The Methodology

Abstract

Method of measuring and collecting data Collected by Dairy Herd Information Affiliates using ICARapproved methods and quality certification standards administered by the Council on Dairy Cattle Breeding Time period for data inclusion First calvings from 1960 and later; pedigree from birth years 1950 and later Age groups (e.g. parities) included First 5 parities included; first lactation required before later lactations can contribute to sire evaluation Other criteria (data edits) for inclusion of records Valid sire identification required; lactations from cows with >40 DIM and cows removed from the herd with >15 DIM included; TD by 90 DIM required; owner-sampler records used from herds that meet identification, outlier, and bulk tank comparison limits Criteria for extension of records (if applicable) Records with <305 days extended to 305 days using MT best prediction for milk, fat, and protein Sire categories All sires (AI and NS) evaluated together; about 1900 AI and 1000 NS new bulls evaluated each year Environmental effects, preadjustments Multiplicative adjustments for calving age and month within each breed, times milked per day (adjusted to twice daily milking), previous DO, and heterogeneous variance; base age for mean and variance adjustments is 36-month-old, 2nd-parity cows; unequal variances across time, across herds, and across breeds adjusted to HOL base variance calculated from standardized records of first lactation cows that calved in 2007 Method (model) of genetic evaluation MT BLUP RP AM