Evaluation of rectal temperature in diagnosis of puerperal metritis in dairy cows

The objective of this field trial was to evaluate the body temperature within the interval of 10 days post partum in cows with puerperal metritis, as confirmed by a clinical examination, in comparison with cows without clinical symptoms of this disease. In addition, the body temperature in cows having a purulent and putrid character of lochia was compared. Rectal temperature was measured daily in 92 randomly selected cows. The cows were examined clinically on day 10 ± 3 post partum and were divided according to the character of lochia into Group M1 (purulent lochia, n = 29), Group M2 (putrid lochia, n = 28) and Group C (normal lochia, n = 35). The number of cows with a fever (temperature > 39.0°C or > 39.5°C) at least once during 10 days post partum was higher in Groups M1 and M2 compared to Group C (86.2% and 92.9% vs. 54.3%, P < 0.01 and P < 0.001, or 41.4% and 71.4% vs. 14.3%, P < 0.05 and P < 0.001). In addition, there was a higher number of cows with a temperature > 39.5°C in Group M2 in comparison with Group M1 (P < 0.05). More cows showed consistent temperatures > 39.0°C for three days or > 39.5°C for two days in Group M2 compared to Group C (42.9% vs. 8.6%, P < 0.01 or 25.0% vs. 2.9%, P < 0.05). Average daily temperatures were higher in Group M2 compared to Group C on Days 1, 3, 5 and 7 (P < 0.05) as well as on Days 2 and 6 (P < 0.01) post partum. The results reveal the following: higher incidence of body temperature > 39.0°C in cows with puerperal metritis; risk period for fever from Day 3 to Day 7 post partum; higher incidence of fever in cows with putrid lochia compared to cows with purulent lochia; body temperature > 39.5°C being a more accurate indicator of puerperal metritis than temperature > 39.0°C. Despite that, the occurrence of fever was irregular. In conclusion, measurement of body temperature does not represent a sufficiently accurate diagnostic method for puerperal metritis although it may be considered a useful indicator for assessment of the severity of the disease.