The gestation period for a cow or heifer, which is the time between conception and giving birth, typically lasts around 280 to 285 days, or roughly 9 months. However, this can vary somewhat depending on the breed and individual factors.
Most cows and heifers will give birth within this time frame, but it's important to note that there can be natural variation, and factors such as health, nutrition, and environmental conditions can influence the exact duration of pregnancy. Farmers and ranchers often closely monitor their cows and heifers to ensure a safe and healthy birth process.