Hematological, biochemical and hormonal parameters for the evaluation of the heat stress of the heifers in integrated livestock forest systems

• Grant number: 19/20039-5
• Support type: Regular Research Grants
• Duration: February 01, 2020 - January 31, 2022
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal researcher: Cristiana Andrighetto
• Grantee: Cristiana Andrighetto
• Home Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil
• Assoc. researchers: Gustavo Pavan Mateus

Abstract

New strategies are being implemented, to increase the productivity of beef cattle, maintaining sustainability, one of the technologies for this purpose are integrated crop livestock systems. Integrated livestock forest systems are a modality of the integrated crop livestock systems and get better productivity, implementing production techniques integrating animals with forage, plants and trees in the same place. Trees in pastures provides shading that improve better thermal comfort to the animals, promoting satisfactory effects on the productivity of the herd. The heat stress modify the physiological mechanisms aiming to maintain the homeostasis of the animal, inducing neuroendocrine, physiological and behavioral responses that will maintain the homeostasis of the animal. The objective of the project will be to evaluate the performance, hematological parameters, acute phase protein and hormonal concentrations of Nellore heifers and crossbreeding Angus x Nellore heifers in integrated livestock forest system with 340 eucalyptus ha-1 and conventional pasture. The experiment will be conducted at Agência Paulista de Tecnologia dos Agronegócios, located in Andradina, SP. It will be used randomized block design in factorial designs with two treatments and two genetic groups. Thirty-two Nellore heifers and thirty-two crossbreeding Angus x Nellore heifers with initial weight around 280 kg and with initial age 12 months. It will be used eight animals for paddock (four Nellore heifers and four Angus x Nellore heifers), with four repetitions (paddock) and two treatments. The treatments will be: Treatment 1: conventional pasture, without the forest component; Treatment 2: Integrated livestock forest systems, with eucalyptus planted in triple lines trees (340 eucalyptus ha-1). The following evaluations will be performed: herbage mass, bromatological analysis, animal performance, temperature and humidity index (THI), globe temperature and humidity index (GTHI), respiratory rate, blood cell analysis, triiodothyronine, thyroxine, total protein, albumin, globulin, cortisol, and haptoglobin. The data will be analyzed using the SAS 9.4. program. (AU)