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Genetics of Alternative Definitions of Feed Efficiency in Grazing Lactating Dairy Cows

Thursday, August 21, 2014
Posters (The Westin Bayshore)
Alan M Hurley , Teagasc, Moorepark, Fermoy, Co. Cork, Ireland
Sinead McParland , Teagasc, Moorepark, Fermoy, Co. Cork, Ireland
Emer Kennedy , Teagasc, Moorepark, Fermoy, Co. Cork, Ireland
Eva Lewis , Teagasc, Moorepark, Fermoy, Co. Cork, Ireland
Michael O'Donovan , Teagasc, Moorepark, Fermoy, Co. Cork, Ireland
Nicolas Lopez-Villalobos , Massey University, Palmerston North, New Zealand
Donagh P Berry , Animal & Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland
Abstract Text:

ABSTRACT:

ABSTRACT: The objective of this study was to derive alternative definitions of feed efficiency in lactating dairy cows and estimate their associated genetic variance components. Net energy intake from grass and concentrate was estimated up to four times per lactation for 2,859 lactations from 1,526 Holstein-Friesian cows on experimental farms in southern Ireland. A total of 12 definitions of feed efficiency were derived plus energy balance. Variance components were estimated using animal repeatability linear mixed models. Heritability of the traits ranged from 0.09 to 0.64. Many of the phenotypic correlations between the traits differed considerably from one implying that each trait is measuring a different aspect of efficiency compared to other measures.

Keywords:

feed efficiency

dairy cattle

genetic parameters

See more of: Posters: Genetics of Trait Complexes - Feed Intake and Efficiency (Group 2)
See more of: Genetics of Trait Complexes: Feed intake and efficiency
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