Agriculture Reference
In-Depth Information
Farrowing kinetics, as well as many other developmental processes during gestation, can
be influenced by sow feeding during gestation and consequent body condition. Over-
feeding of the sow during pregnancy can indirectly compromise piglets by affecting the
mother's farrowing ability; if sows are obese and piglets become too big, the inter-birth
interval will increase, as will the potential for umbilical cord occlusion and stillbirth
(Leenhouwers
et al.
, 2001). Conversely, if the sow is under-fed during gestation there
are detrimental effects on placental size, fetal growth and the deposition of fetal body
reserves for use after birth (Wu
et al.
,
2004). Malnutrition in gestation can also lead to
impaired mammary gland development (Head and Williams, 1992; Kim
et al.
, 1999),
poor lactational output and may affect the future reproductive capabilities of the offspring
(Kerr and Cameron, 1995; O'Dowd
et al.
, 1997). There may even be intergenerational
influences (Gluckman and Hanson, 2004), as maternal metabolic function may itself have
been programmed when the mother was a fetus. Chapter 4 (Farmer and Hurley, 2015)
and 8 (Quesnel
et al.
, 2015) discuss late-gestational feeding management in greater detail.
Sows of advanced parity give birth to a higher number of stillborn piglets (Leenhouwers
et al.
, 2003; Randall and Penny, 1970) and farmers report that sows giving birth to dead
piglets often consistently produce stillborn piglets in subsequent litters, thus highlighting
a genetic component to this trait (Roehe
et al.
, 2010).
Colostrum availability
The early intake of colostrum by the newborn piglet is vital to its survival. Not only is
the initiation and maintenance of the thermogenic response to cold (discussed in a later
section) dependent on intake and metabolism of colostrum (Herpin
et al.
, 1994), but uptake
of maternal immunoglobulins directly from ingested colostrum is the only way for the
piglet to acquire passive immune protection (Rooke and Bland, 2002). Lactational output
and colostrum composition are dealt with in detail in Chapter 8 (Quesnel
et al.
, 2015) and
Chapter 9 (Hurley, 2015), respectively, and therefore will not be further discussed here,
except to highlight the growing evidence that in prolific genotypes colostrum transfer is
limited by sow yield rather than piglet acquisition (Devillers
et al.
, 2011).
For the first few hours after the onset of farrowing, colostrum is freely available (De
Passillé and Rushen, 1989). There is then a transition to cyclical let-downs occurring
approximately every 20 min. This nursing development is covered in more detail in
Chapter 13 (Špinka and Illmann, 2015), but it is apparent that if the sow does not display
appropriate maternal behaviour during this time, colostrum intake by the offspring can
be seriously compromised.
Maternal behaviour
For a piglet to ingest colostrum early in life it must have safe and easy access to the
udder. Thus the sow must be reasonably passive; lying laterally, exposing her udder and
emitting rhythmic grunts as an auditory cue to her newborns to suckle. Restless maternal
behaviour, particularly during farrowing, not only prevents early intake of colostrum but
