The objectives of this study at Ohio State University were to compare slice characteristics and sensory attributes of bacon from immunologically castrated (IC) barrows with bacon from other sexes using a trained sensory panel.

Lead researcher, D.D. Boler and co-authors in Columbus, at Iowa State University and Zoetis, explain in their paper in Journal of Animal Science that bacon was obtained for sensory evaluation from three experiments.

In Experiment 1, trimmed and squared bellies (n=180) of IC barrows, IC barrows fed ractopamine hydrochloride (IC+RAC), physically castrated (PC) barrows, intact males (IM) and gilts were used. Data were analysed as a general linear mixed model and pen (n=48) served as the experimental unit. Treatment (sex or diet) was a fixed effect in all three experiments.

In Experiment 2, untrimmed, natural fall bellies (n=96) from IC and PC barrows fed 0 or 30 per cent or a withdrawal distillers dried grains with solubles (DDGS) programme when slaughtered five weeks after the second dose (25 weeks of age) were used.

In Experiment 3, untrimmed, natural fall bellies (n=96) from IC and PC barrows fed the same experimental diets as in experiment 2 but slaughtered at seven weeks after the second dose (27 weeks of age) were used.

Data from Experiments 2 and 3 were analysed as a 2×3 factorial arrangement in a randomised complete block design and pen was the experimental unit.

Bellies from all three experiments were processed using the same protocols.

In Experiment 1, IM had the greatest (P<0.0001) boar aroma and flavour scores among all treatments. No differences were detected among the other treatment groups for boar aroma or flavor. Intact males had the least (P<0.0001) desirable cured bacon aroma and flavour among all treatments. No differences were detected among the other treatment groups for bacon aroma or flavor.

There were no differences in bacon aroma or off-flavour between IC and PC barrows slaughtered at five weeks after the second dose regardless of DDGS feeding programme. Bacon from PC barrows was saltier (P<0.01) than bacon from IC barrows when slaughtered at five weeks after the second dose.

There were no differences in bacon aroma, off-aroma, bacon flavour or saltiness between IC and PC barrows slaughtered at seven weeks after the second dose regardless of DDGS feeding programme.

Total slice area of bacon slices from IC barrows slaughtered at five weeks after the second dose were less (P<0.01) than PC barrows but the differences diminished (P=0.16) when slaughtered at seven weeks after the second dose.

Overall, panellists successfully detected boar odour and flavour in Experiment 1.

Immunological castration was as effective as physical castration at eliminating boar aroma and boar flavour in bacon even when feeding differing DDGS feeding programmes or when slaughtered at five or seven weeks after the second dose.

Reference

Little K.L., J.M. Kyle, B.M. Bohrer, A.L. Schroeder, C.A. Fedler, K.J. Prusa and D.D. Boler. 2014. A comparison of slice characteristics and sensory characteristics of bacon from immunologically castrated barrows with bacon from physically castrated barrows, boars, and gilts. J. Anim. Sci. 92: 5769-5777

March 2015