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Genetic parameters for residual feed intake, methane emissions, and body composition in New Zealand maternal sheep

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posted on 2023-05-03, 19:53 authored by Patricia Johnson, Sharon HickeySharon Hickey, Kevin Knowler, Janine Wing, Brooke BrysonBrooke Bryson, Melanie Hall, Arjan JonkerArjan Jonker, Peter JanssenPeter Janssen, Ken Dodds, John McEwanJohn McEwan, Suzanne RoweSuzanne Rowe
There is simultaneous interest in improving the feed efficiency of ruminant livestock and reducing methane (CH4) emissions. The relationship (genetic and phenotypic) between feed efficiency (characterized as residual feed intake: RFI) and greenhouse gases [methane (CH4) and carbon dioxide (CO2)] traits in New Zealand (NZ) maternal sheep has not previously been investigated, nor has their relationship with detailed estimates of body composition. To investigate these relationships in NZ maternal sheep, a feed intake facility was established at AgResearch Invermay, Mosgiel, NZ in 2015, comprising automated feeders that record individual feeding events. Individual measures of feed intake, feeding behavior (length and duration of eating events), and gas emissions (estimated using portable accumulation chambers) were generated on 986 growing maternal ewe lambs sourced from three pedigree recorded flocks registered in the Sheep Improvement Limited database (www.sil.co.nz). Additional data were generated from a subset of 591 animals for body composition (estimated using ultrasound and computed tomography scanning). The heritability estimates for RFI, CH4, and CH4/(CH4+CO2) were 0.42 ± 0.09, 0.32 ± 0.08, and 0.29 ± 0.06, respectively. The heritability estimates for the body composition traits were high for carcass lean and fat traits; for example, the heritability for visceral fat (adjusted for body weight) was 0.93 ± 0.19. The relationship between RFI and CH4 emissions was complex, and although less feed eaten will lead to a lowered absolute amount of CH4 emitted, there was a negative phenotypic and genetic correlation between RFI and CH4/(CH4+CO2) of −0.13 ± 0.03 and −0.41 ± 0.15, respectively. There were also genetic correlations, that were different from zero, between both RFI and CH4 traits with body composition including a negative correlation between the proportion of visceral fat in the body and RFI (−0.52 ± 0.16) and a positive correlation between the proportion of lean in the body and CH4 (0.54 ± 0.12). Together the results provide the first accurate estimates of the genetic correlations between RFI, CH4 emissions, and the body composition (lean and fat) in sheep. These correlations will need to be accounted for in genetic improvement programs.

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Rights statement

© 2022 Johnson, Hickey, Knowler, Wing, Bryson, Hall, Jonker, Janssen, Dodds, McEwan and Rowe. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

Frontiers Media S.A.

Journal title

Frontiers in Genetics

ISSN

1664-8021

Citation

Johnson, P. L., Hickey, S., Knowler, K., Wing, J., Bryson, B., Hall, M., Jonker, A., Janssen, P. H., Dodds, K. G., McEwan, J. C., & Rowe, S. J. (2022). Genetic parameters for residual feed intake, methane emissions, and body composition in New Zealand maternal sheep. Frontiers in Genetics, 13, 911639. https://doi.org/10.3389/fgene.2022.911639

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