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October 2016 25
Pork News & Views
October 2016
Capturing Potential through
Nutrition: Group Housed
Gestating Sows
Capturing Potential through Nutrition: Group
On Sept 6th and 7th at the Group Sow
Housing Seminar in Stratford, Quincy Buis,
a recent
M.Sc. graduate from the University
of Guelph, and I delivered a presentation
titled “Capturing Potential Through Nutri-
tion: Group Housed Gestating Sows”. The
presentation focused on energy and protein
requirements for gestating sows, feeding
strategies to meet these requirements, and
on additional nutritional aspects to consider
with group housed sows, such as feeding
fibre to increase satiety.
Let’s start with the basics… The ultimate
goal when feeding sows is to increase her
lifetime productivity by optimizing the
number of healthy pigs weaned per sow per
lifetime. When doing this, we also need to
consider things like feed costs, sow welfare,
sow health and nutrient losses to the environ-
ment. Many farms are now approaching and
surpassing 30 pigs weaned/sow/year, and
nutrition plays a very large part in this.
When managing sows, regardless of their
housing system, we need to minimize body
condition and weight changes throughout
her reproductive life. During gestation
we want her to gain weight related to her
pregnancy, and allow for maternal growth in
younger animals (parity 3 or 4 and below)
without putting on excess weight or condi-
tion. In lactation we want to minimize sow
weight loss as much as possible. In order
to achieve these goals, we need to meet her
nutrient demands as accurately as possible
throughout the gestation phase.
The two most important nutrients when
feeding gestating sows are energy and amino
acids (protein). Additionally, we must make
sure we are meeting the micronutrient
requirements (vitamins and minerals) of
these animals. We must also consider feeding
strategies to increase satiety (the feeling of
fullness) in restricted fed gestating sows.
First we will look at protein and energy
requirements throughout gestation. The
requirements for both of these are lower at
the start of gestation and increase over time.
Figure 1 shows the typical protein deposition
patterns for different components through-
out gestation. Between day 20-70 we see
rapid placental growth, and starting around
day 50, we see exponential fetal growth. For
this reason, the dietary lysine requirements
of a sow are about 33% higher in the last 3rd
of gestation (Figure 2). Keeping in mind the
fact that younger sows also require protein
for their own growth, we see a 38% decrease
in lysine requirements between a parity 1 and
parity 4+ sow (Figure 2).
Standard practice in the swine industry is to
increase the amount of feed a sow gets as
she moves towards the end of her gesta-
tion period. These graphs show that simply
increasing the amount of diet (and keeping
the protein to energy ratio the same) may
not meet the needs of the sow. Strategies
such as phase feeding or precision feeding
should be considered when feeding pregnant
sows. With phase feeding, you change the
diet composition as she progresses through
gestation, thus allowing you to more closely
match her nutrient requirements. Precision
feeding is a newer technique which is becom-
ing more practical with the use of electronic
sow feeders. With precision feeding, you can
have two different diets (low and high pro-
tein for example), and blend them together
on a daily basis at the feeder, allowing you to
target each sow specifically for her parity and
stage of gestation. This technique will not
only allow you to meet the nutrient require-
ments more closely, but it will also help you
reduce feed costs and nutrient losses to the
environment (Clowes et al., 2002; Pomar et
al., 2012), and may improve sow productivity
and longevity.
The final point I am going to discuss in
this article is using fibre to increase satiety
in gestating sows. Typically, sows are limit
fed because over-feeding leads to reduced
productivity, difficulty farrowing and reduced
longevity. Limit feeding sows can lead to
Day 1-89
Day 90-114
+33%
-38%
0
0.7
0.6
0.5
0.4
0.3
0.2
Parity 1 Parity 2 Parity 4+
Day of gestation
20 40 60 80 100
Fetus
Placenta & Fluids
Uterus
Mammary
1500
2000
1000
500
0
Figure 1. Typical protein deposition patterns
for fetus, mammary tissue, placenta and
fluids as a function of time (Brazer et al.,
2012; NRC 2012).
Figure 2. Estimated lysine requirements of
gestating sows in early (light blue bars) and
late (dark blue bars) gestation for parities 1, 2
and 4+.
Day of gestation
15 29 43 57 71 85 99 113
+45%
+194%
Engery Lys
SID Lys, g/d
ME, kecal/d
0
1000
2000
3000
4000
5000
6000
7000
0
5
10
15
20
25
Figure 3. Estimated energy (green line) and
lysine (purple line) requirements of the
gestating gilt (Buis et al., 2016).