Question

Cyclical changes during reproduction in sheep are called
1. Oestrus cycle
2. Menstrual cycle
3. Sexual cycle
4. Asexual cycle

Answer 1

Correct Answer - Option 1 : Oestrus cycle

The correct answer is Oestrus cycle.

• Oestrus or heat is the period of intense sexual desire or sexual excitement experienced by females.

Oestrus cycle process:

• Proestrum: 2 days. 
  • Period of building up the growth of Graffian Follicle which helps for the nourishment of ovum fluid contains a hormone called "oestrogen‟.
  • This marks the animal coming in heat.
  • It causes changes in the uterus, blood supply.
• ​Oestrum: 1 day. 
  • The shortest part of the estrus cycle. 
  • ​During which the female is ready to receive male.
  • ​This is the period of desire.
• Metoestrum: 4 days.
  •  Implantation of the embryo takes place.
  • Corpus luteum takes place.
  • Prevents the growth of graffiti follicles thereby arresting the oestrus cycle.
• Diestrum: 14 days.
  • The longest part of the estrus cycle​
  • Further development of the uterus takes place.
  • If the animal has not conceived, involution of the uterus take place.

• Duration of oestrus cycle in different animals:

Animal	Duration of the oestrus cycle
Indigenous cow	12 - 18 hours
Exotic / crosses	12 - 18 hours
Buffalo	24 - 36 hours
Sheep	24 - 36 hours
Goat	34 - 48 hours