Diurnal Temperature Patterns in Unrestrained Cows

Radio telemetry was used to measure the temperature in three different locations within the bodies of unmolested cows. The diurnal temperature pattern was measured over a four-day period in the reticulum, the crop area, and in a pararectal area. The reticular temperature of four mature cows varied from 32.2 C after drinking water, to a high of 40.5 C prior to feeding. Usually 60-90 rain were required for the temperature to reach the predrinking level. I-Iowever, other than at drinking time, reticular temperatures were between 39 and 40 C. The subcutaneous temperatures varied from 31.9 to 38.4 C and dropped rapidly when the animals were turned out for" exercise dm'ing outdoor temperatures of approximately 10 C. The pararectal temperatures were most constant, but ranged between 34.4 and 39.2 C, reaching a peak during feeding. When the a.nimals were lying down, pararectal temperatures dropped but the subcutaneous temperatures rose until they approached or exceeded the pararectal temperatures.