Cow Gestation Calculator

March 2024
A cow that bred on 4 Mar 2024 has an approximate calving date of

Thursday, December 12, 2024

Key Gestation Milestones

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Cow Gestation Milestones

  1. Day 0 (4 Mar 2024) - Conception: The gestation period starts from the day of conception, which could be either through natural breeding with a bull or through artificial insemination.
  2. Days 18-21 (22 Mar 2024) - First Embryonic Movement: Around day 18 to 21, the first embryonic movements can be detected. This is an early stage where the embryo is not yet firmly attached to the uterus.
  3. Day 30-35 (3 Apr 2024) - Confirmation of Pregnancy: By day 30 to 35, a veterinarian can often confirm pregnancy through rectal palpation or ultrasound. This is when the embryo is well attached to the uterine wall.
  4. Day 42-45 (15 Apr 2024) - Gender Differentiation: Around day 42 to 45, the gender of the fetus starts to differentiate, though it can't be determined externally at this point.
  5. Day 90 (2 Jun 2024) - End of Embryonic Phase: By day 90, the embryonic phase ends and the fetal stage begins. This is a critical period for fetal development.
  6. Day 120 (2 Jul 2024) - Halfway Point: Around day 120, the pregnancy is roughly at the halfway point. The fetus grows significantly from this point onwards.
  7. Day 150 (1 Aug 2024) - Visible Fetal Movements: By day 150, fetal movements may become visible or can be felt by a veterinarian during an examination.
  8. Day 180 (31 Aug 2024) - Start of Third Trimester: Around day 180, the cow enters the third trimester. This period is crucial for fetal growth and development.
  9. Day 250 (9 Nov 2024) - Colostrum Formation: Starting around day 250, the cow begins to produce colostrum, the first form of milk that is rich in nutrients and antibodies.
  10. Day 270-280 (9 Dec 2024) - Pre-Calving Signs: As the cow approaches the end of the gestation, pre-calving signs become evident. These include udder development, relaxation of the pelvic ligaments, and swelling of the vulva.
  11. Day 283 (Approximately 12 Dec 2024) - Calving: The average gestation period culminates in calving. This process should be monitored for any complications.

How Do You Calculate a Cow's Calving Date?

3 young calves lying in a field looking at the camera
  1. Determine the Date of Conception
    • Natural Breeding: Note the date(s) the cow was with a bull. If the exact date of conception is unknown, use the last date of exposure to the bull.
    • Artificial Insemination (AI): If the cow was artificially inseminated, the date of AI is used as the date of conception.
  2. Know the Average Gestation Period
    • The average gestation period for a cow is about 283 days. However, this can vary slightly by breed and individual circumstances. For example, some breeds or individual cows may have a slightly shorter or longer average, typically ranging between 279 to 287 days.
  3. Add the Gestation Period to the Conception Date
    • Use our calculator to determine the due date for the specific conception date.
    • For precision, consider any breed-specific variations in gestation length.
  4. Adjust for Observable Factors (If Necessary)
    • If you know the cow or its breed tends to have shorter or longer gestation periods, adjust the expected date accordingly.
    • Environmental factors, nutrition, and the health of the cow can also influence the gestation length.
  5. Monitor the Cow for Signs of Impending Calving
    • As the expected calving date approaches, watch for signs of calving like udder development, relaxation of pelvic ligaments, and changes in behavior.
    • These signs can help refine the estimate as the due date nears.

Keep accurate records of breeding and AI dates for all cows in the herd. This data is crucial for managing future breeding and calving events.

Gestation Periods For Different Cow Breeds

Here's a table showing the gestation duration in days for various breeds of cow:

BreedGestation Duration (Days)
Brown Swiss290
Belgian Blue285

Cow Gestation Reference Table

Below is a reference table showing the calving date for all days of the year.

Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date Date ExposedCalving Date
1 Jan10 Oct1 Feb10 Nov1 Mar9 Dec1 Apr9 Jan1 May8 Feb1 Jun11 Mar1 Jul10 Apr1 Aug11 May1 Sep11 Jun1 Oct11 Jul1 Nov11 Aug1 Dec10 Sep
2 Jan11 Oct2 Feb11 Nov2 Mar10 Dec2 Apr10 Jan2 May9 Feb2 Jun12 Mar2 Jul11 Apr2 Aug12 May2 Sep12 Jun2 Oct12 Jul2 Nov12 Aug2 Dec11 Sep
3 Jan12 Oct3 Feb12 Nov3 Mar11 Dec3 Apr11 Jan3 May10 Feb3 Jun13 Mar3 Jul12 Apr3 Aug13 May3 Sep13 Jun3 Oct13 Jul3 Nov13 Aug3 Dec12 Sep
4 Jan13 Oct4 Feb13 Nov4 Mar12 Dec4 Apr12 Jan4 May11 Feb4 Jun14 Mar4 Jul13 Apr4 Aug14 May4 Sep14 Jun4 Oct14 Jul4 Nov14 Aug4 Dec13 Sep
5 Jan14 Oct5 Feb14 Nov5 Mar13 Dec5 Apr13 Jan5 May12 Feb5 Jun15 Mar5 Jul14 Apr5 Aug15 May5 Sep15 Jun5 Oct15 Jul5 Nov15 Aug5 Dec14 Sep
6 Jan15 Oct6 Feb15 Nov6 Mar14 Dec6 Apr14 Jan6 May13 Feb6 Jun16 Mar6 Jul15 Apr6 Aug16 May6 Sep16 Jun6 Oct16 Jul6 Nov16 Aug6 Dec15 Sep
7 Jan16 Oct7 Feb16 Nov7 Mar15 Dec7 Apr15 Jan7 May14 Feb7 Jun17 Mar7 Jul16 Apr7 Aug17 May7 Sep17 Jun7 Oct17 Jul7 Nov17 Aug7 Dec16 Sep
8 Jan17 Oct8 Feb17 Nov8 Mar16 Dec8 Apr16 Jan8 May15 Feb8 Jun18 Mar8 Jul17 Apr8 Aug18 May8 Sep18 Jun8 Oct18 Jul8 Nov18 Aug8 Dec17 Sep
9 Jan18 Oct9 Feb18 Nov9 Mar17 Dec9 Apr17 Jan9 May16 Feb9 Jun19 Mar9 Jul18 Apr9 Aug19 May9 Sep19 Jun9 Oct19 Jul9 Nov19 Aug9 Dec18 Sep
10 Jan19 Oct10 Feb19 Nov10 Mar18 Dec10 Apr18 Jan10 May17 Feb10 Jun20 Mar10 Jul19 Apr10 Aug20 May10 Sep20 Jun10 Oct20 Jul10 Nov20 Aug10 Dec19 Sep
11 Jan20 Oct11 Feb20 Nov11 Mar19 Dec11 Apr19 Jan11 May18 Feb11 Jun21 Mar11 Jul20 Apr11 Aug21 May11 Sep21 Jun11 Oct21 Jul11 Nov21 Aug11 Dec20 Sep
12 Jan21 Oct12 Feb21 Nov12 Mar20 Dec12 Apr20 Jan12 May19 Feb12 Jun22 Mar12 Jul21 Apr12 Aug22 May12 Sep22 Jun12 Oct22 Jul12 Nov22 Aug12 Dec21 Sep
13 Jan22 Oct13 Feb22 Nov13 Mar21 Dec13 Apr21 Jan13 May20 Feb13 Jun23 Mar13 Jul22 Apr13 Aug23 May13 Sep23 Jun13 Oct23 Jul13 Nov23 Aug13 Dec22 Sep
14 Jan23 Oct14 Feb23 Nov14 Mar22 Dec14 Apr22 Jan14 May21 Feb14 Jun24 Mar14 Jul23 Apr14 Aug24 May14 Sep24 Jun14 Oct24 Jul14 Nov24 Aug14 Dec23 Sep
15 Jan24 Oct15 Feb24 Nov15 Mar23 Dec15 Apr23 Jan15 May22 Feb15 Jun25 Mar15 Jul24 Apr15 Aug25 May15 Sep25 Jun15 Oct25 Jul15 Nov25 Aug15 Dec24 Sep
16 Jan25 Oct16 Feb25 Nov16 Mar24 Dec16 Apr24 Jan16 May23 Feb16 Jun26 Mar16 Jul25 Apr16 Aug26 May16 Sep26 Jun16 Oct26 Jul16 Nov26 Aug16 Dec25 Sep
17 Jan26 Oct17 Feb26 Nov17 Mar25 Dec17 Apr25 Jan17 May24 Feb17 Jun27 Mar17 Jul26 Apr17 Aug27 May17 Sep27 Jun17 Oct27 Jul17 Nov27 Aug17 Dec26 Sep
18 Jan27 Oct18 Feb27 Nov18 Mar26 Dec18 Apr26 Jan18 May25 Feb18 Jun28 Mar18 Jul27 Apr18 Aug28 May18 Sep28 Jun18 Oct28 Jul18 Nov28 Aug18 Dec27 Sep
19 Jan28 Oct19 Feb28 Nov19 Mar27 Dec19 Apr27 Jan19 May26 Feb19 Jun29 Mar19 Jul28 Apr19 Aug29 May19 Sep29 Jun19 Oct29 Jul19 Nov29 Aug19 Dec28 Sep
20 Jan29 Oct20 Feb29 Nov20 Mar28 Dec20 Apr28 Jan20 May27 Feb20 Jun30 Mar20 Jul29 Apr20 Aug30 May20 Sep30 Jun20 Oct30 Jul20 Nov30 Aug20 Dec29 Sep
21 Jan30 Oct21 Feb30 Nov21 Mar29 Dec21 Apr29 Jan21 May28 Feb21 Jun31 Mar21 Jul30 Apr21 Aug31 May21 Sep1 Jul21 Oct31 Jul21 Nov31 Aug21 Dec30 Sep
22 Jan31 Oct22 Feb1 Dec22 Mar30 Dec22 Apr30 Jan22 May1 Mar22 Jun1 Apr22 Jul1 May22 Aug1 Jun22 Sep2 Jul22 Oct1 Aug22 Nov1 Sep22 Dec1 Oct
23 Jan1 Nov23 Feb2 Dec23 Mar31 Dec23 Apr31 Jan23 May2 Mar23 Jun2 Apr23 Jul2 May23 Aug2 Jun23 Sep3 Jul23 Oct2 Aug23 Nov2 Sep23 Dec2 Oct
24 Jan2 Nov24 Feb3 Dec24 Mar1 Jan24 Apr1 Feb24 May3 Mar24 Jun3 Apr24 Jul3 May24 Aug3 Jun24 Sep4 Jul24 Oct3 Aug24 Nov3 Sep24 Dec3 Oct
25 Jan3 Nov25 Feb4 Dec25 Mar2 Jan25 Apr2 Feb25 May4 Mar25 Jun4 Apr25 Jul4 May25 Aug4 Jun25 Sep5 Jul25 Oct4 Aug25 Nov4 Sep25 Dec4 Oct
26 Jan4 Nov26 Feb5 Dec26 Mar3 Jan26 Apr3 Feb26 May5 Mar26 Jun5 Apr26 Jul5 May26 Aug5 Jun26 Sep6 Jul26 Oct5 Aug26 Nov5 Sep26 Dec5 Oct
27 Jan5 Nov27 Feb6 Dec27 Mar4 Jan27 Apr4 Feb27 May6 Mar27 Jun6 Apr27 Jul6 May27 Aug6 Jun27 Sep7 Jul27 Oct6 Aug27 Nov6 Sep27 Dec6 Oct
28 Jan6 Nov28 Feb7 Dec28 Mar5 Jan28 Apr5 Feb28 May7 Mar28 Jun7 Apr28 Jul7 May28 Aug7 Jun28 Sep8 Jul28 Oct7 Aug28 Nov7 Sep28 Dec7 Oct
29 Jan7 Nov29 Mar6 Jan29 Apr6 Feb29 May8 Mar29 Jun8 Apr29 Jul8 May29 Aug8 Jun29 Sep9 Jul29 Oct8 Aug29 Nov8 Sep29 Dec8 Oct
30 Jan8 Nov30 Mar7 Jan30 Apr7 Feb30 May9 Mar30 Jun9 Apr30 Jul9 May30 Aug9 Jun30 Sep10 Jul30 Oct9 Aug30 Nov9 Sep30 Dec9 Oct
31 Jan9 Nov31 Mar8 Jan31 May10 Mar31 Jul10 May31 Aug10 Jun31 Oct10 Aug31 Dec10 Oct