Agriculture Reference
In-Depth Information
less affected by seasonal infertility when compared with sows housed in group systems.
Love
et al.
(1993) found no seasonal effect on farrowing rate in sows individually-housed
during gestation. Conversely, Thacker (2002) reported that seasonal infertility is greater
among group-housed sows than sows housed in gestation crates. This seasonal variation
can lead to longevity issues or increased culling and/or mortality during certain times of
the year (Stalder
et al.
, 2007b).
High ambient temperatures result in reduced appetite, milk production, and body
reserve mobilization in lactating sows (Prunier
et al.
, 1997). Similarly, Koketsu and
Dial (1997) reported that sows farrowing during the summer had lower litter weights
and longer weaning to service intervals compared with sows that farrowed during the
other seasons. All of these factors likely play a role in the delayed return to oestrus and
increased sow culling for reproductive failure that typically occur after weaning in high
temperature conditions.
Several studies reported that mortalities are more frequent during the months with
elevated temperatures (Chagnon
et al.
, 1991; Deen and Xue, 1999; Engblom
et al.
, 2008;
Koketsu, 2000). In a study by Chagnon
et al.
(1991) a third of sow deaths occurred during
the months of July and August and Sanz
et al.
(2007) also reported that temperatures
>32 °C contribute to sow mortality. Jones (1967, 1968) observed that more than 55% of
sows died during the winter months. Therefore, management of ambient temperature
through various cooling or heating devices is essential to reduce sow mortality. Also,
producers should not overlook the effect that people or workers have on sow longevity
(Thacker, 2002). The summer months are times when workers take vacations and
inexperienced personnel therefore handle more tasks on a sow farm. This in turn could
explain a portion of the problems associated with these months.
19.9
People/management or stockmanship skills effects on
sow longevity
Management practices and stockmanship of people employed on pig farms influence some
factors that contribute to sow culling and/or mortality. Castro and Piva (1999) suggested
that management and human resources play an important role on all productivity aspects
of modern swine operations. Furthermore, English (2002) pointed out the importance of
good stockmanship on swine welfare and productivity. Shortage of labour, and especially
skilled, knowledgeable, experienced labour, can lead to inadequate care and management
of animals and result in an increase in sow mortality and culling rate (Loula, 2000; Young
and Aherne, 2005). According to Loula (2000), the observation of sows for signs of
disease and/or injury is an important key to reduce sow mortality as, at least in the case
of culling or euthanasia, it is the employee's subjective decision that determines whether
a sow will be removed (Engblom
et al.
, 2008). Hence, appropriate training programs for
employees are essential, particularly for those without livestock experience, in order to
develop the observational skills and attention to details required on a successful swine
operation (Stalder
et al.
, 2007a).
