Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Animal Production Science Animal Production Science Society
Food, fibre and pharmaceuticals from animals
RESEARCH ARTICLE

Entire male pig production in Europe

G. Bee A C , P. Chevillon B and M. Bonneau B
+ Author Affiliations
- Author Affiliations

A Agroscope – Institute for Livestock Sciences, La Tioleyre 4, 1725 Posieux, Switzerland.

B IFIP – ‘Institut du Porc’, La motte au vicomte, 35651 Le Rheu, France.

C Corresponding author. Email: giuseppe.bee@agroscope.admin.ch

Animal Production Science 55(12) 1347-1359 https://doi.org/10.1071/AN15279
Submitted: 4 June 2015  Accepted: 31 August 2015   Published: 20 October 2015

Abstract

In Europe the proportion of male pigs that are left ‘entire’ has been high for many years in the British Isles and Iberian Peninsula, and has recently increased in The Netherlands and to a lesser extent in Germany and France. Various European Union partners agreed in 2010 on a road map to abandon piglet castration by 1 January 2018. Despite significant commercial in-confidence research on instrumental methods for detecting boar-tainted carcasses at slaughter plants, nothing is currently being adopted at an industrial scale. A few abattoirs sort out the most heavily tainted carcasses, using human nose methods. However, there are major concerns with their accuracy, which is currently not documented in any publicly available technical report. The importance of androstenone and skatole for boar taint is still debated but a recent study (CAMPIG; G Backus, H Snoek, MA Oliver, M Font i Furnols, M Aluwé, F Tuyttens, M Bonneau, P Chevillon, MD Aaslyng, D Moerlein, L Meier-Dinkel, J Trautmann, J-E Haugen, unpubl. data) has established preliminary equations relating consumer dissatisfaction to androstenone and skatole levels. These equations still need further consolidation to integrate the impact of very high and very low androstenone levels on consumer acceptability. Reducing the incidence of boar taint at a production level and at the same time overcoming possible greater aggressive behaviour of entire male pigs are also critical for abandoning castration. Genetic selection is the most efficient way to reduce androstenone, but the selection of boar-taint-free genetic lines without any adverse consequence on the reproductive and growth performance will take time. Skatole levels can be efficiently reduced via feeding specific feedstuffs and good control of the animals’ environment. Provided that the incidence of boar taint can be reduced to an acceptable level and the residual tainted carcasses can be sorted out at a reasonable price by mutually recognised methods, the abandonment of castration will result in high benefits, up to one-billion euros for both the pork industry, via a drastic reduction of production costs, and society at large, through improved animal welfare and reduced impact on the environment.

Additional keywords: animal welfare, boar taint, castration, consumer acceptance, detection, threshold.


References

Aluwé M, Bekaert KM, Tuyttens FAM, Vanhaecke L, De Smet S, De Brabander HF, De Brabander DL, Millet S (2011a) Influence of soiling on boar taint in boars. Meat Science 87, 175–179.
Influence of soiling on boar taint in boars.Crossref | GoogleScholarGoogle Scholar | 21074948PubMed |

Aluwé M, Millet S, Bekaert KM, Tuyttens FAM, Vanhaecke L, De Smet S, De Brabander DL (2011b) Influence of breed and slaughter weight on boar taint prevalence in entire male pigs. Animal 5, 1283–1289.
Influence of breed and slaughter weight on boar taint prevalence in entire male pigs.Crossref | GoogleScholarGoogle Scholar | 22440181PubMed |

Aluwé Md, Langendries KCM, Bekaert KM, Tuyttens FAM, De Brabander DL, De Smet S, Millet S (2013) Effect of surgical castration, immunocastration and chicory-diet on the meat quality and palatability of boars. Meat Science 94, 402–407.
Effect of surgical castration, immunocastration and chicory-diet on the meat quality and palatability of boars.Crossref | GoogleScholarGoogle Scholar |

Aluwé M, Tuyttens FAM, Millet S (2015) Field experience with surgical castration with anaesthesia, analgesia, immunocastration and production of entire male pigs: performance, carcass traits and boar taint prevalence. Animal 9, 500–508.
Field experience with surgical castration with anaesthesia, analgesia, immunocastration and production of entire male pigs: performance, carcass traits and boar taint prevalence.Crossref | GoogleScholarGoogle Scholar | 25434616PubMed |

Ampuero S, Bee G (2006) The potential to detect boar tainted carcasses by using an electronic nose based on mass spectrometry. Acta Veterinaria Scandinavica 48, P1
The potential to detect boar tainted carcasses by using an electronic nose based on mass spectrometry.Crossref | GoogleScholarGoogle Scholar |

Andersson K, Schaub A, Lundstrom K, Thomke S, Hansson I (1997) The effects of feeding system, lysine level and gilt contact on performance, skatole levels and economy of entire male pigs. Livestock Production Science 51, 131–140.
The effects of feeding system, lysine level and gilt contact on performance, skatole levels and economy of entire male pigs.Crossref | GoogleScholarGoogle Scholar |

Baes C, Mattei S, Luther H, Ampuero S, Sidler X, Bee G, Spring P, Hofer A (2013) A performance test for boar taint compounds in live boars. Animal 7, 714–720.
A performance test for boar taint compounds in live boars.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3s7ptFejtA%3D%3D&md5=85d8734e3a3f62b2641b4558f21d907eCAS | 23211445PubMed |

Batorek N, Candek-Potokar M, Bonneau M, Van Milgen J (2012) Meta-analysis of the effect of immunocastration on production performance, reproductive organs and boar taint compounds in pigs. Animal 6, 1330–1338.
Meta-analysis of the effect of immunocastration on production performance, reproductive organs and boar taint compounds in pigs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3s3gs1yisw%3D%3D&md5=efc753a543015acb5021a0905e39ca8aCAS | 23217237PubMed |

Bee G, Ampuero Kragten S (2015) Dietary hydrolysable tannins from chestnut have the potential to reduce the risk of boar tainted carcasses. Journal of Animal Science 93, 36

Bekaert KM, Aluwé M, Vanhaecke L, Heres L, Duchateau L, Vandendriessche F, Tuyttens FAM (2013) Evaluation of different heating methods for the detection of boar taint by means of the human nose. Meat Science 94, 125–132.
Evaluation of different heating methods for the detection of boar taint by means of the human nose.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXjslajtbk%3D&md5=8864195f764657214a7cedea34f17847CAS | 23403304PubMed |

Blanch M, Panella-Riera N, Chevillon P, Furnols MFI, Gil M, Gil JM, Kallas Z, Oliver MA (2012) Impact of consumer’s sensitivity to androstenone on acceptability of meat from entire male pigs in three European countries: France, Spain and United Kingdom. Meat Science 90, 572–578.
Impact of consumer’s sensitivity to androstenone on acceptability of meat from entire male pigs in three European countries: France, Spain and United Kingdom.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhvFOjsw%3D%3D&md5=8fb1aed0ffb2b2fe0c6d61c23f4ffc3dCAS | 22030109PubMed |

Bonneau M, Kempster AJ, Claus R, Claudi-Magnussen C, Diestre A, Tornberg E, Walstra P, Chevillon P, Weiler U, Cook GL (2000a) An international study on the importance of androstenone and skatole for boar taint: I. Presentation of the programme and measurement of boar taint compounds with different analytical procedures. Meat Science 54, 251–259.
An international study on the importance of androstenone and skatole for boar taint: I. Presentation of the programme and measurement of boar taint compounds with different analytical procedures.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXmtFCqsw%3D%3D&md5=e9c6b59e829c4dea681d78556c659e6fCAS | 22060695PubMed |

Bonneau M, Walstra P, Claudi-Magnussen C, Kempster AJ, Tornberg E, Fischer K, Diestre A, Siret F, Chevillon P, Claus R, Dijksterhuis G, Punter P, Matthews KR, Agerhem H, Béague MP, Oliver MA, Gispert M, Weiler U, Von Seth G, Leask H, Font I, Furnols M, Homer DB, Cook GL (2000b) An international study on the importance of androstenone and skatole for boar taint: IV. Simulation studies on consumer dissatisfaction with entire male pork and the effect of sorting carcasses on the slaughter line, main conclusions and recommendations. Meat Science 54, 285–295.
An international study on the importance of androstenone and skatole for boar taint: IV. Simulation studies on consumer dissatisfaction with entire male pork and the effect of sorting carcasses on the slaughter line, main conclusions and recommendations.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXmtFCqtg%3D%3D&md5=cafc9d3dde8f84a75fb27bcb55cdd74bCAS | 22060698PubMed |

Buhl AC (2013) Animal Welfare Law in Motion? – Comment on the latest amendments to the Animal Welfare Act in Germany. Global Journal of Animal Law. 1, 1–7.

Byrne DV, Thamsborg SM, Hansen LL (2008) A sensory description of boar taint and the effects of crude and dried chicory roots (Cichorium intybus L.) and inulin feeding in male and female pork. Meat Science 79, 252–269.
A sensory description of boar taint and the effects of crude and dried chicory roots (Cichorium intybus L.) and inulin feeding in male and female pork.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXjs1Kjsrc%3D&md5=1dfbbcb90d90383fa5546ab569901635CAS | 22062753PubMed |

Čandek-Potokar M, Škrlep M, Batorek Lukač N, Zamaratskaia G, Prevolnik Povše M, Velikonja Bolta Š, Kubale V, Bee G (2015) Hydrolysable tannin fed to entire male pigs affects intestinal production, tissue deposition and hepatic clearance of skatole. The Veterinary Journal in press.

Carroll JA, Berg EL, Strauch TA, Roberts MP, Kattesh HG (2006) Hormonal profiles, behavioral responses, and short-term growth performance after castration of pigs at three, six, nine, or twelve days of age. Journal of Animal Science 84, 1271–1278.

Dijksterhuis GB, Engel B, Walstra P, Furnols MFI, Agerhem H, Fischer K, Oliver MA, Claudi-Magnussen C, Siret F, Beague MP, Homer DB, Bonneau M (2000) An international study on the importance of androstenone and skatole for boar taint: II. Sensory evaluation by trained panels in seven European countries. Meat Science 54, 261–269.
An international study on the importance of androstenone and skatole for boar taint: II. Sensory evaluation by trained panels in seven European countries.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXmtFCqsA%3D%3D&md5=e0908ca63f5552d72947d2622b76e0d2CAS | 22060696PubMed |

Dunshea FR, Allison JR, Bertram M, Boler DD, Brossard L, Campbell R, Crane JP, Hennessy DP, Huber L, de Lange C, Ferguson N, Matzat P, McKeith F, Moraes PJ, Mullan BP, Noblet J, Quiniou N, Tokach M (2013) The effect of immunization against GnRF on nutrient requirements of male pigs: a review. Animal 7, 1769–1778.
The effect of immunization against GnRF on nutrient requirements of male pigs: a review.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhsFOisbzM&md5=c1bbbb4e8a05ded32f4a911ccdcef7cfCAS | 23931578PubMed |

Ebschke S, von Borell E, Weber M (2014) Animal welfare assessment of fattening boars with entire males and anti GnRF vaccinated male swine. Züchtungskunde 86, 342–357.

EFSA (2004) Opinion of the scientific panel on animal health and welfare on a request from the Commission related to welfare aspects of the castration of piglets. EFSA Journal 91, 1–18.

European Commission (2010) European declaration on alternatives to surgical castration of pigs. Available at http://ec.europa.eu/food/animal/welfare/farm/initiatives_en.htm [Verified 21 December 2012]

Font-i-Furnols M (2012) Consumer studies on sensory acceptability of boar taint: a review. Meat Science 92, 319–329.
Consumer studies on sensory acceptability of boar taint: a review.Crossref | GoogleScholarGoogle Scholar | 22682684PubMed |

Fredriksen B, Nafstad O (2006) Surveyed attitudes, perceptions and practices in Norway regarding the use of local anaesthesia in piglet castration. Research in Veterinary Science 81, 293–295.
Surveyed attitudes, perceptions and practices in Norway regarding the use of local anaesthesia in piglet castration.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28zot12kug%3D%3D&md5=e3b07dc1313dfb5f8eabe9cd721cd0b0CAS | 16427102PubMed |

Fredriksen B, Font I, Furnols M, Lundström K, Migdal W, Prunier A, Tuyttens FAM, Bonneau M (2009) Practice on castration of piglets in Europe. Animal 3, 1480–1487.
Practice on castration of piglets in Europe.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38vpt1amsw%3D%3D&md5=32a4fad36f144622a7f8bc98feeb6177CAS | 22444981PubMed |

Fredriksen B, Johnsen AMS, Skuterud E (2011) Consumer attitudes towards castration of piglets and alternatives to surgical castration. Research in Veterinary Science 90, 352–357.
Consumer attitudes towards castration of piglets and alternatives to surgical castration.Crossref | GoogleScholarGoogle Scholar | 20605033PubMed |

Frieden L, Neuhoff C, Große-Brinkhaus C, Cinar MU, Schellander K, Looft C, Tholen E (2012) Breeding potential of selection against boar taint. Züchtungskunde 84, 394–411.

Frieden L, Grosse-Brinkhaus C, Neuhoff C, Schellander K, Looft C, Tholen E (2014) Breeding potential of selection against boar taint. Züchtungskunde 86, 319–341.

Gerritzen MA, Kluivers-Poodt M, Reimert HGM, Hindle V, Lambooij E (2008) Castration of piglets under CO2-gas anaesthesia. Animal 2, 1666–1673.
Castration of piglets under CO2-gas anaesthesia.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38vptFaqsQ%3D%3D&md5=d9ca7f58ac19d1828589ef7b71252c6aCAS | 22444019PubMed |

Giersing M, Lundstrom K, Andersson A (2000) Social effects and boar taint: significance for production of slaughter boars (Sus scrofa). Journal of Animal Science 78, 296–305.

Grindflek E, Meuwissen THE, Aasmundstad T, Hamland H, Hansen MHS, Nome T, Kent M, Torjesen P, Lien S (2011) Revealing genetic relationships between compounds affecting boar taint and reproduction in pigs. Journal of Animal Science 89, 680–692.
Revealing genetic relationships between compounds affecting boar taint and reproduction in pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXjtlSmt7c%3D&md5=6cc099f8902bd78b69202e3dc1f7c151CAS | 21346135PubMed |

Haberland AM, Luther H, Hofer A, Tholen E, Simianer H, Lind B, Baes C (2014) Efficiency of different selection strategies against boar taint in pigs. Animal 8, 11–19.
Efficiency of different selection strategies against boar taint in pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhvFCrtbfM&md5=7b080aad29c39e9df41d5e6987782252CAS | 24176119PubMed |

Hagdrup CJ (2009) The Danish experience, from 27 years with skatole analysis samples from entire male pigs. In ‘Report of the EAAP/ALCASDE Boar Taint Detection Workshop’, 28 October 2009, Bologna. (Ed. JE Hauge) pp. 34–37.

Hansen LL, Larsen AE, Jensen BB, Hansenmoller J, Bartongade P (1994) Influence of stocking rate and feaces deposition in the pen at different temperatures on skatole concentration (boar taint) in subcutaneous fat. Animal Production 59, 99–110.
Influence of stocking rate and feaces deposition in the pen at different temperatures on skatole concentration (boar taint) in subcutaneous fat.Crossref | GoogleScholarGoogle Scholar |

Hansen LL, Larsen AE, Hansen-Moller J (1995) Influence of keeping pigs heavily fouled with feces plus urine on skatole and indole concentration (boar taint) in subcutaneous fat. Acta Agriculturae Scandinavica Section A-Animal Science 45, 178–185.
Influence of keeping pigs heavily fouled with feces plus urine on skatole and indole concentration (boar taint) in subcutaneous fat.Crossref | GoogleScholarGoogle Scholar |

Hansen LL, Mejer H, Thamsborg SM, Byrne DV, Roepstorff A, Karlsson AH, Hansen-Moller J, Jensen MT, Tuomola M (2006) Influence of chicory roots (Cichorium intybus L) on boar taint in entire male and female pigs. Animal Science 82, 359–368.
Influence of chicory roots (Cichorium intybus L) on boar taint in entire male and female pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XptlCjsbs%3D&md5=8859e1a4a7c2c705c575292ee62ad527CAS |

Hansen-Moller J, Andersen JR (1994) Boar taint – analytical alternatives. Fleischwirtschaft 74, 1005–1009.

Haugen JE, Brunius C, Zamaratskaia G (2012) Review of analytical methods to measure boar taint compounds in porcine adipose tissue: the need for harmonised methods. Meat Science 90, 9–19.
Review of analytical methods to measure boar taint compounds in porcine adipose tissue: the need for harmonised methods.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXht1ens7%2FK&md5=900740cded49ff16a52af1ccb6c57339CAS | 21803507PubMed |

Hay M, Vulin A, Genin S, Sales P, Prunier A (2003) Assessment of pain induced by castration in piglets: behavioral and physiological responses over the subsequent 5 days. Applied Animal Behaviour Science 82, 201–218.
Assessment of pain induced by castration in piglets: behavioral and physiological responses over the subsequent 5 days.Crossref | GoogleScholarGoogle Scholar |

Hodgson DS (2006) An inhaler device using liquid injection of isoflurane for short term anesthesia in piglets. Veterinary Anaesthesia and Analgesia 33, 207–213.
An inhaler device using liquid injection of isoflurane for short term anesthesia in piglets.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XotVyrtL8%3D&md5=e5560214fdc3da4c5ce80730705b1784CAS | 16764584PubMed |

Hodgson DS (2007) Comparison of isoflurane and sevoflurane for short-term anesthesia in piglets. Veterinary Anaesthesia and Analgesia 34, 117–124.
Comparison of isoflurane and sevoflurane for short-term anesthesia in piglets.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXksVCqtLk%3D&md5=486148dcdd0cfa0d805f0cb8e1440991CAS | 17316392PubMed |

Holinger M, Hillmann E, Fruh B (2014) Prevalence of injuries and the resulting requirements in housing conditions of entire male pigs. Tierarztliche Umschau 69, 235–239.

Holinger M, Früh B, Hillmann E (2015) Group composition for fattening entire male pigs under enriched housing conditions–influences on behaviour, injuries and boar taint compounds. Applied Animal Behaviour Science 165, 47–56.
Group composition for fattening entire male pigs under enriched housing conditions–influences on behaviour, injuries and boar taint compounds.Crossref | GoogleScholarGoogle Scholar |

Huber-Eicher B, Spring P (2008) Attitudes of Swiss consumers towards meat from entire or immunocastrated boars: a representative survey. Research in Veterinary Science 85, 625–627.
Attitudes of Swiss consumers towards meat from entire or immunocastrated boars: a representative survey.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1crpsFSjuw%3D%3D&md5=cf95e76dc06dfa21c0504c063e5a6665CAS | 18433811PubMed |

Jensen MT, Hansen LL (2006) Feeding with chicory roots reduces the amount of odorous compounds in colon and rectal contents of pigs. Animal Science 82, 369–376.
Feeding with chicory roots reduces the amount of odorous compounds in colon and rectal contents of pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XptlCjsbg%3D&md5=9a547ef32d3b22312d56b2eddefb4c93CAS |

Kirsching A, Bázár G, Házás Z, Romvári R (2012) Classification of meat with boar taint using an electronic nose. Acta Agriculturae Slovenica 100, 99–103.

Kjeldsen N (1993) Practical experience with production and slaughter of entire male pigs. In ‘Measurement and prevention of boar taint in entire male pigs. Vol. 60’. (Ed. M Bonneau) pp. 137–144. (Institut National de la Recherche Agronomique: Paris, France)

Kluivers-Poodt M, Houx BB, Robben SRM, Koop G, Lambooij E, Hellebrekers LJ (2012) Effects of a local anaesthetic and NSAID in castration of piglets, on the acute pain responses, growth and mortality. Animal 6, 1469–1475.
Effects of a local anaesthetic and NSAID in castration of piglets, on the acute pain responses, growth and mortality.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhtFansrzJ&md5=b149796dbc202d882c5b49e4b3294d17CAS | 23031520PubMed |

Kohler I, Moens Y, Busato A, Blum J, Schatzmann U (1998) Inhalation anaesthesia for the castration of piglets: CO2 compared to halothane. Journal of Veterinary Medicine Series A 45, 625–633.
Inhalation anaesthesia for the castration of piglets: CO2 compared to halothane.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXjtVyktw%3D%3D&md5=85237ff4c3c2d2360dc70b40897358bdCAS | 9923145PubMed |

Llamas Moya S, Boyle LA, Lynch PB, Arkins S (2008) Effect of surgical castration on the behavioural and acute phase responses of 5-day-old piglets. Applied Animal Behaviour Science 111, 133–145.
Effect of surgical castration on the behavioural and acute phase responses of 5-day-old piglets.Crossref | GoogleScholarGoogle Scholar |

Lösel D, Lacorn M, Buttner D, Claus R (2006) Flavor improvement in pork from barrows and gilts via inhibition of intestinal skatole formation with resistant potato starch. Journal of Agricultural and Food Chemistry 54, 5990–5995.
Flavor improvement in pork from barrows and gilts via inhibition of intestinal skatole formation with resistant potato starch.Crossref | GoogleScholarGoogle Scholar | 16881706PubMed |

Mathur PK, ten Napel J, Bloemhof S, Heres L, Knol EF, Mulder HA (2012) A human nose scoring system for boar taint and its relationship with androstenone and skatole. Meat Science 91, 414–422.
A human nose scoring system for boar taint and its relationship with androstenone and skatole.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XmtlSrtbo%3D&md5=6f88e6066fdf9a97158b11536b167a3dCAS | 22436660PubMed |

Matthews KR, Homer DB, Punter P, Beague MP, Gispert M, Kempster AJ, Agerhem H, Claudi-Magnussen C, Fischer K, Siret F, Leask H, Furnols MFI, Bonneau M (2000) An international study on the importance of androstenone and skatole for boar taint: III. Consumer survey in seven European countries. Meat Science 54, 271–283.
An international study on the importance of androstenone and skatole for boar taint: III. Consumer survey in seven European countries.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXmtFCqsQ%3D%3D&md5=09eed35194fe74a0d1595da615a9d910CAS | 22060697PubMed |

Meier-Dinkel L, Sharifi AR, Tholen E, Frieden L, Bucking M, Wicke M, Morlein D (2013) Sensory evaluation of boar loins: trained assessors’ olfactory acuity affects the perception of boar taint compounds. Meat Science 94, 19–26.
Sensory evaluation of boar loins: trained assessors’ olfactory acuity affects the perception of boar taint compounds.Crossref | GoogleScholarGoogle Scholar | 23357575PubMed |

Meier-Dinkel L, Gertheiss J, Müller S, Wesoly R, Mörlein D (2015) Evaluating the performance of sensory quality control: the case of boar taint. Meat Science 100, 73–84.
Evaluating the performance of sensory quality control: the case of boar taint.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXhs1Klu7vN&md5=8d5ab80b55274f9c3c8c53e1d459e62dCAS | 25310880PubMed |

Meinert L, Claudi-Magnussen C, Støier S (2013) Limits in the detection of boar taint: the human nose score test works with the human sense of smell in the sorting of meat. Fleischwirtschaft 93, 24–27.

Meuwissen THE, Goddard ME (2001) Prediction of identity by descent probabilities from marker-haplotypes. Genetics, Selection, Evolution. 33, 605–634.
Prediction of identity by descent probabilities from marker-haplotypes.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD3MnpsFSjsA%3D%3D&md5=5022916ba645155f9eee2bed3386746aCAS |

Moore KL, Mullan BP, Campbell RG, Kim JC (2013) The response of entire male and female pigs from 20 to 100-kg liveweight to dietary available lysine. Animal Production Science 53, 67–74.
The response of entire male and female pigs from 20 to 100-kg liveweight to dietary available lysine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhvVSkur%2FJ&md5=dca07deb3aeb3e89b2b036a7064675e4CAS |

Mörlein D, Meier-Dinkel L, Moritz J, Sharifi AR, Knorr C (2013) Learning to smell: repeated exposure increases sensitivity to androstenone, a major component of boar taint. Meat Science 94, 425–431.
Learning to smell: repeated exposure increases sensitivity to androstenone, a major component of boar taint.Crossref | GoogleScholarGoogle Scholar | 23611883PubMed |

Mortensen AB, Sorensen SE (1984) ‘Relationship between boar taint and skatole determined with a new analysis method. In Proceedings of the 30th European Meeting of Meat Research Workers’, 9–14 September 1984, Bristol, UK. pp. 394–396.

Øverland M, Kjos NK, Fauske AK, Teige J, Sorum H (2011) Easily fermentable carbohydrates reduce skatole formation in the distal intestine of entire male pigs. Livestock Science 140, 206–217.
Easily fermentable carbohydrates reduce skatole formation in the distal intestine of entire male pigs.Crossref | GoogleScholarGoogle Scholar |

Pauly C, Spring P, O’Doherty JV, Ampuero Kragten S, Bee G (2008) Performances, meat quality and boar taint of castrates and entire male pigs fed a standard and a raw potato starch-enriched diet. Animal 2, 1707–1715.
Performances, meat quality and boar taint of castrates and entire male pigs fed a standard and a raw potato starch-enriched diet.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhvVKmtr4%3D&md5=4ecee2fc82529d6da2a778b43bbd5ba3CAS | 22444024PubMed |

Pauly C, Spring P, Odoherty JV, Ampuero Kragten S, Bee G (2009) Growth performance, carcass characteristics and meat quality of group-penned surgically castrated, immunocastrated (Improvac) and entire male pigs and individually penned entire male pigs. Animal 3, 1057–1066.
Growth performance, carcass characteristics and meat quality of group-penned surgically castrated, immunocastrated (Improvac) and entire male pigs and individually penned entire male pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhtVSnsL%2FJ&md5=7d81f2a4f83da8348ef24aae79cb36aaCAS | 22444824PubMed |

Pauly C, Spring-Staehli P, O’Doherty JV, Kragten SA, Dubois S, Messadène J, Bee G (2010) The effects of method of castration, rearing condition and diet on sensory quality of pork assessed by a trained panel. Meat Science 86, 498–504.
The effects of method of castration, rearing condition and diet on sensory quality of pork assessed by a trained panel.Crossref | GoogleScholarGoogle Scholar | 20580494PubMed |

Prunier A, Bonneau M (2006) Y a-t-il des alternatives à la castration chirurgicale des porcelets? Productions Animales 19, 347–356.

Prunier A, Mounier AM, Hay M (2005) Effects of castration, tooth resection, or tail docking on plasma metabolites and stress hormones in young pigs. Journal of Animal Science 83, 216–222.

Prunier A, Bonneau M, von Borell EH, Cinotti S, Gunn M, Fredriksen B, Giersing M, Morton DB, Tuyttens FAM, Velarde A (2006) A review of the welfare consequences of surgical castration in piglets and the evaluation of non-surgical methods. Animal Welfare (South Mimms, England) 15, 277–289.

Puppe B, Schon PC, Tuchscherer A, Manteuffel G (2005) Castration-induced vocalisation in domestic piglets, Sus scrofa: complex and specific alterations of the vocal quality. Applied Animal Behaviour Science 95, 67–78.
Castration-induced vocalisation in domestic piglets, Sus scrofa: complex and specific alterations of the vocal quality.Crossref | GoogleScholarGoogle Scholar |

Quiniou N, Courboulay V, Salaün Y, Chevillon P (2010) Conséquences de la non castration des porcs males sur les performances de croissance et le comportement: comparaison avec les ma^ les castre’ s et les femelles. Journées de la Recherche Porcine 42, 113–118.

Rikard-Bell CV, Pluske JR, van Barneveld RJ, Mullan BP, Edwards AC, Gannon NJ, Henman DJ, Dunshea FR (2013) Dietary ractopamine promotes growth, feed efficiency and carcass responses over a wide range of available lysine levels in finisher boars and gilts. Animal Production Science 53, 8–17.
Dietary ractopamine promotes growth, feed efficiency and carcass responses over a wide range of available lysine levels in finisher boars and gilts.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhvVSkurzM&md5=eb1ded3270ab0da9f313a518f454777fCAS |

Robic A, Faraut T, Prunier A (2014) Pathways and genes involved in steroid hormone metabolism in male pigs: a review and update. The Journal of Steroid Biochemistry and Molecular Biology 140, 44–55.
Pathways and genes involved in steroid hormone metabolism in male pigs: a review and update.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXht1Gru7k%3D&md5=5bf3f723ebe3e6f9572fc343ad823a48CAS | 24239507PubMed |

Rydhmer L, Hansson M, Lundström K, Brunius C, Andersson K (2013) Welfare of entire male pigs is improved by socialising piglets and keeping intact groups until slaughter. Animal 7, 1532–1541.
Welfare of entire male pigs is improved by socialising piglets and keeping intact groups until slaughter.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3srls1yhuw%3D%3D&md5=51ff1fb919d82fb886eaa8cdb5ecd514CAS | 23590926PubMed |

Sellier P, Bonneau M (1988) Genetic-relationships between fat androstenone level in males and development of male and female genital-tact in pigs. Journal of Animal Breeding and Genetics 105, 11–20.
Genetic-relationships between fat androstenone level in males and development of male and female genital-tact in pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXhvVSgt7s%3D&md5=7e8b53ff3dd3beb6b469147e384cc687CAS |

Sellier P, Le Roy P, Fouilloux MN, Gruand J, Bonneau M (2000) Responses to restricted index selection and genetic parameters for fat androstenone level and sexual maturity status of young boars. Livestock Production Science 63, 265–274.
Responses to restricted index selection and genetic parameters for fat androstenone level and sexual maturity status of young boars.Crossref | GoogleScholarGoogle Scholar |

Strathe AB, Velander IH, Mark T, Kadarmideen HN (2013a) Genetic parameters for androstenone and skatole as indicators of boar taint and their relationship to production and litter size traits in Danish Landrace. Journal of Animal Science 91, 2587–2595.
Genetic parameters for androstenone and skatole as indicators of boar taint and their relationship to production and litter size traits in Danish Landrace.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXpvFCrs7Y%3D&md5=e70d3d69b3eef4ff5925d8309f908170CAS | 23508028PubMed |

Strathe AB, Velander IH, Mark T, Ostersen T, Hansen C, Kadarmideen HN (2013b) Genetic parameters for male fertility and its relationship to skatole and androstenone in Danish Landrace boars. Journal of Animal Science 91, 4659–4668.
Genetic parameters for male fertility and its relationship to skatole and androstenone in Danish Landrace boars.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhs1SqtL3F&md5=4c9c0bc88e5efcbc12c30dabb04e67f1CAS | 23942714PubMed |

Svendsen O (2006) A04 Castration of piglets under carbon dioxide (CO2) anaesthesia. Journal of Veterinary Pharmacology and Therapeutics 29, 54–55.
A04 Castration of piglets under carbon dioxide (CO2) anaesthesia.Crossref | GoogleScholarGoogle Scholar |

Taylor AA, Weary DM (2000) Vocal responses of piglets to castration: identifying procedural sources of pain. Applied Animal Behaviour Science 70, 17–26.
Vocal responses of piglets to castration: identifying procedural sources of pain.Crossref | GoogleScholarGoogle Scholar | 10986420PubMed |

Thomas W, Lubomir K, Gerhard B, Philippe V (2014) In house validation of a reference method for the determination of boar taint compounds by LC-MSMS. Publications Office of the European Union. Available at https://ec.europa.eu/jrc/en/publication/eur-scientific-and-technical-research-reports/house-validation-reference-method-determination-boar-taint-compounds-lc-msms [Verified 10 September 2015]

Trautmann J, Gertheiss J, Wicke M, Mörlein D (2014) How olfactory acuity affects the sensory assessment of boar fat: a proposal for quantification. Meat Science 98, 255–262.
How olfactory acuity affects the sensory assessment of boar fat: a proposal for quantification.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXhtFKjsrrL&md5=59848d25ab6b28f2a0b99668104b22c6CAS | 24976560PubMed |

Tuyttens FAM, Vanhonacker F, Langendries K, Aluwe M, Millet S, Bekaert K, Verbeke W (2011) Effect of information provisioning on attitude toward surgical castration of male piglets and alternative strategies for avoiding boar taint. Research in Veterinary Science 91, 327–332.
Effect of information provisioning on attitude toward surgical castration of male piglets and alternative strategies for avoiding boar taint.Crossref | GoogleScholarGoogle Scholar |

Tuyttens FAM, Vanhonacker F, Verhille B, De Brabander D, Verbeke W (2012) Pig producer attitude towards surgical castration of piglets without anaesthesia versus alternative strategies. Research in Veterinary Science 92, 524–530.
Pig producer attitude towards surgical castration of piglets without anaesthesia versus alternative strategies.Crossref | GoogleScholarGoogle Scholar |

van Staaveren N, Teixeira DL, Hanlon A, Boyle LA (2015) The effect of mixing entire male pigs prior to transport to slaughter on behaviour, welfare and carcass lesions. Plos One 10,
The effect of mixing entire male pigs prior to transport to slaughter on behaviour, welfare and carcass lesions.Crossref | GoogleScholarGoogle Scholar | 25830336PubMed |

van Wagenberg CPA, Snoek HM, van der Fels JB, van der Peet-Schwering CMC, Vermeer HM, Heres L (2013) Farm and management characteristics associated with boar taint. Animal 7, 1841–1848.
Farm and management characteristics associated with boar taint.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3sfitVSiuw%3D%3D&md5=dc1c0461efa4256444502ad8d92e713fCAS |

Vanhonacker F, Verbeke W (2011) Consumer response to the possible use of a vaccine method to control boar taint v. physical piglet castration with anaesthesia: a quantitative study in four European countries. Animal 5, 1107–1118.
Consumer response to the possible use of a vaccine method to control boar taint v. physical piglet castration with anaesthesia: a quantitative study in four European countries.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38vovV2iug%3D%3D&md5=fbdaa4724bb9b9ad280fd12f4cd08defCAS | 22440106PubMed |

Vazquez JM, Martinez EA, Roca J, Lucas X, Parrilla I (2001) Sex-sorting boar sperm: problems and possibilities. Archiv Fur Tierzucht-Archives of Animal Breeding 44, 141–144.

Vazquez JM, Parrilla I, Roca J, Gil MA, Cuello C, Vazquez JL, Martinez EA (2009) Sex-sorting sperm by flow cytometry in pigs: issues and perspectives. Theriogenology 71, 80–88.
Sex-sorting sperm by flow cytometry in pigs: issues and perspectives.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1cjnt1egsw%3D%3D&md5=b26bdca32faff342449e4eab913b8f10CAS | 18977521PubMed |

Vhile SG, Kjos NP, Sorum H, Overland M (2012) Feeding Jerusalem artichoke reduced skatole level and changed intestinal microbiota in the gut of entire male pigs. Animal 6, 807–814.
Feeding Jerusalem artichoke reduced skatole level and changed intestinal microbiota in the gut of entire male pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XkvVektL0%3D&md5=a5aaa2b7bce3915cf2d625a688e80d8aCAS | 22558928PubMed |

von Borell E, Baumgartner J, Giersing M, Jaggin N, Prunier A, Tuyttens FAM, Edwards SA (2009) Animal welfare implications of surgical castration and its alternatives in pigs. Animal 3, 1488–1496.
Animal welfare implications of surgical castration and its alternatives in pigs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38vpt1amsA%3D%3D&md5=db19a247200fc1dc0459c2f216fd3cbaCAS | 22444982PubMed |

Walker B, Jaggin N, Doherr M, Schatzmann U (2004) Inhalation anaesthesia for castration of newborn piglets: experiences with isoflurane and isoflurane/N2O. Journal of Veterinary Medicine Series a-Physiology Pathology Clinical Medicine 51, 150–154.
Inhalation anaesthesia for castration of newborn piglets: experiences with isoflurane and isoflurane/N2O.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXmvVGhurg%3D&md5=8e95508e45c9e62b642e15056c4a11c0CAS |

Walstra P, Claudi-Magnussen C, Chevillon P, Von Seth G, Diestre A, Matthews KR, Homer DB, Bonneau M (1999) An international study on the importance of androstenone and skatole for boar taint: levels of androstenone and skatole by country and season. Livestock Production Science 62, 15–28.
An international study on the importance of androstenone and skatole for boar taint: levels of androstenone and skatole by country and season.Crossref | GoogleScholarGoogle Scholar |

Wealleans AL, Litten-Brown JC, Mueller-Harvey I, Givens I, Silacci P, Bee G (2013) Effects of increasing hydrolysable tannin levels in diets of boars on growth, carcass traits, boar taint, and cytochrome P450 gene expression. Journal of Animal Science 91, 39

Wesoly R, Weiler U (2012) Nutritional influences on skatole formation and skatole metabolism in the pig. Animals (Basel) 2, 221–242.
Nutritional influences on skatole formation and skatole metabolism in the pig.Crossref | GoogleScholarGoogle Scholar |

Willeke H, Claus R, Muller E, Pirchner F, Karg H (1987) Selection for high and low-level of 5-alpha-androst-16-en-3-one in boars. 1. Direct and correletad response of endocrinologic traits. Journal of Animal Breeding and Genetics-Zeitschrift Fur Tierzuchtung Und Zuchtungsbiologie 104, 64–73.
Selection for high and low-level of 5-alpha-androst-16-en-3-one in boars. 1. Direct and correletad response of endocrinologic traits.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2sXkslWjsr4%3D&md5=b80755308ce0408eb4c5bc77df8590b5CAS |

Windig JJ, Mulder HA, ten Napel J, Knol EF, Mathur PK, Crump RE (2012) Genetic parameters for androstenone, skatole, indole, and human nose scores as measures of boar taint and their relationship with finishing traits. Journal of Animal Science 90, 2120–2129.
Genetic parameters for androstenone, skatole, indole, and human nose scores as measures of boar taint and their relationship with finishing traits.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhtFehsbrN&md5=8d24d60a7f90e1225694dab78ea8b941CAS | 22247111PubMed |

Zamaratskaia G, Squires EJ (2009) Biochemical, nutritional and genetic effects on boar taint in entire male pigs. Animal 3, 1508–1521.
Biochemical, nutritional and genetic effects on boar taint in entire male pigs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhsVehs7vK&md5=dbb505499f50ad67768241d0128dd1e3CAS | 22444984PubMed |

Zamaratskaia G, Rydhmer L, Chen G, Madej A, Andersson HK, Lundstrom K (2005) Boar taint is related to endocrine and anatomical changes at puberty but not to aggressive behaviour in entire male pigs. Reproduction in Domestic Animals 40, 500–506.
Boar taint is related to endocrine and anatomical changes at puberty but not to aggressive behaviour in entire male pigs.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2MnkslWntA%3D%3D&md5=33ca5bd19b410ea0545791a89d011eefCAS | 16324073PubMed |

Zammerini D, Wood JD, Whittington FM, Nute GR, Hughes SI, Hazzledine M, Matthews K (2012) Effect of dietary chicory on boar taint. Meat Science 91, 396–401.
Effect of dietary chicory on boar taint.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XmtlSrtbw%3D&md5=5df3a7ddb0d99a42f8d4c11635bb30f1CAS | 22353791PubMed |