Labex Korea – Several indicators of productivity have traditionally been used as a basis for evaluating and selecting species commercially exploited, generating impressive results on the productivity genetic gain.
The individual yield has experienced amazing advances, but achieving these limits has its price – the animal welfare – which for many researchers the results are not desired. The birds peck their mates up to death, piglets chewing the tails of the others and cattle with double muscle need cesareans for the parturition. These are some of the collateral effects observed in some species subjected to intense selection based on productivity indicators.
The uses of management practices to mitigate these collateral-effects have been widely criticized by society, which does not allow animals to suffer in all parts of the chain. This new wave leads breeding programs to rethink the strategies of selection, which means to include indicators of animal welfare to predict genetic value, in expectation of reducing management practices that lead to animal suffering.
The tail length in sheep is an example of the application of indicators that can be important for animal welfare, which is linked to the incidence of subcutaneous lesions caused by the flies’ larvae, especially in summer. Whereas the trait is hereditary, its inclusion in the selection indices will reduce it, alleviating the problem.
In the case of cattle production of mochas lines have also been a challenge because cut-horn is a painful surgical intervention, which in most cases is performed without the use of anesthetic, causing excessive pain to calves. For bovine with double muscling the challenges are greater, because the cesarean needs is linked with bone structure deficiencies, responsible for sustaining muscle load, which is not enough to enable a normal birth. The challenge is to find out the right combination of factors related to the production and reproduction.
Selection for phenotypic traits, aiming animals welfare, it’s just a matter of equalization of these with productive performance, theoretically, a simple challenge, compared the need for inclusion of indicators of social behavior on the selection process. The intensive production of pigs and poultry has found serious challenges to reduce cannibalism using management practices that may be in a short time prohibited.
Hens have their beaks cut at birth and piglets tail cut as practices to prevent the occurrence of cannibalism, which in both species, under normal conditions of handling, it is a social behavior, which stresses the birds and affects the productivity. The major challenge is to define of indicators “social” and selection models to be used in order to balance welfare and performance indicators. It would be impossible to create a mechanism for measuring individual behavior to selection effect, so the idea is to identify correlated indicator easy to be measured.
Viability could be the most likely trait to be linked, because it involve the two genetic components – individual and family ability to survival – according researchers from Wageningen University. These components are closely linked to social behavior that has a strong genetic component. A family where mortality is accelerated corresponds to an anti-social group, which should be eliminated. The researchers are seeking to identify the genes involved, believing it to be possible to reduce the mortality rate of 3 to 4% per generation using more sociable animals.
In theory the prospects are relatively good, but in practice there are difficulties to explore the full potential of these benefits. Adding of measures of welfare in a breeding program reduces the intensity of selection for traits with greater economic interest. There is an indication that more sociable birds are more delayed, reducing the productive longevity, a characteristic that is not interesting to the producer, who prefers cutting beaks.
The expected changes in the process of defining the traits to be incorporated into the selection process are directly linked to changes in the scenario imposed by the market, which basically depends of pressures and guidelines imposed by the consumer. New models of production systems, e.g. production on the ground, that banning the use of cages in egg production, creates the need for investment by breeding companies to development of more sociable hens’ strains.
However, for a long time, issues related to animal welfare will be solved through developing management practices more humanitarian, seeking for a smaller animal stress. There are many bottlenecks to be overcome before the incorporation welfare indicators in a commercial breeding program.
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