Recent research highlights the significant impact of heat stress on dairy cows, revealing that high temperature-humidity index (THI) levels can drastically reduce rumination time and elevate body temperature.

Cows exposed to high THI levels, specifically between 73 and 78, experienced a 2% increase in body temperature compared to those in lower risk categories.

In the highest THI classification, cows showed a remarkable 70% reduction in rumination time, indicating severe behavioral changes due to heat stress.

The study utilized advanced precision livestock farming technologies to monitor various health indicators, including behavior, body temperature, and blood gas parameters, to assess the effects of heat stress.

Infrared thermography (IRT) emerged as a promising non-invasive method for monitoring dairy cow health, enhancing welfare management by providing reliable temperature measurements.

The research found a low correlation between the difference in rectal temperature and eye temperature with ambient temperature and THI, while a moderate correlation was observed with relative humidity.

Electrolyte imbalances were also noted, with sodium and potassium levels decreasing significantly in cows at high risk of heat stress, while chloride levels increased.

Blood gas analysis revealed critical changes under severe heat stress, including a notable decrease in partial carbon dioxide pressure and an increase in partial oxygen pressure.

These findings underscore the necessity for continuous monitoring and proactive management strategies to mitigate the adverse effects of heat stress on dairy cow health and productivity.

Future research may focus on refining critical THI thresholds based on physiological responses to further enhance dairy cattle welfare and productivity.

Conducted in a controlled environment from June to July 2024, the study involved 56 clinically evaluated Lithuanian Holstein cows, emphasizing the importance of stable climatic conditions for accurate results.

Measurements were taken under stable climatic conditions to ensure the reliability of the data collected, avoiding extreme temperatures that could skew results.