Meta-análise de parâmetros genéticos em ovinos e bubalinos

Abstract

MEDRADO, B. D. META-ANALYSIS OF GENETIC PARAMETERS IN SHEEP AND BUBALINE. 2021. 108p. Tese (Doutor em Ciência Animal nos Trópicos) - Escola de Medicina Veterinária e Zootecnia - Universidade Federal da Bahia, 2021. This study aimed to perform meta-analyzes of economic traits to estimate heritability and genetic correlations in sheep and buffalo species. The model with random effects was used in the meta analyzes, which included a total of 308 articles regarding sheep or buffaloes, 892 heritability coefficients, and 643 genetic correlations. The meta-analysis with sheep estimated heritability ranging from 0.1213 to 0.3912 for growth traits, from 0.0398 to 0.3047 for reproductive traits, 0.1724 to 0.2582 for resistance to nematodes traits, 0.3616 to 0.5808 for wool traits, and from 0.2063 to 0.3299 for carcass traits. The estimates of genetic correlations were mainly positive and ranged from 0.2500 to 0.9665, except for eggs per gram of feces with both body weight (-0.18) and hematocrit (-0.48). For buffalo, the weighted averages of heritabilities ranged from 0.2344 to 0.3811 for growth traits, 0.1134 to 0.2069 for reproductive traits, 0.1058 to 0.3130 for milk production traits, and from 0.1651 to 0.2751 for milk quality traits, and was 0.2075 for resistance to mastitis measure by somatic cell score. Most genetic correlations were positive, ranging from 0.1342 to 0.9884, but some correlations were negative such as expected between milk yield x fat percentage (-0.2103) and milk yield x protein percentage (-0.1967). Because they were obtained through the combination of many studies, carried out in different environments, with different breeds and methodologies, the estimates of the genetic parameters obtained in the present study can be used in breeding programs under different conditions. Thus, these results can support the development of genetic improvement programs in sheep and buffaloes, especially in developing and underdeveloped countries, that do not yet have a data control that allows to accurately estimate the parameters analyzed here, where these animals are of great economic importance.