Impact of heat stress on the productive traits of Girolando cattle

• Grant number: 24/18006-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2024
• End date: June 30, 2025
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Renata Negri dos Santos
• Grantee: Beatriz Emiko Suda
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil
• Associated research grant: 24/08528-9 - Effects of heat stress on production traits of the Girolando breed and selection for tolerance to heat stress, AP.R

Abstract

Despite the myriad of research in dairy farming, there is a gap regarding the implications of genotype-environment interaction in the selection of suitable animals for each environment. In this sense, there is a growing interest in modeling and quantifying the effects of heat stress on the productive characteristics of Girolando animals raised in tropical and subtropical regions. And from this knowledge, establish methodologies for evaluating and selecting more efficient and heat-stress-tolerant animals, according to the different regions of the country, and collaborate for the development of sustainable dairy farming. The project aims to investigate the effect of heat stress on the quality of dairy from Girolando cattle raised in tropical climates and provide subsidies for the development of evaluation and selection methodologies for heat tolerance in different breed compositions of Girolando in the country in subsequent research. The data used (phenotypes and pedigree) will be collected by Breed Association and made available by Embrapa Dairy Cattle. Data of test-day milk yield, protein, fat and somatic cell score of different breed compositions, of first calving order, collected between 2000 and 2024 will be used. Climate data will be freely accessed on the website of the National Institute of Meteorology. The identification of the heat comfort threshold and quantification of production losses will be performed for each breed composition. To visualize the impact of heat stress on the different breed compositions, the heat comfort limit will be estimated through a two-phase linear regression analysis applied to the least squares mean and subsequent quantification of production losses. For the analyses, the main software used will be R, REMLF90, BLUPF90.