Editor's note: The following information is provided by Milk Products, LLC.
As summer temperatures creep up over 90 degrees F, heat stress can negatively impact calf health and performance. Heat stress causes increased respiration and body temperature, rapid dehydration and reduced immune system function. In addition, the calf’s maintenance energy requirement is elevated — similar to the effects of cold stress.
According to Dave Cook, technical service manager at Milk Products, LLC, “In cold weather, calves burn more energy to keep themselves warm, while in hot weather they burn more energy keeping themselves cool. Both calf growth and health can be negatively affected if heat stress is not managed.”
Efforts should be made to identify and avoid heat stress in calves. If you see increased respiratory rates, openmouthed breathing, decreased appetite and reluctance to move your calves may be suffering from heat stress.
This summer, consider the following tips to assure proper calf health and growth.
- Reduce sun exposure — Use barns and hutches that do not allow sunlight to contact the calf. Eighty percent shade cloth is recommended on greenhouse barns and translucent hutches. Many years ago, researchers at Penn State University showed daytime air temperatures inside translucent hutches were 3.6° to 5.4°F (2 to 3°C) higher than outside air. They also noted higher calf body temperatures, higher respiration rates, higher water intake and lower feed intake in translucent hutches when compared to opaque hutches.
- Improve air flow — Naturally ventilated buildings should have all vents completely opened, including ridge and eave vents, as well as sidewall curtains. Hutches should also have vents and doors opened, and the back end may be elevated using wooden or concrete blocks to improve ventilation. Hutches should also have enough space in between them to provide for air circulation.
- Bedding — “The ideal bedding for calves during hot weather is a subject of debate,” Cook said. “Inorganic sources such as sand or wood shavings offer advantages over organic sources such as straw. Also, sand and shavings do not insulate the calf as much and they don’t decompose so may reduce the fly population.”
If the pens or hutches are on concrete or a hard dirt surface, sand or wood shavings may be a better choice than straw. No matter the season, the key is to keep the calves clean and dry. Choose the bedding material that best fits the housing and labor situation.