Efeitos do índice de temperatura e umidade sobre componentes e qualidade microbiológica do leite cru em ambiente tropical.

Abstract

Milk is a very important food compound, both in economic and social means, being the basis for most cultures around the world. Brazil is one of the biggest world milk producers, which gives great importance to researches involving such field, given its potential to enhance both productivity and animal welfare. Thermic environment is an issue which can interfere both in the quality of life for dairy cows and its productivity. Given such context, the present study aimed to analyze the interference of Tempearature and Humidity Index Sensible Heat (THIsh) over physical-chemical and microbiological parameters in raw milk samples from half-blood cows from the municipality of Araxá, Minas Gerais, Brazil. Temperature and humidity data were provided by the National Institute of Meteorology (INMET), whereas the milk sample parameters data were given by a city cooperative. The time frame for this sudy was from October 10th 2016 to December 20th 2018. All data were submitted to statistical analysis in order to establish if there were any influence of heat stress over milk quality. The results indicated that the animals were under thermic comfort during November 2016, May to Semptember 2017, and February, May to September and November 2018. During the rest of the time, these animals were under heat stress, which can harm the full expression of its genetic potential. Amongst the quality parameters, only the fat suffered influence from THIsh values, with heat-stressed cows producing milk with low quantities of fat. The results show a negative correlation between THIsh and milk fat, indicating that thermic environment can interfere on milk quality, which demonstrates the importance of seeking thermic comfort for producing animals. It is necessary to conduct further studies in order to completely elucidate the effects of thermic environment over milk composition.