Since cows can’t call or text you and tell you when they are going to calve, it’s not always easy to predict the onset of labor. However, there are a few signs to help identify when birth is imminent. For example, there is evidence that cow body temperature decreases before calving.
German researchers recently conducted three experiments that were published in the October Journal of Dairy Science to determine the accuracy of this measure. They tracked vaginal and rectal temperatures twice daily and found that, indeed, cow temperatures were lower beginning about 48 hours prior to calving. But, the scientists concluded that the data wasn’t precise enough to accurately predict when calving would start.
They suggest that while cow temperature data can provide valuable information, you should still watch for traditional signs— like the relaxation of the ligaments around the tail head — to know when calving is ready to begin.