Quick answer
Hereford cattle are pregnant for about 285 days, two days more than the 283-day rule. Most Hereford calves arrive between day 275 and day 295.
A Hereford cow bred on May 1 calves around Feb 10 (283 days would say Feb 8).
How long are Hereford cows pregnant?
Most breed references put the Hereford gestation period at about 284 to 286 days, a shade longer than the 283 days printed on most generic charts. This Hereford gestation chart uses 285 days. It is a small difference, but it adds up: plan a Hereford calving season with 283 days and the first calves look “late” before they have even started.
Herefords are not alone in this. The British breeds sit close together, with Angus a few days shorter and Hereford and Highland a couple of days longer. Continental breeds run longer still. If your own herd records say something different, type your herd’s average under More options → my own gestation in the calculator and every date follows it.
Hereford gestation chart, month by month
Here is the whole Hereford pregnancy for a cow bred on May 1, with the date each job falls due. For your own cow, put her breeding date into the calculator above and tap Full pregnancy timeline: you get the same chart with her dates.
| Stage | Day | Bred May 1 → date | What to do |
|---|---|---|---|
| Bred | Day 0month 1 | May 1 | Day 0. Write down the date and the bull or AI sire. |
| Heat check | Day 21month 1 | May 22 | Watch for her to come back into heat from May 19 to May 25. No heat is the first good sign. |
| Preg check | Day 35month 2 | Jun 5 | Ultrasound from about day 30, palpation from about day 35–45, a blood test from day 28. |
| Calf sexing | Day 60month 3 | Jun 30 | Ultrasound between day 55 and 90 can show a bull or heifer calf. |
| End of 1st trimester | Day 95month 4 | Aug 4 | The calf is about the size of a rat. Keep her on a steady diet. |
| Last trimester starts | Day 190month 7 | Nov 7 | Most of the birth weight goes on from here. Step up energy and protein. |
| Pre-calving vaccines | Day 243month 9 | Dec 30 | Scours vaccines 3–6 weeks before calving, as the label and your vet advise. |
| Move to calving area | Day 264month 9 | Jan 20 | Clean, dry pasture or pen. Check her twice a day from now on. |
| Calving window opens | Day 275month 10 | Jan 31 | Earliest normal calving date. |
| Due date | Day 285month 10 | Feb 10 | The Hereford average: 285 days after breeding. |
| Call the vet if not calved | Day 295month 10 | Feb 20 | More than about 10 days past the due date needs a vet check. |
The three trimesters of a Hereford pregnancy are each about 95 days. The first is about getting her confirmed pregnant and keeping her calm. The second is the cheapest time to put condition on a thin cow. In the third, from about day 190, the calf puts on most of its birth weight and she needs more energy and protein.
Hereford gestation table
Calving dates for every breeding day of the year at 285 days. Find the breeding month along the top and the breeding day down the side; the cell is the calving date.
| Bred | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Oct 13 | Nov 13 | Dec 11 | Jan 11 | Feb 10 | Mar 13 | Apr 12 | May 13 | Jun 13 | Jul 13 | Aug 13 | Sep 12 |
| 2 | Oct 14 | Nov 14 | Dec 12 | Jan 12 | Feb 11 | Mar 14 | Apr 13 | May 14 | Jun 14 | Jul 14 | Aug 14 | Sep 13 |
| 3 | Oct 15 | Nov 15 | Dec 13 | Jan 13 | Feb 12 | Mar 15 | Apr 14 | May 15 | Jun 15 | Jul 15 | Aug 15 | Sep 14 |
| 4 | Oct 16 | Nov 16 | Dec 14 | Jan 14 | Feb 13 | Mar 16 | Apr 15 | May 16 | Jun 16 | Jul 16 | Aug 16 | Sep 15 |
| 5 | Oct 17 | Nov 17 | Dec 15 | Jan 15 | Feb 14 | Mar 17 | Apr 16 | May 17 | Jun 17 | Jul 17 | Aug 17 | Sep 16 |
| 6 | Oct 18 | Nov 18 | Dec 16 | Jan 16 | Feb 15 | Mar 18 | Apr 17 | May 18 | Jun 18 | Jul 18 | Aug 18 | Sep 17 |
| 7 | Oct 19 | Nov 19 | Dec 17 | Jan 17 | Feb 16 | Mar 19 | Apr 18 | May 19 | Jun 19 | Jul 19 | Aug 19 | Sep 18 |
| 8 | Oct 20 | Nov 20 | Dec 18 | Jan 18 | Feb 17 | Mar 20 | Apr 19 | May 20 | Jun 20 | Jul 20 | Aug 20 | Sep 19 |
| 9 | Oct 21 | Nov 21 | Dec 19 | Jan 19 | Feb 18 | Mar 21 | Apr 20 | May 21 | Jun 21 | Jul 21 | Aug 21 | Sep 20 |
| 10 | Oct 22 | Nov 22 | Dec 20 | Jan 20 | Feb 19 | Mar 22 | Apr 21 | May 22 | Jun 22 | Jul 22 | Aug 22 | Sep 21 |
| 11 | Oct 23 | Nov 23 | Dec 21 | Jan 21 | Feb 20 | Mar 23 | Apr 22 | May 23 | Jun 23 | Jul 23 | Aug 23 | Sep 22 |
| 12 | Oct 24 | Nov 24 | Dec 22 | Jan 22 | Feb 21 | Mar 24 | Apr 23 | May 24 | Jun 24 | Jul 24 | Aug 24 | Sep 23 |
| 13 | Oct 25 | Nov 25 | Dec 23 | Jan 23 | Feb 22 | Mar 25 | Apr 24 | May 25 | Jun 25 | Jul 25 | Aug 25 | Sep 24 |
| 14 | Oct 26 | Nov 26 | Dec 24 | Jan 24 | Feb 23 | Mar 26 | Apr 25 | May 26 | Jun 26 | Jul 26 | Aug 26 | Sep 25 |
| 15 | Oct 27 | Nov 27 | Dec 25 | Jan 25 | Feb 24 | Mar 27 | Apr 26 | May 27 | Jun 27 | Jul 27 | Aug 27 | Sep 26 |
| 16 | Oct 28 | Nov 28 | Dec 26 | Jan 26 | Feb 25 | Mar 28 | Apr 27 | May 28 | Jun 28 | Jul 28 | Aug 28 | Sep 27 |
| 17 | Oct 29 | Nov 29 | Dec 27 | Jan 27 | Feb 26 | Mar 29 | Apr 28 | May 29 | Jun 29 | Jul 29 | Aug 29 | Sep 28 |
| 18 | Oct 30 | Nov 30 | Dec 28 | Jan 28 | Feb 27 | Mar 30 | Apr 29 | May 30 | Jun 30 | Jul 30 | Aug 30 | Sep 29 |
| 19 | Oct 31 | Dec 1 | Dec 29 | Jan 29 | Feb 28 | Mar 31 | Apr 30 | May 31 | Jul 1 | Jul 31 | Aug 31 | Sep 30 |
| 20 | Nov 1 | Dec 2 | Dec 30 | Jan 30 | Mar 1 | Apr 1 | May 1 | Jun 1 | Jul 2 | Aug 1 | Sep 1 | Oct 1 |
| 21 | Nov 2 | Dec 3 | Dec 31 | Jan 31 | Mar 2 | Apr 2 | May 2 | Jun 2 | Jul 3 | Aug 2 | Sep 2 | Oct 2 |
| 22 | Nov 3 | Dec 4 | Jan 1 | Feb 1 | Mar 3 | Apr 3 | May 3 | Jun 3 | Jul 4 | Aug 3 | Sep 3 | Oct 3 |
| 23 | Nov 4 | Dec 5 | Jan 2 | Feb 2 | Mar 4 | Apr 4 | May 4 | Jun 4 | Jul 5 | Aug 4 | Sep 4 | Oct 4 |
| 24 | Nov 5 | Dec 6 | Jan 3 | Feb 3 | Mar 5 | Apr 5 | May 5 | Jun 5 | Jul 6 | Aug 5 | Sep 5 | Oct 5 |
| 25 | Nov 6 | Dec 7 | Jan 4 | Feb 4 | Mar 6 | Apr 6 | May 6 | Jun 6 | Jul 7 | Aug 6 | Sep 6 | Oct 6 |
| 26 | Nov 7 | Dec 8 | Jan 5 | Feb 5 | Mar 7 | Apr 7 | May 7 | Jun 7 | Jul 8 | Aug 7 | Sep 7 | Oct 7 |
| 27 | Nov 8 | Dec 9 | Jan 6 | Feb 6 | Mar 8 | Apr 8 | May 8 | Jun 8 | Jul 9 | Aug 8 | Sep 8 | Oct 8 |
| 28 | Nov 9 | Dec 10 | Jan 7 | Feb 7 | Mar 9 | Apr 9 | May 9 | Jun 9 | Jul 10 | Aug 9 | Sep 9 | Oct 9 |
| 29 | Nov 10 | Jan 8 | Feb 8 | Mar 10 | Apr 10 | May 10 | Jun 10 | Jul 11 | Aug 10 | Sep 10 | Oct 10 | |
| 30 | Nov 11 | Jan 9 | Feb 9 | Mar 11 | Apr 11 | May 11 | Jun 11 | Jul 12 | Aug 11 | Sep 11 | Oct 11 | |
| 31 | Nov 12 | Jan 10 | Mar 12 | May 12 | Jun 12 | Aug 12 | Oct 12 |
To print it, or to see it for a particular year with weekdays, open the printable cattle gestation table and pick Hereford in the breed menu.
Hereford gestation calendar by breeding month
A quicker way to read it: bred on the 1st or the 15th of each month, this is when a Hereford calves.
| Bred in… | Bred on the 1st → calves | Bred on the 15th → calves | Calving month |
|---|---|---|---|
| January | Oct 13 | Oct 27 | October |
| February | Nov 13 | Nov 27 | November |
| March | Dec 11 | Dec 25 | December |
| April | Jan 11 | Jan 25 | January |
| May | Feb 10 | Feb 24 | February |
| June | Mar 13 | Mar 27 | March |
| July | Apr 12 | Apr 26 | April |
| August | May 13 | May 27 | May |
| September | Jun 13 | Jun 27 | June |
| October | Jul 13 | Jul 27 | July |
| November | Aug 13 | Aug 27 | August |
| December | Sep 12 | Sep 26 | September |
A Hereford cow bred in May or June calves the following February or March, the classic spring calving season for Hereford herds.
Horned, Polled Hereford and Hereford crosses
Horned and Polled Herefords are the same breed for gestation purposes. Crossbred calves fall between their parents, and the sire has the bigger say:
| Cattle | Typical gestation | Pick in the calculator |
|---|---|---|
| Hereford (horned or polled) | about 284–286 days | Hereford (285) |
| Black Baldy (Angus × Hereford) | about 282–283 days | Average (283) |
| Red Baldy (Red Angus × Hereford) | about 283–284 days | Average, or your own number |
| Hereford × Simmental | about 285–287 days | Simmental (287) or Hereford |
| Braford (Hereford × Brahman) | about 287–290 days | Other Bos indicus cross (286) |
These figures are approximate. For a cross, the safest choice is the breed of the calf’s sire, or your own herd’s average once you have a couple of seasons of records.
Hereford heifers and calving ease
Hereford calves are often a bit heavier at birth than Angus calves, and a longer gestation is part of the reason: those extra days are days of growth. With mature cows that rarely matters. With first-calf heifers it can.
- Use a calving-ease bull on heifers. Look at the calving ease and birth weight EPDs when you choose the heifer bull. Calving-ease sires often shorten gestation a little as well.
- Breed heifers early. Put Hereford heifers to the bull two to four weeks before the cows. They calve first, while you still have time to watch them, and they get those weeks back to recover before the next season.
- Watch from ten days before. Start checking heifers about ten days before their Hereford due date, not on it. Once the water bag or feet show, give a heifer about an hour of real progress before you step in.
- Feed them apart. Heifers are still growing. A Hereford heifer that calves thin is the hardest animal in the herd to get bred back.
Planning a Hereford calving season
Because Herefords carry a couple of days longer, count back 285 days from the day you want calving to start. For Hereford calves from March 1, turn the bull in or start AI around May 20, two days earlier than a 283-day plan. Breed the heifers about three weeks before that.
The cattle breeding calendar does this for the whole year: pick Hereford in its breed menu and it lists the bull-in, heat-check, preg-check and calving dates. The calving calculator splits the calving season into 21-day periods.
In a mixed herd of Herefords and Angus, the Herefords will calve about five days after Angus cows bred on the same day. Sort the calving pen by breed and the late-looking Herefords stop worrying you.
Hereford gestation FAQ
How long is the Hereford gestation period?
About 284–286 days, which this Hereford gestation chart rounds to 285 days. That is roughly 9 months and 12 days, two days longer than the 283-day average for cattle.
How do I read a Hereford gestation chart?
Find the breeding date and read across to the calving date. On the table above, the breeding month is along the top and the breeding day down the side. A Hereford bred on May 1 is due around Feb 10.
Do Hereford cows calve late?
Only compared with a 283-day chart. Measured against their own breed average of about 285 days, most Hereford cows calve within about 10 days either side of the due date.
Is Polled Hereford gestation different from Horned Hereford?
No. Polled and Horned Herefords are the same breed, and their gestation length is the same: about 285 days.
How long is a Black Baldy cow pregnant?
About 282–283 days. A Black Baldy is an Angus × Hereford cross, so her gestation falls between Angus (about 280) and Hereford (about 285). The calf’s sire has the biggest influence.
When should a Hereford heifer be bred?
Most Hereford heifers are bred at about 14–15 months of age, once they reach about 60–65% of their mature weight, so they calve at about two years old. Breed them two to four weeks ahead of the cows.
Last updated November 9, 2026 · Every date on this page comes from the same data the calculators use.