Cattle health and general welfare can be severely impacted by Heat Stress.

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General cow health can be severely impacted by the effects of summer heat stress.

The following calculator can be used to assess the impact on a farm's bottom line. The calculations behind this portion of the calculator come from research done by the University of Manitoba. There is a link at the end of this article where you can upload your numbers and receive a copy of calculations for your farm. 

Heat stress can cause an increase in the incidences of mastitis, fall lameness, metabolic, and respiratory issues. Each of these issues comes at a cost. See what preventing them look like for this US dairy farmer milking 100 cows.

Subclinical and clinical mastitis

It can be a serious issue on some farms.  Using research information from the University of Montreal we developed this portion of the cost calculator.  The idea is to give farmers a realistic idea of what mastitis issues could be costing your operation.

Replacement Costs

Each year cows are culled because of the impact of heat stress either in the holding area or in the barn.  In worst cases, cows are culled because of metabolic issues they couldn’t recover from, lameness that didn’t respond to treatment or failing to get back in calf. Used current market reports for this cost.

Fall Lameness and hoof health

Lameness is a major issue because of heat-stress.  When cows get hot instinct tells them to do two things 1. STOP EATING – rumination creates a lot of body heat.  2. STAND and PANT. In order to pant a cow must stand, standing for long periods of time causes more stress and pressure on hooves which creates hoof health issues in the fall.  Bunk line soaker systems offer cooling relief but increase standing time which also increases the incidence of fall lameness.  Cooling in the beds entices cows to lie down, which is exactly where we want them. Using research information from the Department of Agriculture in Manitoba to develop this portion of the cost calculator. 


What do the experts say…

According to OMAFRA - Sub-acute ruminal acidosis (SARA), also known as chronic or sub-clinical acidosis, is a well-recognized digestive disorder that is an increasing health problem in most dairy herds. Results from field studies indicate a high prevalence of SARA in high-producing dairy herds as producers respond to the demands for increased milk production with higher grain, lower fibre diets that maximize energy intake during early lactation. Dairy herds experiencing SARA will have a decreased efficiency of milk production, impaired cow health and high rates of involuntary culling.

Environmental mastitis and summer heat can cause a dollar drain in your herd, but the effect of both can be reduced. The level of mastitis and somatic cell counts rise as temperature and humidity levels move upward. Somatic cells are elevated in response to environmental stress - such as high summer temperatures - and it may take weeks or months for them to decrease. Environmental mastitis increases during this time because of the increased likelihood of teat end exposure to bacteria. Cattle are physically more stressed during the summer.

According to DHI research and results - Heat stress is a physiological response to extreme environmental heat such as heat waves. Heat stress can result in mortality in dairy cows when extreme heat is both rapidly changing and has a long duration. As a result of climate change, heat waves, which are defined as 3 days of temperatures of 32 °C or above, are an increasingly frequent extreme weather phenomenon in Southern Ontario. Heat waves are increasing the risk for on-farm dairy cow mortality in Southern Ontario.

Heat stress indices (HSIs) are generally based on temperature and humidity and provide a relative measure of discomfort which can be used to predict increased risk of on-farm dairy cow mortality. In what follows, the heat stress distribution was described over space and presented with maps. Similarly, on-farm mortality was described and mapped.

During a heat wave, the average total number of on-farm dairy cow deaths registered with DHI across Southern Ontario was 94 deaths per 3-day period. The average is thus approximately 1 death per 30 farms. Deaths during all heat waves followed a similar spatial pattern to the density of dairy farms and the distribution of heat stress in Southern Ontario during a heat wave. As a result, on-farm dairy cow deaths most frequently occurred in the southwestern portion of Ontario or the central and northeastern areas. Most cows were 3 years old at the time of death and the mean age of cows at the time of on-farm death was 5 years. Cows ranged in age from 1 year to 15 years at the time of death. Holstein-Friesian represented 94 % of on-farm dairy cow deaths, and similarly, 94 % of the dairy cow population in Southern Ontario is Holstein-Friesian. Of all farms included in the study, 229 farms reported only 1 death over the 27 days of the entire study period. The maximum number of deaths on a single farm during a heat wave was 4. Farms included in this investigation ranged in size from 22 cows to 1,268 cows, while deaths were most frequently reported on-farms with 51–100 cows.

University of Wisconsin veterinarian Nigel Cook says, "Worldwide, about 23% of dairy cattle experience lameness issues, with three types of hoof lesions causing most of those problems. Prevention efforts for the top three lesions could have a significant impact on dairy welfare and performance."

Dr. Cook goes on to say, "Heat stress plays a key role in cattle behaviour related to lameness. In hot conditions, cows tend to accumulate heat while lying and cool down when they stand. Rest time can drop by four hours per day during a six-day heatwave, elevating the risk of lameness. Air movement in the stalls helps cows lose heat and facilitates rest during hot weather. Cook recommends positioning fans over all rows of stalls. “With proper management”, Cook says, research shows dairies can achieve high milk production while minimizing lameness."

Fall Lameness can be a result of summer heat stress. A professional hoof trimmer from Western Canada says, " the four hooves of a cow can’t take standing on hard surfaces for extended periods of time. She’s already dealing with waiting times before milking, eating, etc., and the hot weather might just tip the scales towards lameness problems." Cows need to be cooled and enticed to lay in their stalls, evaporative cooling focused above their stalls can have amazing results on decreasing the instances of fall lameness.


What can CowKühlerZ do…

CowKühlerZ is a complete formula that works to limit the effects of heat stress on dairy cattle.  It does this by maintaining core body temperature.  Monitoring the THI in the barn or holding area and adjusting itself automatically to suit the conditions.  Keeping the cow in her thermal comfort zone is the best way to prevent the detrimental effects of heat stress. By proactively manipulating the conditions based on the environment, the damaging effects of heat stress can be minimized. CowKühlerZ is that it can do this using a fraction of the energy and water of other systems on the market.


Customer Testimonial

This customer has seen a huge improvement in all facets of cattle health on his farm.

Metabolic issues (like Ruminal Acidosis, ketosis, twisted stomach and milk fever) just don’t happen anymore. Metabolically we don’t have any issues anymore after installing the CowKühlerZ system the late pregnant and early lactation cows are healthy and performing very well. This is a significant improvement and has had a great impact on our operation.

Our somatic cell count has stayed where it always was prior to installing the CowKühlerZ system. The addition of the fine droplets over the stalls has had no effect on our somatic cell count. The droplets evaporate quickly and the stalls don’t get wet. The cows are lying in their stalls where we want them.

We have had a significant improvement in our instance of Fall Lameness. We used to treat about 10% of our heard and that’s down significantly to about 3%. That’s a benefit that we weren’t expecting but that can definitely be attributed directly to the CowKühlerZ system.

Preventing Heat Stress has had a ripple effect on our operations. The difference wasn’t immediately noticeable but over the course of a few years they become very apparent. It’s a full circle, the cows are more comfortable they are performing better and we are a more successful operation because of our decision to go with CowKühlerZ. A farmer near Ottawa ON

In Conclusion 

Preventing the impacts of heat stress can have a major impact on the health and well-being of your herd. Additional benefits can be found in both production and reproduction also, please check them out on the website. These numbers do not take into account energy savings or water-saving over and above other systems on the market.

Taking a few minutes to calculate heat stress losses and their impact on your dairy’s bottom line can help you strategize for better heat stress prevention, which could mean more milk, improved fertility and healthier cows and calves.

If you would like to run your numbers through the cost calculator please follow the link and fill in the form below and we will send you a PDF version of your calculator.

Cost calculator Link


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