Test-day model for national genetic evaluation of milk production traits

摘要: Genetic evaluation for milk, fat and protein yields, using 270-day lactation yields in an across-breed animal model (AM), has been performed New Zealand since 1996. A new system developed to calculate breeding values from herd-test data. In the current AM, a yield record is calculated based on 1 10 test-day records. The environmental effect of herd-test-day (HTD) removed during calculation. However, this done outside without reference genetic level HTD contemporary group. (TDM) can simultaneously account fixed effects such as groups, genetic, permanent (PE) temporary random that affect trait. By including model, TDM allows environment specific each be better taken into account, resulting improved accuracy evaluation. accommodate changes PE over time by fitting polynomials these effects. regression (RR) Legendre days milk (DIM) RR cow's curve have different shape. evaluations are more stable than obtained lactations because they differences maturity rate persistency lactation. sire (BVs) were compared those AM. For sires with 30 daughters, correlations between BVs two models 0.990, 0.988 0.990 respectively. demonstrated stability undergoing their widespread proof. There was less variation change reproof August through October show greatest early under AM outliers breed.