The start of February means that we are slowly but surely getting through the coldest time of the year. Winter’s harsh conditions mean that farmers must take extra care to protect livestock from cold stress which can cause harm to health, growth, and production.
Newborn calves are particularly susceptible to cold stress due to their poor insulation, low surface-mass ratio, and lack of ruminal fermentation, as summarized by Roland et al., (2016). Penn State Extension states that calves less than one month old are most comfortable between 55-70°F (about 13-21°C) and can experience cold stress below 50°F (10°C). In the North Country it’s unlikely we will see temperatures consistently above 50°F for the next couple of months. Thus, we are continuously battling cold stress in our youngest calves right now.
Other livestock operations like poultry and swine use heat lamps to supplement heat to young animals. On dairy farms, newborn calves may be placed in clean heated boxes, wrapped in blankets, or washed with warm water. Once they are dry, their primary sources of non-nutritive heat supplementation include deep and dry bedding, calf jackets, and some kind of enclosure.
A recent study by Sonntag et al., (2025) from the Free University of Berlin used heat lamps (HLs) to determine whether calves preferred heated vs non-heated hutches and if their behavior changed when housed in heated hutches. Researchers used 36 calves that were one to six days old. Calves were blocked in pairs by similar age and body condition. One individual was housed in a paddock containing four hutches with zero (HL0), one (HL1), two (HL2), or three (HL3) heat lamps switched on in random order. During this ‘preference phase’, the calf was allowed to pick whichever hutch she preferred. The other calf experienced a ‘control phase’ and was housed in a paddock with one non-heated hutch. Calves were housed in this setup for four days, then switched for three days so that their total study period was one week.
Ambient temperature was an average of 41.7°F (5.4°C) throughout the study. The heat lamps influenced hutch temperature; HL0 averaged 43.9°F (6.6°C) and each additional lamp added 3 to 6.5°F (2.6 ± 1.0°C). Calves did not show preference toward warmer hutches, but they tended to prefer the hutches closest to neighboring calves. All calves spent about 90% of their time in hutches and while lying time was not different between treatments, it slightly decreased with age.
This study suggests that calves housed around 40°F didn’t express heat seeking behavior and that shelter alone was sufficient to avoid cold stress. An older study by Borderas et. al. (2009) from the University of British Columbia observed that newborn calves (≤ 3 days old) housed in a pen without physical barriers significantly preferred the area of the pen closest to a heat lamp. The average temperature in this barn was 37 to 50°F (6.27 ± 3.12 °C).
It’s plausible that calves housed in hutches can withstand colder ambient temperatures and do not need heat lamps. Hutches can provide a great wind break and allow calves to huddle in a smaller space, especially if properly insulated with deep bedding. Conversely, research suggests heat lamps may be a good option for housing newborn calves in more open areas like pens.
Either way, it would certainly be interesting to see if calf preference for heated areas is impacted by colder temperatures like what we experience in the Northeast. We know that calves can grow and thrive with calf jackets in hutches over the winter. I‘ve also seen farmers keep calves in an indoor area before moving them to a hutch or board up their hutches in the first days of life. Depending on your facilities, heat lamps may be an effective tool for keeping calves warm.
Do you already use heat lamps on your operation? Have you found them safe, cost effective, and easy to manage day-to-day? Is there a better way to supplement heat, like the use of infrared panels that decrease fire risk? I’m intrigued to hear your thoughts and if you believe this is beneficial to your calves’ health and welfare.
— Alexandria Bartlett