290th

Updated: July 7, 2026

This fact notwithstanding, a competent observer found that, of 160 cows, 67 were delivered before the 280th day; 68 between the 280th and the 290th day; and 25 after the 290th day. Although nothing unnatural was observed in any instance, the first animal was delivered 67 days before the last, and in 5 instances gestation continued 308 days.

J. Morris (Josiah Morris) Slemons - The Prospective Mother, a Handbook for Women During Pregnancy