Feeding an Open Cow All Winter Is Expensive, and Preg Checking Tells You Who to Keep
Knowing which cows are pregnant and which are not is essential for running an efficient herd. Pregnancy checking lets you cull open cows before investing in their winter feed, estimate calving dates, plan labor and facilities, and evaluate how your breeding program is doing. Several methods are available, each with different timing, accuracy, and cost trade-offs.
This guide covers the main pregnancy detection methods, when to use each, and how to put the results to work in your management decisions.
Why Pregnancy Check
Economic Impact
| Scenario | Cost/Benefit |
|---|---|
| Feeding open cow through winter | $200-400+ in feed |
| Early identification and sale | Salvage value, no wasted feed |
| Delayed breeding identified | Can still intervene or cull |
| Calving date estimation | Better labor planning |
Management Benefits
Pregnancy checking lets you estimate calving dates for planning, sort cows by expected calving, evaluate bull performance, identify and address breeding problems, and adjust nutrition based on stage of gestation.
Pregnancy Detection Methods
Method 1: Rectal Palpation
This method requires a veterinarian, trained and experienced producer, or AI technician with palpation training. The cow is restrained in a chute, the examiner inserts an arm rectally, and the uterus is palpated through the rectal wall. The examiner assesses size, tone, and contents, feeling for fetal structures, the amniotic vesicle, or cotyledons.
| Days Bred | What's Detected |
|---|---|
| 35-40 | Membrane slip, asymmetry |
| 45-60 | Amniotic vesicle (grape to orange size) |
| 60-90 | Fetus palpable, cotyledons |
| 90+ | Fetus easily palpable |
| 150+ | Large fetus, fremitus (arterial pulse) |
Method 2: Ultrasound
Ultrasound requires a veterinarian or trained technician. A rectal probe is used to visualize the uterus on a screen, and the examiner looks for an embryo, heartbeat, and fluid.
| Days Bred | What's Detected |
|---|---|
| 25-28 | Embryo visible as small bright spot |
| 28-30 | Heartbeat visible |
| 30-45 | Fetus development visible |
| 45-60 | Sex determination possible |
| 60+ | Detailed fetal examination |
Method 3: Blood Testing (PSPB, PAG)
Blood tests detect pregnancy-associated glycoproteins (PAGs) or pregnancy-specific protein B (PSPB). A blood sample is collected and sent to a laboratory, which tests for pregnancy proteins and returns results in 24 to 48 hours. Testing is most reliable after 35 days. Be aware that these proteins persist after fetal loss, which can produce false positives. Wait 90 days after calving to avoid residual proteins from the previous pregnancy.
The advantages are that no special on-farm equipment is needed, it works well for operations without ultrasound access, and samples can be collected during other routine handling. The drawbacks include the inability to determine stage or detect twins, possible false positives after recent pregnancy loss, and a cost of typically $3 to $5 per head.
Method 4: Observation (No Test)
Some operations rely on observation alone, particularly those with year-round bulls, very small herds, or remote locations.
| Timing | What You Can See |
|---|---|
| 3+ weeks | Failure to return to heat |
| 5+ months | Belly enlargement |
| 7+ months | Obvious visual pregnancy |
| Last month | Udder development, relaxation |
Timing Recommendations
When to Pregnancy Check
| Goal | Optimal Timing |
|---|---|
| Early identification | 30-45 days (ultrasound) or 45-60 days (palpation) |
| Practical timing | 45-90 days post-breeding |
| Calving date estimation | 60-120 days |
| Before marketing opens | Any time, sooner saves feed |
| Fetal sex determination | 55-90 days (ultrasound) |
Sample Timeline (60-Day Breeding Season)
| Event | Date | Action |
|---|---|---|
| Bulls in | June 1 | Breeding starts |
| Bulls out | July 31 | Breeding ends |
| Earliest pregnant | June 1 | Possibly |
| Latest conceived | July 31 | Possibly |
| Pregnancy check | October 1-15 | 60-120 days post-breeding |
| Cull open cows | October-November | Before winter feeding |
Interpreting Results
Pregnancy Status
| Finding | Classification | Action |
|---|---|---|
| Confirmed pregnant | Bred | Keep, plan for calving |
| Confirmed open | Not pregnant | Cull or breed back |
| Early/uncertain | Recheck | Schedule follow-up exam |
Estimating Calving Dates
| Stage at Check | Approximate Time to Calving |
|---|---|
| 60-day pregnancy | ~220 days (~7 months) |
| 90-day pregnancy | ~190 days (~6 months) |
| 120-day pregnancy | ~160 days (~5 months) |
| 180-day pregnancy | ~100 days (~3 months) |
Sorting by Stage
Group cows by when they were bred: early-bred cows will calve first, mid-bred will calve days 22 through 42, and late-bred will calve days 43 through 60 or later. Sorting by stage lets you feed according to nutritional needs and manage calving pastures more effectively.
What to Do with Results
Managing Open Cows
| Option | Rationale |
|---|---|
| Cull and sell | Most common, economical choice |
| Rebreed (fall breeding) | If want split calving |
| Keep for terminal breeding | Limited value |
| Investigate cause | If many opens, find problem |
Managing Bred Cows
Use pregnancy data for calving pasture assignments, labor allocation, and identifying special attention groups like heifers and high-risk animals.
Evaluating Breeding Program
Key Metrics
First-service conception rate should target 60 to 65 percent. Overall pregnancy rate should target 90 to 95 percent. First-cycle conception rate should also target 60 to 65 percent.
Comparing Results
| Metric | Excellent | Good | Needs Improvement |
|---|---|---|---|
| 21-day conception | >65% | 55-65% | <55% |
| Overall pregnancy | >95% | 90-95% | <90% |
| Open rate | <5% | 5-10% | >10% |
Identifying Problems
When pregnancy rates fall below expectations, look at cow body condition, nutrition adequacy, disease (trichomoniasis, BVD, etc.), bull-to-cow ratio, and breeding season length.
Record Keeping
Essential Records
| Field | Purpose |
|---|---|
| ID | Individual identification |
| Date checked | When exam performed |
| Status | Pregnant/Open/Uncertain |
| Stage estimate | Calving date prediction |
| Examiner | Who performed check |
| Method | Palpation, ultrasound, blood |
| Notes | Twins, abnormalities |
Sample Recording Form
| Cow ID | Date | Status | Stage (days) | Expected Calving | Notes |
|---|---|---|---|---|---|
| 123 | 10/15 | Bred | 90 | Feb 15 | - |
| 456 | 10/15 | Bred | 60 | Mar 15 | Early group |
| 789 | 10/15 | Open | - | - | Cull |
| 234 | 10/15 | Bred | 120 | Jan 15 | Very early |
Special Considerations
Heifers vs. Cows
Heifers may require more patience during the exam and represent an important first-year evaluation opportunity. Check them earlier if possible.
Checking After AI
Ultrasound is ideal for early confirmation after artificial insemination because you know the exact breeding date for accurate timing and can evaluate AI versus cleanup bull conception.
Twin Detection
Ultrasound detects twins early, while palpation picks them up later when two fetuses become palpable. Twin detection matters because twin pregnancies carry higher risk, and those cows may benefit from separate management.
Pregnancy Loss
Early pregnancy loss (before 45 days) is more common than most producers realize. Recheck any suspicious cows, and keep in mind that blood tests may stay positive briefly after a loss.
Cost Considerations
Method Cost Comparison
| Method | Per-Head Cost | Equipment Cost |
|---|---|---|
| Palpation (vet) | $4-8 | None |
| Ultrasound (vet) | $6-12 | Vet's equipment |
| Blood test | $3-5 + handling | Minimal |
| Self-palpation | Time only | Training investment |
Cost-Benefit Analysis
Pregnancy checking 100 cows costs $400 to $800 depending on the method. Feeding one open cow through winter runs about $300. If 5 cows are open, that is $1,500 saved, giving a net benefit of $700 to $1,000.
Choosing a Method
Decision Factors
| Factor | Recommended Method |
|---|---|
| Need early detection | Ultrasound or blood |
| Want stage estimation | Palpation or ultrasound |
| No vet access easily | Blood test |
| Large numbers quickly | Experienced palpator |
| Want fetal sex | Ultrasound (45-90 days) |
| Budget constrained | Palpation |
| Need twin detection | Ultrasound |
Practical Recommendations
For most beef operations, rectal palpation by a veterinarian or trained producer is the standard approach. Blood testing works well as an alternative when no skilled palpator is available. Ultrasound earns its higher cost when fetal sexing is valuable, twin detection is important, or you are checking high-value animals.
Summary
Action Items
- Schedule pregnancy checking 45-90 days after breeding season ends
- Choose appropriate method based on timing, resources, and goals
- Record all results for each cow
- Sort cows by breeding date/expected calving
- Cull open cows before investing winter feed
- Evaluate breeding program using pregnancy data
- Plan calving season based on results
The Bottom Line on Pregnancy Checking
Pregnancy checking is one of the highest-return management practices in beef cattle production. The information you get lets you move non-productive animals out of the herd, plan labor and facilities, adjust nutrition to match each cow's stage, and evaluate how your breeding program is performing. Whether you use rectal palpation, ultrasound, or blood testing, the investment in pregnancy diagnosis pays for itself many times over.
Related Resources
- Breeding Season Planning
- Calving Date Calculator
- Body Condition Scoring Guide
- Calving Record Templates
References
- Beef Cattle Research Council. "Pregnancy Testing in Beef Cattle." beefresearch.ca
- University of Nebraska-Lincoln. "Pregnancy Detection Methods in Cattle." beef.unl.edu
- Texas A&M AgriLife Extension. "Pregnancy Diagnosis in Cattle." agrilifeextension.tamu.edu
- Oklahoma State Extension. "Pregnancy Testing." extension.okstate.edu
- BioPRYN. "Blood Pregnancy Testing for Cattle." biopryn.com
