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Oestrous Cycle - Anatomy & Physiology (view source)
Revision as of 12:51, 10 September 2008
, 12:51, 10 September 2008→Oestrous Cycle
=== Oestrous Cycle ===
=== Oestrous Cycle ===
* Polyoestrous
* The first ovulation in heifers is usually without behavioural oestrus. This is termed 'silent heat'.
* Cyclical activity persists except during pregnancy, for 3-6 weeks post-calving and during high milk yield.
* In heifers, the average length of the oestrous cycle is 20 days (18-22).
* In cows, the average length of the oestrous cycle is 21 days (18-24).
* The average duration of oestrus is ~ 15 hours (2-30 hours).
* The body temperature of dairy cows dalls ~0.5◦C the day before oestrus. It then increases in oestrus before falling by ~0.3◦C at ovulation.
* Vaginal pH also fluctuates throughout the oestrous cycle, but is lowest (7.32) on the day of oestrus.
* Ovulation is spontaneous, occuring ~12 hours after the end of oestrus.
* Within 2 days of service, there is yellow-white vulval discharge of mucus. This contains neutrophil leucocytes from the uterus.
* At ~48 hours post-oestrus, irrespective of service, there is a bright red sanguineous discharge from the uterine caruncles.
= Links =
= Links =
[[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_-_Anatomy_%26_Physiology|Pharmacological Manipulation of Oestrous Cycles]]
[[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_-_Anatomy_%26_Physiology|Pharmacological Manipulation of Oestrous Cycles]]