Keep Calves Cool During the Dog Days of Summer

02:33PM Jul 02, 2019
Heins Family Farms 21
Heins Family Farms in Higginsville, MO
( Wyatt Bechtel )

The scorching summer sun has thermometers boiling and the humidity in the air is downright stifling. Want to hear the scary part? We’re only halfway done with the season!

Heat stress is a major concern on dairy operations during the dog days of summer, but the majority of farmers tend focus on the lactating animals first. While it is critical to keep the milking herd cool, we can’t forget to help calves chill off, too. 

Here are five tips to keep calves refreshed during this sizzling heat! 

Hutches and Heat Stress - Provide shade – Installing 80% shade cloth 3 to 4 feet above hutches has been shown to reduce air temperature inside hutches by 3 to 4˚F. Even situating hutches among shade trees can help.

Allow calves to move around – Calves that are confined to hutches may be at greater risk of heat stress than those that are able to choose where they lie. Outdoor pens or tethers allow calves more freedom to select a comfortable spot.

Face hutches east – In the summer, opening hutches to the east should maximize air movement and minimize solar heating. A spacing of 4 feet between hutches and 10 feet between rows is advised to allow air to circulate freely.

Elevate hutches – Several research studies have proven advantages to elevating hutches in hot weather. One way to do this is to prop up the back of the hutch with concrete blocks. Advantages to elevating hutches include increased airflow; lower temperature inside the hutch; reduced calf respiratory rates; and lower airborne bacteria levels inside the hutch.

Water Availability Critical for Summer Calves - Research has indicated that the amount of water needed by nursery calves depends not only on the environmental conditions but also on the incidence of scours and the amount of milk/milk replacer and starter intake. 

Water intake is closely related to starter intake which in turn drives rumen development. However, water intake may increase independent of starter intake when temperature is above the UCT for calves. Research has shown the amount of liquid in milk replacer also affects amount of water consumed. Water temperature can also affect water intake.

Do Calves Need More Milk in Hot Weather? - In hot conditions, calf starter intake is depressed and the energy cost to maintain normal body temperature is increased; thus the energy available for growth and development is reduced. Feeding more milk could be a solution to increase energy intake during summer, as it is very unlikely a healthy calf will refuse to drink milk.

Managing Heat Stress and Fly Control in Young Calves - When the summer months can be summarized with 2 words, rain and heat, there are many complications that can arise on farms, particularly with young calves.  

Bedding is a key player in both heat stress and fly control. Ensuring that a calf’s bedding is dry helps to decrease the incidence of flies gathering in the damp conditions and laying their eggs. Dry bedding reduces the amount of ammonia the calf is breathing and helps to keep the calf’s coat clean and dry, also eliminating a favorite spot for flies to rest. While straw is a favorable bedding for winter months, sawdust is more beneficial in the summer as it is less effective at insulating the calf. However, regardless of the preferred bedding, ensuring that there is adequate, dry bedding is what makes the difference. 

Cool Down Those Calves! - Although the Temperature-Humidity Index (THI) is used as a reference for heat stress in dairy cows, it can also be used for calves. Calf and heifer growers should keep in mind that calves do best when the temperature is between 55 and 78 degrees.

Some management practices to keep calves healthy during hot and humid weather:

  • Use sand bedding to keep calves cooler.
  • Increase airflow and air exchange to provide adequate fresh air.
  • Feed fresh grain daily to ensure good intakes during the hot weather.
  • Perform stressful activities such as moving and handling early in the morning.
  • Provide ample amounts of cool, clean water to prevent depressed feed intake.
  • Make housing adjustments, such as installing shade over outdoor calf hutches and pens, and other changes that will help lower the impact of high ambient temperatures on calves.