Agriculture Reference
In-Depth Information
housing conditions and environmental conditions such as temperature and humidity.
An exception is the recommendation in France to feed older sows 0.4 kg/d more than
gilts from d 101 of gestation until parturition. And in the Netherlands, it is common to
provide gestating sows 0.15 to 0.25 kg/d more during the winter time, although that is
not confined to the transition period.
7.4
Recent advances
7.4.1
Nutrient requirements during transition using a factorial
approach
The nutrients required during late gestation can be calculated daily using a factorial
approach in which separate requirements for sow maintenance, fetal growth, mammary
growth, uterine tissues (uterus, placenta, fluids and membranes), colostrum production
and heat loss associated with these reproductive traits are summed (Feyera and Theil,
2014; Figure 7.4). From a nutritional point of view, the amount of energy required for
reproduction prior to parturition is rather small even in late gestation (12% of intake),
whereas the amount of protein required is much higher (41% of intake; Noblet
et al.
,
1985). The requirements and dynamics with respect to weights of sows and weights of
their offspring are well described and this can be seen in Chapter 6 (Trottier
et al.
, 2015).
For instance, the requirement for metabolizable energy of gestating sows is regarded
as being constant per kg of metabolic live weight (405 kJ/kg
0.75
; NRC, 2012), yet, fetal
growth is known to follow an exponential growth curve. The dynamic changes of
Maintenance +
additional losses
Placenta +
uids + membranes
Fetal growth
Dietary nutrients
(energy, lysine, nitrogen)
Uterus
Mammary growth
Colostrum
and milk
Figure 7.4. Mathematical model describing the nutrient requirements of transition sows. Additional losses
refer, for energy, to costs above maintenance associated with reproductive outputs and, for nitrogen, they
refer to additional oxidation of proteins due to e.g. amino acid imbalances. Note that after parturition, no
nutrients are required for fetal growth, placenta, fluids and membranes, and that the uterus regresses and
supplies nutrients to the circulation, which can be used for milk production. The losses in feces are not shown.
