Agriculture Reference
In-Depth Information
often are fed to late-gestating sows), or due to both reasons. On the contrary, too high
a feeding level is a risk factor for developing the post-partum dysgalactia syndrome
(Papadopoulos
et al.
, 2010) and it may even increase sow mortality (Abiven
et al.
, 1998).
In addition, excessive feed supply for an extended period of time may lead to obese
sows, and this is associated with prolonged duration of farrowing (Oliviero
et al.
, 2010).
Inclusion of vegetable protein in late gestation diets has been reported to reduce the
occurrence of agalactia in sows compared with the inclusion of protein originating from
fish meal and meat and bone meal (Göransson, 1990). Likewise, reducing the energy
density of the diet (Göransson, 1989b) or reducing the energy supply during the last
few days before parturition (Göransson, 1989a) were shown to reduce the incidence of
agalactia. In general, sows that experience a farrowing-related disease often respond by
reducing the synthesis of colostrum or milk, or both. At present it is not clear why, but
part of the explanation may be a significant shift in nutrient prioritization (e.g. amino
acids may preferentially be used for producing new immunoglobulins to combat the
disease instead of being used for protein synthesis and secreted into colostrum or milk).
Another plausible explanation could be an insufficient water intake around farrowing
which potentially may reduce milk yield.
7.2.11
Heat production of transition sows
The sow heat production increases during the transition period mainly due to milk
production. The amount of energy required for maintenance (ME) is constant per unit of
metabolic live weight (kg
0.75
), except at parturition. Indeed, the ME is higher for lactating
sows (460 kJ/kg
0.75
) than for late gestating sows (405 kJ/kg
0.75
; NRC 2012). During the
last 10 d of gestation, the metabolic live weight of the sow hardly changes even though
the fetuses grow rapidly, and consequently the energy required for maintenance is rather
constant. For a young sow weighing 200 kg, the ME requirement is 21.5 MJ/d, whereas
it is around 29.2 MJ/d for a multiparous sow weighing 300 kg. These data illustrate that
the live weight of sows plays a central role for the energy requirement. If a standard
sow diet is used, then young sows with a live weight of 200 kg require 1.7 kg of feed to
meet their energy requirement for maintenance, whereas older sows with a live weight
of 300 kg require 2.2 kg of feed. At parturition, the live weight of sows typically drops by
approximately 20 kg due to litter birth and delivery of placenta and uterine fluids, but
the associated drop in sow metabolic live weight is almost counteracted by the increase
in ME from 405 kJ/kg
0.75
prior to parturition to 460 kJ/kg
0.75
after parturition. Thus, the
energy required for maintenance can be considered constant throughout the transition
period. However, sows produce additional heat, which is associated with reproductive
costs and diet-induced thermogenesis (Noblet
et al.
, 1985; Van Milgen
et al.
, 1997). he
contribution of the diet-induced thermogenesis to the additional heat loss of sows is not
known but in late gestating sows (d 104 of gestation, fed 3.5 kg/d) the total additional heat
loss can be estimated as 7.5 MJ/d by subtracting the calculated ME (NRC, 2012) from the
observed heat production in late gestation (Theil
et al.
, 2002). Right after parturition, the
additional heat loss is likely very low because the sow does not produce large quantities
of colostrum or milk. In contrast, from the onset of copious milk production on d 2
onwards, the additional heat loss increases considerably daily. The additional heat loss as
it relates with milk synthesis can be estimated as:
