The effect of the Naked Neck genotype (<Emphasis Type="Italic">Nana</Emphasis>), feeding and outdoor rearing on growth and carcass characteristics of free range broilers in a hot climate |
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Authors: | André Martinho de Almeida Urs Zuber |
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Institution: | 1.Instituto de Investiga??o Científica Tropical,Lisboa,Portugal;2.CIISA—Centro Interdisciplinar de Investiga??o em Sanidade Animal,Lisboa,Portugal;3.Departamento de Zootecnia,Universidade de évora,évora,Portugal;4.IICT-CVZ, Fac. Med. Veterinária,Av. Univ. Técnica,Lisboa,Portugal |
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Abstract: | Alternative poultry production with special reference to free range broilers has increased significantly since the nineties
in many regions of the world. Numerous factors influence the productive performance of this type of broilers: genotype (namely
the use of naked neck animals), feeding and access to an outdoor area. The aim of this paper is to study the influence of
each of these factors on the productive performance of free range broilers under commercial rearing conditions. A total of
3200, day old chicks of both sexes from naked neck and normally feathered genotypes were used in this trial. After a joint
initiation phase, animals were divided into four different treatments with the combination of two concentrates (high vs low
energy content) and management (access to outside park or not). Experiment lasted a total of 12 weeks. Live weight date was
recorded weekly and a samples of animals from the trial were sacrificed at the age of 8, 10 and 12 weeks, when carcass characteristics
were determined. Besides sex, the only factor that seems to affect growth characteristics was genotype as naked neck animals
had poorer growth rates than normally feathered. No effect was detected on carcass yields and percentages of carcass components
for any of the variables. From the data presented in this trial the practises associated with free range production are of
relative inconsequence to the technical animal production parameters and can only be justified by a pressing need to differentiate
these products from standard poultry products in what concerns both welfare issues and meat characteristics. The results also
indicate that genetic material from alternative poultry production in Europe can be a useful option in poultry production
development projects in the tropics. |
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