Bayesian analysis of response to selection: a case study using litter size in Danish Yorkshire pigs.
Implementation of a Bayesian analysis of a selection experiment is illustrated using litter size [total number of piglets born (TNB)] in Danish Yorkshire pigs. Other traits studied include average litter weight at birth (WTAB) and proportion of piglets born dead (PRBD). Response to selection for TNB was analyzed with a number of models, which differed in their level of hierarchy, in their prior distributions, and in the parametric form of the likelihoods. A model assessment study favored a particular form of an additive genetic model. With this model, the Monte Carlo estimate of the 95% probability interval of response to selection was (0.23; 0.60), with a posterior mean of 0.43 piglets. WTAB showed a correlated response of -7.2 g, with a 95% probability interval equal to (-33.1; 18.9). The posterior mean of the genetic correlation between TNB and WTAB was -0.23 with a 95% probability interval equal to (-0.46; -0.01). PRBD was studied informally; it increases with larger litters, when litter size is >7 piglets born. A number of methodological issues related to the Bayesian model assessment study are discussed, as well as the genetic consequences of inferring response to selection using additive genetic models.
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Danish Institute of Agricultural Sciences, DK-8830 Tjele, Denmark. snfdsgenetics.agrsci.dk
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Andersen
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D000822:Animal Husbandry; D000818:Animals; D001499:Bayes Theorem; D005260:Female; D008098:Litter Size / Q000235:genetics*; D008297:Male; D008957:Models, Genetic; D009010:Monte Carlo Method; D012098:Reproduction / Q000235:genetics; D012641:Selection, Genetic; D013552:Swine / Q000235:genetics*