9/02/2021 | Press releases

Many parameters affect Egg Weight (E.W.). It is linked to genes, for instance, E.W. can vary from 1g to 1.5g between NOVOGEN Classic and Light strains. However, within this genetic potential, many factors can majorly influence egg weight even more than genetic factors, as you can manage between 1g to 5g of E.W. with Farm Management and Nutrition.

Body weight

Based on market requirements, it is important to define the desired egg weight before birds start laying.

Indeed, pullet body weight at start of lay is the main factor that influences egg weight. When birds become adults, margins for action are much more limited. Higher pullet Body Weight (B.W.) at sexual maturity means higher egg weight, the opposite is also true. One way to manage B.W. at sexual maturity is the lighting programme and stimulation. Below are some estimations of B.W. variation and light stimulation timing on the E.W:

  • +/- 100g of pullet B.W. is equivalent to +/- 0.7g to 1g of E.W.
  • 1 week of delay in light stimulation is equivalent to +/- 1g of E.W.

Variations in body weight at sexual maturity or the age at sexual maturity are two efficient ways to adjust egg weight according to market requirements. For those two factors, it is necessary to adjust the management strategy according to the B.W. of birds and not their age alone. Consequently, the birds have to be weighed on a weekly basis during the whole rearing period.

Nutrition in production

Once in production, the only way to adjust E.W. is through nutrition. The older the birds, the less efficient the Nutrition tools. In order to analyze it, we have carried out meta-analyses of nutrition with many institutional publications.

The first criteria are energy and oil/fat. 100kcal more energy will increase the E.W. by 0.85% on average, when 1 point more fat (from oil, not fat inside raw materials) will increase it to 1.1%. Adding oil seems more efficient than energy, and it’s less risky. Too much energy in the diet could produce fatty birds—the ideal situation is to provide at least 1% of oil with the same energy level.

Protein and Amino Acids (A.A.) also affect the E.W. From this meta-analysis, we saw that 1 point more protein will increase the E.W. to 1.65%. Increase Methionine and Lysine of 0.01% will also increase E.W. respectively of 0.5% and 0.4%. Protein seems to have a strong impact, but it could only be due to diets with low levels of protein (less impact at the field level used). As for A.A., Methionine is an important criterion to manage according to E.W. We recommend a range for the Methionine/Lysine ratio for the management of your target E.W.:

  • High E.W. = Ratio ≥ 58
  • Low E.W. = Ratio ≤ 46

Not enough Lysine will negatively affect E.W. as well as production. Determining the right amount for your local conditions is crucial.

Naturally, E.W. increases with the age of the flock. Many farmers want to avoid too many big eggs at the end of the flock. This criterion is selected in the NOVOGEN R&D programme in order to keep E.W. as stable as possible during the production cycle. However, Nutrition can also help to maintain E.W. Typically, it is recommended to invest at the onset of lay to reach a high peak of production and fast E.W. increase. Afterwards, it is possible to begin to optimize the feed formula. The target is to decrease the energy intake, the protein intake, and the A.A. intake (especially Methionine) to avoid big eggs. Since Lysine and Methionine are also involved in the laying percentage, it is necessary to provide enough of both or production could drop faster. Nutrition is always a compromise between feed cost and results, which depends on each farm condition. Further information can be found in our Nutrition guide and the technical team remain available to exchange on this topic.

Adjusting E.W. is manageable, but with less efficiency when birds are older. It is easier to manage your E.W. during rearing and not production. It is also more economical to invest in pullets (less feed intake and more efficiency) than in adult birds (less scope for adjustment).

Additional information

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