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Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology (view source)
Revision as of 14:10, 12 September 2008
, 14:10, 12 September 2008→Ewe
* Peak mating activity occurs 25-35 days later.
* Peak mating activity occurs 25-35 days later.
* However, this is much work for little benefit because it cannot be used for ewes in deep anoestrus.
* However, this is much work for little benefit because it cannot be used for ewes in deep anoestrus.
=== Immunization ===
* Use of an immunogen, produced by conjugating a derivative of adrostenedione with human serum albumin, increases lambing rates.
* When injected, it stimulates the production of antibodies to androstenedione.
* The antibodies bind free androstendione in the blood.
* This results in an increase in the number of lambs born, although the precise reason for this is unknown.
* Inject twice:
** 8 weeks before tupping
** 4 weeks before tupping
* If ewes have been treated in the previous season, only one injection is required at 4 weeks before tupping.
* Only inject ewes which are to be fed adequately during pregnancy, due to the dangers of pregnancy toxaemia.
* Immunization against inhibin will soon be available for commercial use.
** This will reduce the inhibitory effect of inhibin on FSH secretion from the anterior pituitary gland.
** The subsequent increase in FSH will lead to an increase in the nuber of developing follicles, thus better lambing rates.
== Cow ==
== Cow ==