While managing weather often feels like a modern agricultural challenge, extreme environmental variability has always been a defining force in livestock and arable production. Although climatic extremes dominate today’s headlines, farmers have been managing the seasonal swings of hot and cold for as long as livestock have been domesticated. 

Cattle perform most efficiently in temperatures between 4.5 and 21°C, yet nearly every major agricultural region experiences conditions well outside this range for extended periods of time each year. 

While cattle are adaptable and capable of acclimatising to less-than-ideal environments, recent years have brought more frequent and more extreme temperature swings. Of particular concern is the impact of excessive heat on cattle health and productivity – a condition broadly referred to as heat stress.

What is heat stress

Heat stress is a complex physiological disorder that occurs when an animal cannot dissipate enough heat to maintain normal body function. All major livestock species can experience heat stress, but cattle are uniquely vulnerable because they sweat poorly – only about 10% as effectively as humans. Without efficient sweating, they rely heavily on respiratory cooling and heat loss through the skin. 

Dairy breeds are especially sensitive due to their high metabolic rate. Their rumen generates substantial internal heat during fermentation, and one of the first responses to rising temperatures is reduced feed intake to limit metabolic heat production. Reduced feed intake also leads to reduced water consumption, which is particularly problematic for lactating cows that require large volumes of water. These nutritional and fluid deficits contribute to the hallmark signs of heat stress in dairy cows: decreased reproductive performance, reduced milk yield, and lower fat and protein deposition in their milk.

Cattle respond to rising temperatures through several mechanisms: sweating limited to the head, neck, and back; increased respiratory rate; reduced feed intake; redistribution of blood flow from internal organs to the skin; and behavioural changes such as seeking shade and standing more. When any of these adaptive pathways are overwhelmed, heat stress can develop.

Physical cooling strategies have long been standard in the livestock industry. Well-designed ventilation, ample shade, strategically placed sprinklers and fans to enhance evaporative cooling, and optimised water access form the foundation of heat abatement. While these tools remain essential, advances in our understanding of bovine thermoregulation now allow producers to support cattle biologically as well. Producers can now complement physical cooling with targeted nutritional support. Increased respiration and reduced feed and water intake often lead to electrolyte imbalances, making electrolyte supplementation and improved water uptake key strategies. Feed additives can also help protect the gastrointestinal tract. 

Efficient rumen function

During heat stress, blood is diverted away from the gut, predisposing cattle to cell damage and “leaky gut” syndrome; innovative supplements such as betaine can help maintain gut integrity under these conditions. And perhaps the most impactful approach is the use of live microbial additives to support efficient rumen function. By improving digestion and reducing excess metabolic heat, these products help cattle maintain performance even when facing challenging temperatures.

Just as livestock owners and managers utilise multiple physical and environmental tools to manage heat, today’s high-producing herds must incorporate a multi-prong approach to managing the biological side of heat stress abatement. A successful program includes layered strategies to accomplish the following goals:

• Maintain, or ideally increase, dry matter intake
• Improve ration digestion for adequate energy and protein absorption
• Protect and repair critical cellular tissue (digestive, reproductive, immune)
• Support biological cooling mechanisms: respiration and skin evaporation 
• Maintain normal biological function (milk production, breeding, health)

These goals may sound like basic concepts, and they are, but fundamental for any well-thought-out nutrition program, supported by nutritionists, veterinarians, and livestock professionals for decades. And to their credit, our industry has done an exceptional job of achieving record levels of milk (and milk component) production while maintaining acceptable animal health and reproduction.

Over the last 50+ years, we’ve nearly perfected most management strategies involving feeding, housing, and management. Tomorrow’s improvements will need to come from the “little things”; small details or new ideas that will unlock the next tier of productivity and health performance. At Anpario, we understand the science behind heat stress and offer a comprehensive portfolio of nutritional solutions designed to support cattle during periods of elevated environmental temperatures.

Here are 4 simple strategies we offer that provide proven benefits on the farm.

1. Feed a probiotic

Reduced dry matter intake accounts for at least 30-50% of the reduction in milk production commonly seen during times of high heat stress. Feeding a high-quality, live microbial product is one of the best practices available for accomplishing several of our heat stress management goals. The Generator range of probiotics consistently shows improved dry matter intake for both cows and calves while simultaneously increasing the digestibility of the diet, leading to increased efficiency and production. 

A customer calf trial in the USA showed a 22.3% increase in calf starter intake when feeding probiotics. As a result, average daily gain and weaning weight were significantly increased. This result directly combats one of the primary effects of heat stress, a decline in feed intake. Numerous dairy producers have reported similar results in lactating cows when feeding probiotics before, during, and immediately after periods of substantial heat stress. 

Dry matter intakes remained near normal levels even though neighbouring non-users reported declines of 10% or more in intakes. Consequently, milk production was maintained, and overall profit was improved.

In adult dairy cattle, multiple university and farm trials evaluating Generator DFMs have shown improvements in milk yield and milk solids. The Generator range of probiotics contains multiple strains of bacteria selected for their high levels of propionate production in the rumen. Propionate is an efficient glucose precursor, and the subsequent increased levels of blood glucose are essential for maintaining proper immune function, metabolic processes, and efficient reproduction without sacrificing high levels of milk output.

11 split-herd commercial studies evaluating the range of products showed an average of 1.4kg of additional milk production, along with higher fat and protein output. This increase resulted in an ROI of greater than 3:1. Herds affected by heat stress often show even higher returns due to not only improved milk production but also increased reproductive performance and fewer metabolic health incidences. 

By utilising multiple strains of research-backed rumen-specific and lower-gut colonising bacteria, Generator probiotics support the entire digestive tract, providing protection and benefits across multiple herd types, management styles, and combined stress factors. Many of the bacterial strains selected for inclusion have positive effects on immune modulation and improved gut wall integrity when subjected to challenges from pathogens, poor feed quality, or environmental factors that are costly to the price-conscious producer. 

2. Incorporate electrolyte supplements into daily routines

Administering electrolytes is a common, albeit underutilised and inconsistently applied, strategy for dealing with a direct effect of heat stress. Increased breathing rates combined with decreased feed intake can lead to a harmful lack of sodium, potassium, magnesium and buffers within animals’ bodies.

Numerous electrolyte products are available on the market, but many are not beneficial due to their lack of proper ingredient balance, inappropriate administration guidelines, or omission of new technologies that are established to aid animal rehydration. 

Anpario’s electrolyte range includes formulations suitable for both calves and adult cattle and contains a balanced suite of traditional electrolytes plus complementary technologies that drastically increase the effectiveness of electrolyte administration. Particular to combating heat stress, GoldLyte contains betaine, an established osmolyte which protects individual cells from heat stress-related damage and maintains cellular function.

It also plays a crucial role in helping to “drive” water from the digestive system into the blood and body tissue, resulting in better rehydration compared to water alone. Additional trace minerals and vitamins A, D, E, and B-complex aid metabolic processes and combat oxidative stress, both of which are prevalent during heat stress. In adult cows users often report improved reproductive performance (more natural oestrus, higher conception rate) as egg and embryo viability is a frequent casualty of high oxidative stress due to heat stress.

Effective electrolyte supplementation also supports increased water intake. Water consumption is directly correlated to overall feed intake thus electrolytes offer a second strategy to help maintain feed intake during times of temperature and humidity stress. 

3. Supplement with phytogenics 

100% natural Oregano Essential Oil (OEO) contains up to 100 active components which work in synergy to offer well-documented properties, including antimicrobial, anti-inflammatory, immunomodulatory and antioxidant functions, all of which have a role in supporting optimal bovine health and performance during heat stress. OEO is shown to be helpful in supporting cellular health through its antioxidant and immune-supportive properties, both of which can become compromised during periods of heat stress.

Orego-Stim (OS) from Anpario, which contains a high-quality, single-source 100% natural OEO, has been used to minimise the production of heat shock proteins and oxidative stress markers that result from exposure to temperatures above their thermoneutral maximums. In a university trial carried out in Brazil, OS was shown to significantly reduce oxidative stress in dairy cows, with increased blood glutathione levels and decreased blood dichlorofluorescein levels. Calves born from supplemented cows also had improved antioxidant status. 

When included in an animal’s water or feed, Orego-Stim supports gut health, thereby reducing heat production resulting from inefficient digestion. Its flavour profile helps maintain feed and water intakes, particularly valuable during hot weather when eating and drinking rates often drop drastically. 

Consider the benefits of novel technologies like capsaicin for heat stress abatement

Oral supplementation with chilli pepper extracts to influence physiologic cooling of animals from the inside out is growing in popularity. Capsaicin has been used topically for many years to relieve muscular aches and pains in humans.

Research in recent years with numerous livestock species has shown that this fat-soluble compound paradoxically minimises the effects of heat stress by interacting with the TRPV1 Receptor, which is found throughout the body. Upon activation by capsaicin, TRPV1-R modulates the body’s reaction to heat and pain. This receptor is found in the mouth and the rest of the gastrointestinal tract and is the mechanism responsible for the effect spicy foods have on your taste buds.

It may seem counterintuitive to use “hot” additives to cause body cooling, but upon activation, this receptor-mediated mechanism tricks the central nervous system into feeling the effects of heat, resulting in counteracting blood vessel dilation and sweating. Cattle also experience the spicy flavour of the product, driving animals to water as an additional benefit to the heat-stressed individual. Feeding pepper extracts provides a convenient, feed-based method to supplement external cooling of cattle during hot conditions.

PhytoCool is one such solution, combining capsaicin with a powerful combination of electrolytes and 100% natural OEO to optimise natural physiological and metabolic responses when managing heat stress Today’s cows are elite performers, pushing the limits of their genetic potential much like a modern Olympic athlete. 

Just as with human performance, careful management of the fundamentals of nutrition and physiology forms the foundation for achieving peak output while maintaining resilience under stress. 

As extreme heat becomes more frequent and widespread, Anpario solutions bring modern innovation to proven practices, unlocking new opportunities for producers to protect performance and productivity even in the most challenging summer conditions. n 

References are available from the author on request