Environmental parameters to assessing of heat stress in dairy cattle—a review

Abstract

Considering the significant influence of high ambient temperature and heat waves on the well-being and productivity of dairy cows, it is to be expected that, in the course of the next few decades, climate conditions for raising cattle will deteriorate. Research has shown that heat stress causes many negative consequences in terms of physiological and behavioural disturbances and significant losses in milk production. The effort to reduce the risk of the occurrence of heat stress among dairy cows also involves the search for new environmental methods of predicting heat stress. The aim of this paper is to review and systematise the current state of knowledge on the topic of the most widely used environmental methods of determining and predicting heat stress in dairy cows and also to show the directions of studies for the future. Based on an analysis of the most popular indexes, the study evaluated their suitability for forecasting heat stress related to maintenance systems and climate conditions for cows. However, the negative results of heat stress often appear with a delay, and a carry-over effect may be experienced (summer heat stress may affect the cows until autumn). The time of the year and breed of cows could have a big impact on when animals become sensitive to increasing heat loads. This likely can be a big contributor to the discrepancies within the different heat stress equations. It is essential to prevent the occurrence of heat stress, predicting it by observing local microclimate conditions and using meteorological forecasts. Thanks to these measures, a breeder may prepare and implement suitable solutions for protecting the animals.

On the Effect of the Temperature-Humidity Index on Buffalo Bulk Milk Composition and Coagulation Traits

“…In particular, often these two environmental parameters are combined into a unique index, the temperature-humidity index (THI), to evaluate cow heat stress and milk losses, and to monitor the thermoregulation (3). Several formulas have been proposed to calculate THI in dairy cows (4), with the Kibler formula being denoted as the most popular one due to its simplicity and efficacy.…”

Ecological substantiation of the normalization of the state of the air environment in the uninsulated barn in the hot period

“…The single data given by the authors (Trofimov et al, 2014;Sofronov et al, 2016;Voloshchuk & Khotsenko, 2017) on the dynamics of the indicators of temperature and relative humidity in the buildings, without taking into account their integral effect, do not fully reflect the state of comfort of the cows, to evaluate which in hot period the temperature-humidity index is used (Vtoryi et al, 2018;Mijic et al, 2019;Pinto et al, 2019;. Researchers believe (Hammami et al, 2013;Herbut et al, 2018) that the index value below 68 corresponds to comfortable conditions for animals and is the limit above which they are prone to heat stress. The THI value at the level of 68-71 corresponds to a slight stress, within 72-79 -to moderate stress, while at 80-89 cows are in a state of severe, and 90-99 very strong (hard) stress.…”

Auswirkungen hoher Umgebungstemperaturen auf laktierende Milchkühe – unter praxisüblichen Bedingungen in Norddeutschland von Bedeutung?

“…Zur genaueren Charakterisierung der klimatischen Bedingungen wird oftmals der Temperatur-Luftfeuchtigkeits-Index ( Temperature Humidity Index [THI]) verwendet, der neben der Umgebungstemperatur auch die relative Luftfeuchte berücksichtigt, wobei in der Literatur verschiedene Formeln zur Berechnung vorliegen [42] [43]. Für Untersuchungen in Niedersachsen erwies sich die Formel des NRC ( [44]; s. Material und Methoden) als besonders geeignet [41].…”