Elopaino, kuntoluokka ja maidon pitoisuudet lehmän energiataseen kuvaajana

201

Reliability of breeding values for feed intake and feed efficiency traits in dairy cattle: When dry matter intake recordings are sparse under different scenarios

In Press, Corrected Proof201

Bpop: an efficient program for estimating base population allele frequencies in single and multiple group structured populations

Base population allele frequencies (AF) should be used in genomic evaluations. A program named Bpop was implemented to estimate base population AF using a generalized least squares (GLS) method when the base population individuals can be assigned to groups. The required dense matrix products involving (A22 )-1v were implemented efficiently using sparse submatrices of A-1, where A and A22 are pedigree relationship matrices for all and genotyped animals, respectively. Three approaches were implemented: iteration on pedigree (IOP), iteration in memory (IM), and direct inversion by sparsity preserving Cholesky decomposition (CHM). The test data had 1.5 million animals genotyped using 50240 markers. Total computing time (the product (A22)-11) was 53 min (1.2 min) by IOP, 51 min (0.3 min) by IM, and 56 min (4.6 min) by CHM. Peak computer core memory use was 0.67 GB by IOP, 0.80 GB by IM, and 7.53 GB by CHM. Thus, the IOP and IM approaches can be recommended for large data sets because of their low memory use and computing time

Lypsylehmien muuntokelpoisen energian saannin mallinnus rehuhyötysuhdeominaisuuksien kehittämistä varten

201

Valintaindeksi jälkeläisarvosteltujen keinosiemennyssonnien kokonaisjalostusarvon kuvaajana

vokKirjasto Aj-

Genomisessa eläinmallissa käytetään sekä genotyypitettyjen että genotyypittämättömien eläinten tietoja

201

Multitrait-multiparity model for joint genetic evaluation of Nordic bulls for udder health traits

not availabl

Detection of bias in animal model pedigree indices of heifers

The objective of the study was to test whether the pedigree indices (PI) of heifers are biased, and if so, whether the magnitude of the bias varies in different groups of heifers. Therefore, two animal model evaluations with two different data sets were computed. Data with all the records from the national evaluation in December 1994 was used to obtain estimated breeding values (EBV) for 305-days’ milk yield and protein yield. In the second evaluation, the PIs were estimated for cows calving the first time in 1993 by excluding all their production records from the data. Three different statistics, a simple t-test, the linear regression of EBV on PI, and the polynomial regression of the difference in the predictions (EBV-PI) on PI, were computed for three groups of first parity Ayrshire cows: daughters of proven sires, daughters of young sires, and daughters of bull dam candidates. A practically relevant bias was found only in the PIs for the daughters of young sires. On average their PIs were biased upwards by 0.20 standard deviations (78.8 kg) for the milk yield and by 0.21 standard deviations (2.2 kg) for the protein yield. The polynomial regression analysis showed that the magnitude of the bias in the PIs changed somewhat with the size of the PIs