Knowing a cow's normal temperature is one of the cheapest diagnostic skills on the farm — a thermometer costs little and tells you whether "she looks off" is a real problem or not.
The normal range A healthy adult dairy cow sits at 38.0–39.0 °C (100.4–102.2 °F). Calves run slightly warmer, up to about 39.5 °C. Treat readings this way:
- Below 38.0 °C — subnormal. In a fresh cow this can signal milk fever (hypocalcaemia) or a cow going into shock; it's as serious as a high fever. - 38.0–39.0 °C — normal. - 39.0–39.5 °C — borderline; recheck in a few hours, consider what she's been doing. - Above 39.5 °C — true fever. Find the source (see "Mastitis vs other causes of fever"). - Above 41 °C — emergency. Severe infection or heat stress; act now.
Take it properly or the number lies - Use a digital thermometer; it's faster and safer than glass. - Insert into the rectum against the wall (not into a ball of dung — that reads low). - Hold for the full reading; don't pull early. - Take it in the cool of the morning. A cow that's been walking, standing in full sun, or is heavily pregnant can read up to 0.5 °C high without being ill. - Heat stress vs. fever: if several cows are high, it's hot weather, and they're panting — that's heat stress, not infection. A single high cow in a comfortable herd is more likely sick.
Build it into a routine Take the temperature of any cow that's off feed, dropping milk, recently calved, or just "not herself." Logging it in Vache turns a vague worry into a tracked data point — and a fever logged today is the hook that surfaces the right next-step article when you need it.
Sources Merck Veterinary Manual — The Physical Examination of Cattle. Penn State Extension — Vital Signs in Cattle. AHDB Dairy — Fresh Cow Monitoring.