Selection for persistency and profitability in layers

Professor Dr. Rudolf Preisinger


Prof. Dr. Rudolf Preisinger, Chief Technical Officer at the EW Group, held a presentation on the selection of Lohmann’s layer lines for the traits of persistence and profitability during a celebration organized by Ali, held at Fiumana Predappio (FC), Italy.
Geneticists must anticipate at least five years ahead as to what the market trends will be like as well as consumer orientation. When alternative breeding and organic egg production were introduced some years ago, no one believed that these would someday become dominant market trends.
At the time when the prospect of a prohibition of beak treatment was outlined, no one would have ever imagined that it would actually happen in several European countries. The same goes for male chicks, whose culling will be prohibited and replaced by determining sex in the egg. In fact, European legislation forbidding any kind of amputation to animals has been in place for a long time now. In the next five years, the determination of sex in the egg will be a reality, as will be the demand for layer nutrition where only non-GM raw materials and ingredients are to be used in the formulation.

The Lohmann Tierzucht genetic selection programme in Europe
Future selection goals are geared towards extending the production period and increasing the number of eggs per hen, improving shell quality, the number of saleable eggs and improving hen liveability.
At Lohmann Tierzucht, chickens are tested in enriched cages as well as in colony systems. A special testing procedure has been developed for floor housing where the hen is equipped with a small sensor on the foot pad that monitors when the bird goes in the nest to lay, her behaviour and what she does in the nest.

What do you ask a hen laying today?
Laying hens have to be strong and robust, pay frequent visits to the nest, have a docile behaviour, maintain a good plumage until the end of their lives, and lay strong-shelled eggs every day. Birds must be handled appropriately to avoid the phenomena of pecking, cannibalism and decreases in production.
A special set-up has been developed which involves the automatic closure of the nest entrance with a door. There is a hole inside the nest where the egg is laid into a final collection tube. This set-up helps monitor deposition behaviour and the quality of the egg. It is also important that hens choose a nest quickly with the minimum of selection time.
A genetic programme must focus on the future market needs of the industry, which is becoming increasingly cage-free, for example in Europe and North America. Increased profitability can only be achieved with longer cycles, less feed consumption for eggs sold, where due diligence and respect is paid to animal welfare, and high egg quality, both internally and externally.

Testing Lohmann hens to determine persistence and productivity
The production cycle must be broken down into segments in order to act on each segment in detail. Currently, the most relevant production features seen are persistent laying and shell stability throughout the production cycle.
When individual Lohmann hens are tested for a period of about 190 days, 3% laid 189 eggs over a span of 190 days, i.e. almost one egg per day; 40% laid an average of one egg per day for 63 days; and 25% laid an egg for 15 days before taking an interval of about a day.
Such persistent laying over a period of 100 days or more, requires that the flock have adequate nutrition to support shell formation and egg size.

In this experiment, it was noted that most hens laid one egg per day for more than 50 days, almost without interruption. In 50% of the cases, the interval was only one day, or two at the most, and then the hen resumed laying immediately. The testing concluded that persistency of lay and shell stability are the keys to success. The main challenge remains, that is to find hens that lay a strong-shelled egg every day.
Laying persistency and shell quality are of course only a few of a hen’s reproductive traits and in fact, the overall selection process is much more complex and includes various indexes such as number of eggs; egg weight; yolk and albumen quality; colour and shell strength; nesting behaviour; limiting floor eggs and many more indexes.

New selection traits: a look at the future
The new traits on which genetics are focused today, are the reduction in the length of the upper beak – a subject that has been researched on for years; the shape of the beak; feather cover; nesting behaviour and laying on the perch.

Genomic selection
Genomic selection and DNA analysis allow for a better selection of birds, especially for males. When a chick is hatched, a drop of blood is obtained and then placed on a piece of filter paper from which, about 50,000 markers for each male can be analysed, i.e. 50,000 pieces of available information, all allowing for more accurate selection. Testing is then performed and the genomic data obtained improves the selection process.
Genomic selection can be seen to improve laying persistency by about an additional 25%; gives a higher figure of egg per hen; feed efficiency improves; as does egg quality. In other words, genomic markers allow us to select the right candidates in advance and in a much more precise way.
The Lohmann hen will then have a perfect plumage, have high laying levels with an average of 100 eggs in 100 days and with only a one day break, then resume production for 90 days, 80 days etc., while being nourished appropriately to produce high quality eggs.