For the agricultural industry, summer is a key month of high productivity. For many crops, it is the peak harvesting season and many farms are at their busiest during this time of the year. However, one particular sector of the industry begs to differ – dairy farming.
Contrary to popular belief, summer is a lean season for dairy farms. Both the output and quality of milk are reduced during the hotter months of the year, leading to potentially severe economic consequences for dairy farms and related businesses.
We will explore the factors behind this phenomenon, and look at the solutions available in the market – namely cooling systems for dairy farms.
Heat Stress – Why Hot Summers are Bad for Cows
Cattle are highly sensitive to temperature changes during warm weather. The average body temperature of a cow is 101.5 °F – that is at least 3 degrees hotter than the normal body temperature of human beings.
Humans start sweating at around 77 °F, in normal humidity. For dairy cattle, the mercury only needs to go above 72 °F for them to start feeling uncomfortable. And that is in normal conditions with 50% humidity.
If it’s a highly productive breed, the temperature thresholds can be much lower – as low as 65 °F. This is because a cow’s body also produces an incredible amount of heat. This happens during the process of digesting the grass and plant fibers in the stomach and converting it into milk.
When the cows are out in the sun, they also absorb additional heat from the sunshine. Cows dissipate this heat mainly by breathing. Even though cows do perspire, it is not very effective.
Inside barns, heat stress can occur when ambient temperatures reach a stage where the cow can no longer remove excess heat from its body via its mouth and nose. On a hot enough day, this can even happen in a well-ventilated facility equipped with cooling systems and fans.
What Happens to a Cow’s Body During Heat Stress?
Cows may not show any strong symptoms of heat stress, at least in the early stages. They will pant a lot and breath with their mouths open. Their necks may be extended, and they might show signs of fatigue or lethargy. Sometimes, they may appear unsteady when standing.
Respiration rates will increase as the cow tries to bring temperatures back under control. A normal rate is between 40 to 60 breaths per minute, and it can go as high as 100 or more. The body temperature at this stage could be anywhere between 102.5 to 105 °F or more.
If the numbers go above the upper range mentioned in the previous paragraph, it is usually a life-threatening stage of severe heat stress that requires urgent corrective measures to prevent death. The main noticeable impact of heat stress will be in milk production.
Let\’s take a look at the various levels of heat stress and its impact:
Mild Heat Stress
At this stage, ambient temperatures between 68 to 71 °F will cause the cow’s rate of breathing to start increasing and be between 60 to 75bpm. The internal body temperature will be hovering between 102.5 to 103 °F. Mild heat stress could lead to a decrease of up to 2.5 lbs in milk production per day/per head.
Mild to Moderate Heat Stress
This stage usually occurs when temperatures increase to a range between 72 and 79 °F, and the internal body temperature climbs to between 103 – 104 °F. The rate of breathing continues to increase, reaching 75-85 breaths per minute. The daily milk production could be reduced by up to 6 lbs per day/per head.
Moderate to Severe Heat Stress
If the temperature is in the mid or high 80s, a cow’s respiration rate can climb to 100 breaths per minute. The body at this point is trying to reduce internal temperatures that have risen closer to 105 °F. At this stage, milk production is severely affected, with a decrease of up to 9lbs per day/per head.
Severe Heat Stress
This is a veterinary emergency that can occur when the ambient temperatures cross 90 °F. The cow’s rate of respiration hits a peak of up to 104, and body temperatures can go dangerously high above 105 °F. It can hit milk production by a decrease of up to 10lbs per day/per head.
The Various Effects of Heat Stress on Cattle
At temperatures above 68 °F, cows are less inclined to feed – a biological protective measure that reduces the chance of overheating due to digestion. The decline in milk production is a direct effect of a reduction in feed intake.
The cow will also do another thing to cool off – it will spend more time standing up instead of lying down. Since cows lie down to aid digestion, this compounds the impact of lower feeding on milk production. As a result of these natural responses, milk production could be reduced between 15 to 25%.
Other impacts of heat stress on a cow include the following:
- Lower immunity leads to increased susceptibility to infections and diseases that increase treatment costs
- Lower cell growth and a higher rate of cell death in the udders, further affecting their capacity to yield high-quality milk
- Decrease in fertility, leading to further delays in conception and increased maintenance costs
- Lower birth weight in calves born to cows during heat stress, with poorer outcomes and productivity later in life
- Increased risk of death due to uterine infections, ketosis, and other health issues
- Increased rate of abortions and a higher chance of sterility among cows by up to 10%
The Economic Impact of Heat Stress on Dairy Farms
Thanks to the combination of lower productivity, increased waste of feed, higher veterinary bills, and delays or complications in breeding and pregnancies, a dairy farm can suffer catastrophic losses due to summer heat waves.
Assuming 120 days of summer with high ambient temperatures, the reduced feed intake, and milk reduction could cost the producer anywhere from $100 – $180 per head annually. Any increase in the calving interval leads to fewer days of productivity each year.
In the high summer heat, the conception rate for cows can fall from 40% in winters to a low of 20%. Across 2-3 months, this could create an additional 20 open days. If we estimate a per day cost of $5 for each open day, that alone adds up to another $100 loss per head each year.
Far more severe are the healthcare and treatment implications of heat stress. Culling can increase by up to 10%, with each culled cow representing a loss of at least $1800. Additional treatment costs range from $180 for uterine infections to $300 for udder infections.
Add the cost of $500 per aborted cow and we have losses for the total herd at around $350 per cow annually, taking into account the projected increase in medical issues during a heat wave. In the US, this toll is not equally dispersed across the country.
The Great North-South Divide
Weather conditions can vary widely between different regions of the continental United States. Based on historical weather data, studies by economists indicate that 14% of every year dairy cattle experience stressful heat.
This is based on a median Temperature Humidity Index (THI) of 72. Combining both the effects of temperature and humidity, THI is the single value used to measure thermal stress. It is used in weather studies and reports for safety warnings.
In the studies, a THI reading of 72 was considered the limit above which cows start experiencing heat stress. And the 14% estimate is not evenly spread across the US – many states in the north do not experience any days of heat stress.
Meanwhile, California, the largest area for the industry with over 1.8 million dairy cows, receives more than its fair share of heat waves. Warmer states like California experience THI above 72 for almost half the year.
It has dire implications for dairy farms in warmer states – 16% more animal culls, 17% higher mortality, 1780lbs annual loss in productivity per cow, and net income loss of up to $675 per cow, as opposed to just $70 per cow in colder states.
The US is home to more than nine million dairy cows. The cumulative impact of heat stress could exceed $1.5 billion each year for the dairy industry. And with rising summer temperatures and severe heat waves due to climate change, things could get a lot worse.
Dairy farms everywhere need to urgently address the issue of heat stress. Numerous options are available, with varying levels of efficiency, cost, and effectiveness.
Ways to Prevent Heat Stress in Dairy Cattle
Over the years, dairy farmers have developed various measures and practices to protect their herds from heat. It’s both a matter of humane treatment of animals which is very important, as well as an economic imperative, the reasons for which we have already gone over.
The following are the most common countermeasures, starting from the inexpensive, most elementary measures:
Shade
This is the bare minimum that is required in all dairy farms. Shade protects the cows from solar radiation. It is highly recommended for both dry cows as well as lactating ones during the summer months. Shade structures can include barns, pole sheds, and other commercially available solutions.
Space is a critical aspect to consider when building and installing a shade structure. Each adult cow requires at least 40 square feet of space for optimal comfort. Overcrowding would be heavily counterproductive as it would raise the temperatures inside the structure.
Air Cooling
Ventilation is vital in any structure housing farm animals. Air exchange by natural means can involve open windows and doors that bring in the breeze and help cool down the cows further. But this is a highly ineffective form in severe heat waves.
Tunnel ventilation involving fans and inlets represents the next step up from basic air ventilation. The ventilation system can be either one way or with a cross-vent design that keeps the air circulation at the cow level.
The velocity of the air pumped in is also critical. For instance, during mild heat stress (THI above 72), increasing the velocity of air by 10 miles per hour can help cool a cow and bring its respiration rate from 68 breaths per minute to a comfortable 57 breaths per minute.
Water Cooling
Adding water to the cooling processes can reduce the energy loss in cows as they combat heat stress. Water sprinklers are often used in conjunction with cooling fans to help keep the median body temperatures of the cows at safe levels.
Another advanced option involves the use of high-pressure fogging systems. Instead of sprinkling water droplets on the cows, a fogging system creates a fine mist that can dramatically bring down the ambient temperatures inside a structure.
Why an Advanced High-Pressure Fogging System is the Best Solution for Dairy Cooling
Extreme heat waves with temperatures climbing above 90 and even 100 °F are quickly becoming commonplace across America. Traditional cooling methods like natural air ventilation or even fan-based air cooling are simply inadequate to combat these temperatures.
Sprinklers, while effective to an extent, can be incredibly wasteful. And with water at a premium in drought-prone regions of California, sprinkler systems are not the solution. If not properly monitored, it can lead to pools of water on the floor and a higher risk of udder infections.
Sprinkler systems also use up a lot of power. Dairy farms in California often spend up to $140,000 each year on utility bills alone. With a high-power fogging system like the MicroCool IBEX, many of these problems can be solved.
The MicroCool Advantage – What is Special About the IBEX?
The IBEX is an industrial-grade, heavy-duty humidifier fogging system. The culmination of more than 3 decades of research and development, it uses highly precise ROC nozzles to create a fine mist of water.
When water is converted into mist or aerosols, it has a more potent effect on the ambient air temperature. You can bring down the ambient temperature of a barn rapidly using the precision misting system.
This phenomenon, called flash evaporation, can bring down surrounding air temperatures by as much as 35 °F. In peak summer heat in California and other southern states, this can be a godsend. The MicroCool IBEX system also has several other advantages:
- Highly Customizable: the ROC fogging lines are available in both stainless steel and polyester flexible hose options and can be designed to fit any dairy facility’s unique requirements.
- Low Water Consumption: a high-pressure misting system requires much less water than sprinklers for a better cooling effect. The IBEX is computer controlled and can be used to provide cooling mists at precise intervals for maximum water savings.
- Efficiency: using features like variable frequency drives, a high-efficiency motor, and pressure transducers, the evaporative cooling system reduces power consumption by up to 60% over other traditional cooling systems.
- Durability: all parts are made from corrosion-resistant materials like stainless steel and brass. Electrical control panels come with 508A UL standard certification for maximum safety and reliability.
For optimal protection against heat stress in dairy cattle, evaporative cooling is the best option. MicroCool is a highly reputed provider of advanced cooling solutions across all states. Our latest products harness state-of-the-art evaporative cooling systems and promise rapid action with high precision and high efficiency.
To learn more about the MicroCool IBEX system and how we can help your cattle cooling needs, contact us using any of the options available on this page.