Sessions

The changing climatic conditions of Hungary present new challenges for livestock producers. Consequently, it is essential to investigate how heat stress affects their production.

In my thesis, I examined the feed intake and feed efficiency of 56 Blonde d'Aquitaine young bulls at a modern precision livestock farming (PLF) cattle performance testing station in the Balaton Uplands as a function of ambient temperature and relative humidity.

Data regarding the animals' feed intake and live weight were recorded using the Vytelle SENSE precision performance testing system. Measurements of temperature and relative humidity both inside and outside the barn were conducted using temperature and humidity sensors, with an RS-485 industrial sensor used as a reference.

The Temperature-Humidity Index (THI) was used to determine the degree of heat stress. Using the available climatic data, I determined the heat load to which the animals were exposed on given days. Comparing this with the performance testing results allowed me not only to determine the effects of heat stress on the feed intake and live weight gain of the entire herd, but also to identify individuals that are more resilient to heat. To achieve this, I accounted for the changes in each animal’s individual performance between lower and higher THI ranges and compared each animal's production to the herd average.

In my research, I also examined the correlation of heat stress resilience with age, live weight, and sire lineage. In the investigated herd, no significant correlation with heat tolerance was found regarding live weight or age; however, in the case of sire lineage, the results suggest that further research on a larger sample size is warranted.