Sow longevity - The Gestating and Lactating Sow - page 426

high demands on their locomotion system (Kroneman et al. , 1993) as they have to
compete for resources such as feed and shelter (Muirhead, 1983). Studies compared the
effect of housing sows in stalls or in groups on their locomotion ability and reported that
sows kept in groups without bedding had significantly more locomotion problems than
sows kept in stalls during gestation (Anil et al. , 2005; Backus et al. , 1997; Harris et al. ,
2006; Kroneman et al. , 1993; Pluym et al. , 2011). Studies indicate that more than 96%
of group-housed sows and 80% of confined sows during gestation have at least one toe
lesion (Anil et al. , 2007; Enokida et al. 2011; Gjein and Larssen, 1995; Grégoire et al. , 2013;
Pluym et al. , 2011). Olsson and Svendsen (2002) reported no differences in toe injury
between group-housed sows with the dunging area being either solid concrete partially
slatted with concrete slats, or partially slatted with plastic slats. Smith and Robertson
(1971) reported excessive culling among sows housed on partially slatted floors in stalls
or in groups during gestation. D'Allaire et al. (1989), found that annual culling rates were
higher in herds that had totally or partially slatted floors during gestation compared with
culling rate from sows housed on solid floors. The MAFF (1981) reported that when feet
and leg injuries occurred in dry sows, there was no difference between sows housed on
solid or perforated flooring.
Quality of the floor is related to feet and leg injuries and culling rate due to lameness
(Barnett et al. , 2001). Under natural conditions, the ground is usually soft and damp
(Heinonen et al. , 2006). However, most flooring types used in pig production are hard
surfaces with little or no bedding provided. Flooring should not become deformed,
deteriorate or require extraordinary maintenance (Baxter and Mitchell, 1977; Peet,
1983). Additionally, the flooring used in sow housing facilities should minimize animal
discomfort and injury and provide them the opportunity for safe movement in dry and
wet conditions (Cowin, 1978). Furthermore, the flooring should provide the pigs with
the possibility to walk using a normal gait instead of forcing them to alter their gait in
order to reduce the risk of slips and injury (Von Wachenfelt et al. , 2008). Low friction
can cause slips and falls damaging the joints (McKee and Dumelow, 1995). Hard floors
can cause sows to have bruised and swollen legs when lying on the floor. Over abrasive
floors can result in excessive toe wear of sows, whereas too little abrasiveness could lead
to overgrown toes (McKee and Dumelow, 1995).
Solid concrete floors are associated with increased lameness and toe abrasions (Webb
and Nilsson, 1983) as the floor's roughness and abrasiveness contribute to horn removal
from the toe (Zoric et al. , 2008). Furthermore, prolonged standing on bare concrete
may increase the pressure applied to the toe (Hinterhofer et al. , 2006) and irritate the
corium. There is an increased risk of lameness when sows are housed on slatted concrete
compared with sows housed on solid concrete floorings (Heinonen et al. , 2006; Nakano
et al. , 1981). Slatted floors present some challenges to the animals, such as an uneven
walking surface, a reduced weight bearing surface, a lack of bedding and sharp slat edges
(KilBride et al. , 2009). Heinonen et al. (2006) scored 846 sows and gilts in 21 Finnish
herds for lameness and reported that animals housed on slatted floors had twice the
odds of being lame and 3.7 times the odds of being severely lame than animals housed
on solid floors.