# Cattle Reproduction: Estrous Cycle, Heat Detection, Ovulation & Gestation

> Reproductive physiology of the cow: puberty 10–12 months, 21-day estrous cycle (18–24), estrus 18 h (6–24), ovulation 10–12 h after the end of estrus, gestation 279–287 days — cited figures and heat-detection signs.

- Source page: https://wevet.in/reproduction/cattle/
- Type: Reproduction
- Publisher: WeVet
- Updated: 2026-11-01
- Audience: veterinarians and veterinary students

Key reproductive figures for cattle from the MSD Veterinary Manual [1][3], the estrous cycle as described by Mississippi State University Extension [4], heat detection from LSU AgCenter [5] and gestation length from eXtension [2].

## Key figures

| Feature | Cattle | Source |
|---|---|---|
| Age at puberty | 10–12 months; usually first bred at approx. 14–15 months | [1] |
| Cycle | Polyestrous all year; 21 days (18–24) | [1] |
| Duration of estrus | 18 h (6–24) | [1] |
| Ovulation | 10–12 h after the end of estrus | [1] |
| Best time to breed | Insemination from mid-estrus until 6 h after the end of estrus | [1] |
| First estrus after calving | 20–60 days | [1] |
| Gestation | 279–287 days; 283 days is common for most breeds | [2] |

The MSD gestation table gives 9 months for cattle [3]. Gestation length varies with the age of the dam, breed and sex of the calf; cows carrying bull calves tend to have a slightly longer gestation [2].

## The estrous cycle

- The estrous cycle of cattle is the period from one estrus (heat, the phase of sexual receptivity) to the next [4].
- The ovulated follicle turns into the corpus luteum (CL) by approximately day 5 of the cycle [4].
- Around day 17, prostaglandin F2α lyses the CL, which regresses in about three to five days [4].
- Periods when a cow or heifer does not show estrous cycles are called anestrous or acyclic [4].

## Heat detection

- The only definitive sign of estrus is standing still while another animal attempts to mount [5].
- Secondary signs include a reddened, moist and slightly swollen vulva and a clear mucus discharge; roughed-up tailhead hair and missing hair or mud on the flanks suggest that mounting has occurred, and some of these signs can also be seen after estrus has ended [5].
- Standing heat lasts only about 16 hours in beef cattle and can range from 6 to 24 hours [5].
- Cattle are more likely to show estrus behaviour during darkness; when heat checks are limited to twice a day, check early in the morning and as late in the evening as practical [5].
- Cows ovulate 24 to 32 hours after the onset of estrus [5].

## How the sources compare

| Feature | MSD Veterinary Manual [1] | LSU AgCenter [5] |
|---|---|---|
| Duration of estrus | 18 h (6–24) | About 16 h in beef cattle (6–24) |
| Timing of ovulation | 10–12 h after the end of estrus | 24–32 h after the onset of estrus |

## Frequently asked questions

### How long is the estrous cycle of a cow?

21 days, with a range of 18–24 days; cattle are polyestrous all year [1].

### How long does a cow stay in heat?

The MSD Veterinary Manual gives 18 hours (6–24) [1]; LSU AgCenter gives about 16 hours in beef cattle, ranging from 6 to 24 hours [5].

### When should a cow be inseminated?

From mid-estrus until 6 hours after the end of estrus; ovulation occurs 10–12 hours after the end of estrus [1].

### When does a cow come into heat after calving?

The first estrus after parturition occurs at 20–60 days [1].

## References

[1] Features of the Reproductive Cycle (table) — MSD Veterinary Manual. https://www.msdvetmanual.com/multimedia/table/features-of-the-reproductive-cycle
[2] How long does a cow's pregnancy last? — Beef Cattle — eXtension (Cooperative Extension). https://beef-cattle.extension.org/?p=212
[3] Approximate Gestation Periods (table) — MSD Veterinary Manual. https://www.msdvetmanual.com/multimedia/table/approximate-gestation-periods
[4] The Estrous Cycle of Cattle (Publication 2616) — Parish JA, Larson JE, Vann RC — Mississippi State University Extension Service (2016). https://extension.msstate.edu/sites/default/files/publications/publications/p2616_0.pdf
[5] Standing estrus (heat) and heat detection aids in cattle — LSU AgCenter (2022). https://www.lsuagcenter.com/articles/page1640214223584

---
Numbers in [brackets] cite the references above. For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.
Ask follow-up questions in WeVet (free AI assistant for veterinarians): https://wevet.in/