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| Author(s): |
Bruna Folegatti Santana
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT) |
| Defense date: | 2019-11-08 |
| Examining board members: |
José Bento Sterman Ferraz;
Rafael Espigolan;
Ricardo da Fonseca
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| Advisor: | José Bento Sterman Ferraz; Ricardo Vieira Ventura |
| Abstract | |
Inbreeding mating schemes are commonly used as strategies to increase herd uniformity, due to increasing the frequency of homozygous genotypes in the population. This study aims to identify the effects of inbreeding on progeny uniformity in a commercial herd of beef cattle in Nellore breed. A total of 3,320 animals composed the genotype data set, in three panels densities (~30,00, ~75,000, ~780,000 SNPs). Markers in low densities were imputed to high, through the FImpute software. Breeding values (EBVs) were estimated for 595,232 animals in pedigree, considering nine traits: birth weight (BW), weaning weight (WW); weight at 18 months (W18); post-weaning weight gain (PWG345), scrotal circumference at 18 months (SC), precocity (PR), muscularity (MUSC), days to reach 180 Kg (D180), and days to reach 300 Kg (D300). The variability of EBVs was calculated between offspring of the same progenitor (minimum of 10 progenies), for each trait, and bulls were split into two groups: High Prepotency and Low Prepotency. The groups were compared regarding three inbreeding coefficients, one calculated by pedigree records (FPED), other according to a genomic relationship matrix (FGRM) and one by runs of homozygosity (ROH) proportion over autosomal genome (FROH). The bulls were also compared according to ROH characterization. Although the inbreeding coefficients did not differ between groups, there were indications of an association between prepotency and ROH segments in bulls of high prepotency. Results also point that the genome position where homozygosity is found may influence prepotency. (AU) | |
| FAPESP's process: | 17/10103-2 - Inbreeding effects on progeny uniformity of Nellore sires |
| Grantee: | Bruna Folegatti Santana |
| Support Opportunities: | Scholarships in Brazil - Master |