Volume 165, April 2015, Pages 47–56
Group composition for fattening entire male pigs under enriched housing conditions—Influences on behaviour, injuries and boar taint compounds
Highlights
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- Single-sex and mixed-sex groups with entire and castrated males were compared under enriched housing conditions.
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- Groups with entire males did not differ in terms of behaviour.
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- Welfare of female pigs was not impaired when penned together with entire males.
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- More skin lesions were detected in single-sex compared to mixed-sex groups.
Abstract
In
organic farming, the production of pork from entire male pigs seems to
be the most promising alternative to castration, as organic animal
husbandry aims at high standards of animal welfare and elimination of
mutilations. However, previous research on behaviour of entire male pigs
was mostly carried out under barren housing conditions and is thus not
entirely transferrable to enriched housing conditions. In the present
study, we investigated single-sex and mixed-sex groups of entire male
pigs and compared them with mixed-sex groups of castrated male pigs
under organic housing conditions. On a commercial farm, 362 pigs
(average weight 22.7 kg, average age 80 days) were assigned to pens with
groups of 20 (+1) pigs according to three treatments: single-sex groups
with entire males (EE), mixed-sex groups with entire males and females
(EF) and mixed-sex groups with castrated males and females (CF). Skin
and tail lesions, lameness and the behaviours ‘head knocking/biting’,
‘fighting’ and ‘mounting’ were assessed on five days during the
fattening period. Average carcass weight for all sexes was 92 kg. After
slaughter, female reproductive organs were inspected for signs of
pregnancy. Fat samples of entire male pigs were analysed for
concentrations of androstenone and skatole. Entire males showed more
aggressive and mounting behaviours than castrated males (p < 0.001),
and no difference was found between entire males from the EE and EF
treatments. Welfare of female pigs was not impaired when penned together
with entire males compared to when penned together with castrates,
neither in terms of skin lesions nor in terms of received aggressive
behaviour. Pigs in the EE treatment had higher lesion scores than those
in the EF and CF treatments (p < 0.05 and p < 0.01,
respectively), while the two latter treatments did not differ. In the
inspected female reproductive organs, no pregnancy could be detected.
The concentration of androstenone in fat indicated that the presence or
absence of females in a group did not have an effect on the male pigs.
Of the 177 slaughtered entire male pigs, only one carcass was classified
as containing boar taint by a human nose test. Our findings suggest
that under enriched housing conditions, entire males can be kept in
single–sex groups as well as in mixed-sex groups with females without
compromise in animal welfare.
Keywords
- Agonistic behaviour;
- Mounting;
- Skin injuries;
- Organic;
- Androstenone
- Corresponding author. Tel.:
+41 62 865 7263; fax: +41 62 865 7273.
Copyright © 2015 Elsevier B.V. All rights reserved.
