Agriculture Reference
In-Depth Information
F
300
50
F
45
F
250
40
F
35
200
30
25
150
20
15
100
10
H
L
5
50
0
0
100
200
300
400
500
600
Stage (days)
Fig. 4.3.
Simulated long-term effect of appetite during lactation (L: 5.0 kg/day, H: 7.0 kg/day) on the change
in body weight and backfat thickness over the first four parities (F: farrowing). (From Dourmad
et al
., 2008.)
than for H sows, and this was compensated
for by a higher weight gain during gestation.
The same was observed for backfat thickness:
L sows were leaner at weaning and fatter at
farrowing. This results in an increased risk of
reproductive problems in L sows, both at
weaning because they are too lean, and at far-
rowing because they are too fat. Average daily
feed intake over the complete reproductive
cycle (3.5 kg/day) did not differ between L and
H sows. However, SID lysine and digestible
phosphorus requirements during lactation
were much higher, per kilogramme of feed, in
L than in H sows, whereas no noticeable differ-
ence was found during gestation.
During gestation, the strategy to reach
the target of body condition at farrowing is
first to adapt the total energy or feed supply
according to body condition at mating, parity,
expected litter performance and housing con-
ditions. In this context, measuring or estimat-
ing sow BW and BT is important to adapt the
feeding allowance to the situation of each
sow. When the total amount of feed or energy
is defined, different strategies can be used to
partition this amount over gestation. It is gen-
erally recognized that increasing feed allow-
ance in late pregnancy, over the last
3
weeks,
may improve piglet vitality and survival at
birth, especially in hyperprolific sows. The
strategy during the first two-thirds of preg-
nancy is less clear and may depend on the
type of housing and the available equipment
for feed distribution. Two strategies are
mainly found in practice during that period:
either a rather constant level of feeding, or a
period of overfeeding of thin sows, over about
4
weeks, followed by a period of restriction.
This second strategy, which allows a rapid re-
constitution of sow body reserves in early
gestation, is becoming more common in the
context of European Union legislation on
sow welfare, which requires group housing
after
4
weeks of pregnancy. Defining a feeding
strategy for gestating sows may also require
Dealing with the Variability of
Requirements
An important question in the practical nu-
trition of sows is how to deal with variability
in requirements among sows. This variability
originates from variability in reproductive
performance (e.g. litter size), in productive
capacity (e.g. milk production) and appetite
(e.g. during lactation). Moreover, the re-
quirements also differ according to parity
and physiological stage.
