Heat stress in beef farming
Arianna Zanella, DVM
Explanation and consequences
Heat stress is the result of an imbalance between the heat produced and the heat dissipated by the animals, and the consequences vary from mild involvement to death in the most vulnerable animals. During the summer period heat stress manifests itself as hyperthermia and the consequences are manifold:
- increased respiratory and cardiac rates;
- increased sweating with loss of large amounts of electrolytes and consequent dehydration;
- decreased ingestion up to 15-20% and increased energy requirements up to 20-30% to maintain body temperature;
- reduction in daily weight gain (Chester-Jones report a 37% reduction in weight gain in animals subjected to heat stress over a long period);
- increased oxidative stress and immunodepression;
- increased frequency of DFD (Dark Firm Dry) meat at slaughter due to low muscle glycogen reserves;
- increased incidence of disease and mortal
- environmental: temperatures and relative humidity, wind speed and solar radiation;
- susceptibility of the individual: race, sex, temperament, genetics and pervious illnesses;
- management: access to food and water, animal handling and manipulation.
All this makes clear the importance of intervening to optimize environmental conditions also in beef farming. Therefore, several strategies have been developed over time to improve animal welfare during the summer season and can be classified into:
- managing access to food and water;
- optimization of animal handling;
- forced ventilation.
- improvement of air quality by reducing the concentration of harmful gases;
- improvement of the quality of the shelters due to the lower humidity and with the consequent reduction of the quantity of material used for the bedding;
- reduction in the presence of flies;
- increased heat loss from animals.
All this allows therefore an important improvement of welfare conditions avoiding the decrease of ingestion and obtaining a drastic reduction of pathologies and mortality. Obviously, this translates into financial gain for the farm: improvement of daily weight gain, feed efficiency and meat quality at the slaughterhouse.