Abstract
In this paper, results of the effect of direct and indirect selection of quantitative fertility traits of cattle end heritability level are presented. Study of the quantitative genetic parameters was carried out on three large farms of Black and White, Holstein-Friesian cattle. Investigation included 3900 first calving cows, daughters of 54 bull sires. The effect of genetic group of the head of cattle (genotype) and of the herd on fertility and milk traits of heifers and first calving cows of Black and White breed was investigated. Genetic group of the head of cattle (genotype) had no significant effect in variation of the fertility traits compared to general average (P<0.01). The effect of herd caused statistically significant and highly significant deviation from the general average, P < 0.05 and P < 0.01. Established heritability coefficients for fertility traits had low values for age at insemination (0,112), duration of pregnancy (0,045) and duration of service period (0,097). Results were obtained by applying mathematicalstatistical analysis of data - using mixed model (Harvey, 1990). Mathematical-statistical analysis of data was carried out using linear methods with fixed influence through model of Least Squares (LS method). Genotype of the head of cattle caused no significant deviation of fertility traits (P>0,05).
Highlights
If we consider current changes in genetic improvement of cattle andM.M
Ostojić-Andrić great progress in reproduction technologies, it is obvious that programmes which are used today need to be changed and improved, especially because of problems occurring with the disease BSE - bovine spongiform encephlopatia or "mad cow disease”
In countries with most developed genetics in cattle breeding, embryo technology is used which enables rapid genetic progress. This is realized through application of new biotechnological methods and procedures aiming to improve the fertility and embryo technology in breeding of cattle of high genetic potential, biotechnological methods in the field of genetics and population genetics, application of new models and methods aiming to improve the conventional quantitative approach – higher accuracy of the estimation of breeding value of heads of cattle, introduction of molecular-biological procedures in genetical analysis of traits of economical importance
Summary
If we consider current changes in genetic improvement of cattle andM.M. Petrović, S. Ostojić-Andrić great progress in reproduction technologies, it is obvious that programmes which are used today need to be changed and improved, especially because of problems occurring with the disease BSE - bovine spongiform encephlopatia or "mad cow disease”. In countries with most developed genetics in cattle breeding, embryo technology is used which enables rapid genetic progress. This is realized through application of new biotechnological methods and procedures aiming to improve the fertility and embryo technology in breeding of cattle of high genetic potential, biotechnological methods in the field of genetics and population genetics, application of new models and methods aiming to improve the conventional quantitative approach – higher accuracy of the estimation of breeding value of heads of cattle, introduction of molecular-biological procedures in genetical analysis of traits of economical importance
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