Earliest Sign of Pregnancy – Rectal Palpation in Cattle

Earliest sign of pregnancy on per rectal palpation in adult cattle is:

Correct Answer: Fully developed C.L. on one ovary

The earliest sign of pregnancy on per rectal palpation in adult cattle is the presence of a fully developed Corpus Luteum (C.L.) on one ovary. This can be detected as early as 18–21 days post-breeding.

Why C.L. is the Earliest Sign

• After ovulation and fertilization, the C.L. of pregnancy (Corpus Luteum verum) forms and persists — it does not regress as it would in a non-pregnant cycle.
• A well-developed, persistent C.L. (soft, protruding, mushroom-like body) on rectal palpation strongly suggests pregnancy.
• This is detectable BEFORE other signs like membrane slip or fremitus.

Timeline of Pregnancy Signs on Rectal Palpation in Cattle

• 18–21 days: Fully developed, persistent C.L. on one ovary ✔ (earliest)
• 35–40 days: Slippage of foetal membrane (membrane slip)
• 70–80 days: Palpation of amniotic vesicle
• 80–120 days: Fremitus (vibration of middle uterine artery)

Why Other Options Are Wrong

• Slippage of foetal membrane → appears at 35–40 days, not the earliest.
• Palpation of amniotic vesicle → detected around 70–80 days.
• Fremitus → middle uterine artery pulsation is felt at 80–120 days — relatively late sign.