When dairy calves are born, they are essentially monogastric animals, according to researchers Kara Bekebrede and Donna Amaral-Phillips from the University of Kentucky. However, rumen development in young calves is critical for long-term productivity in the milking herd.
That’s why, in addition to milk, calves need to be fed a fermentable substance and water that will enter the rumen. This helps establish a rumen microbe population and promotes development of rumen palpillae, finger-like projections on the surface of the rumen that absorb nutrients from the rumen contents.
The researchers recommend adding free-choice water and about 0.1 pounds of calf starter to calves’ diets starting at three days of age. They say small quantities of fresh starter should be offered daily and slowly increased until calves are eating 1.5 to 2.0 pounds of grain for three consecutive days, at which time calves can be weaned.
They point out that a four-week-old calf that has received starter has a more developed rumen than a 12-week-old calf fed a strictly milk diet.
An informative fact sheet on the subject can be viewed here.