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Study of phenotypic causal networks of Babesia bovis, tick resistance and body weights at different ages in HEREFORD and BRAFORD cattle using structural equation model

Grant number: 17/08940-3
Support type:Scholarships abroad - Research Internship - Doctorate
Effective date (Start): August 28, 2017
Effective date (End): August 27, 2018
Field of knowledge:Agronomical Sciences - Animal Husbandry
Principal Investigator:Henrique Nunes de Oliveira
Grantee:Ligia Cavani
Supervisor abroad: Guilherme Jordao de Magalhaes Rosa
Home Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
Local de pesquisa : University of Wisconsin-Madison (UW-Madison), United States  
Associated to the scholarship:15/13024-0 - Genomic study on infection rate of Babesia bovis and association with resistance of tick in Hereford and Braford cattle, BP.DR

Abstract

Tick and tick-borne diseases, including the babesia (B. bovis), constitute a major drawback to improve productivity of beef cattle in the tropics, especially for systems in which taurine animals and their crosses are used. The control of ticks using acaricide treatments decreased the likelihood of babesiosis outbreaks that may cause high mortality rate. New applications of animal breeding and genetics can bring important new insights regarding phenotypic traits, e.g. the relationship between economically important traits. The objective of this research is to search for causal structures among infection level of B. bovis and tick counts traits, and body weights at different ages in Hereford and Braford cattle. Phenotypes for tick counts and blood samples, for DNA extraction, were obtained from approximately 1,860 Hereford and Bradford beef cattle, from herds from south region of Brazil. The B. bovis quantification was performed using the qPCR assays to obtain the NC mt-cyB values from genomic DNA of each animal with specific primers for this protozoan and the absolute quantification method. Also, weight traits included birth weight, and weight adjusted to 205 and 550 days of age. The inductive causation (IC) algorithm will be applied to the residual (co)variances obtained from a standard Bayesian Multiple Trait Model, and structural equation model will be fitted to the causal network inferred by the IC algorithm application.