Agriculture Reference
In-Depth Information
2 or 3 m
2
), and Barnett
et al.
(1992) noted that gilts regrouped at a space allowance of 1
m
2
had elevated cortisol concentrations and an impaired immune response at 21 d after
regrouping, compared with gilts housed at 2 m
2
.
19.6.2
Gestation housing and longevity
Pig housing systems have to meet the animal's and the producer's requirements.
Productivity, management, welfare, health and economy are some of the main criteria to
take into consideration when designing housing systems for pregnant sows (Den Hartog
et al.,
1993). Gestation housing is dealt in more details in Chapter 3 of the present topic
(Spoolder and Vermeer, 2015). Housing systems can be divided into individual (tethers,
gestation stalls) and group systems. The classification of the different group housing
systems is based on the feeding system used and includes static or dynamic groups.
Comparisons between group- and individually-housed sows for different traits that
can have an influence on sow longevity include trauma or injuries (lameness, shoulder
sores, vulva biting, etc.), general management (working conditions, sow observation),
health (cross infections, new infections, exercise, etc.), nutrition, welfare, and other traits
(Stalder
et al.
, 2007a).
Bates
et al.
(2003) did not find a difference in the proportion of sows returning to oestrus
between sows housed in gestation stalls or group-housed with an electronic sow feeder
during gestation. However, the percentage of sows returning to oestrus by 7 d post-
weaning was 72% for the group-housed sows and only 68.4% for the sows housed in
gestation stalls. Farrowing rate was also higher in group-housed sows (94.3%) when
compared with stall-housed sows (89.4%). Backus
et al.
(1997) reported that gestating
sows housed in stalls took fewer days to return to oestrus after weaning than sows that
were group-housed with electronic feeders; however, the number of piglets born alive
tended to be similar in both groups (10.9 piglets born alive sows housed in individual
stalls vs. 11.0 piglets born alive for sows housed in groups). Barbari (2000) reported
lower farrowing rates in farms that have group vs. individual gestational housing. Sows
not returning to oestrus are often culled thereby shortening their productive lifetime or
reducing their longevity.
Results comparing mortality rates between individually housed sows and sows that were
tethered during gestation are contradictory. Abiven
et al.
(1998) indicated that farms
housing sows in individual stalls were at a greater risk of high mortality when compared
with farms that tether sows during gestation. On the other hand, D'Allaire
et al.
(1992)
reported that sows housed in individual stalls during gestation were less likely to die when
compared with tethered sows. Stone (1981) and Friendship
et al.
(1986) both reported
that improved sow longevity did not appear to be associated with sows housed either
in individual stalls or grouped in pens during gestation. Group-housing offers more
freedom of movement and space and consistent possibility to exercise; thereby increasing
muscle weight which may improve sow agility (Marchant and Broom, 1996). However,
group-housing presents other types of challenges such as higher hierarchical interactions
and aggression between sows as well as more feet and leg disorders (Backus
et al.
1997;
Kroneman
et al.
, 1993). Additionally, when sows are housed in groups, they experience
