Start of Foetal Period in Bovine Gestation

In case of bovine gestation, the period of foetus starts from:

Correct Answer: 45th day onward

In bovine (cattle) gestation, the period of the foetus begins from the 45th day of pregnancy onwards, and continues until birth. Before this, the conceptus is classified as an embryo.

Stages of Bovine Gestation

• Period of Ovum: Fertilization to day 10–12 — the fertilized egg travels through the oviduct and arrives in the uterus
• Period of Embryo: Day 13 to day 45 — organogenesis; the heart forms and starts beating on the 22nd day
• Period of Foetus: Day 45 onward until birth — all major organ systems are formed; growth and differentiation continue

Why Day 45?

By day 45, all major organ systems are differentiated and the developing offspring transitions from an embryo to a foetus. This is the same transition used in human developmental biology (embryo → foetus at week 8–9 ≈ 56–63 days).