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Maternal Recognition of Pregnancy - Anatomy & Physiology (view source)
Revision as of 18:21, 3 July 2012
, 18:21, 3 July 2012→Queen
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== Introduction ==
In most domestic species, maintenance of pregnancy requires prolonging the life of the corpus luteum/corpora lutea. As a result, progesterone concentrations remain elevated. This results in negative feedback on the hypothalamus and anterior pituitary gland, thus inhibiting follicular development and ovulation. In polyoestrous species, it prevents the return to oestrus. In many species, the placenta will take over or supplement the corpus luteum as the source of progesterone.
== Overview ==
== Overview ==
* The ruminant conceptus undergoes rapid elongation between day 14 and 16.
* The ruminant conceptus undergoes rapid elongation between day 14 and 16.
* During this period, IFN-τ is secreted at high levels before decreaseing.
* During this period, IFN-τ is secreted at high levels before decreasing.
* Small embryos produce much less IFN-τ than larger embryos.
* Small embryos produce much less IFN-τ than larger embryos.
* There is a hige proportion of embryo loss in the first 3 weeks of gestation, as small embryos fail to secrete enough IFN-τ in this critical period. Thus they do not block luteolysis.
* There is a hige proportion of embryo loss in the first 3 weeks of gestation, as small embryos fail to secrete enough IFN-τ in this critical period. Thus they do not block luteolysis.
== Bitch ==
== Bitch ==
* The corpus luteum of the cycle and the corpus luteum of pregnancy have similar lifespans.
* Under normal cyclic condition, the corpus luteum is long-lived.
* When luteolysis does occur, it is close to the end of the normal gestation period.
* Dioestrus is almost the same length as gestation.
== Queen ==
== Queen ==
* Induced ovulator, so if mating does not occur no corpora lutea will form.
* In this situation, a post-oestrus period of 8-10 days occurs before the next oestrus.
* In a queen that has been mated, corpora lutea form and their lifespan is the same as gestation (~60 days).
* Thus, corpora lutea do not undergo luteolysis before pregnancy is established.
* In the event of pseudopregnancy (mated without conception), once formed the corpora lutea last ~40 days.
* The lifespan of the corpora lutea in a pregnant queen is extended to ~60 days by the action of pituitary prolactin.
* There is no need for a conventional 'maternal recognition of pregnancy'.
[[Category:Pregnancy and Parturition]]
[[Category:Bullet Points]]