Estudo Morfométrico de Ovinos da Raça Crioula Lanada no Sul do Brasil: Um Subsídio para a Conservação In Situ
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2011-02-23
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Universidade Federal de Goiás
Resumo
Intense selection pressure is associated with global economy and market
conjectures, which has great influence and threatens the sustainability of genetic
varieties used in traditional crop and livestock production. Abrupt change of such
breeds for exotic ones is decreasing genetic diversity and has extinguished many
domestic varieties worldwide. The Crioula Lanada sheep breed is a Brazilian
cultural, ecological and genetic patrimony which was almost extinct in the mid
twentieth century. Conservation activities were established in Southern Brazil with
collaboration of a farmer´s association and the foundation of an institutional flock.
Currently, breed population is still small and little information about these animals
is available. It is necessary that characterization studies subsidize the
conservation of this important genetic resource so that farmers can make the best
of its use in different production systems. A phenotypical study was undertaken to
help handling activities and in situ conservation. 15 morphometric variables (cm)
and body weight (kg) were evaluated in 67 male and 812 female sheep, distributed
in five age categories and raised in four municipalities of Rio Grande do Sul and
two of Santa Catarina, Southern Brazil. The influence of age, sex, wool type and
geographic location (fixed effects) on morphometric measures was tested, in
addition to correlation, factor analysis and the discrimination of the Crioula Lanada
sample in Serrana or Fronteira ecotype. Variance, means test, descriptive,
correlation analysis and multivariate statistics were carried out using the Statistical
Analysis System Program (SAS, 2002). Age, sex and geographic location
revealed significant effect (p<0,001) on morphometric measures. Different
averages between age categories depend on which variable is being analyzed,
being all means equivalent when considering animals older than 3 years. Most
correlations where significant (p<0,05), being thoracic perimeter with body weight
the strongest (0,72). Correlation between head and body measures were medium
or weak, being strong between body weight. Head and body variables are more
related among themselves. Leg, arm and tail measurements revealed weak
correlations with body weight, besides not being different (p>0,05) among age
categories. Using multivariate statistics, it was possible to explain 81% of variance
with only two factors, whereat three groups of variables were identified: one with
body measures, the second with head measures and the third with thoracic
measures and body weight. 95% of Fronteira sheep were correctly classified in its
geographic location being possible to correctly classify animals of each herd of the
Serrana ecotype and the ecotypes themselves. The results found in this study can
be used as a dialectic instrument to study farmers perceptions and develop an in
situ conservation program for the Crioula Lanada breed
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SILVA, Marcelo Corrêa da. Morphometric Traits in Crioula Lanada Sheep in Southern Brazil: A Contribution for In Situ Conservation. 2011. 88 f. Dissertação (Mestrado em Ciências Agrárias - Veterinaria) - Universidade Federal de Goiás, Goiânia, 2011.