Nutritive value of potato-based silages for dairy bulls.

Diet acceptability, nutrient digestibility, and nitrogen and energy partition were measured in growing Holstein bulls to compare corn silage with three potato-based silages which consisted of (fresh basis): 1) 50% potatoes, 20% hay; 2) 60% potatoes, 20% hay, 20% whole oats; 3) 50% potatoes, 25% hay, 25% whole oats. The 50% potato 50% hay silage dry matter was consumed at 3.0% of body weight per day which was greater than for any of the other three silages. Consequently, daily consumption of each nutrient was generally higher for this silage even though it was lower in content of many nutritional components. Except for ether extract, the digestion coefficients for the 50% potato 50% hay silage were higher than for the other three silages. The addition of whole oats to the potato-based silage tended to depress apparent digestibility of the nutritional components below those for corn silage. Both nitrogen and energy utilization were higher for the 50% potato 50% hay silage than for any of the other three experimental silages. Efficiency of use of absorbed nitrogen was higher for the oat-containing potato-based silages than for corn silage while the oat-containing silages were comparable to corn silage in energy efficiency. The 50% potato 50% hay silage was equal or superior to corn silage in dry matter intake, overall overall digestibility, nitrogen and energy balance for growing Holstein bulls.