Lecture 17 - Cyclicity

ovulatory cycle

bird cycle

follicular phase

phase of the ovulatory cycle

oviposition

process of laying an egg

25-27

eggs are typically oviposited every ____ hours

10-30

hens will ovulate about ____ minutes after oviposition

pause day (skip day)

day that no ovulation occurs & therefore no egg is oviposited

sequence (clutch)

pattern of egg laying

younger birds

What birds will have larger sized sequences/clutches?

season

several estrous cycles that occur during a time period

polyestrus

many cycles

monoestrus

one cycle

anestrus

no cycling

estradiol

predominant hormone elevated during estrus

polyestrus

cycles throughout the year

1. cow

2. queen

3. pig

3 examples of animals that are polyestrus & cycle throughout the year

mare

example of animal that is a long day seasonal polyestrus

long day seasonal polyestrus

begin cycling as day length increases

spring

Long day seasonal polyestrus have their breeding season when?

short day seasonal polyestrus

begin cycling as day length decreases

1. ewe

2. doe

2 examples of animals that are short day seasonal polyestrus

autumn

Short day seasonal polyestrus have their breeding season when?

dog

example of an animal that is monoestrus

1. pregnancy

2. lactational

3. stress

4. seasonal

5. pre-pubertal

5 causes of anestrus

GnRH

inhibition of ____ release results in anestrus

1. glucose

2. leptin

3. fatty acids

3 compounds affecting GnRH release to start puberty

suckling stimulus prevents GnRH release

How is anestrus maintained during lactation?

pineal gland

gland produces melatonin

melatonin

Produced by the pineal gland & affects GnRH release

Tryptophan → Serotonin → Melatonin

3 main steps of conversion of indoleamines to melatonin