Bovine Therio 3 Part 2 Conception and Pregnancy Flashcards
Zygote becomes an embryo after
Male and female syngamy
Embryo refers to
An early non distinguishable stage
Conceptus is
The product of conception
Conception in the bovine occurs in the
Oviduct
How long does it take the embryo to reach the uterus in cows
3-4days
What stage is the embryo when it reaches the uterus in bovines
Morula stage 16-32 cells
Hatching of the zona pellucida of the bovine conceptus takes how long
9days
What are the requirements for the attachment of the bovine conceptus to the uterus (4)
Development within the zona pellucida
Hatching of the blastocyst
Maternal recognition of pregnany
Formation of extra embryonic membranes (precursor to placenta)
What is responsible for maternal recognition of conception in bovines and ovines
Production and release of the specific pregnancy protein interferon-T (INF-T)
How does INF-T assist in pregnancy recognition in cows
Inhibits luteolysis of CL by
- Inhibition of oxytocin receptors on the uterine luminal epithelium
- Induction of a PGF synthesis inhibitor
What type of placenta is found in cattle and sheep
Synepithelial-chorial
Cotyledons: Cows 120; Sheep 80
Foetal Fluids: 5L at 5mths; 20L at term
In pregnant bovines, what is the main source of progesterone
CL
The bovine placenta is capable of maintaining enough progesterone from day
150-265
What is the consequence of removal of the CL in pregnant bovines
Before day 200, it leads to abortion
At what point in the bovine pregnancy does progesterone level begins to drop
250-260days
