Feeding the modern genetic layer

28-09-2007 | |
Feeding the modern genetic layer

Highly productive breeds are available nearly all over the world and we know very detailed recommendations for feeding different layer hybrids bred by each primary breeding company. Some practical challenges, However, still need to be overcome, says Robert Pottgüter.

High productivity in layers is common under nearly optimal
conditions, but how will the modern genetic layer perform under less optimal
conditions? Is it possible to fulfil the nutritional recommendations from the
breeding companies for different breeds anywhere in the world? We don’t know a
universally accepted ideal amino acid profile for layers like we do for
broilers. Another major problem in feeding modern genetic layers is to determine
the energy content of all raw materials with a universally accepted and valid
evaluation system. Currently, nearly every country or region works with a
different system. In addition, will the typical corn-soy diets that are so
widely in use now be as readily available in the future? What are the
consequences of the bans on many feed supplements, antibiotic growth promoters
(AGPs) and medications? These aspects need to be discussed from a nutritional
point of view and also in terms of feed production.

Energy evaluation
One major
challenge for all nutritionists is energy evaluation of all available raw
materials and complete feed. The majority of the energy in the feed for our
birds is based on crude protein, crude fat, crude starch, and sugar. Which
measurement should we use: metabolisable energy (ME) expressed as kilocalories
(kcal) or as mega-joules (MJ)? Which metabolisable energy system should we use?
Should we use the tables from the WPSA (World Poultry Science Association) or
should we work with a kilocalorie formula based on the main nutrients mentioned
above when we use the well-known kilocalorie unit system? The same question is
evident when we work with a ME system expressed as mega-joules. Every energy
evaluation system we use must be easy to handle for raw materials and complete
feed. It should also be possible to use this system with currently used
optimisation programmes to create and optimise practical diets. When nutrient
values of raw materials change, it is better to use systems with slight
inaccuracies rather than not adjusting matrix data at all. This has to be done,
for example, by variation of starch content in grains or protein and fat content
in oil seed meal or cakes.

 Robert Pottgüter received his Diplom- Ingenieur-
Agrar at the Georg August Universität Göttingen in Germany. He has spent 24
years working as poultry feed product manager for deuka Deutsche Tiernahrung
GmbH & Co. KG in Düsseldorf, Germany and, since 2006, as a nutritionist
expert at Lohmann Tierzucht GmbH. Feeding modern layers starts with the day-old
chick, because during this first period the performance of the layer hen is
determined
.

With all systems or formulas, energy is the most expensive restriction in feed
optimisation. The energy content of the feed also has a major influence on feed
conversion ratio (FCR) and overall productivity. As a consequence, everybody
should check complete feed regularly for its energy content, especially if the
complete feed paid for. In order to accomplish these tasks, it is obvious that a
system is needed, which is based on easily analysed nutrients. This requirement
is the opposite of a ‘scientific only’ approach to conduct digestive trials with
animals to determine the ME-content of every raw material. This easy-to-use
energy evaluation system is needed for raw materials and complete feed as well.
The mega-joule formula from WPSA expressed as ME in mega-joules
per kilogramme represents such a system. The formula
includes the main nutrients, namely crude protein, crude fat, crude starch and
sugar, and is regression-based on animal trials.

Calculating from mega-joules to kilocalories and vice versa is done using the
factor 4,187. Which energy evaluation system should we use when enzymes are
included in the feed formulation and how will we work with the so-called energy
uplift? The energy uplift of NSP enzymes has been determined first with
broilers, and depends mainly on improved fat digestibility. However, layer diets
are completely different from broiler diets because layer diets, for instance,
very often show  low levels of added fat and oil. Should the energy uplift
be based on single raw materials and the adjustment of matrix data, or should it
be based on a percentage addition to the complete mixture? The uplift depends on
the inclusion level of raw materials with higher NSP content, if in fact this
uplift really exists. When using energy uplift to calculate the ME value of the
diet, the NSP content of the main raw materials needs to be analysed. Although
many questions in terms of using enzymes are not yet answered, it is recommended
to use NSP enzymes to promote healthier digestion. The enzymes must be used in
liquid form and “end-of-line” dosage if the feed has to be heat
treated.

Egg weight and quality

Egg weight and quality An important further challenge in
feeding layers is the short-term influence on egg weight. The optimal egg weight
depends on market demands in different countries, and is impossible to influence
very quickly by means of genetic changes. Nevertheless, while every breed is
bred for a certain egg weight, it is much easier to adjust egg weight by management and feeding. As we know, the main limiting
nutrients for egg weight are methionine, protein and linoleic acid. The content
of crude fat and the energy density of the feed also have a big influence on egg
weight during the laying period. One of the most common ways to adjust the egg
weight is to use a phase-feeding programme. Egg producers in most world markets
want to achieve a rapid increase in early egg weight followed by a very gradual
increase after peak production. Controlled feeding with the goal of reduced feed
intake and adjustment of house temperature are other means by which to influence
egg weight. In terms of egg quality, it is important to keep water quality in
mind. Egg producers should always ask: “Would I drink this water myself?” The
drinking water should be analysed regularly to avoid egg quality problems.
Mineral content is an example because it can certainly influence the eggshell
strength and overall egg quality. Water is also a carrier of vaccines,
medications and sometimes additional vitamins. The water system has to be
cleaned regularly to ensure healthy birds and optimal egg quality. In hot
climatic conditions, water is also necessary for cooling the birds.

Protein and amino acids
When
talking about protein and amino acids, there is much more common knowledge in
most countries concerning raw materials. Every breeding company has (to some
extent) different recommendations in feeding, especially regarding amino acids
for the different breeds. Also, since only the total amino acid content can be
analysed easily, the feed has to be formulated based on available amino acids.
The better the feed is adjusted in available amino acids, the lower the crude
protein content may be. In many situations, this is an easy way to save money on
feed formulation. Therefore, all nutritionists should use internationally
recognised methods to build the best amino acid matrix for each raw material.
For example, a well-known data tool is aminodat by Degussa or similar
information from Adisseo and Novus. For all who are involved in feeding layers,
it is a general recommendation to create an ideal amino acid profile for layers.
This should be the approach used by all scientists working in poultry
nutrition.

 
Raw materials
A big challenge in
terms of raw materials is to know the actual nutrient content of each batch.
Basic nutrients which should be analysed regularly are crude protein and total
content of methionine, lysine and threonine (analysis of more amino acids is
beneficial if possible). Starch is the most important energy source. It is also
necessary to analyse crude fat and the main minerals calcium, phosphorus, sodium
and chloride.
 
These are the very essential nutrients in every raw material needed to
build a raw material matrix. This matrix needs to be adjusted on a regular
basis. It is absolutely impossible to build a matrix based only on “tables from
the Internet”. While this seems to be obvious, it is very often forgotten.
Standard raw materials for poultry feed are corn (maize) and soya. Concerning
these major raw materials, we see increasing prices in the market due to the
high demand of soya worldwide and the increasing use of maize for the production
of ethanol and bio-energy. In many countries, other grains like wheat,
triticale, barley, oats, rye and sorghum are used successfully, together with
NSP enzymes.
 
Additionally, every feed producer has to look for grain by-products, such
as bran and corn or wheat germ as valuable raw materials for poultry feed. Soya
is a major vegetable protein source for poultry diets all over the world. There
are other raw materials high in protein content in addition to soybeans,
examples being rapeseed or canola meal, sunflower meal, peas, meat and bone meal
and fish meal of different varieties. All nutritionists are responsible for
looking for and testing new or unknown raw materials for layer diets. With the
inclusion of raw materials (grains) that are lower in energy content, we see an
increasing demand for fat or oil in layer diets. Fats and oils have the highest
energy density of all feed raw materials; up to three times higher than grain.
Added fats and oils bind dust and increase the palatability of mash feed, which
is often very important for supporting feed intake. Fat is not only an important
raw material, as crude fat it also is a very important nutrient.
 
Feeding diets higher in crude fat content promotes good liver health and is
beneficial for avoiding fatty liver syndrome. In hot climate feeding, it is also
essential to use diets higher in crude fat content and lower starch content in
order to reduce heat increment during digestion. It should be basic knowledge to
know the fatty acid profile (especially linoleic acid) when using fat and oil as
raw materials for layer diets. Increasing or decreasing linoleic acid content of
the diet is a well-known method of adjusting egg weight.

 

Other challenges
One of the other
challenges for feeding layers includes the use of Salmonella-free feed. This is
a standing request of every breeding company because consumers demand and expect
Salmonella-free food products. One of the biggest challenges in producing
Salmonella-free feed is to avoid any kind of recontamination during delivery and
storage of the feed until it is consumed by the birds.
 
Although some special supplements like organic acids are very useful to
achieve this aim, the major problem is very often the storage and handling of
the feed at the farms. Vegetarian and ecological/bio feed may also be a
challenge in the future. In many countries it is necessary to formulate layer
feeds without using any raw materials of animal origin, but rather with plant
origin ingredients only. Based on our own experience over several decades as a
breeding company, it can be said that the feeding of vegetarian feed is no
problem in any diets for layer type birds.
 
Feeding modern layers starts with the day-old chick, because during
this first period the performance of the layer hen is determined.
 
However, every nutritionist should use raw materials of animal origin such
as meat and bone meal when it is possible and legal for use in layer feed. These
raw materials are very cost effective in feed optimisation and provide highly
available nutrients. Furthermore, ecological/bio feed has become a big challenge
in some countries in the northern hemisphere. The main precondition of this feed
is that a ban on the inclusion of synthetic amino acids must be observed. In
general, this leads to a deficiency of methionine in nearly every diet. As we
know, methionine is the first limiting amino acid and this must be taken into
account when these diets are formulated. The European ban on all antibiotic
growth promoters (AGPs) in all poultry and livestock feed poses a big challenge
regarding the use of (alternative) feed additives in layer feed without
compromising animal health and performance.
 
Summary
While we may never be able
to solve all challenges to feed the modern genetic layer, we have to strive to
ensure profitable egg production in all regions of the world. Challenges include
the need for a universally accepted energy evaluation system and an equally
acceptable amino acid profile as nutritional baselines for layers. Concerning
more economical aspects, we need more emphasis on the use of raw materials other
than corn and soya as the main raw materials in layer diets.
 
New solutions have to be created to overcome the ban of AGPs and to stress
the use of alternatives. Examples of modern supplements are enzymes,
particularly phytase and NSP-enzymes, which should be implemented in every layer
diet, especially those diets with lower amounts of or no corn (maize).
Furthermore, there is an increasing need for an open discussion with consumer
advocacy groups and others interested in knowing how quality products are
produced with keeping animal welfare aspect in mind.
 
Source: Feed Mix Volume 15 No. 05

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