Pedigree analysis in the Brazilian Zebu breeds

Zebu breeds play an important role in cattle production systems in Brazil. To assess the genetic variability from animals in the Herd Books of Nelore, Gir and Guzerat breeds, generation intervals, inbreeding, effective population size and parameters of gene origin (effective number of founders, ance...

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Published in:Journal of animal breeding and genetics (1986) 2009-04, Vol.126 (2), p.148-153
Main Authors: Faria, F.J.C, Filho, A.E.V, Madalena, F.E, Josahkian, L.A
Format: Article
Language:English
Subjects:
Animal populations
Animals
Bos indicus
Brazil
Breeding of animals
Cattle
Cattle - genetics
effective population size
generation interval
Genetic diversity
genetic variability
Genetic Variation
Genetics, Population
Inbreeding
Pedigree
pedigree analysis
Population Density
Selective breeding
zebu
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Summary:Zebu breeds play an important role in cattle production systems in Brazil. To assess the genetic variability from animals in the Herd Books of Nelore, Gir and Guzerat breeds, generation intervals, inbreeding, effective population size and parameters of gene origin (effective number of founders, ancestors and founder genomes) were calculated using pedigree records from 1938 to 1998. Breed subdivision was quantified by Wright's F-statistics. Calculations were separately carried out for consecutive 4-year intervals in the period 1979-98. Generation interval was around 8 years for the three breeds. Total inbreeding increased in all the breeds reaching values of 2.13%, 2.28% and 1.75%. Effective population size decreased from 85 to 68 in Nelore, from 70 to 45 in Gir and remained nearly constant around 104 in Guzerat. The quantities assessing the number of contributing ancestors decreased with time in all the breeds, and in the last analysed period the most important ancestor accounted for 14%, 3.1% and 4.1% in Nelore, Gir and Guzerat, respectively. Results indicate that the studied breeds are suffering from a loss of genetic variability which can result in negative effects on breeding and conservation purposes.
ISSN:0931-2668
1439-0388
DOI:10.1111/j.1439-0388.2008.00767.x