production over 1 h measured in PAC [CH₄(g1h)]. Individuals with High (n = 103) or Low (n = 104) CH₄ (g1h), adjusted for liveweight (LW), were selected and re-measured on three occasions 1-4 months later, at another site with more abundant and better quality pasture. Mean of the selected (207) ewes CH₄ (g1h) emissions were ~50% higher than at the first measurement site (0.66 g vs 0.42 g).LW was a significant correlate of CH₄ production (r = 0.47). Correlations between CH₄ (g1h) for the three PAC measurements at Site 2, before adjusting for LW ranged from 0.44 to 0.55. After adjusting for the effect of LW, repeatability was 0.33 at the first and 0.43 at the second site. The correlation between estimates of an animal's emissions at the first and second sites, adjusted for LW, was 0.24. Initial CH₄ production of the selected High group was 32% greater than the Low group (P < 0.0001). On re-measurement there was still a significant difference (9-15%, P < 0.006) between Low and High groups. The initial estimate of heritability of CH₄ (g1h), based on variation between the ewes' sires (0.13), was not maintained across the two sites. This may be due to genotype x environment interactions. We postulate that aspects of rumen physiology, which modulate CH₄ production, could be expressed differently in different nutritional environments. Our results indicate that field use of PAC to screen sheep populations for CH₄ production is both robust and repeatable. However, further investigations are required into the relationship between CH₄ output of individual animals in PAC compared with the more controlled conditions in respiration chambers.

Citation

Animal Production Science, 56(1), p. 116-122

ISSN

1836-5787

1836-0939

Link

https://hdl.handle.net/1959.11/18812

Language

en

Publisher

CSIRO Publishing

Title

Estimates of repeatability and heritability of methane production in sheep using portable accumulation chambers

Type of document

Journal Article

Entity Type

Publication

Author(s)	Goopy, John P Robinson, Dorothy L Woodgate, Reg Donaldson, A Oddy, Hutton Vercoe, P E Hegarty, Roger
Publication Date	2016
Abstract	This study was designed to screen a large number of sheep to identify individuals with high and low methane (CH4) production, and to estimate repeatability and heritability of CH₄ emissions in sheep, utilising portable accumulation chambers (PAC) designed for in-field use. Mature ewes (n = 710) selected from a research flock with known sires had their CH₄ production over 1 h measured in PAC [CH₄(g1h)]. Individuals with High (n = 103) or Low (n = 104) CH₄ (g1h), adjusted for liveweight (LW), were selected and re-measured on three occasions 1-4 months later, at another site with more abundant and better quality pasture. Mean of the selected (207) ewes CH₄ (g1h) emissions were ~50% higher than at the first measurement site (0.66 g vs 0.42 g).LW was a significant correlate of CH₄ production (r = 0.47). Correlations between CH₄ (g1h) for the three PAC measurements at Site 2, before adjusting for LW ranged from 0.44 to 0.55. After adjusting for the effect of LW, repeatability was 0.33 at the first and 0.43 at the second site. The correlation between estimates of an animal's emissions at the first and second sites, adjusted for LW, was 0.24. Initial CH₄ production of the selected High group was 32% greater than the Low group (P < 0.0001). On re-measurement there was still a significant difference (9-15%, P < 0.006) between Low and High groups. The initial estimate of heritability of CH₄ (g1h), based on variation between the ewes' sires (0.13), was not maintained across the two sites. This may be due to genotype x environment interactions. We postulate that aspects of rumen physiology, which modulate CH₄ production, could be expressed differently in different nutritional environments. Our results indicate that field use of PAC to screen sheep populations for CH₄ production is both robust and repeatable. However, further investigations are required into the relationship between CH₄ output of individual animals in PAC compared with the more controlled conditions in respiration chambers.
Citation	Animal Production Science, 56(1), p. 116-122
ISSN	1836-5787 1836-0939
Link	https://hdl.handle.net/1959.11/18812
Language	en
Publisher	CSIRO Publishing
Title	Estimates of repeatability and heritability of methane production in sheep using portable accumulation chambers
Type of document	Journal Article
Entity Type	Publication

Estimates of repeatability and heritability of methane production in sheep using portable accumulation chambers

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