
One of the main focus areas for our team at AgNext is animal welfare; it takes into account a number of factors such as animal well-being, comfort, nutrition, facility design, management, and health. A main area for enhancing animal welfare in cattle operations is adapting management practices and animals to the specific climates where operations are located and climate change to mitigate heat stress. In a recent interview, AgNext’s Dairy Systems Specialist Dr. Diego Manriquez sat down and explained the details of heat stress including symptoms, measurement methods, and ways to mitigate and lessen it in cattle systems.
As a veterinarian with a passion for animal welfare, Dr. Manriquez focuses his research primarily on animal health related to food security and sustainable dairy systems. When asked why cattle experience heat stress, Dr. Diego Manriquez first discussed the mechanisms that bovines have to respond to thermic conditions that surpass their physiological abilities to dissipate and retain heat. Dr. Manriquez exemplified this by contrasting animals that develop thermal plasticity and others that develop physiological adaptations to heat stress, such as cattle. Thermal plasticity refers to an animal’s ability to adapt to a changing environment by visible changes in their bodies. For example, dogs have the ability to change their fur coat and hair thickness in response to hotter climates or seasons. Other mammals, such as humans, have the ability to sweat in response to hotter weather.
On the other hand, Dr. Manriquez explained that cattle lack thermal plasticity, which make them more susceptible to heat stress. To cope with a hotter climate, cattle rely on adaptative mechanisms related to hormonal and metabolic changes to dissipate heat as well as behavioral responses such as panting and modification of their locomotion, drinking, and eating behavior. When these mechanisms fail to keep the body temperature within normal ranges, we can observe symptoms of heat stress that can have long-term effects on the performance and health of cattle, Dr. Manriquez said.
Dr. Manriquez emphasized, “It’s important to consider that we are not going to be able to completely eliminate heat stress in cattle, animals are still going to experience heat stress as [humans] do. So, it’s so important to develop mitigation strategies that go in the point that we decrease the frequency of heat stress, also the intensity and duration of heat stress events. That should be the main objective of the mitigation strategies.”
As we expect the hot season to get warmer and warmer each year, heat stress research and mitigation is more important than ever. There are two main factors to determine the extent of heat stress and Dr. Manriquez broke these down into:
- Animal-level measurements
- Environmental (farm) level measurements
Animal-level measurements can be measured mostly just through observation, because heat stress symptoms in cattle are usually visible. However, there is research performed on thermal stress physiology which includes endocrinology, proteomics, and genetic studies that require sample collection including, for example, blood and hair samples that allow us to investigate the mechanisms of heat stress response which could be used for selection of heat stress resilient animals and develop markers for heat stress. Nonetheless, at farm level heat stress symptoms are a valuable tool to assess the impact of warm weather.
These symptoms include:
- Panting (increased respiration)
- Open mouth
- Animal refusing to lie down
While these are just a few symptoms of heat stress, Dr. Manriquez explained how heat stress symptoms and indicators vary greatly between different factors like coat color and breeds. For example, black Angus cattle tend to experience higher levels of heat stress than red Angus because the black coat attracts more heat and makes it more difficult for the black animals to release heat. Also, dairy cattle are more prone to heat stress than beef cattle because while beef cattle have one source of heat in the rumen, while lactating dairy cows have two sources of heat: the rumen and the mammary gland (udder).
Heat stress reactions can also vary greatly depending on changing temperatures, especially in locations such as Colorado, where there are large temperature fluctuations between daytime and nighttime. This is why environmental, or farm-level measurements are also key for identifying heat stress. Measurements that can be measured at the farm level include:
- Temperature
- Humidity
- Solar radiation
- Wind speed
- Dew point
These can be measured using weather stations, which can be bought by farms, but can also be accessed on public websites and are accurate within 50 miles. So for operations that don’t have their own weather stations, they can find weather station measurements online and expect those measurements to be valuable information for their operations.
After measurement, the second step to heat stress management involves mitigation. Mitigation strategies include:
- Providing shade. It’s important to shade the ground where the animals are instead of just the animals. Shading the ground is more effective in lowering animals’ body temperatures. Additionally, it’s important to consider the orientation of the sun to avoid the ground to get too wet and cause other animal welfare problems.
- Running sprinklers over the animals. The water should be applied to the surface of the animals’ bodies as well as their faces, because the evaporation of the water is what reduces the heat. This simulates how humans sweat to release heat.
- Providing ventilation. Air flow is a good way to prevent overheating, so the cross-ventilated barn design has been used to keep cattle cool inside during hot days.
- Easy access to clean water. Water is important for the function of every animal, especially those living in hot conditions. It’s important to have a water source for cattle that has a dry foundation so the animals don’t get muddy when they drink. Many waterers have concrete bases to keep the animals clean while drinking. The water should be in a location where the cattle don’t have to compete for access. This would look like placing the water in a more open area instead of a corner.

Animal welfare is a vital part of our research at AgNext and we hope to provide information and resources for heat stress mitigation to reduce the frequency and severity of this environmental response. Heat stress is a biological response that cannot be completely stopped, but by monitoring, measuring, and innovating, we can do our best to give cattle the best resources to experience less of it.