Economic Value of Days Open for Holstein Cows of Alternative Milk Yields with Varying Calving Intervals

Value of days open was estimated by budgeting simulation of a commercial herd situation for Holstein cows of alternative milk yields with varying calving intervals. Values for days open were differences of income over feed cost per cow per day among alternative calving intervals of 12, 13, and 15 too. Producing abilities for milk of cows corresponding to a 13-mo calving interval were 5900, 6800, 7700, and 8600 kg 3.5% milk per 300-day lactation. Conditions of herd management were a fixed policy of 65 days dry, herd size of 120 cows, group feeding with income-maximizing rations solved by linear programming, and a herd age structure of 30% of cows <36 mo and 70% of cows >/36 too.