feed broiler cobb

1. T E C H N I C A L F O C U S 9 I S S U E 2 , J U N E 2 0 2 3
There are a number of challenges still to
face in 2023, not only in Europe but in
the rest of the world. Avian influenza will
continue impacting global supply chains with
restrictions on imports and exports of meat
and birds; the increased effect of price-
driven behaviour through foreign exchange
volatility and the economic downturn.
Companies around the world will continue
to face operational challenges of high and
volatile feed prices, high energy and freight
costs, although this seems to have returned
to prices seen in September 2020.
The increase of commodity prices associated
with poultry feed means the optimization
of feed costs is very important. With this in
mind, the question has to be asked “How low
can I go?!” in terms of nutrient specifications
without impacting performance. When
looking at feed cost there are three key
drivers that seem to stand out, available
phosphorus, digestible lysine and energy
level. Accordingly, a study was conducted
assessing the performance response to
lowered available phosphorus and calcium,
energy and digestible Lysine. The trial was
conducted at a Cobb Europe research facility
in the Netherlands from 1 to 34 days of age
using Cobb 500 FF chicks sourced from a
commercial hatchery and placed in floor
pens with 50 birds per pen. Four treatments
shown in Table 1 were arranged in a
randomized block design with 12 replicate
pens per treatment.
During the study period body weight was
measured at 0, 7, 14, 21, 28, and 34 days
of age, feed allocations were recorded at
the same intervals and the weekly FCR was
calculated. Statistical analysis was carried out
on JMP 15 using a one-way ANOVA. The body
weight results in Table 1 demonstrate that
there was no significant treatment effect on
the average body weight.
Although there was no treatment effect
on the average body weight, the mortality-
adjusted FCR does show a significant
treatment effect after 7 days of age.
Treatment 2 with reduced available
phosphorus and calcium shows no
significant effect at all time points when
compared with the control. While treatments
3 and 4 although not significantly different
from each other are significantly different
from the control.
Continued on next page...
I
In poultry production, feed is
an inescapable production cost.
In recent years raw material
costs have risen drastically
highlighting the price volatility of
key ingredients which themselves
have been heavily influenced by
several factors.
Factors driving the price volatility
range from downgraded harvest
forecasts, Covid-19, avian influenza
and the conflict between Russia
and Ukraine. These then impact the
total feed costs as well as the costs
of proteins.
How Low Can
You Go? – What is the
optimal broiler diet nutrient density
in times of economic pressure?
Andrew Catlett
Nutritionist,
Cobb Europe
Starter Grower 1 Grower 2 Finisher
Age 0-12 13-21 22-28 29 to kill
Treatment Specification
Control/T1 As per Cobb 500 2022 Recommendations
T2
Available Phosphorus % 0.54 0.35 0.3 0.25
Calcium % 0.96 0.76 0.54 0.5
T3
Dig Lysine -3% 1.22 1.13 1.03 0.93
Available Phosphorus % 0.54 0.35 0.3 0.25
Calcium % 0.96 0.76 0.54 0.5
Energy Kcal/kg -3% 2900 2860 2960 3010
T4
Dig Lysine -6% 1.18 1.08 1.00 0.90
Available Phosphorus % 0.54 0.35 0.3 0.25
Calcium % 0.96 0.76 0.54 0.5
Energy Kcal/kg -3% 2900 2860 2960 3010
Table 1: Average Body Weight (kg)
AGE (days)
7 14 21 28 34
T1 - Control 0.166a
0.502a
1.091a
1.776a
2.363a
T2 - Avail Phos & Cal 0.166a
0.508a
1.094a
1.776a
2.391a
T3 - Reduced Energy & AA -3% 0.166a
0.497a
1.066a
1.759a
2.355a
T4 - Reduced Energy & AA -6% 0.165a
0.499a
1.078a
1.740a
2.319a
Averages within each age group not sharing a common superscript within a column differ
significantly (P < 0.05).
Table 2: Average FCR adj
AGE (days)
7 14 21 28 34
T1 - Control 0.891a
1.032a
1.202a
1.330a
1.437ab
T2 - Avail Phos & Cal 0.889a
1.027a
1.203ab
1.329a
1.436b
T3 - Reduced Energy & AA -3% 0.898a
1.043b
1.224c
1.350b
1.457ac
T4 - Reduced Energy & AA -6% 0.901a
1.046b
1.078ab
1.358b
1.477c
Averages within each age group not sharing a common superscript within a column differ
significantly (P < 0.05).

2. T E C H N I C A L F O C U S 10 I S S U E 2 , J U N E 2 0 2 3
C O B B - VA N T R E S S . C O M
The results of the study show that there
is potential to lower available phosphorus
and calcium without affecting performance
significantly. When considering the
performance of treatments 3 and 4 more
caution needs to be applied. Although
body weight was not significantly affected,
the significant increase in the amount of
feed could potentially cancel out the feed
cost saving initially created by adjusting
the nutrient specifications. However, upon
evaluating the feed cost saving and the feed
cost per bird as shown in Table 4, there
is a definite scope to evaluating reduced
specifications during periods of increased
raw material prices.
The trial uncovered a potential to decrease
feed costs, however, there was a small risk.
As shown in Table 5, the data indicated that
as the level of digestible lysine decreased,
the subsequent FCR and time to reach
3.278 kg increased. However, there was a
diminishing return in FCR as the digestible
lysine level increased (Figure 1). The results
also indicated a similar titration in the grower
and finisher phases.
Breast meat yield was also evaluated and
demonstrated a clear response to digestible
lysine levels between 1.18 and 1.26%
(Figure 2). Like FCR, breast meat yield had a
diminished response at a certain point (1.26%).
Studies like these are critical when evaluating
nutrient specifications because the
relationship between feed cost, time taken
to reach a certain weight and breast meat
yield can be determined. The old saying
“Rob Peter to pay Paul”, is very true if the
impact of the specification changes are
not understood, as well as the context in
which birds are produced. The studies show
reducing specifications may be applicable
in small bird markets and the focus isn’t on
breast meat yield. Conversely, in markets
where bigger birds are grown and breast
meat yield is important, an economic needs
evaluation should be considered with data
from processing plants and feed mills.
Table 4: Average feed cost per ton for each treatment over the whole feeding program
Average Feed Cost
per Ton
Feed Cost Saving Feed Cost/Kg Live
T1 - Control €556.93 - £0.800
T2 - Av P & Ca €551.84 -€5.09 £0.791
T3 - AA -3% €553.01 -€23.93 £.0777
T4 - AA -6% €528.49 -€28.44 £0.781
Table 5: The digestible Lysine level in the starter, the subsequent FCR and the number
of days taken to reach 3.278 kg
% Dig. Lys in Starter Feed FCR Days to Reach 3.278 kg
1.18 1.642 45
1.2 1.612 44
1.22 1.592 43
1.24 1.575 42.5
1.26 1.560 42
1.28 1.543 42
1.3 1.535 41.5
1.32 1.526 41
1.34 1.520 41
Figure 1. The relationship between FCR and digestible Lysine.
About the author:
Andrew attended the University of
KwaZulu Natal completing a Bachelor
of Science in Agriculture specialising
in Animal and Poultry Science. After
graduating Andrew relocated to the
UK where he worked in research for
5 years before joining Moy Park as
Nutritionist. While working at Moy Park
Andrew completed is MSc in Applied
Poultry Science. Before Joining Cobb
Europe in February 2022, he worked
within the Sub-Saharan Africa market as
a nutritionist for Cargill and Adisseo.
Figure 2. The relationship between breast meat yield and levels of digestible lysine.