Cattle Flashcards
What has happened to fertility as milk yield has risen?
Decreased
How many days is the window to get a cow pregnant? How many services can you fit in this time?
45-85 days post calving - 3 services
What is the submission rate?
% who get pregnant in the 2-month window
In what kind of calving does submission rate not matter?
Year-round
What % should oestrus detection be?
80%
What % is oestrus detection actually?
50%
At what age is first puberty?
10-12 months (5-20 months)
At what % adult weight is first puberty?
50% beef, 35-45% dairy
Which breeds have early puberty?
Dairy
At what age should you first serve a cow?
15 months
At what % adult weight should you first serve a cow?
60%
What % of adult weight should a cow be when she first calves?
100%
What are freemartins?
XX/XY chimaeras
What is fertility like in male and female freemartins?
Heifers infertile, bulls subfertile
How can you identify a freemartin?
Palpation, ultrasound, genetic test
What is the clitoris like in a freemartin?
Enlarged, hairy
What is the cycle length in a cow?
21 days
What are days 16-17 like in the cow cycle?
Luteal with high progesterone
What are the 4-5 days after luteolysis like in the cow?
Follicular
Which are the only follicular waves which ovulate in response to oestrogen?
The dominant ones
Which two substances are exchanged between the ovarian/uterine vein and artery?
Oxytocin and PGF2a
What % of pregnant cows will still show signs of oestrus?
50%
What does a normal, active ovary resemble?
Walnut in shell, knobbly
What does a less active ovary resemble?
Hazelnut