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Genetic diversity is one of the most important issues in studies on conservation of cattle breeds and endangered species. The objective of this study was to estimate the levels of genetic differentiation between locally adapted taurine (Bos taurus taurus) and zebu (Bos taurus indicus) breeds in Brazil, which were genotyped for more than 777,000 SNPs. The fixation index (F ), principal component analysis (PCA), and Bayesian clustering were estimated. The F highlighted genetic differentiation between taurine and zebu breeds. The taurine lines, Caracu and Caracu Caldeano, had significant genetic differentiation (F close to 5%) despite their recent selection for different uses (meat and milk). This genetic variability can be used for conservation of locally adapted animals, as well as for breeding programs on zebu breeds. Introgression of zebu in locally adapted breeds was identified, especially in Curraleiro Pé-Duro breed. The Gyr breed, however, had low breed purity at genomic level due to its very heterogeneous mixing pattern.

ABSTRACT. Genetic variability at 11 microsatellite markers was analyzed in five naturalized/local Brazilian horse breeds or genetic groups. Blood samples were collected from 328 animals of the breeds Campeira (Santa Catarina State), Lavradeira (Roraima State), Pantaneira (Pantanal Mato-Grossense), Mangalarga Marchador (Minas Gerais State), as well as the genetic group Baixadeiro (Maranhão State), and the exotic breeds English Thoroughbred and Arab. We found significant genetic variability within evaluated microsatellite loci, with observed heterozygosis varying between 0.426 and 0.768 and polymorphism information content values of 0.751 to 0.914. All breeds showed high inbreeding coefficients and were not in Hardy-Weinberg equilibrium. The smallest genetic distance was seen between the Pantaneira and Arab breeds. The principal component analyzes and Bayesian approach demonstrated that the exotic breeds have had a significant influence on the genetic formation of the local breeds, with introgression of English Throroughbred in Pantaneira and Lavradeira, as well as genetic proximity between the Arab, Pantaneira and Mangalarga Marchador populations. This study shows the need to conserve traits acquired by naturalized horse breeds over centuries of natural selection in Brazil due to the genetic uniqueness of each group, suggesting a reduced gene flow between them. These results reinforce the need to include these herds in animal genetic resource conservation programs to maximize the genetic variability and conserve useful allele combinations.

RESUMOAmostras de sangue foram obtidas de 138 equinos registrados da raça Campeiro, com idade média de 9,7±5,4 anos, sendo 14 machos (10,15%) e 124 fêmeas (89,85%). Observaram-se valores médios da atividade sérica de GGT: 13,73±4,08 U/L; AST: 246,34±72,87U/L; ALT: 5,13±1,18U/L; FA: 284,32±53,33UI/L; CK: 132,54±72,25U/L; LDH: 511,38±143,65U/L; e das concentrações séricas de ureia: 38,65±12,62mg/dL e de creatinina: 1,24±0,24mg/dL. Os valores médios de AST, FA, ALT, ureia e creatinina foram semelhantes aos propostos na literatura para outras raças. Os valores de CK, GGT e LDH foram superiores aos comumente utilizados como referências. Não houve diferença nas concentrações de nenhum dos componentes séricos avaliados nas diferentes idades analisadas. Maiores valores médios nas concentrações de ureia e menores de creatinina foram observados nas fêmeas em relação aos machos, assim como a maior atividade sérica de FA em fêmeas gestantes em relação às éguas vazias. O perfil bioquímico sérico de equinos sadios da raça Campeiro apresenta variações peculiares que devem ser levadas em consideração na interpretação de exames laboratoriais.Palavras-chave: equino, Campeiro, análises clínicas, bioquímica sérica, enzimas GGT: 13.73 ABSTRACT Blood samples were obtained from 138 equines of the Campeiro breed with mean ages of 9.7±5.4 years, including 14 males (10.15%) and 124 mares (89.85%). Mean values of serum of

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