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Titolo:
A COMPUTATIONALLY FEASIBLE TEST DAY MODEL FOR GENETIC EVALUATION OF YIELD TRAITS IN THE UNITED-STATES
Autore:
WIGGANS GR; GODDARD ME;
Indirizzi:
USDA ARS,ANIM IMPROVEMENT PROGRAMS LAB BELTSVILLE MD 20705 UNIV NEW ENGLAND ARMIDALE NSW AUSTRALIA
Titolo Testata:
Journal of dairy science
fascicolo: 8, volume: 80, anno: 1997,
pagine: 1795 - 1800
SICI:
0022-0302(1997)80:8<1795:ACFTDM>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
AUSTRALIAN BLACK; DAIRY PRODUCTION; ANIMAL-MODELS; MISSING DATA; WHITE COWS; PARAMETERS; TRANSFORMATION; LACTATIONS;
Keywords:
TEST DAY MODEL; GENETIC EVALUATION; MULTITRAIT ANALYSIS; YIELD TRAITS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
25
Recensione:
Indirizzi per estratti:
Citazione:
G.R. Wiggans e M.E. Goddard, "A COMPUTATIONALLY FEASIBLE TEST DAY MODEL FOR GENETIC EVALUATION OF YIELD TRAITS IN THE UNITED-STATES", Journal of dairy science, 80(8), 1997, pp. 1795-1800

Abstract

A multitrait analysis of test day yields is proposed that includes 60traits [3 yield traits (milk, fat, and protein), 2 parity groups (first and later) per yield trait, and 10 stages of lactation per parity]. To reduce the computations needed for the 60 traits, test day effectsare estimated within the herd before analysis across herds, the rank of the genetic (co)variance matrix is reduced, a canonical transformation is used with missing values replaced by their expectations, and a repeatability model is applied to allow inclusion of parities after second. Historical 305-d records are included through their correlationswith test day effects. Possible benefits from this model include 1) more accurate estimation of environmental effects from including the influence of particular days of recording, 2) optimal use of informationfrom all test days (especially for lactations with long intervals from calving to first test or between tests), 3) improved accuracy of evaluations for component yields through contributions from information for milk yield, and 4) greater stability of bull evaluations from accounting for genetic differences among daughters in the shape of lactation curve and maturity rate.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 22/09/20 alle ore 16:45:57