How much milk will calves drink?
When milk intake is not restricted expect calves to drink large amounts of milk. Expect large variations among calves in milk consumption. Expect significant changes in levels of milk intake from week-to-week. In environments with significant pathogen exposure, appetites tend to be depressed during infections. Expressed as a percentage of live weight, milk consumption tends to go down as dairy heifer calves with free-choice milk, water and calf starter grain get past about three to four weeks of age.
In the figure above note the 9.5 qts.daily for the average Holstein calf daily milk intake at 5 days. Note also about an 18 percent difference between the lowest and highest calf in milk consumption at 5 days of age. In the figure below the difference between lowest and highest calf in milk consumption at 4-7 days of age is about 20 percent as well.
In the figure above the daily weights show the depressed intakes when the calves were working through intestinal infections. While not reported in the published data we can guess that the calves may have had the common parasite (e.g., cryptosporidiosis) and bacterial (e.g., colibacillosis) issues.
For the Holstein calves in the figure above (about 160 lbs.) as they approached 35 days their milk intake (as a percent of live weight) dropped down to about 14 percent. For the calves in the figure below in the range of 22-28 days declined to an average of 14 percent.
References: Jasper, J. and D.M. Weary “Effects of ad libitum milk intake on dairy calves.” Journal of Dairy Science 85:3054- 3058 (2002). Wise, G. H. and J.P. LaMaster “Responses of calves to open-pail and nipple-pail systems of milk feeding.” Journal of Dairy Science 51:452-456 (1968).