Page 1 of 2
By Dr. Ron Meijerhof , Poultry Performance Plus, Voorst, the Netherlands
In the world of broiler meat production, developments happen quickly. The increase in broiler performance in commercial breeds has been tremendous. This performance is not only established in growth per day, but also in feed conversion, carcass yield, breast meat yield, mortality, leg quality, etc. The modern broiler of today is barely comparable with the bird of 20 or 30 years ago due to very intense and very sophisticated genetic selection.This is nicely demonstrated in a famous experiment in the USA. A group of researchers compared two lines of broilers, one with the genetic characteristics of the broiler lines of 40 years ago, and one with the characteristics of today. They also developed two different feeds, one with the characteristics of 40 years ago, and a modern broiler feed. When the different lines were given the different feeds, it became very clear that the improvement in performance is largely due to the genetic improvement, as the birds of today did well on the feed of 40 years ago, but the birds with the genetic profile of 40 years ago hardly benefited from the modern feed.
From an economical standpoint, it is very clear that a breeding company has no choice than to focus its selection program mainly on broiler traits and to a much lesser extent on breeder traits. As the cost price of a day old chick is only a fraction of the cost price of a full grown broiler, a 10% improvement in broiler traits is worth much more money than a 10% improvement in breeder traits. After all, we are not in this business to produce hatching eggs or day old chicks, but to produce meat.
The broiler-breeder paradox
Unfortunately, selecting on one trait has often consequences for other traits that are not necessarily directly associated with the trait that we select on. One clear example is the influence of selecting for growth on reproductive performance. It is often assumed that there is a negative correlation between broiler and breeder traits, sometimes called the broiler-breeder paradox. This paradox states that if the broiler characteristics in a line improve, its reproductive capacity will be impaired.
Unfortunately, selecting on one trait has often consequences for other traits that are not necessarily directly associated with the trait that we select on. One clear example is the influence of selecting for growth on reproductive performance. It is often assumed that there is a negative correlation between broiler and breeder traits, sometimes called the broiler-breeder paradox. This paradox states that if the broiler characteristics in a line improve, its reproductive capacity will be impaired.
 |
| Despite very high genetic growth potential for broiler offspring, most commercial breeder flocks reach 85% peak production or even more. |
Although from a biological standpoint this is true, our modern broiler lines paint a different picture. The genetic potential for growth and broiler characteristics has never been as high as now, however it is not uncommon for most commercial broiler breeder flocks to have 85% peak production or more. There are differences between the different breeds, but reaching 85 or even 90% peak of production is a level where 15 years ago producers could only have dreamed of.
We must have great respect for the geneticists that work in the different breeding companies, as well as for the research institutes and universities that have contributed to developing the tools that made these progresses possible, because they have been able to overcome the broiler-breeder paradox.
Modern management
However, if we take a closer look at the different commercial lines, we see that the genetic improvements have an impact on the management strategies that we have to apply. As broilers are the end product of different lines with different characteristics, each breeding program has to make a choice of which broiler traits are represented in which line. Although in reality all lines are selected on more or less all traits, the focus on which traits should be present in which lines is not equal for all breeds.
However, if we take a closer look at the different commercial lines, we see that the genetic improvements have an impact on the management strategies that we have to apply. As broilers are the end product of different lines with different characteristics, each breeding program has to make a choice of which broiler traits are represented in which line. Although in reality all lines are selected on more or less all traits, the focus on which traits should be present in which lines is not equal for all breeds.
As a high growth potential in a female breeder has a negative effect on reproduction, some breeds focus their broiler traits more on the males than on the females. The result is that egg production in these lines goes very well, but the males with a higher growth potential need stricter management in rearing and production to have satisfying results. As they tend to get overweight more easily, it is more difficult to keep them active and in good condition then when the focus for broiler traits is more on the females.
If the females are genetically more selected on broiler traits, we see that female management is more difficult but a good fertility is easier in reach, resulting sometimes in flocks with 90% hatch of eggs set for a period of more than 10 weeks. Probably the biggest challenge for geneticists is to keep all the lines in balance with each other, in such a way that in the field the product can cope with all the circumstances that we can apply to them, as the same breed will be used at different places and in different conditions.
Page 1 of 2 | Next Page »
Source: World Poultry, Vol. 27, No. 8, 2011
