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Choice of Scales for Delivery of Genetic Evaluations to the Public. Can We Harmonize Trait Scales?. International marketing and education is difficult because scales differ Advertisements cross national borders
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Choice of Scales for Delivery of Genetic Evaluations to the Public
Can We Harmonize Trait Scales? • International marketing and education is difficult because scales differ • Advertisements cross national borders • 9 of 19 full-page bull advertisements contained only pictures, no numbers! (Holstein International, March, 2004) • Internet sites provide foreign evaluations • Joint data analyses could produce evaluations on a common scale
Time to Change Bases • Every 5 years (2005, cows born in 2000) • 18 of 25 countries: AUS, BEL, CZE, DEU, ESP, EST, GBR, HUN, IRL, ISR, ITA, JPN, NLD, NZL, POL, SVN, USA, ZAF • At beginning of year? • Every year • 6 countries: CAN, CHE, FIN, FRA, NOR, SWE • At beginning of year except FRA=June • Each evaluation • 1 country: DNK
Possible Things To Do • Change mean and variance base • Change units and/or direction • Change evaluation models • Put different breeds on the same base • Submit to the Interbull test run • Prepare educational materials
Somatic Cell Count • Measured with same standard metric unit (cells / ml) in every country • Transformed by log 2, log 10, or log e • Reversed scales in 9 of 19 countries • Added means of 100, 3, 4, etc. • Changed SD to report EBV, PTA, or STA Different choice in almost every country!
Yield Trait Scales • True protein in 5 of 21 countries: • AUS, FRA, HUN, POL, USA (as of 2000) • True% = Crude% —.19 (e.g. 3.00% vs 3.19%) • Protein yield (kg) reduced by 5 - 6% • Age-parity adjustments differ • 16 of 25 countries adjust to average parity • 5 adjust to mature, 4 adjust to 1st parity • Separate lactation proofs available • 2 scales (RBV and EBV) seems too much
Conformation Scales • Standardized Genetic Merit (PTA SD) • Mean = 0, SD = 1 • 9of 21 countries: CHE, CZE, DNK, FRA, HUN, GBR, ITA, JPN, USA • Relative Breeding Values • Mean = 100, SD = 4, 7, 10, 12 • 8 countries in northern Europe • PTA, EBV, or other (4 countries)
Selection Index Scales • Units and SD not well documented • Top bull for total merit (February ‘04) • DNK 114, DEU 145, AUS 162, FRA 179 • NZL 246, NLD 366, GBR 826 • USA 857 (NM), USA 1918 (TPI) • ESP 2148, CAN 2360, ITA 2944 • Ranking on home scale may include traits not evaluated by Interbull
Conclusions • Base and scale changes go together • Many countries plan to change in Feb 2005 • Too many different scales cause confusion • Direction of udder health / SCS unclear • Recommended scales may help • Only 3 months until September test run