Skip to content
AgridianDairy KB

Percent of herd pregnant

Definition

Section titled “Definition”

Percent pregnant is a point-in-time (snapshot) measure: on a given day, the share of cows in a defined group that are confirmed pregnant. It is a herd status number, not a rate over time.

The denominator must be stated, because the common choices give very different numbers:

  • All cows (milking + dry, LACT>0): dry cows are almost all pregnant, so this gives the highest number.
  • Milking cows only (excludes dry cows): the usual ”% of milking herd pregnant”.
  • Milking cows past the VWP: removes fresh cows that can’t be pregnant yet. Useful for comparing herds with different calving patterns.

Decide also:

  • Bred cows waiting for a check (RC 4) are not pregnant in the numerator, but they stay in the denominator. Some reports show ”% pregnant + bred” separately.
  • Do-not-breed cows stay in the denominator for a herd-status view; leave them out for a breeding-performance view, and say which.

Percent pregnant is driven by pregnancy rate, but also by calving pattern, culling and the DIM mix of the herd. A herd with a large group of fresh cows after a calving peak shows a low % pregnant even with a good PR. Use it as a quick check and for forecasting dry-offs and calvings, not as the main reproduction KPI.

Formula

Section titled “Formula”

Plain text:

% pregnant (milking)  = milking cows confirmed pregnant / milking cows × 100


% pregnant (all cows) = (pregnant milking cows + pregnant dry cows) / all cows × 100

LaTeX:

\%\mathrm{Preg}_{\text{milking}} = \frac{N_{\text{preg, milking}}}{N_{\text{milking}}} \times 100
\qquad
\%\mathrm{Preg}_{\text{all}} = \frac{N_{\text{preg, milking}} + N_{\text{preg, dry}}}{N_{\text{cows}}} \times 100

How to pull it in DC305

Section titled “How to pull it in DC305”

PCT gives the percentage directly: the share of animals in the FOR group that meet the first condition. DCC (days carrying calf) is above 0 only for pregnant animals, so it counts pregnant cows whether they are milking (RC 5) or dry (RC 6), and it leaves out a cow dried off open.

PCT DCC>0 FOR LACT>0                % pregnant, all cows (milking + dry)
PCT DCC>0 FOR LACT>0 RC<>6          % pregnant, milking cows
PCT DCC>0 FOR LACT>0 BY PEN         % pregnant by pen
COUNT ID FOR LACT>0                 all cows
COUNT ID FOR LACT>0 RC=5-6          pregnant (RC 5) plus dry (RC 6)
COUNT ID FOR LACT>0 RC=5            pregnant milking cows
SUM BY RC FOR LACT>0                all statuses at once

RC codes are 0 no status, 1 DNB, 2 fresh, 3 open, 4 bred, 5 pregnant, 6 dry, 7 sold/died, 8 bull calf (see RC codes). RC=5-6 is an inclusive range and <> means “not equal”. If a pregnant DNB cow carries RC 1, RC=5-6 misses her; DCC>0 does not.

RC is current status, so these counts are for today. For a past date, rebuild status from events. For a trend, record the snapshot on the same day each month.

Typical range

Section titled “Typical range”

Herd context: US Holsteins, freestall or dry-lot, year-round calving, VWP 50–60 days, 21-day PR in the 20s.

Denominator Typical Good
Milking cows 40–50% > 50%
All cows (milking + dry) 50–60% > 60%
  • Seasonal calving herds swing widely through the year; compare the same month year on year.
  • Heat stress lowers % pregnant with a lag of a few months after summer.

Common mistakes

Section titled “Common mistakes”
  • Not stating the denominator. All cows versus milking cows can differ by roughly 10 points.
  • Counting bred-not-checked cows as pregnant.
  • Assuming every dry cow is pregnant, when some cows are dried off open.
  • Treating it as a fertility rate. It mixes fertility with calving pattern and culling; use pregnancy rate and cumulative pregnancy by DIM for performance.
  • Comparing snapshots taken at different points in the calving season.
  • Late pregnancy-check entries. If checks are entered days late, today’s count is low.
Section titled “Related”