Agriculture Reference
In-Depth Information
al.
, 2002, 2006). Administration of oxytocin in these studies resulted in increased piglet
bradycardia and meconium staining, with severe acidosis and compromised survival.
Thus, the misuse of drugs designed to improve farrowing outcome is an important risk
factor in mortality due to stillbirth and in the extent to which a live-born piglet has
suffered from hypoxia.
Postpartum management: colostrum intake and fostering
To ensure that all piglets ingest vital colostrum soon after birth, stockpeople can speed
landmark behaviours by placing piglets at a teat and assisting suckling. Giving assistance
to low vitality piglets will improve survival outcome. For example, Muns
et al.
(2014)
demonstrated that providing an oral supplementation of sow colostrum to piglets
weighing less than 1.35 kg within 4 h of birth increased IgG levels at d 4 postpartum.
Such interventions are of particular importance when litter size exceeds functional teat
number and when a greater number of low vitality, growth-retarded piglets are present.
Other interventions include split suckling and cross-fostering to achieve litter equalisation
or standardisation (i.e. similar size piglets).The use of nurse sow systems and the use of
artificial rearing systems can also assist in improving survival (see Baxter
et al.
, 2013 for
a full review of the managerial strategies and welfare implications of large litter size).
Split suckling is a technique employed on the initial sows farrowing in a batch when
fostering opportunities are limited. It involves dividing the litter into two groups and
allowing each group a specified period of non-competitive time at the udder to ingest
colostrum. This can be labour intensive and careful time management is needed to ensure
piglets on this regime are attended to regularly and alternated correctly. Therefore, if
fostering opportunities are available, it is the preferred option. If performed correctly,
cross-fostering enhances piglet survival (Cecchinato
et al.
, 2008; English
et al.
, 1977)
and can reduce the need for further management interventions for piglets that would
otherwise suffer from remaining in a large litter, or those low birth weight piglets that
are failing to compete for a productive teat with their larger littermates
.
However, there
are various welfare concerns associated with some fostering practices. These concerns
relate to the time after birth when fostering occurs and the problems with over-fostering
(Baxter
et al.
, 2013). Moving too early (i.e. before 6 h old) may deprive the piglet of access
to colostrum, whilst moving too late (i.e. after 24-48 h old) results in greater fighting
(Horrell, 1982), more disrupted suckling episodes and a greater chance of rejection by
the foster mother (Price
et al.
, 1994). Some farm managers will repeatedly cross-foster
piglets, moving them from sow to sow in an attempt to achieve more even weaning
weights. However, such practices are very disruptive for both the sow and piglets and thus
counter-productive, with continuously cross-fostered piglets failing to suckle regularly,
acquiring facial lacerations and showing no improvement in weaning weights (Robert
and Martineau, 2001).
The use of nurse sows as a solution to the challenges of large litters is now close to
ubiquitous in countries such as Denmark and the Netherlands, where hyper-prolific
breeding programmes have resulted in the
consistent production of surplus piglets.
However, such systems have yet to be widely used in other countries. There are two main
