When milk intake is not restricted, calves are expected to drink large amounts of milk, says Dr. Sam Leadley, calf and heifer specialist with Attica Veterinary Associates, Attica, N.Y. At peak consumption, that could be more than 12 quarts per day.
Leadley says a good deal of variation among calves is to be expected, with significant changes in intake levels from week to week. "In environments with significant pathogen exposure, appetites tend to be depressed during infections," he says.
Expressed as a percentage of live weight, milk consumption tends to go down as dairy heifer calves with free-choice milk or milk replacer, water and calf starter grain advance beyond three to four weeks of age.
Figure 1 shows a similar consumption pattern of three Holstein calves over time, although there is an 18-percent difference between the lowest and highest calf in milk consumption at five days of age. This disparity continues and becomes even greater at older ages.The decline in milk consumption around 7 to 13 days of age was the result of the calves working through a period of intestinal infection.
In the study depicted in Figure 1, calves" milk consumption began to level off to about 14 percent of bodyweight at around 35 days of age. Another study showed a similar decrease in consumption occurring at 22 to 28 days of age.