At about 30 days of gestation in a mare, rectal palpation findings most consistent with early pregnancy include which statement?

• A. Uterine horns small with pronounced tone and a ventral bulge at the base of the gravid horn
• B. Uterine horns enlarged with placental signs evident
• C. No palpable conceptus
• D. A fetal heartbeat audible by auscultation

Answer: (D)

At about 30 days, the most reliable early indicator of pregnancy in the mare is hearing the fetal heartbeat during auscultation. The fetal heart begins beating around this time, and using a fetoscope or Doppler you can detect that heartbeat, which confirms both pregnancy and fetal viability even if rectal palpation signs are still variable or subtle.

Rectal palpation at this stage can be inconclusive because the conceptus is small and the most distinct, early signs are not as consistently detectable as a heartbeat. Other options describe findings that are either unlikely at 30 days (placental signs are usually a bit later) or would imply no conceptus being detectable (no palpable conceptus). A heartbeat audible by auscultation directly demonstrates an active, living fetus and is the best corroborating sign among the choices.