During the summer months, there’s one task that surfaces to the top of every dairy farmer’s agenda: how to beat the heat. It’s crucial to mitigate heat stress in all dairy cattle, including calves in hutches, during the hot summer weather. Jennifer Van Os, assistant professor and extension specialist at the University of Wisconsin-Madison, explored temperature conditions within calf hutches. She offered recommendations to alleviate the heat in a University of Wisconsin-Madison Division of Extension webinar.

Reducing heat gain and promoting heat loss are two critical goals of heat abatement strategies. Van Os and her team explored both active and passive methods of heat reduction, focusing on the passive and natural ventilation potential within calf hutches. To investigate a calf’s preferred conditions, they created pairs of calves and placed them in a combined facility containing two hutches. One of the hutches was considered “unventilated” with only the front opening, while the other hutch had several avenues of airflow. The second hutch was considered “passively ventilated,” with the installation of after-market port holes, a propped rear bedding door, and the front opening.

During the first 10 weeks of the calves’ lives, the calf hutch temperatures were measured at several points without the calves inside of them. These points covered the calves’ preweaning, weaning, and postweaning periods and determined a significant temperature decline in the microclimate of the passively ventilated hutch. The two calves were then placed in their combined pen, where calf behavior and preferences were monitored. When outside of either of the hutches, the calves experienced elevated respiration rates and levels of heat stress. With just one hour spent within a passively ventilated hutch, the calves’ respiration rates drastically lowered, leading to the conclusion that the calves are being cooled through this ventilation system.

As the calf behavior was monitored, it became evident that both calves preferred the passively ventilated hutch during their weaning and postweaning period. Van Os stated “. . . as calves are developing and producing more metabolic body heat, they’re recognizing the difference in hutch microclimates and responding to that.” However, in the preweaning period, the calves found either hutch preferable. Van Os suspected this behavior was due to the calf’s development, and at this period, the calves are indifferent to the varying levels of heat.

It’s important to note that calves prefer to be with company, resulting in the calves often staying in pairs. The study unveiled that even with two calves in the passively ventilated hutch at the same time, the overall temperature remained lower than in the unventilated hutch.

The addition of passive ventilation to calf hutches is a simple, yet effective solution that can reduce heat stress among dairy calves. Calves are the beginning to any dairy operation, and these ventilation additions are a perfect way to help calves “beat the heat” this summer.

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(c) Hoard's Dairyman Intel 2024
July 8, 2024
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