Gestation
The length of pregnancy in cattle, about nine months or roughly 280 to 290 days.
Also: pregnancy, in calf
A cow carries her calf for about nine months. The average is around 283 days in many taurine breeds, a little shorter in some, such as the Jersey and Angus, and longer in zebu, often about 285 to 295 days. Bull calves tend to be carried a day or two longer than heifer calves. Pregnancy can be confirmed by a vet feeling the uterus through the rectum, by ultrasound or by a milk or blood test. Farmers count forward from the mating or insemination date to predict calving. Most cows have a single calf; twins are uncommon, though more frequent in dairy cows than in beef cows.