Of all the management decisions a beef producer makes across the year, pregnancy testing consistently delivers the highest return on investment of any single activity. The arithmetic is straightforward: a non-pregnant cow consumes the same quantity of feed as a pregnant cow through the winter or dry season feeding period — typically six to eight months — and produces nothing at the end of it. Identifying and removing empty cows before that feed-intensive period begins converts a certain cost into a recoverable one. The cost of pregnancy testing is typically $5 to $15 per head; the cost of carrying an empty cow through winter on supplementary hay or grain is many times that.

When to pregnancy test

The timing of pregnancy testing is driven by two competing requirements: testing early enough to capture the feed-cost saving of culling empties before the expensive period, and testing late enough that the earliest pregnancies are detectable with confidence. The standard recommendation for both rectal palpation and ultrasound is 6 to 8 weeks after the end of the joining period.

At 6 weeks of gestation, a skilled operator can reliably detect pregnancy by rectal palpation in most cattle. At 8 weeks, detection confidence is very high by both methods, and ultrasound can additionally age the pregnancy and, in many cases, determine foetal sex. Testing earlier than 6 weeks increases the risk of missing early pregnancies and of incorrectly declaring cows empty — increasing your rate of mismothering to carry empty cows is the error you most want to avoid.

For a typical temperate southeastern Australian system with joining in November to December and the joining period ending in January, pregnancy testing in March (6 to 8 weeks after joining ends) captures enough time to cull empties before the expensive May to August period. For northern systems with wet-season joining, test in the late dry season before wet-season grass deterioration begins. The principle is the same regardless of region: test early enough to act on the results before the next major feed cost begins.

Rectal palpation

Rectal palpation — the manual examination of the reproductive tract through the rectal wall by a trained practitioner — is the traditional pregnancy testing method and remains widely used across Australia, particularly for large mobs where cost per head is a priority. A skilled palpator can test 200 to 300 cows per hour in well-designed yards, making it cost-effective at scale.

The palpator inserts a gloved, lubricated arm into the rectum and palpates the reproductive tract — the uterus, cervix, ovaries, and associated structures — through the rectal wall. Pregnancy is detected by feeling the enlarged uterus, the developing foetus (as a palpable structure from about 6 weeks), and the slipping of the foetal membranes (the chorioallantois) between thumb and forefinger, which produces the characteristic sensation of two layers of tissue sliding against each other. Experienced palpators can accurately age a pregnancy by the size of the foetus and uterus to within 2 to 4 weeks across the full gestation period.

Limitations of palpation: it requires significant skill and experience to be accurate, particularly for early pregnancies under 8 weeks; it is inherently more invasive than ultrasound and, if performed carelessly, carries a small risk of uterine damage or early pregnancy loss; and it cannot determine foetal sex or detect twins reliably. These limitations are relevant primarily for early gestations and high-value breeding programs — for commercial beef operations testing 3-month-plus pregnancies, palpation is reliable and cost-effective.

Real-time ultrasound

Real-time B-mode ultrasound has become the gold standard for pregnancy testing in Australian beef operations over the past two decades, and for good reason. A 5 MHz linear or sector transducer applied per-rectally (the probe is inserted into the rectum and positioned against the rectal wall overlying the reproductive tract) produces a real-time image of the uterus on a small screen, allowing the operator to see the pregnancy directly rather than inferring it by feel.

The key advantages of ultrasound over palpation are:

  • Earlier and more reliable detection: pregnancy can be reliably detected by ultrasound from as early as 25 to 30 days after conception — well before palpation is reliable. This allows earlier culling of empties and potentially earlier supplementary mating.
  • Foetal aging: the foetus can be aged to within 5 to 7 days in early pregnancy and to within 10 to 14 days in later pregnancy by measuring specific anatomical landmarks. This allows you to distinguish between cows that conceived early (likely good fertile cows) and those that conceived late (potentially indicating delayed return to cycling — a flag for nutritional or health issues).
  • Foetal sexing: from approximately 55 to 75 days of gestation, a skilled operator can determine foetal sex by identifying the genital tubercle. For operations breeding for specific sex ratios or for stud operations where sex of calf is commercially significant, this has real value.
  • Twin detection: twins are readily visible on ultrasound and easy to miss by palpation in early pregnancy. Twin-bearing cows need more nutrition in late pregnancy — identifying them allows targeted supplementary feeding rather than guessing.

The cost of ultrasound pregnancy testing is typically slightly higher per head than palpation (due to equipment cost and typically slightly slower throughput), but the additional information delivered — foetal age, sex, and twin status — frequently justifies the difference, particularly for operations with more than 50 to 100 breeders.

What to do with the results

The pregnancy test result divides your cows into three groups, each requiring a different management response:

Empty cows: these are your primary culling candidates. Empty cows that have had a fair opportunity to conceive (been in good body condition, joined to a working bull for an adequate period) should be sold promptly. Holding them through winter adds cost without adding value. Calculate the cost of carrying each empty cow through winter on current hay prices — typically $200 to $400+ per cow in a poor-hay year — and compare it to the current cull cow price. In most years, culling empties immediately is the correct economic decision.

Pregnant cows — early conception: cows in the earliest third of the conception range were the most fertile animals in your herd — they cycled and conceived first. These are your best breeders and most valuable animals. Flag them for retention in the replacement selection process if you are keeping daughters.

Pregnant cows — late conception: cows in the latest third of the conception range cycled late and conceived at the end of the joining period. This can indicate nutritional issues at joining (low body condition score suppresses ovarian activity), health problems, or simply lower inherent fertility. Where foetal age shows a cluster of late-conception cows in the mob, investigate the joining-period nutrition rather than blaming genetics — a mob that was below BCS 2.5 at joining will consistently produce a poor spread of early-conception animals regardless of their genetic merit.

Calculating the cost of an empty cow

The feed cost of an empty cow through a six-month supplementary feeding period (typical for temperate southern Australia) can be calculated straightforwardly. A dry, non-pregnant cow in good condition (BCS 2.5 to 3) requires approximately 8 to 10 kg of dry matter per day to maintain condition — equivalent to approximately 10 to 12 kg of average-quality hay (assuming 80 to 85% dry matter). At current hay prices of $250 to $350 per tonne, the feed cost alone is $0.63 to $1.05 per day, or $115 to $190 over a six-month winter period. Add the cost of water, management time, and facility use, and a properly costed empty cow through winter costs $150 to $250+ per animal. Against a culling cost of $8 to $15 per head for pregnancy testing, the economics of preg testing are overwhelming.

Pregnancy testing and joining strategy

Pregnancy test results also inform your joining strategy for the following year. If your conception rate is below 85% of cows joined, investigate before assuming poor bull performance — the most common causes of low conception rates in Australian beef herds are low body condition score at joining (below BCS 2.5 in a significant proportion of cows), inadequate bull-to-cow ratio (below 1:25 in maiden heifers, below 1:40 in mature cows during a 6-week joining), and bull infertility from injury or disease that has not been detected. A pre-joining bull breeding soundness evaluation (BBSE) — semen assessment, libido score, and physical examination — conducted 6 to 8 weeks before joining identifies infertile bulls before they waste a joining season.

For the full cattle management calendar, see our Cattle Care Guide. For breed information relevant to your production system, see our Cattle Breeds Guide.

For more, see our Keeping Cattle in Australia: The Complete Beginner's Guide and Beef Cattle Breeds in Australia: Choosing the Right Breed for Your Property.