Olfactory evaluation of boar taint: effects of factors measured at slaughter and link with boar taint components

There is a commitment by the European pig sector to ban surgical castration of male piglets in the European Union in 2018. One alternative to castration is to raise entire male pigs, with an increased risk of boar taint. A field study was performed to 1) evaluate inter- and intra-farm variation in boar taint prevalence, 2) investigate factors measured at slaughter influencing boar taint and 3) evaluate the relationship between sensorial scoring by a trained panel and the concentration of boar taint components. From 34 farms, neck fat samples were collected from all entire male pigs in at least 2 slaughter batches per farm (78 batches; 9167 animals). In addition to olfactory boar taint analysis, data was also collected on fresh skin lesions (score 0-3) at the slaughter line, slaughter weight, lean meat percentage, duration of transport, time spent in lairage, total delivery duration, day length, shortening of days and outdoor mean temperature. Using the hot iron method, neck fat samples were scored (8-point scale) for boar taint. Average boar taint prevalence (score ≥3) was 5.6 ± 2.5% and the mean difference between the maximum and minimum prevalence per farm was 4.3 ± 3.2%. Androstenone (AND), skatole (SKA) and indole (IND) concentrations were measured for a subset (n= 254) of the samples. According to binomial univariate mixed models, entire male pigs with a higher skin lesion score had higher odds of having boar taint (P=0.031), as did fatter entire male pigs (P<0.001). In the binomial multivariate mixed model lean meat percentage (P