In our experiments, all calves successfully recovered and were energetically looking for milk shortly after recovery. Warm water immersion is the procedure of choice if you are in a hurry for the calf to recover or if the calf has a compromised ability to produce heat. A compromised ability to produce metabolic heat will occur if the calf is premature or if it is deeply hypothermic. One reason a premature animal can not produce adequate internal heat is that their lungs are not fully developed. Therefore, the calf can not take up ample oxygen to run the internal metabolic engine at full speed.
Many farmers give alcohol to hypothermic calves in an effort to speed recovery.
In our experiment the alcohol did not increase the rate of recovery of hypothermic calves in the warm water treatment. The blankets and the heat lamp techniques were also successful in rewarming the calves. Although these techniques were significantly slower, they also required less labour. The heat lamps must be protected or the lamps may be broken by a struggling calf. Calving in the winter is a challenge, particularly if you must deal with the occasional hypothermic calf.