Olfactory evaluation of boar taint: effect of factors measured at slaughter and link with boar taint compounds

Abstract

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 interand 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 two slaughter batches per farm (78 batches; 9167 animals). In addition to olfactory boar taint analysis, data were also collected on fresh skin lesions (score 0 to 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 (eight-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 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 < 0.001) and outdoor mean temperature ( P = 0.005) remained as only significant factors. Based on our results, we can conclude that these statistically significant at least partially influence the prevalence of boar taint. According to the binomial univariate mixed models SKA concentration in liquid fat seems a better predictor for boar taint than AND. There were no significant synergetic effects between boar taint compounds.

Developing and Understanding Olfactory Evaluation of Boar Taint

“…During the first stage we started with a preliminary scale of boar taint intensity and evaluated the method as it was being used ( Table 1). This scale was used in a first observational study [15]. During the second stage, we replaced the 8-point scale with a 5-point scale to separate the non-boar taint scale, changed the criteria for the final evaluation of boar taint status, and made practical changes to the scoring method itself based on experience and results from the experiments discussed later.…”

“…Analysis was done using UHPLC-HR-Orbitrap-MS to determine AND, SKA and IND concentrations (µg/g liquid fat) [18]. Cut-offs were chosen to be 2.0 µg/g, 0.25 µg/g, and 0.15 µg/g respectively [15].…”

Monitoring of behavior, sex hormones and boar taint compounds during the vaccination program for immunocastration in three sire lines

“…Two weeks after the second vaccination, AND concentration in fat was significantly lower than V2 in all sire lines. None of the samples exceeded the cutoff of 2000 µg/kg(Heyrman et al, 2017) at V2 and V2+2. At slaughter, levels were higher compared to V2+2 for all sire lines, and even significantly higher than at V2 for BP and FP.…”

“…SKA at S was significantly lower than at V2 and V2+2 in all sire lines. At V2, SKA levels above the cutoff of 250 µg/kg were found in 6 of 45 samples(Heyrman et al, 2017) (4/16 CD and 2/16 FP). At V2+2, 2 of 48 samples exceeded cutoff level (1/16 CD and 1/17 FP) and at S, 2 of 54 samples exceed cutoff level (2/20 FP).…”

Σχεδιασμός, βελτιστοποίηση και εφαρμογή αλγορίθμων machine learning και deep learning, με δυνατότητα αυτόματης εκτέλεσης διασταυρούμενης επικύρωσης και ανανέωσης βάσει των διατηρούμενων συνόλων πολυδιάστατων και σύνθετων δεδομένων

“…Μια προσέγγιση που παρέχει πολύτιμες γνώσεις είναι η διεξαγωγή στατιστικών δοκιμών στα συγκεντρωμένα δεδομένα, όπως δοκιμές συσχέτισης που χρησιμοποιούνται για την αναζήτηση συσχετίσεων μεταξύ μεταβλητών και δοκιμές σύγκρισης μέσων τιμών των μεταβλητών. Τα τεστ παλινδρόμησης αξιολογούν εάν μια αλλαγή σε μια μεταβλητή προκαλεί αλλαγές στην άλλη μεταβλητή, όπως διεξάγεται στο [63]. Μια άλλη προσέγγιση που εμφανίζεται τα τελευταία χρόνια είναι η εφαρμογή τεχνικών μηχανικής μάθησης.…”