PMID- 17032785
OWN - NLM
STAT- MEDLINE
DCOM- 20061218
LR  - 20061011
IS  - 1525-3163 (Electronic)
IS  - 0021-8812 (Linking)
VI  - 84
IP  - 11
DP  - 2006 Nov
TI  - Genetic effects on preweaning weight gain of Nelore-Hereford calves according to 
      different models and estimation methods.
PG  - 2925-33
AB  - Additive and nonadditive genetic effects on preweaning weight gain (PWG) of a 
      commercial crossbred population were estimated using different genetic models and 
      estimation methods. The data set consisted of 103,445 records on purebred and 
      crossbred Nelore-Hereford calves raised under pasture conditions on farms located 
      in south, southeast, and middle west Brazilian regions. In addition to breed 
      additive and dominance effects, the models including different epistasis 
      covariables were tested. Models considering joint additive and environment 
      (latitude) by genetic effects interactions were also applied. In a first step, 
      analyses were carried out under animal models. In a second step, preadjusted 
      records were analyzed using ordinary least squares (OLS) and ridge regression 
      (RR). The results reinforced evidence that breed additive and dominance effects 
      are not sufficient to explain the observed variability in preweaning traits of 
      Bos taurus x Bos indicus calves, and that genotype x environment interaction 
      plays an important role in the evaluation of crossbred calves. Data were 
      ill-conditioned to estimate the effects of genotype x environment interactions. 
      Models including these effects presented multicolinearity problems. In this case, 
      RR seemed to be a powerful tool for obtaining more plausible and stable 
      estimates. Estimated prediction error variances and variance inflation factors 
      were drastically reduced, and many effects that were not significant under 
      ordinary least squares became significant under RR. Predictions of PWG based on 
      RR estimates were more acceptable from a biological perspective. In temperate and 
      subtropical regions, calves with intermediate genetic compositions (close to 1/2 
      Nelore) exhibited greater predicted PWG. In the tropics, predicted PWG increased 
      linearly as genotype got closer to Nelore.
FAU - Carvalheiro, R
AU  - Carvalheiro R
AD  - Departamento de Zootecnia, Universidade Estadual Paulista, Campus Jaboticabal, 
      Sao Paulo, Brazil. rcar@fcav.unesp.br
FAU - Pimentel, E C G
AU  - Pimentel EC
FAU - Cardoso, V
AU  - Cardoso V
FAU - Queiroz, S A
AU  - Queiroz SA
FAU - Fries, L A
AU  - Fries LA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Anim Sci
JT  - Journal of animal science
JID - 8003002
SB  - IM
MH  - Animals
MH  - Brazil
MH  - Cattle/*genetics/*growth & development
MH  - Crosses, Genetic
MH  - Environment
MH  - Genotype
MH  - Models, Biological
MH  - Weaning
MH  - Weight Gain/*genetics
EDAT- 2006/10/13 09:00
MHDA- 2006/12/19 09:00
CRDT- 2006/10/13 09:00
PHST- 2006/10/13 09:00 [pubmed]
PHST- 2006/12/19 09:00 [medline]
PHST- 2006/10/13 09:00 [entrez]
AID - 84/11/2925 [pii]
AID - 10.2527/jas.2006-214 [doi]
PST - ppublish
SO  - J Anim Sci. 2006 Nov;84(11):2925-33. doi: 10.2527/jas.2006-214.