Over the last 25 years, the selection for productivity has led to an increase of 70 eggs and 5kg of egg mass at 70 weeks. At the other side, feed efficiency, expressed as kg of feed per kg of eggs produced, has gone from 3 to 2. This gain is enormous if we consider that feed costs are about 60 per cent to 70 per cent of the total production costs. Such progress demands a continuous adaptation of the management techniques and feed in the rearing and production period.

Controlling Feed Intake

During the 10 first weeks, the pullets do not control their feed intake related to the energy content of the feed. Hence, in this period any increase of energy in the feed stimulates the growth of the birds.

That is why it is recommended to use a high energy feed during the first five weeks of the rearing period. This promotes the consumption because of the easier uptake and the reduction in eating time. This improves as well as the growth of the pullet as the feed conversion.

Pullets are grain eaters and their consumption depends on the presentation, and in particular the particle size of the feed. As from 5 weeks of age the recommendations are following:

• Particles <0.5mm: 15 per cent maximum
• Particles >3.2mm: 10 per cent maximum

At least 75 to 80 per cent of the particles should have a size between 0.5 and 3.2mm.

From 10 weeks onwards, the birds gradually get the ability to regulate their feed intake related to the energy level of the feed. The objective then becomes to increase the feed intake capacity, so that the birds can increase their feed intake with 40 per cent during the first weeks of production. During this period, it is important to stimulate the development of the digestive tract by using feed with the same or lower energy content as the feed used during the production period.

Amino Acid Needs

The amino acids needs depend on the age and the feed conversion. For young pullets (less than five weeks) the needs are the same as for broilers.

Above six weeks of age, the amino acids needs are less well known, but it is inevitable that amino acid deficiency always results in a reduction in growth, an increase in the feed conversion and also a change in body composition. However, too fat chicks at the entrance to laying eggs have more prolapse.

Nutritional Recommendations for the Rearing Period

Novogen's nutritional recommendations are adapted to allow an optimal skeleton development and body weight of the pullets during the first five weeks with a feed similar to feed used for broilers with higher energy level and concentration of amino acids.

From five to 10 weeks of age, the Company recommends lowering the energy level of the feed. During this period, the pullets have developed a natural appetite so growth is not affected and the pullet is getting better prepared to a less energetic feed.

From 10 weeks of age, Novogen recommends a lower energy level to stimulate the development of the digestive tract to be better prepared for the onset of lay when the needs increase very rapidly.

The recommended energy levels of the 'pullet' and 'pre-lay' feed types depend on the energy levels used during the production period. To avoid penalising growth during the onset of lay and the ability to reach a high peak, the choice of energy levels will have to depend on the local circumstances of formulating feed and the energy level of the feed used during the production period.

November 2012