Oestrous Cycle
- Breeding season in Britain is August-February with greatest activity in October, November and December. However, closer to the equator, does will cycle all year round.
- Polyoestrous
- Interoestrous interval of 20-21 days, but this is irregular at the start of the breeding season.
- Duration of oestrus is 30-40 hours.
- Ovulation occurs 12-36 hours after the onset of oestrus.
Cyclic Changes in the Ovaries
- Ovaries vary in shape, depending on the stuctures present.
- The longest dimention is ~2.2cm.
- The largest follicles reach a maximum diameter of ~1.2cm.
- When these follicles protrude from the surface of the ovary, they often have a bluish tinge.
- There are four follicular waves of growth, with ovulation occuring during the fourth wave.
- Corpora lutea are pink in colour
Endocrine Changes during the Oestrous Cycle