Signs a Cow Is About to Give Birth

Recognizing the signs that a cow is about to give birth is one of the most practical skills in cattle management. Catching calving problems early — and knowing when to let nature take its course vs. when to intervene — can save calves and cows. This guide covers the signs from weeks out to hours before calving.

Not sure when your cow is due? Use our cattle gestation calculator to find the expected calving date based on the breeding date.

Weeks Before Calving: Early Signs

Udder Development (2–4 Weeks Before)

One of the earliest visible signs is udder filling — also called “bagging up.” The udder becomes noticeably larger and firmer as it fills with colostrum. First-calf heifers may begin bagging up 2–4 weeks before calving, while mature cows may not show significant udder development until 1–2 weeks out.

Behavioral Changes (1–2 Weeks Before)

As calving approaches, most cows begin to separate themselves from the herd — a natural instinct to find a quiet, sheltered location. Watch for cows that lag behind the herd, seek out corners of the pasture, or repeatedly investigate bedded areas in the barn.

24–48 Hours Before Calving: Definitive Signs

Ligament Relaxation (Most Reliable Sign)

The most reliable predictor of imminent calving is relaxation of the sacrococcygeal (tailhead) ligaments — the firm cords that run on either side of the tail head. As calving approaches, these ligaments soften and eventually become difficult or impossible to palpate. The area on either side of the tailhead will look sunken or hollow.

When you can no longer feel these ligaments, the cow will typically calve within 12–24 hours. This is the single most reliable pre-calving sign.

Vulvar Swelling and Discharge

The vulva becomes swollen, reddened, and elongated as calving nears. A mucous discharge — initially clear and stringy, sometimes with a slight blood tinge (“bloody show”) — indicates cervical dilation and imminent labor. This typically appears 24–48 hours before calving.

Waxing of Teats

Small beads or droplets of colostrum (often amber-colored and waxy in appearance) form at the teat ends — a phenomenon called “waxing.” When you see waxing, calving is usually within 12–24 hours. Not all cows wax, particularly mature cows that may drip colostrum rather than wax.

Active Labor: The Three Stages

Stage 1: Cervical Dilation (2–6 Hours)

Stage 1 labor is characterized by uterine contractions as the cervix dilates. The cow may appear restless — repeatedly lying down and getting up, looking at her flank, kicking at her belly. She may go off feed and seem uncomfortable. This stage typically lasts 2–6 hours in cows and 2–4 hours in heifers.

Stage 2: Active Delivery (30 Minutes to 2 Hours)

Stage 2 begins when the water sac appears at the vulva. Strong abdominal contractions begin, and the calf enters the birth canal. Under normal circumstances, the front feet and nose should appear first. Stage 2 should be complete within 30 minutes to 2 hours. If the cow has been pushing for more than 2 hours with no progress, call your veterinarian.

Stage 3: Placenta Expulsion (Within 8–12 Hours)

The placenta (afterbirth) should pass within 8–12 hours after calving. Retained placenta (failure to pass within 12 hours) is a common complication that requires veterinary attention to prevent uterine infection (metritis).

Signs That Require Immediate Veterinary Attention

• No progress in stage 2 labor after 2 hours of strong contractions
• Only hind feet visible (breach presentation)
• One foot visible but not both (leg back or head turned)
• The cow is down and unable to rise
• Water sac visible but no contractions for more than 30 minutes
• Prolapsed uterus after calving

Post-Calving Checklist

• Ensure the calf stands and nurses within 2 hours of birth
• Confirm the calf receives adequate colostrum (2 quarts within the first 6 hours)
• Dip the navel in 7% iodine solution
• Monitor the cow's temperature for 3–5 days post-calving (fever may indicate metritis)
• Confirm placenta is passed within 12 hours
• Record birth date, calf tag, and weight