THE ANALYSIS OF PARAMETERS CONTROL OF THE ANIMALS THERMAL STRESS STATE CHARACTERIZING’S MATHEMATICAL MODELS ON DAIRY FARMS

Abstract

The mathematical models’ analysis for indoor microclimate parameters’ monitoring characterize of their negative impact on animals and humans degree in terms of their effect on thermal stress is presented. The heat and humidity index features’ mathematical dependencies, based on temperature and relative air humidity’s assessment; the environment’s thermal index loading, that also takes account into the air flows speed in the room and thermal radiation on the body are considered. A cows thermal stress index based on animals’ clinical-and-physiological indicators, cows’ respiratory rate and pulse is proposed. During the studies there in the climate chamber microclimate’s conditions were simulated in the ranges from 15°C till 35 °C of air temperature and from 50% till 80% for relative humidity, the air flow velocity was lesser than 0,2 m/s. The animals’ respiratory and pulse rate and body temperature were recorded. As a result of the research, an animals’ respiratory and pulse rate increasing was found. Based on the obtained data, a mathematical model quantitatively characterizes the thermal stress degree in depending on the respiratory and pulse rate values is proposed. The cows’ heat, humidity and thermal stress indexes’ values proposed by the authors are compared. These study results’ analysis suggests that cows respiratory and pulse rate monitoring allows to take into account the animals’ individual characteristics under thermal stress. A variant of the cows heat humidity and thermal stress indexes integrated application is proposed.