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Genetics parameters and genomic wide association study for linear conformation traits, ease milking and temperament in dairy Gyr

Grant number: 18/23664-5
Support type:Scholarships in Brazil - Master
Effective date (Start): March 01, 2019
Effective date (End): August 31, 2020
Field of knowledge:Agronomical Sciences - Animal Husbandry
Principal Investigator:Danísio Prado Munari
Grantee:Samla Marques Freire Cunha
Home Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
Associated scholarship(s):19/09736-6 - Genetics parameters and genomic wide association study for linear conformation traits, milking ease and temperament for dairy Gir, BE.EP.MS

Abstract

The dairy cattle industry mainly objective is the increase of milk production and the decrease of costs generated by the replacement of animals in the herd. Leading to achieve these goals, the conformation traits, milking ease and temperament can be used to help in the selection of more productive animals, with better body conformation and easy management. The aim of this study is to verify if in the Gir breed it is possible modify the conformation traits of mammary system traits (anterior udder, posterior udder, udder depth, teats length, teats diameter), of feet and legs (foot angle, legs - side view, legs - rear view), of corporal dimension (thoracic perimeter, body length, navel length, rump length, rump height, rump angle, width of the ischia and width between the ilium) of milking ease and temperament by selection and how this traits interfere with milk production. Besides that, we intend evaluate possible association between single nucleotide polymorphisms (SNP) and the study traits. The data set belongs to the Programa Nacional de Melhoramento do Gir Leiteiro, available by Embrapa Gado de Leite. The proposed animal model for the traits will include fixed effects and random effects of genetic additive and permanent environment of animals and residual. At first, the fixed effects for conformation body traits, milking ease and temperament will be contemporary group (farm and evaluation season), evaluation year, appraiser, preferential treatment and cow age at evaluation as covariate. For milk production the fixed effects will be contemporary group (farm and year of birth), season of birth, preferential treatment and cow age at birth as a covariate. Will be performed single and two-trait analyses to estimates genetic parameters, by using Bayesian methodology. The genome-wide study association will be performed using the single-step GBLUP methodology (ssGBLUP). After that, the genes include in the significant regions will be identified using the Bos taurus taurus genome available on the Genome Data Viewer on NCBI and after that the gene enrichment will be performed using DAVID software.