Modeling of social dominance with binary expression assuming single dominant animal per pen

The objectives of this study were 1) to evaluate the effectiveness of the proposed method by Misztal and Rekaya (2007) in the case of binary expression of social dominance and to compare their findings with Muir and Schinckel (2002) and 2) to develop a Bayesian procedure for assignment of social dominant status for jointly penned animals. The effect of dominance advantage was only present in records of dominant animals and was a fixed value in Model 1, or equal to the effect of social dominance plus constant in Model 2. The estimate of the dominance advantage was unbiased when the covariance was 0, was biased upwards when the covariance was positive, and downwards if negative. The probability of identifying the true dominant animal in each pen was 0.31, 0.51, 0.75, and 0.85 when the dominance effect was 0.5, 1, 1.5, and 2 residual standard deviations, respectively.