How it works
Cattle gestation averages about 283 days, a little over nine months, and breed moves that by up to two weeks. Dairy breeds run short, Continental and Brahman-influenced cattle run long, and bull calves are usually carried a day or two longer than heifers. Twins arrive earlier, often by a week or more.
Average gestation by breed
| Breed | Average gestation | Notes |
|---|---|---|
| Holstein, Jersey | about 279 days | Shortest of the common breeds. Dry off 60 days before this date. |
| Angus | about 281 days | Bred for calving ease; heifers are usually mated to low birth-weight bulls. |
| Shorthorn | about 282 days | |
| Hereford | about 285 days | |
| Simmental, Charolais, Limousin | about 289 days | Big calves; watch first-calf heifers closely. |
| Brown Swiss | about 290 days | |
| Brahman and Brahman crosses | about 292 days | Longest. Expect to wait nearly ten days past an Angus date. |
Planning a tight calving season
Count back 283 days from the day you want calves on the ground, and turn the bull in then. Leave him in for 60 to 65 days, which covers three heat cycles, and pull him out. Your whole calving season then lands in about nine weeks, and every cow that did not settle is obvious because she has no calf. A tight season means one vaccination round, one weaning date and an even, saleable calf crop instead of stragglers.
The countdown
- Day 18-24: watch for returns to heat after AI or bull turn-out.
- Day 28-35: ultrasound can confirm pregnancy; blood tests work from about day 28 too.
- Day 35-45 onward: a vet can palpate.
- 60 days out: dry off a milking cow.
- 30 days out: move her to a clean, sheltered calving area and check your calving kit.
- Last week: the udder tightens, the tailhead ligaments slacken, and she separates from the herd.
Calving, and when to intervene
Stage one is restlessness and isolation and lasts two to six hours, longer in heifers. Stage two is the actual delivery: a cow should calve within about an hour of the water bag appearing, a heifer within two. Two front feet with the nose resting on them is normal.
Call for help if a heifer has pushed for two hours or a cow for one with no progress, if you see a tail or a head with no feet, if only the hind feet show (soles up), or if she stops trying. After calving, the placenta should pass within 8 to 12 hours; a cow still holding it after 24 hours needs the vet, and the calf should be up and sucking within two hours.
How to use it
Enter the AI date or the day the bull was put in. For pasture breeding, add the day the bull was pulled so you get the full calving window. Pick the breed, or the sire's breed for crossbred calves.
Reference chart
| Breed | Average gestation |
|---|---|
| Average (most breeds) | 283 days |
| Angus | 281 days |
| Hereford | 285 days |
| Holstein | 279 days |
| Jersey | 279 days |
| Shorthorn | 282 days |
| Simmental | 289 days |
| Charolais | 289 days |
| Limousin | 289 days |
| Brown Swiss | 290 days |
| Brahman | 292 days |
Frequently asked questions
How long is a cow pregnant?
About 283 days, just over 9 months. Most cows calve within about 10 days either side of the average for their breed.
Which breeds have the longest gestation?
Brahman and Brahman-cross cattle, along with Continental breeds like Brown Swiss, Simmental, Charolais and Limousin, often run 287–292 days. Holsteins and Jerseys are nearer 279 days.
When can you tell if a cow is pregnant?
A vet can usually confirm pregnancy by ultrasound from about 28–35 days after breeding, or by rectal palpation from about 35–45 days. Blood tests are another option from about 28–30 days.
How long after calving can a cow be bred?
Most producers aim to rebreed 60–90 days after calving to keep a calf every 12 months. The first heat often returns 30–60 days after calving.
Figures are typical values from university extension guidance (sources and method). Estimates only. Individual animals vary — confirm pregnancy and health questions with your veterinarian.