Correlations between Environmental Factors and Milk Production of Holstein Cows

Abstract

Global climate change is a challenge for dairy farming. In this regard, identifying reliable correlations between environmental parameters and animals’ physiological responses is a starting point for the mathematical modeling of their effects on the future welfare and milk production of cows. The aim of the study was to examine the relationship between environmental parameters and the milk production of cows in hot period. Archival data from the Ukrainian Hydrometeorological Center were used to study the state of insolation conditions (IC), wind direction (WD), wind strength (WS), air temperature (AT), and relative humidity (RH). The temperature–humidity index (THI) (Kibler, 1964) and temperature–humidity index in the hangar-type cowshed (THICHT) (Mylostyvyi et al., 2019) served as integral indicators of the state of the cowshed’s microclimate. The daily milk yield (DMY), yield of milk fat (MF) and milk protein (MP), and percentage of milk fat (PMF) and protein (PMP) were taken into account by the DairyComp 305 herd management system (VAS, USA). Statistical data processing was performed using the mathematical functions of Microsoft Excel (Microsoft Inc.) and Statistica 10 (StatSoft Inc.). There was a weak correlation between IC and DMY at r = −0.2, between RH and DMY at r = +0.4, and between RH and MF at r = +0.2. Between DMY, MF, MP, and WS made up r = –0.2 to 0.4. Between DMY, MF, MP, and AT made up r = −0.2 to 0.5 (p < 0.05). The effects of weather factors on animal productivity will be the subject of further research.