Cold stress can significantly affect health, growth, and future reproduction in a newborn calf if not managed properly. Due to their poor insulation, low surface mass ratio, and lack of ruminal fermentation, calves are more susceptible to cold stress. Penn State studies have shown that calves less than 1 month old are most comfortable at temperatures between 55°F and 70°F, but can also begin to experience cold stress at temperatures of 50°F, said Miner Institute’s Alexandria Bartlett in a Farm Report newsletter.

A recent study used heat lamps to determine if calves have heat-seeking behavior and if their behavior changed depending on what type of housing they were in. Researchers used 36 calves aging 1 to 6 days old. Calves were grouped in pairs based on age and body condition.

One individual calf was placed in a paddock containing four hutches with either zero (HL0), one (HL1), two (HL2), or three (HL3) heat lamps placed in random order. By doing so, calves were allowed to choose the specific hutch they preferred. The other calf was housed in a paddock with a hutch that did not have a heat lamp as the control. Calves were housed in this setup for four days and switched for three, equating to a week. The average ambient temperature was 41.7 °F. HL0 hutches interior temperature averaged 43.9°F, and each lamp count contributed an additional 3°F to 6.5°F.

It was found that calves did not have a preference toward warmer hutches but instead preferred to be in hutches near neighboring calves. All calves spent 90% of their time in the hutch. “It’s plausible that calves housed in hutches can withstand colder ambient temperatures,” Bartlett noted. Calves housed in open pens might be more prone to the inclusion of heat lamps. It is also important to note that when using heat lamps, be sure to take precautionary measures as they can also present safety risks.