Welfare Aspects of Raising Entire Male Pigs and Immunocastrates
by
, ,
Eberhard von Borell
1,*, 
Michel Bonneau
2,
Mirjam Holinger
3,
Armelle Prunier
4,
Volker Stefanski
5,
Susanne Zöls
6 and
Ulrike Weiler
5,† 1
Department of Animal Husbandry and Ecology, Martin-Luther-University Halle-Wittenberg, Theodor-Lieser-Str. 11, 06120 Halle, Germany
2
IFIP, The French Pork and Pig Institute, La Motte au Vicomte, B.P. 35104, 35651 Le Rheu, France
3
Department of Livestock Sciences, Research Institute of Organic Agriculture FiBL, Ackerstrasse 113, 5070 Frick, Switzerland
4
PEGASE, INRAE, Institut Agro, 35590 Saint Gilles, France
5
Department of Behavioural Physiology of Livestock, University of Hohenheim, Schloss Hohenheim 1, 70599 Stuttgart, Germany
6
Clinic for Swine, Ludwig-Maximilians-University Munich, Sonnenstrasse 16, 85764 Oberschleissheim, Germany
*
Author to whom correspondence should be addressed.
†
In memory of and gratitude to Ulrike Weiler who passed away on 26 July 2020.
Animals 2020, 10(11), 2140; https://doi.org/10.3390/ani10112140
Submission received: 6 October 2020
/
Revised: 11 November 2020
/
Accepted: 14 November 2020
/
Published: 17 November 2020
(This article belongs to the Special Issue Surgical Castration of Piglets and Its Alternatives: National Strategies, Consequences for Animal Welfare, Production Systems and Product Quality)
Simple Summary
Surgical castration of male piglets without pain treatment and anaesthesia is not only a welfare problem but also violates the integrity of the animals. The favoured alternatives of raising entire male pigs (EM) with or without immunocastration (vaccination against boar taint) may, however, impose additional welfare problems under the current housing and management conditions. This focused review is intended to summarise the current state of scientific knowledge and practical reports on critical welfare issues and risk factors. Raising EM with or without subsequent immunocastration could be a welfare conform, future-oriented alternative to conventional surgical castration of pigs, provided that they are kept in a healthy and socially stable environment with sufficient physical resources, as safeguarded by measures of enhanced animal care and management control.
Abstract
For a long time, scientists assumed that newborns have a severely limited sense of pain (if any). However, this assumption is wrong and led to a “start of the exit” from piglet surgical castration. Some of the currently discussed or already implemented alternatives such as general or local anaesthesia during surgical castration raise additional welfare concerns as well as legal problems and/or are hardly applicable. The favoured long-term, welfare-friendly “gold standard” is to raise entire male pigs (EM). However, this may also impose certain welfare problems under the current conventional housing and management conditions. The specific types of behaviour displayed by EM such as mounting and aggressive behaviours but also increased exploration, which are partially linked to sexual maturation, increase the risk for injuries. The current status of knowledge (scientific literature and farmer experiences) on housing of EM suggests that environmental enrichment, space, group-stability, social constellation, feeding (diet and feeder space), health and climate control are critical factors to be considered for future housing systems. From an animal welfare point of view, an intermediate variant to be favoured to reduce problematic behaviour could be to slaughter EM before reaching puberty or to immunize boars early on to suppress testicular function. Immunization against endogenous GnRH can reduce EM-specific problems after the 2nd vaccination.
Keywords:
welfare; entire males; immunocastration; behaviour; housing; management
