Evaluating alternate models to estimate genetic parameters of calving traits in United Kingdom Holstein-Friesian dairy cattle

Genetics Selection Evolution

Research

Mike P Coffey¹  Eileen Wall¹  Sophie A E Eaglen²  John A Woolliams³ 

[1] Animal & Veterinary Sciences Group, SAC, Roslin Institute Building, Easter Bush, EH25 9RG, Midlothian, UK;Animal & Veterinary Sciences Group, SAC, Roslin Institute Building, Easter Bush, EH25 9RG, Midlothian, UK;The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, EH25 9RG, Midlothian, UK;The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, EH25 9RG, Midlothian, UK;

关键词: Genetic Correlation;    Maternal Effect;    Bivariate Model;    Gestation Length;    Prediction Error Variance;   

DOI  :  10.1186/1297-9686-44-23

 received in 2011-10-26, accepted in 2012-07-13,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe focus in dairy cattle breeding is gradually shifting from production to functional traits and genetic parameters of calving traits are estimated more frequently. However, across countries, various statistical models are used to estimate these parameters. This study evaluates different models for calving ease and stillbirth in United Kingdom Holstein-Friesian cattle.MethodsData from first and later parity records were used. Genetic parameters for calving ease, stillbirth and gestation length were estimated using the restricted maximum likelihood method, considering different models i.e. sire (−maternal grandsire), animal, univariate and bivariate models. Gestation length was fitted as a correlated indicator trait and, for all three traits, genetic correlations between first and later parities were estimated. Potential bias in estimates was avoided by acknowledging a possible environmental direct-maternal covariance. The total heritable variance was estimated for each trait to discuss its theoretical importance and practical value. Prediction error variances and accuracies were calculated to compare the models.Results and discussionOn average, direct and maternal heritabilities for calving traits were low, except for direct gestation length. Calving ease in first parity had a significant and negative direct-maternal genetic correlation. Gestation length was maternally correlated to stillbirth in first parity and directly correlated to calving ease in later parities. Multi-trait models had a slightly greater predictive ability than univariate models, especially for the lowly heritable traits. The computation time needed for sire (−maternal grandsire) models was much smaller than for animal models with only small differences in accuracy. The sire (−maternal grandsire) model was robust when additional genetic components were estimated, while the equivalent animal model had difficulties reaching convergence.ConclusionsFor the evaluation of calving traits, multi-trait models show a slight advantage over univariate models. Extended sire models (−maternal grandsire) are more practical and robust than animal models. Estimated genetic parameters for calving traits of UK Holstein cattle are consistent with literature. Calculating an aggregate estimated breeding value including direct and maternal values should encourage breeders to consider both direct and maternal effects in selection decisions.

【 授权许可】

CC BY   
© Eaglen et al.; licensee BioMed Central Ltd. 2012