Lecture 1 Flashcards
(43 cards)
Define polyestrous
Regular oestrous cycles throughout the year
Define seasonally polyoestrus
Regular oestrous cycles at certain times of the year
Define monoestrus
One cycle a year
Duration of oestrous in cattle
21 days
Ovulation in cattle
24-30 hours
LH surge to ovulation
24-28 hours
What does the onset of oestrus coincide with
Surge of LH and FSH
What is the duration of oestrus in cattle
18h
When does luteolysis occur in cattle
Days 16 - 18
What is the number of follicular waves/cycle in cattle
2-4 waves of follicular development
What does progesterone have a negative feedback on
GnRH and LH
What occurs in the follicular phase
Low P4 and increased E2
- Ends in ovulation
When does the luteal phase begin
After ovulation
What increases in the luteal phase
P4
What does the luteal phase end in
Luteolysis
Describe pro-oestrus
Formation of ovulatory follicles + increased E2
Describe oestrus
Sexual receptivity and peak E2
Describe metoestrus
CL formation and start of increased P4
Describe dioestrus
High P4 and longest stage
What does the positive feedback of oestradiol have an effect on the secretion of
GnRH and LH
When the progesterone concentration is low what is there a negative effect on
GnRH and LH secretions
What is folliculaogenesis
Waves of follicular development occur during the oestrous cycle and in prepubertal, an oestrus and pregnant cows
What are the 4 processes involved in follicle waves
Recruitment, selection, dominance and atresia
Define luteolysis
Dinistegration of decomposition of the CL
