How many days is a cow pregnant?

The average gestation period for a cow is 283 days. However, normal gestation can range between 279 and 287 days depending on breed, calf sex, and cow age.

How do you calculate a cow's calving season from bull turnout?

To calculate the calving season start date, add 283 days to the bull turn-in date. To estimate when calving should end, add 283 days to the date bulls were pulled.

Have Questions? Call Us: 406.855.0051

Free Herd Management Tool

Cow Gestation Calculator

Calculate exact calving dates, AI breeding schedules, and natural service bull turnout ranges using the standard 283-day cattle gestation period.

Calculate Calving Date

Select Calculation Mode

Target Due Date mode subtracts 283 days from the desired calving date to calculate the required breeding date.

Select Target Calving Date

Select the date from the calendar and click "Calculate Date" below.

Estimated Service Date

Early Calving Watch (Starts -10 Days) --

Likely Calving Window (±5 Days) --

Select a date above and click Calculate Date to view estimated herd management windows.

Evaluating Bred Cows or Bred Heifers?

Once you've established your target calving window, explore live listings and market trends across the West to find bred cattle that match your operational timeline.

Browse Bred Cattle For Sale View Market Reports

How to Use the Cow Calving Date Calculator

Managing calving seasons efficiently requires precise record-keeping. The average gestation period for beef cattle is 283 days (ranging generally between 279 and 287 days based on breed, heifer age, and environmental factors). This free online tool simplifies herd planning across three operational breeding methods:

Target Calving Due Date Mode: Enter a desired calving date to work backward and establish exact bull turn-out or AI dates.
AI Breeding Date Mode: Enter a single Artificial Insemination date or breeding date to project when calves are expected to arrive.
Natural Service / Bull Turnout Mode: Enter bull turn-in and bull-pull dates to project the expected start date, end date, and total duration of your calving season.

Understanding Calving Management Windows

A single estimated due date rarely covers an entire herd. Our calculator provides vital operational milestones:

Early Calving Watch (10 Days Prior): Calves frequently arrive earlier than the exact 283-day average. Begin closer observation, move cows to calving pastures, and check supplies starting 10 days before the estimated start date.
Calving Season Duration: Knowing your projected calving window helps you schedule labor, monitoring shifts, nutrition management, and veterinary support.