Just like young children, sick calves often signal their illness by exhibiting fevers.
Normal body temperature for a healthy preweaned calf is in a range of 100-103°F, according to UK-based animal health supplier AniMac. It tends to be lower first thing in the morning at around 100°F, and reaches its peak in the afternoon.
But when calves are infected with a disease-causing pathogen, one of the body’s common responses to fight it is fever, according to Mariah Gull, ruminant nutritionist with Calf Distinction. “They may also be depressed, go off feed, and have an elevated pulse rate,” Gull advised. “The calf’s body becomes hot and dry, respiration rate increases, and the calf may become severely depressed and unable to stand.”
Gull said pneumonia is one of the most under-diagnosed diseases in calves. Unlike scours, its symptoms can be very subtle. And permanent lung damage is common, causing production setbacks for animals for the rest of their lives, even if they survive.
That’s why early detection of disease is so critical. Taking calf temperatures is a quick and accurate way to assess calf health. Gull noted digital thermometers – even those designed for humans – can provide speedy and precise readings of rectal temperatures.
Some advice for the procedure:
- Lubricate the bulb end of the thermometer.
- While holding the calf steady with one hand, gently place the bulb end of the thermometer on the calf’s anus.
- Push the full length of the thermometer into the rectum. The thermometer must be directly touching the side of the rectum for an accurate reading.
- Digital thermometers usually beep when they have reached a steady reading. Before removing the thermometer, press the button to store the temperature, or simply read it.
- Withdraw the thermometer and wipe it clean with a paper towel.
- Record the calf’s temperature and any treatments given.
- Keep a thermometer handy at all times so temping calves becomes a routine part of daily calf care.
AniMac officials noted that calves’ thermoneutral zone, in which they do not burn extra energy to regulate their body temperature, is between 50 and 77°F. Other factors like wind and wet haircoats also can cause them to burn energy, requiring more calories and possibly suppressing skeletal growth, weight gain, and immunity.
Calf jackets and deep straw bedding that allow calves to nest can help them maintain a constant body temperature. When calves stay warm and dry through the night, they have less need to play “catch up” with their body temperature through the day.
Anything over 103°F indicates illness that requires treatment; extreme fevers can drive calf body temperatures up to 107°F. If it reaches 108°F, the calf will likely die of heat stroke.
“We rarely get second chances with sick calves,” advised Gull. “Work with your veterinarian to establish a treatment protocol for calves exhibiting abnormal temperatures.”
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