ESTROUS CYCLE:
1) Using the diagram and chart below, indicate the events occurring during the various stages of
the estrous cycle:
Days in cycle
Hormone(s)
Brain Feedback
Ovary
Follicular
activity
CL activity
Uterus/oviduct
Preg:
Non-Preg:
2) What is the definition of anestrous?
3) What is the length of the estrous cycle in a cow?
4) What corresponds to Day 0 of the cycle?
5) What are some of the distinctive behavioral characteristics of an animal in estrous (“heat”),
such as the cow or sow?
6) Which phase(s) of the estrous cycle correspond to the follicular stage?
The luteal stage?
7) When does ovulation occur in the following species?
Ewe:
Sow:
Cow:
Mare:
8) What controls when an animal will cycle?
What is the effect of this if no pregnancy occurs?
How will this be effected if an embryo is present (pregnancy)?
9) What hormone begins to be produced midway through the luteal phase if pregnancy occurs?
10) What is the embryonic signal for maternal recognition of pregnancy in the following species?
Ewe:
Sow:
Cow:
Mare:
11) What are some reasons to synchronize the estrous cycle in production animals?
How can this be done?