How Does Heat Stress Occur and How Can It Be Detected?
How Does Heat Stress Occur and How Can It Be Detected?
Main Causes of Heat Stress:
Ambient temperature rising above 25°C (This threshold may vary depending on the breed, but an average value above 25°C is considered),
Relative humidity exceeding 60%,
Animals being directly exposed to sunlight,
Inadequate ventilation in shelters,
Insufficient water intake by the animals,
Overcrowded animal populations,
High metabolic load in high-producing animals, such as high-yield dairy cows.
When these conditions combine, animals are unable to cool themselves effectively, leading to an increase in body temperature and resulting in heat stress.
How to Identify Heat Stress in Animals?
When the conditions mentioned above occur, animals experiencing heat stress exhibit certain behavioral and physiological signals. By carefully observing your animals and identifying these signs early, you increase your chances of intervening in time and minimizing productivity losses.
Although small ruminants (such as sheep and goats) are generally more resistant to heat compared to cattle, they can also experience heat stress when exposed to the same conditions. Each animal species may show different symptoms of heat stress.
Signs of Heat Stress in Cattle
Büyükbaş hayvanlarda sıcak stresi belirtileri aşağıdaki gibi sıralanabilir:
Nefes sayısının artması (hızlı ve sığ soluma),
Increased respiratory rate (rapid and shallow breathing),
Tongue protrusion and open-mouth breathing,
Increased time spent standing and reluctance to lie down,
Excessive salivation,
Decreased feed intake,
Reduction in milk yield,
Body temperature rising above 39.5°C (103.1°F),
Signs of restlessness and increased movement, or conversely, lethargy and inactivity.
Signs of Heat Stress in Small Ruminants (Sheep, Goats)
Small ruminants, especially woolly breeds such as Merinos and high-yielding dairy goats like Saanen and Halep, are more prone to heat stress.
The signs of heat stress in these animals may include:
Rapid and excessive breathing, flaring of the nostrils,
Open-mouth breathing, especially in goats,
Decreased feed intake,
Weight loss, reduced milk production, and weakened immune function,
Increased inactivity or lethargy,
Seeking shaded areas,
Standing for long periods and avoiding lying down,
Appearing dazed and responding less to stimuli,
Elevated body temperature (above 39.5°C in goats and above 40°C in sheep).
Signs of Heat Stress in Poultry
While heat stress manifests differently across animal species, the general symptoms in poultry are as follows:
Wings spread away from the body (an effort to increase body surface area and cool down),
Panting with open beaks,
Decrease in feed intake accompanied by an increase in water consumption,
Fluffed feathers and inactivity,
Reduced egg quality and productivity in laying birds,
An increase in sudden death cases, which is one of the most obvious signs.
To learn how to prevent heat stress and which products can be used, read our content “How to Protect Animals from Heat Stress?”.