Oct 19, 2013

Layer hens are genetically developed to convert feed to eggs unlike in broiler genetics where the emphasis is on converting feed into body mass.

The most import concept of layer nutrition is to understand that layer hens eat to meet their energy needs. As the energy level of a diet is reduced, the hen will increase her intake in order to maintain her energy requirements for maintenance and production.

While breeder companies supply recommended feeding specifications for their birds, these specs are in most instances over cautious as well as based on top quartile producer records based on world wide collected. This does not mean that the data can be directly applied to the individual on-farm or the Southern African scenario.

Feed mills, together with their nutritionists, take into account raw material availability and costs as well as the local conditions when formulating layer diets.

Feed mills produce a range of rations to best suit the hen’s nutritional needs taking into account the individual housing conditions, stress levels, disease pressures and farmer needs in terms of expected production requirements. Each range has a set energy level with low speced diets having a lower energy level than their high speced counterparts.

Feeds are mostly evaluated by most users critically looking at protein and calcium levels. It is more important to know the lysine levels rather than crude protein.

Within each range of layer diets the actual inclusion rates of the lysine varies. The actual inclusion rate is scientifically determined in order to both optimize the birds needs while ensuring that birds are not overfed expensive nutrients that are both superfluous and a waste as well as detrimental to production.

Protein levels in layer diets are often over speced. Protein is made of building blocks called amino acids. Modern layer diets are formulated on amino acid levels and not total crude protein.

When looking at the results of feed analyses one normally looks at crude protein levels. The correct way is to look at the essential amino acid levels and in most instances the crude protein levels are secondary. So be careful to make an assessment on feed quality based on the crude protein result only.

When pullets are transferred into lay at 16 weeks they are referred to as POL. (Point of Lays)

A POL is normally light framed as the carcass is still maturing. The ability for this small framed hen to consume high levels of feed in a given lighting period is limited. As a result the feed needs to be concentrated. In other words if she can only consume 90 grams a day as determined by her energy needs, we need to ensure that she will still consume the minimum amino acids (and protein) and other essential micro nutrients within the 90 grams.

Feed companies supply a ration that will meet her emerging needs. Eg a layer 90 or 95 for young hens, light in frame and with a low energy requirement.

As the hen matures, her energy needs increase, while her amino acid and other micro nutrients remain fairly static. As a result of the increased demand on energy, we see her consuming more feed. Intakes can rise to 115 or even 120 grams per day.

If she is still being fed a high density ration such as a 90 or 95, she will over consume essential amino acids and other essential micro nutrients. The problem with this scenario is the hen, apart from over eating excessive expensive nutrients, actually has to expend energy to excrete them. This excretion process uses expensive energy in the feed.

A double impact on costs!

The ideal is to match her intake with a suitable lower density ration, where her energy needs a met but her micro and amino acids are NOT overfed. Eg a 100 and more depending on her actual feed intake.

The net results in over consuming high density rations is:

1. expensive as it is a waste

2. costs energy from the bird which is detrimental

3. performance is negatively affected

In summary:

Young hens are fed a high density ration eg 90 or 95

Mid aged hens are fed a slightly lower density ration eg 100 or 105

Mature hens are fed low density rations eg 110 or 115

The above deals with the basic science behind layer feeds against  the hens actual needs. At a practical farm level we need to take this information and apply it to what will work for both the hen and the farmer.

Basically, there are 2 ways feedmills supply their layer rations.

Option 1

This requires that the farmer is in tune with his hen’s intakes and able to understand the on-going physiological changes to a hen’s nutrient requirements.

As stated in earlier, a hen’s mean feed intake is measured on a weekly basis. Based on this intake a ration type is then fed to best fit the hen’s needs. While one works on a mean weekly intake it is probably best to average out the intake over a month before making ration changes. This is because a hen does not fair well with constant feed changes.

Feed intake table

Average Intake (grams) Suitable Ration Type
90 – 95 Layer 90
95 – 100 Layer 95
100 – 105 Layer 100
105 – 110 Layer 105
110 – 115 Layer 110
115 – 120 Layer 115
120 – plus Layer 120

Over a hens life her energy needs increase as she increase in body-weight and her feed efficiency reduces. These are the reasons why a young pullet will start her productive life on a layer 90 or 95 and end up at the end of her cycle on a layer 110 or 115.

By following this system of feeding layer hens, the farmer will optimize the hen’s intakes to her needs while at the same time reducing feed costs on wasted nutrients.

Option 2

This system involves the feedmill making decisions for the farmer and the hen. This will unfortunately not take into account farm related variances.

The feed company supplies two and at the most three optional rations. These are split into phases, namely phase 1, phase 2 and phase 3. The feedmill will also adapt the different phases for seasonal variation.

Pullets are placed directly onto Phase 1. After a period in lay they are then moved onto Phase 2 and if available, Phase 3.

While the principal involved still involves meeting the hen’s energy needs, the system is not as flexible as feeding option 1.

On the positive side, confusion is eliminated