Agriculture Reference
In-Depth Information
transition period. The transition period, here defined as the last 10 d of gestation and the
first 10 d of lactation, encompasses substantial changes for the sow.
Sows entering the transition period are subjected to quite different feeding regimens.
Indeed, farmers, advisers and feed specialists have developed various feeding regimens
merely based on trial and error rather than on scientific knowledge. Ideally, the feeding of
sows during the transition period should be adapted to each individual while considering
the physiological stage (i.e. day of gestation or day of lactation), live weight and level of
productivity (e.g. milk yield) in order to meet the requirements for nutrients. In practice,
however, feeding sows seems to focus much more on minimization of manpower
and elimination of possible mistakes than maximizing sow productivity and, in most
countries, sow feeding pays no attention to factors such as parity or live weight of sows,
reproductive stage and productivity level.
The nutrient requirements of energy, protein and essential amino acids change rapidly
during transition. However, on most farms the feeding system is only capable of
supplying a single diet to each pen, and therefore the shift from a gestation diet to a
lactation diet most often coincides with transfer of the sow to the farrowing unit shortly
before parturition. The nutrient contents of gestation and lactation diets therefore need
to compromise between what is optimal for fetal growth, mammary growth, colostrum
production, milk production, sow maintenance and sow body gain/body mobilisation.
This chapter will focus on the discrepancy between the simplicity of practical sow feeding
and the complexity of sow physiology and on the rapid changes in nutrients required to
ensure optimal sow performance. This chapter will reveal which traits are important to
consider when feeding transition sows, it will give an overview on how hyperprolific sows
are fed today and how they should be fed optimally based on calculated requirements of
energy, lysine and nitrogen using a factorial approach.
7.2
The importance of the transition period
In spite of its short duration, the transition period is very important, mainly because
the number of weaned piglets is a major determining factor for the productivity of
sows and most losses of piglets occur in the first 3 d after parturition (Rootwelt
et al.
,
2013). During the transition period important biological events take place, and many
physiological processes related with reproductive output are markedly altered. Many
of these traits are (or may potentially be) affected by sow nutrition. In the following
paragraphs, the most important traits are described along with the known or expected
impact of feeding.
7.2.1
Neonatal piglet mortality and neonatal energy supply
Neonatal piglet mortality includes both the losses of piglets before and during the
farrowing process (stillborn piglets) and mortality of liveborn piglets. Both losses are
complex issues because multiple factors are involved in their underlying causes. Stillborn
piglets are associated at least partly with the farrowing process (Oliviero
et al.
, 2010). On
