title: Invited review: Phenotypes to genetically reduce greenhouse gas emissions in dairying.
abstract: Phenotypes have been reviewed to select for lower-emitting animals in order to decrease the environmental footprint of dairy cattle products. This includes direct selection for breath measurements, as well as indirect selection via indicator traits such as feed intake, milk spectral data, and rumen microbial communities. Many of these traits are expensive or difficult to record, or both, but with genomic selection, inclusion of methane emission as a breeding goal trait is feasible, even with a limited number of registrations. At present, methane emission is not included among breeding goals for dairy cattle worldwide. There is no incentive to include enteric methane in breeding goals, although global warming and the release of greenhouse gases is a much-debated political topic. However, if selection for reduced methane emission became a reality, there would be limited consensus as to which phenotype to select for: methane in liters per day or grams per day, methane in liters per kilogram of energy-corrected milk or dry matter intake, or a residual methane phenotype, where methane production is corrected for milk production and the weight of the cow. We have reviewed the advantages and disadvantages of these traits, and discuss the methods for selection and consequences for these phenotypes.
authors.affiliation: Animal Breeding and Genomics Center, Wageningen UR Livestock Research, PO Box 338, NL-6700 AH Wageningen, the Netherlands. Electronic address: Yvette.deHaas@wur.nl.
authors.forename: Y
authors.initials: Y
authors.lastname: de Haas
authors.affiliation: Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637 Poznan, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Pszczola
authors.affiliation: Statistics, Informatics, and Applied Modeling Unit, Department of AgroBioChem, Gembloux Agro-Bio Tech, University of Liège, B-5030 Gembloux, Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Soyeurt
authors.affiliation: Animal and Veterinary Sciences, Scotland's Rural College, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, United Kingdom.
authors.forename: E
authors.initials: E
authors.lastname: Wall
authors.affiliation: Department of Molecular Biology and Genetics, Faculty of Science and Technology, Aarhus University, PO Box 50, DK-8830 Tjele, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Lassen
mesh_terms: D000818:Animals; D001947:Breeding; D002417:Cattle; D003612:Dairying; D004032:Diet / Q000662:veterinary; D005260:Female; D008697:Methane / Q000096:biosynthesis; D008892:Milk; D010641:Phenotype
chemical_list: D008697:Methane
keywords: dairy cattle; enteric methane; environmental phenotypes; genomic selection; greenhouse gases