Use of infrared thermography in evaluation of Nelore and Angus breed submitted to heat stress

• Grant number: 15/07624-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2015
• End date: January 31, 2017
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: José Fernando Garcia
• Grantee: Samanta Stábile da Silva
• Host Institution: Faculdade de Medicina Veterinária (FMVA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

The exposure of cattle to extreme weather conditions, such as high temperature and humidity, can negatively affect the growth and reproductive performance of these animals. There are great differences between the responses of each subspecies when exposed to these conditions, once their thermotolerance and adaptability levels differ. To evaluate the effect of exposure to heat and breed on the control response to temperature changes, the present study will evaluate 40 males around one year of age, 20 Nelore and 20 of Angus breed, which will be grouped into four experimental units containing 10 animals each. Two of the groups (Nelore and Angus) will be exposed to natural sunlight throughout all the day along the experiment, and the other two groups will have free access to shade. Infrared thermography will be used in this project beacause is a fast, accurate and non-invasive way to monitor the mechanisms used by the body to return to homeostasis after exposure to heat. Flir i7® thermographic camera (Flir Systems - USA) will be used to take two photographs of each animal (entire lateral extent of the body and testes).The animals will be photographed every five days in three different moments, but always in same periods: 1. Between noon and 3PM (when the effects of heat are more evident), 2. Between 7 to 10PM of the same day and 3. Between 5 and 8AM of the following day, so as to allow evaluation of recoverability of animals exposed to thermal stress. The thermographic images will be studied and compared between races and between groups.