Dias nummer 1 - orgprints.org

Dias nummer 1 - orgprints.org

Possibilities and requirements for organic dairy breeding lines M. Kargo1)2), L. Hjort1), J.R. Thomasen3) 1) Aarhus University, Center for Quantitative Genetics and Genomics, 2) SEGES, Cattle, 3) VikingGenetics Promilleafgiftsfonden for landbrug Key issue How much can breeding goals deviate before it is relevant to split the breed in two or more lines when the breed is used for more than one purpose? Current status organic dairy breeding Most genetic material originates from conventional breeding schemes Some organic farmers select sires based on customized farm indices Organic breeding schemes have not been used on a large scale Trend with customized indices Genetic level for total merit 16

17 18 19 20 21 Birth year 22 23 24 25 Trend with an organic breeding scheme Genetic level for total merit 16

17 18 19 20 21 Birth year 22 23 24 25 When may different breeding lines be relevant? Production system Climate zones

Temperate Tropic Conventional X X Organic X X High tech X X Relative EW for Danish Holstein across environments Trait

Conventional Organic High tech Yield 100 121 93 Feed efficiency 100 123 103 Cow mortality 100

102 112 Milk fever 100 338 202 Mastitis (infectious) 100 205 109 Digital dermatitis 100 101

81 Conception rate, cows 100 48 82 Conception rate, heifers 100 110 106 Longevity 100 108 121

To be published soon Relative EW for Danish Holstein across environments Trait Conventional Organic High tech Yield 100 121 93 Feed efficiency 100 123

103 Cow mortality 100 102 112 Milk fever 100 338 202 Mastitis (infectious) 100 205 109

Digital dermatitis 100 101 81 Conception rate, cows 100 48 82 Conception rate, heifers 100 110 106 Longevity

100 108 121 To be published soon Correlation between breeding goals depends on: Economic weights Given by production circumstances G*E interactions Biologically defined cannot be changed Registration methods Can be harmonized AARHUS UNIVERSITY Breakeven correlations for line division or not Before the genomic era Many progeny tested bulls needed for substantial GG

Large populations needed Break-even correlation appr. 0.85 Today Cow reference populations needed Much smaller than the number of test daughters needed before Break-even correlation >> 0.85 The driving force behind genetic gain before GS Registered production cows Selection intensity Selected progeny tested bulls Accuracy Number of progeny tested young bulls AARHUS

UNIVERSITY The driving force behind genetic gain using GS Production cows Genotyped bull calves Reference population II Reference population Selected Genomic tested bulls Accuracy Selection intensity Reference population III (Improved) possibilities for organic

breeding lines Genomic selection Genetic progress in smaller population (lines of populations) Genetic progress at a lower cost Before any division we need to: Estimate correlations between breeding goals Derive economic weights Estimate genetic parameters for all breeding goal traits Estimate G*E interactions between production systems Estimate the consequences of lines on genetic gain and inbreeding To be investigated in SOBcows and OrganicDairyHealth

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