Hidden Costs of Heat Stress

July 6, 2020

Cooling strategies are for more than just combating summer heat stress production losses. Learn how proper cooling tactics also reduce lameness, prevent premature culling, minimize vet bills, maximize production in fall months, and improve cow comfort.

By: Dr. Matthew Brady, VES Veterinarian 

 

Dairy producers are not strangers to the fact that seasonal heat stress can lead to lost milk production. It is one of the main concerns on the minds of dairy producers around the world and for good reason – lost milk production can cause the most economic impact on operations. 

Financial losses from decreased milk production shouldn’t be the only thing on the minds of dairy producers when it comes to heat stress and evaluating heat abatement strategies. There are other consequences to heat-stressed cattle that are not as apparent or readily correlated to high summer temperatures, one of them being an increase in the incidence and prevalence of lame cattle in the fall months. Lameness has ongoing ramifications on animal health and successful dairy operations long after periods of heat stress have passed.

 

[Heat Abatement (n.) – The act of reducing or eliminating heat stress. (Cooling cows)]

[Lame (adj.) – Having a disabled limb which impairs the freedom of movement, caused by disease, poor management or environmental factors.

 

Lame cattle can often be found in the fall on dairy farms with poor summer cooling strategies. Why is that you might ask? When a cow is heat stressed she will stand up more often than normal in order to have air circulating around more of her body than can be achieved when lying down. While this helps cows reduce their heat stress, it puts more stress on their hooves. 

When cows stand up, it puts pressure on the sole of their hoof. Continued pressure from standing due to heat stress reduces blood flow to the corium, decreases the thickness of the digital cushion, and causes more wear on the sole of the hoof.

 

[Corium (n): The horn producing cells of the hoof]

 

Less blood flow to the corium decreases the rate at which new hoof horn is produced. Typically, it will take roughly three months for new horn growth to reach the outside of the hoof. Given the increase in wear on the sole of the hoof from longer standing times and the decrease in new growth, there will often be a lack of necessary new hoof horn, resulting in thin soles or sole ulcers. These painful conditions cause clinically lame cattle.

Due to the time it takes to wear down hoof horn and the rate at which new horn is produced, these negative effects of summer heat stress and lameness manifest themselves in the fall and can also have a prolonged impact on milk production. 

Lameness is not only an issue for cow comfort, but will also result in decreased milk production. Among many things, milk production requires adequate feed and nutrition. A lame and uncomfortable cow will minimize walking to the feed bunk and will not want to stand long to eat. As you know, as her dry matter intake goes down, so will her milk production. 

Lameness also increases veterinary costs due to treatment and increases the risk of premature culling due to low production or lack of mobility that warrants her removal from the herd. 

Instead, when done properly, heat abatement allows cows to keep cool while lying down and mitigates the risk of becoming lame as discussed above. Fresh, cool air delivered at cow lying level is essential to your cows’ and your herd’s health; Cows stay in the herd longer, are comfortable all year long, and produce consistently no matter the season, a win-win for both cows and producers.

VES dairy experts design cooling (heat abatement) strategies for dairies around the world. We take a scientific approach, analyzing local climates and years of weather data to assess what tactics would work best for every dairy we work with. Our strategy of choice is to provide fresh air at an effective cooling velocity delivered to a cow’s lying level and at least one water-based cooling strategy. When the local climate allows, we pair powered ventilation with High Pressure Fogging to drop the environment’s ambient temperature. Together these methods provide proper heat abatement – increasing lying times and reducing lameness in cattle caused by heat stress.

You can learn more about Effective Cooling velocity fans and water-based cooling strategies such as High Pressure Fogging by connecting with a VES Dairy Expert, and how various other cooling strategies impact your animal’s health and your operation’s performance. 

 

What you need to remember?

    • Summer heat stress impacts more than just milk production. It can create an ongoing battle with lame, unhealthy cattle that stretches into months after the summer season.
    • Lame cattle are often a result of too much standing in an attempt to stay cool. Too much pressure from standing reduces blood flow and proper hoof development, resulting in thin soles and sole ulcers that make cows not want to get up. 
    • Lame cows minimize walking and standing to eat. Cows that don’t eat, don’t produce as much milk, lose body condition, don’t get pregnant, and miss out on proper nutrition for their overall health – negatively impacting your bottom line.
    • Proper heat abatement strategies create inviting and cool stall beds resulting in multiple positive impacts long after summer
    • Heat abatement strategies can be developed with proper power ventilation and high pressure fogging systems. 
    • There are various water-based and non-water based heat abatement strategies, each with their own positive and negative implications to your cow’s health and dairy’s performance. We will highlight all of the options for you in the future. 
    • You should talk with an experienced dairy expert about what cooling strategies and tactics are suitable for the location and climate at your operations.