Size matters: Boar taint in relationship with body composition and testis volume measured by magnetic resonance imaging

The aim of this study was to evaluate the possibility of predicting boar taint in live pigs non-invasively. For this, different magnetic resonance imaging based body composition traits (including testis volume) were compared with androstenone, skatole, and indole levels (ng/g fat) of the carcass` fat tissue after slaughtering. Additionally, in order to find traits which could help in predicting boar taint, the related sensory test results were included in the analysis. A number of 34 entire boars (EB) and 34 immunocastrated boars (IB; first injection at an age of 77 ± 1 days and second injection at an age of 137 ± 1 days) were scanned two times during growth (at 60 and 90 kg live body weight) using magnetic resonance imaging (MRI). Three body regions (shoulder, loin, and ham) were examined. Additionally the testes volume was calculated. After slaughtering, boar taint samples were taken for olfactory testing and stable isotope dilution assays. These data were compared with selected body composition traits in order to analyze the relationship between MRI traits and boar taint. The results showed that IB tend to have greater subcutaneous fat layers (belly fat, shoulder fat, back fat) than EB. Within EB, larger testis volumes and a higher amount of body fat (especially belly fat) are associated with a higher level of androstenone