Gestation period of cow is

Gestation period of cows is 283 - 285 days.
Gestation is the period of development during the carrying of an embryo, and later foetus, inside viviparous animals. It is typical for mammals but also occurs for some non-mammals. The time interval of gestation is called the gestation period.
281 days are the average gestation period for cows with about equal chances for calving on any day from the 275^th to the 287^th day after service.