60 Whole genome prediction of the onset of puberty in a pig growth model based on body weight and feed intake data from boar stations using a Bayesian hierarchical model.

Abstract Pig breeding companies collect data on body weight and feed intake each time boars visit individual automatic feeding stations at boar testing farms. Proper modeling of feed intake and body weight gain is essential for achieving significant genetic progress in feed efficiency and growth. Sigmoidal curves, such as the Gompertz curve, are widely used to model pig growth because they capture the initial rapid exponential growth of pigs until the inflection point. After this point, growth slows until the pig reaches the adult weight at the curve’s plateau. Fitting Gompertz curves also generate, based on the inflection point, an indirect prediction of the onset of puberty (OP). Based on these growth curves, the age at the onset of puberty (AOP) of boars and gilts has been previously determined to be around 5-6 months. The weight at the onset of puberty (WOP) will present significant variation especially depending on the pig line. A Bayesian hierarchical model was previously developed to integrate a whole-genome prediction model using a 25K SNP panel and a pig growth model that fits a Gompertz curve, incorporating a recursive relationship between daily body weight and daily feed intake records. This model allows the prediction of breeding values for the parameters of the growth model. We aimed to apply this model to predict OP-related traits and validate these predictions with reproduction traits. The model was run using data from 25,686 pigs from four commercial lines (Duroc, Landrace, Large-White, and a Synthetic Line). The AOP ranged between 110 and 210 days across different lines, with an average ranging between 146 and 165 days (SD = 8-10 days). The WOP ranged between 75 and 190 kg, with an average ranging between 91 and 134 kilograms (SD = 7-11 kg). The OP in boars is positively correlated, though only low to moderately, with male reproductive performance. Correlations between the OP ranged from 0.13-0.30, 0.15-0.21, and 0.16-0.34 with boars’ trainability (training time until first jump), the age at the first ejaculate collection, and semen quality (sperm motility), respectively, indicating a link between the boar rearing phase and the boar reproductive performance. We are running the model with data (genotypes and phenotypes) from the boar testing farms (training population) to get effect estimates of SNPs on the OP. Based on the SNP effects, we will predict the OP in target populations (with only genotypes) of purebred boars and gilts, and also crossbred gilts. The OP is a trait that holds great potential for pig breeding programs, including the reproduction management of boars and gilts.