TAYLOR LEACH
June 24, 2022
During the summer months, you’ll often see high school football players and athletes working out during the early morning hours while temperatures are still cool. Who can blame them?
As the thermometer starts to creep its way into the upper 80s, 90s or even the 100°F mark, nobody wants to put in physical work during the hottest part of the day - cows included.
As summer temperatures rise, dairy cows are at greater risk for heat stress. Heat stressed dairy cows suffer from:
reduced dry matter intake
reduced milk production
decreased fertility
lameness issues
metabolic issues
According to the University of Wisconsin-Madison Dairy Extension Team, it is important to minimize animal handling during bouts of heat to help prevent heat stress and improve animal welfare.
Know When It’s Too Hot
Animals can experience heat stress discomfort even during milder weather, especially as you factor in humidity. Knowing the daily Temperature Humidity Index (THI) can help producers plan activities around times when they anticipate heat stress in cattle.
The chart (below) is color-coded according to categories of heat stress ranging from mild (lightly shaded) to severe (darkly shaded) for lactating dairy cows.
Minimize Handling
While cows spend the majority of their day either resting or eating, they do spend chunks of time in the parlor, holding area or in headlocks.
According to the extension team, to prevent added heat stress, handle animals during the early morning hours before the temperature rises into the risky THI level. Limit the length of time animals spend in headlocks or other handling equipment where their stress from confinement may exaggerate the heat stress conditions.
When THI is 72 or higher, consider postponing animal handling related tasks which can be performed during cooler weather.
An animal’s internal temperature peaks approximately two hours after the environmental temperature peaks and it takes the animal four to six hours to lower their temperature back to normal. If possible, the evening hours should be left for the animals to cool down and not used for handling unless it is necessary.
Extra care should be taken if the evening temperatures do not drop below 70°F as cattle have no chance to recover before another day of heat and humidity. The longer the heat stretch lasts, the more stressful it is on cattle.
Keep Animals Calm
Animals who are nervous or stressed have higher core body temperatures. When handling or moving cows, move them slowly, calmly and quietly. If possible, try to move them in short distances. Plan ahead to avoid unnecessary movements.
Limit Transport
Trailer rides can be a stressful experience for cattle. Factor in hot temperatures and it can be animal welfare nightmare. The Dairy Extension Team recommends avoiding cattle transport in moderate to severe THI conditions. If possible, postpone transport until cooler and less humid weather arrives.
Provide Plenty of Water
No matter the time of year, clean drinking water should always be readily available for cattle. During the summer months, this becomes even more critical.
Check and clean waterers regularly and monitor increased consumption. As temperatures rise, many cattle may try to drink at the same time. Ensure the refill rate is adequate, so it allows all animals to drink. If necessary, consider adding additional temporary tanks.
dairyherd.com
