Agriculture Reference
In-Depth Information
Selection of gilts with optimal conformation traits is an important factor in preventing
lameness. Tiranti and Morrison (2006) monitored 961 gilts for one year and recorded
conformation scores for front and hind legs. They reported that risk of removal as a
result of lameness increased as rear leg conformation scores became poorer. The Tiranti
and Morrison (2006) findings corroborate previous reports from Grindflek and Sehested
(1996) that female pigs with their hind limbs positioned too far forward when standing
had a decreased longevity. Furthermore, the Tiranti and Morrison (2006) findings support
the results reported by Jørgensen (2000b) that this characteristic was associated with
lameness in females at 6 months of age. Gilts with undesirable limb conformation scores
at the time of selection are at a higher risk of been removed from the herd and being
culled or euthanized because of lameness problems. Selection for limb conformation may
therefore result in improved performance of swine herds over time because of increased
longevity and consequent productivity of the sows (Tiranti and Morrison, 2006).
Toe (also called claw) lesions are very common in sows with up to 100% of the sows in
a breeding herd having at least one claw lesion (Anil
et al.
, 2007; Calderón Díaz
et al.
,
2013; Dewey
et al.
, 1993; Pluym
et al.
, 2011). Lesions on the weight bearing surface that
penetrate sensitive tissue are the most serious (Brooks
et al.
, 1977) because they may
permit the entry of infectious pathogens affecting the joints (Anil
et al.
, 2007; Zoric
et
al.
, 2004). Some of the most common toe lesions found in sows include cracks in the wall
and the white line, overgrown heels and toes and toe erosion (Anil
et al.
, 2007; KilBride
et al.
, 2010; Kirk
et al.
, 2005). Toe lesions may reduce sow longevity and reproductive
performance. Abnormal tow growth was reported to increase culling risk in Spanish
Landrace and Duroc sows (Fernández de Sevilla
et al.
, 2008). Fitzgerald
et al.
(2012)
observed that sows with cracks in the claw's wall weaned fewer piglets per litter and that
sows with overgrown claws had lighter litters at weaning compared with sows with no
such lesions. Toe lesions are recognized as a cause of lameness (Anil
et al.
, 2007; Dewey
et al.
, 1993; Pluym
et al.
, 2011). Although sows with mild lesions may show no evident
signs of pain, severe toe lesions may be painful and cause lameness (Deen, 2009). It is
estimated that between 5 to 20% of lameness is caused by toe lesions (Dewey
et al.
, 1993)
but this area is poorly researched. Whether toe lesions cause lameness depends on the
location (Anil
et al.
, 2007) and severity (Gjein and Larssen, 1995; Heinonen
et al.
, 2006)
of the lesions.
19.5.2
Importance of gilt development
Body composition at mating
Gilt body composition (backfat, loin depth and body weight) at mating can affect sow
longevity. Gilts need to build the body reserves that will allow them to have long productive
herd lives. The key to gilt development is to slow down protein deposition and build fat,
mineral, and other nutritional reserves that the gilt can utilize when lactation dietary
intake is not sufficient to meet needs (Stalder
et al.
, 2007b). Minimum levels of backfat are
needed for replacement gilts in order to maximize the number of piglets born alive in her
lifetime. Brisbane and Chenais (1996) reported that gilts with a backfat thickness >18 mm
were 10% more likely to remain in the herd until at least the fourth parity when compared
