Feed Warm Milk
I watched the calf care person feeding milk on a chilly June morning.
He started with the youngest calf. Back and forth he went from row to row - 120 calves total.
Then he came back to check the youngest calves. Of the ten youngest calves only five of them had drunk their milk. He got inside the wire pen and hand-fed each of the five calves - maybe I should say he worked at bucket training them.
I could reach these pails from outside the pens. So I used my rapid-read thermometer to check temperatures. The readings for these five pails of milk were between 70 and 75F. Recall that the body temperature of these young calves is right round 102F. So, why feed milk that is about thirty degrees colder than the calf? Because that is just the way things work out - the milk he put into their buckets chilled down while he was feeding the rest of the calves.
I suggested an alternative approach. Remember that he does not know from feeding to feeding how many of these youngest calves are and are not going to drink out of the pail by themselves.
We agreed that the largest number of calves that do not drink out of their pail by themselves is seldom more than eight - more often four or five.
I proposed that he routinely fill eight bottles with milk. Put on nipples and set them (4 to each five-gallon pail) into pails filled with warm water. Drop them off at the location of the youngest calves as he starts to feed milk. Just leave them there until he completes milk feeding.
Then, when he returns to the youngest calves dump one bottle of warm milk at a time into a milk-feeding pail. If she drinks fine. If she needs assistance help her then before dumping more bottles.
The idea is to leave the bottles in the warm water until each calf is ready to drink either from the bottle or be bucket-trained. At another dairy a second person is available to work individually with the youngest calves. This 4-bottles-in-a-bucket approach works well here, too. They use four five-gallon pails with sixteen bottles.
Of course, in winter weather the water in the five-gallon pails needs to be much warmer than in June.