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** 0.8 cm from side to side
 
** 0.8 cm from side to side
 
* Transrectal ultrasound is difficult, because the ovaries are difficult to access.  Therefore, folliculogenesis is much harder to visualise than in the cow.
 
* Transrectal ultrasound is difficult, because the ovaries are difficult to access.  Therefore, folliculogenesis is much harder to visualise than in the cow.
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* The ewe is similar to the cow, with 3-4 follicular waves in each oestrous cycle.
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** If there are 3 follicular waves, two will occur during the luteal phase and one during the follicular phase.
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* Even during anoestrus, dominant follicles will reach the same size as those present during cyclical activity.
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* At the onset of oestrus, one or more follicles reach a size of 1cm.
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** Follicular walls are thin and transparent.
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* Rupture of the follicle at ovulation is preceded by the elevation of a small papilla above the general surface.
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* Ovulation occurs through rupture of this papilla ~24 hours after the onset of heat.
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* There is rapid development of the corpus luteum.
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** Development is linear from day 2-12 after ovulation.
 
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