Don’t Burn your Profit—Cool Feeding Concepts for Hot Temperatures.

Heat stress is an ever-recurring topic that gets new attention every year as the summer approaches. Poultry may get severely affected, so we should not get tired of talking about heat stress. With the right strategy in place, you will be well prepared to meet this challenge for your animals. 

In subtropical and tropical climate zones heat stress is a more or less permanent stressor for poultry flocks. But even in moderate climates, heat stress is becoming an increasingly frequent phenomenon during summer months. Climate change is expected to keep playing a major role in driving weather extremes and will continue to literally heat up the situation.  

Heat Susceptibility.

Poultry are especially susceptible to hot temperatures. Having no sweat glands and insulating feathers, they have limited capabilities to give off excess heat. High metabolic rates in high-performing breeds only contribute to the heat load. Chicken will try to cool off mostly through evaporative cooling, quickly leading to increased panting rates and open-beak breathing.

Thermoregulation.

The maintenance of a constant body temperature requires a balance between body heat production and heat emission. The metabolism of warm-blooded animals “burn” up energy from feed and converts it into usable energy needed for all physiological functions, producing heat. The level of energy demand and thus heat production rises with the performance level of livestock: additional energy is needed for meat and egg production. 

The term “heat stress” refers to situations of high environmental temperature in which not enough body heat can be emitted through normal behavior. The increased heat load is detrimental to the animal's health. Depending on climatic conditions, two categories of heat stress can be distinguished:

• Acute heat stress: short, rapid rise in temperature

• Chronic heat stress: high ambient temperature for extended time periods

Figure 1: Heat stress has multiple effects on the animal.

Apart from inducing rising mortality rates, the indirect hidden impacts of both forms of heat stress can lead to: 

• Reduction of feed intake and performance

• Leaky gut syndrome

• Reduced immune status

• Reduced carcass quality

• Economic impacts

Understanding heat stress.

To successfully mitigate these impacting effects, we have to comprehend the underlying physiological reactions caused by hot temperatures. Even a short period of extreme heat stress can create havoc within the animal’s metabolism.

With an increasing heat load, cooling mechanisms become activated. The blood flow is diverted, directing warm blood away from the body core into dilated blood vessels under the skin. Here, excess heat can be given off via convection to the surrounding air. This mechanism comes with a price though: the internal organs, especially the gut, quickly suffer from the reduced circulation. The tissue, usually strongly supplied with blood, becomes hypoxic.

Focus: Inflammatory processes.

Without adequate oxygen supply, the tissue quickly takes lasting damage. Several mechanisms contribute to the damage:

• Heat shock proteins are upregulated, and the inflammatory response is triggered.

• The production of tissue damaging free radicals, such as ROS (radical oxygen species) and RNS (radical nitrogen species), increases.

• The expression of tight junction proteins is reduced.

• The microbiome, a sensitive community of microorganisms in the gut, becomes disbalanced.

The sum of these events leads to a “leaky gut syndrome”, a chronic condition in which the leaking of bacteria and other substances from the damaged gut enhance chronic systemic inflammation and performance losses.

Figure 2: A healthy gut (left) effectively resorbs nutrients.

Welfare and Performance.

Chronic inflammation is not beneficial for animal welfare. A leaky and damaged gut is also not capable of efficient nutrient resorption. In heat stressed poultry flocks, several studies have demonstrated negative impacts on:

• Weight gain

• Carcass quality

• Digestibility and feed conversion ratio

• Laying rate

• Hatchability

• Fertility

Poultry production and the demand for poultry meat is on the rise, with a strong increase of production numbers seen especially in developing and strongly populated countries. Unfortunately, these are also countries in warmer climate regions and heat stress is one of the biggest challenges for economic success. 

Where and how can we act?

Fortunately, we are able to support our animals in many different ways. For direct on-farm support, we can consider making amendments to environmental conditions, such as:

• Stocking density

• Ventilation and spray cooling

• House construction

• Water supply

• Lighting and feeding schedules

Adjusting the feeding management is another way to support the animals during hot periods. Besides shifting the feeding times to the cooler parts of the day, you can also optimize the feed formulation. Some feed additives are especially beneficial for your animals during heat stress. They include:

• Organically bound trace minerals

• Probiotics

• Betaine

You can find more details here and here on how these additives can protect your animals against dehydration, oxidative stress, and intestinal imbalances.

Focus: Willow bark extract.

Another uncomplicated way to provide relief is the use of drinking water supplementation. Especially when feed intake is reduced, valuable substances can be supplied in sufficient amounts via the drinking water. The supply of antioxidants such as vitamin E and selenium but also zinc is beneficial. The use of Vitamin C is also widespread to provide antioxidant support.

Mitigating the inflammatory response is an oftentimes overlooked, but equally important, task. Natural phytoactive substances such as salicin are a great aid in reducing the inflammatory response and increasing antioxidant capacities.

Contained in plant extracts, salicin has been known for centuries for its anti-inflammatory properties. It is also the naturally occurring precursor to the popular NSAID (non-steroidal anti-inflammatory drug) acetylsalicylic acid.

The powerful combination of willow bark extract, vitamin C and betaine in Stress Pack Xtra provides short-term support for your animals anytime they face heat stress or inflammatory challenge.

Figure 3: The powerful combination of salicin, vitamin C and betaine

Are you faced with short heat stress periods in the summer or with ongoing heat challenge in warmer climate zones? Contact our experts to define the perfect heat stress strategy!