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| − | ==Introduction==
| + | Immediately following parturition, the female enters a period of reproductive repair called the '''Puerperium''' and begins lactation. For a period of time these two processes overlap. |
| − | * Immediately following parturition, the female enters a period of reproductive repair called the '''puerperium''' and begins lactation. For a period of time these two processes overlap.
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| | * During the puerperium '''uterine involution''' and return to ovarian function occurs. | | * During the puerperium '''uterine involution''' and return to ovarian function occurs. |
| | ** '''Involution''' is the reduction in size and remodelling of the endometrium so that the uterus can initiate and sustain another pregnancy. | | ** '''Involution''' is the reduction in size and remodelling of the endometrium so that the uterus can initiate and sustain another pregnancy. |
| − | * The time required for complete uterine involution and [[Oestrous Cycle - Anatomy & Physiology|ovarian activity]] to resume varies among species.
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| − | * In many polyoestrous animals, the shortest possible puerperium is desirable because eligibility for a subsequent pregnancy is of high economic importance.
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| − | == Myometrial Contraction and Expulsion of Lochia ==
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| − | * Myometrium undergoes strong, repeated contractions.
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| − | * The purpose of these contractions is:
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| − | ** Facilitate discharge of fluids and tissue debris from the [[Uterus - Anatomy & Physiology|uterus]].
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| − | ** Compress the uterine vasculature and help minimize possibility of haemorrhage.
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| − | ** Reduce the overall size of the [[Uterus - Anatomy & Physiology|uterus]].
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| − | * In most species, frequent post-partum suckling occurs and [[Pituitary_Gland_- Anatomy & Physiology#Oxytocin|oxytocin]] is secreted.
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| − | * In suckled animals, uterine contractions occur on a frequent basis.
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| − | ** In dairy cows, the calf is usually removed 24 hours after parturition and milking takes place only 2-3 times a day.
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| − | *** Oxytocin episodes are reduced.
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| − | *** Myometrial contractions not as frequent
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| − | *** Delayed uterine involution
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| − | *** Delayed uterine involution limits fertility.
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| − |
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| − | === Reduction in Uterine Volume ===
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| − |
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| − | * Immediately after parturition, the uterus undergoes rapid but highly coordinated atrophy.
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| − | * Uterine mass rapidly reduced to non-pregnant size.
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| − | * All species: marked size reduction in the first several days after parturition.
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| − | * Most species: myometrial contractions occur in 3-4 minute intervals for the first several postpartum days.
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| − | * Strong myometrial contractions subside within several days.
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| − |
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| − | === Lochia ===
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| − |
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| − | * Shortly after parturition, a discharge called '''lochia''' is expelled from the vulva.
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| − | ** Lochia is a blood- tinged fluid containing '''remnants of the foetal placenta and endometrial tissue'''.
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| − | * Lochial discharge is normal in all species.
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| − | ** In dairy cows, lochial discharge occurs at day 2-9 postpartum.
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| − | *** Increase in blood and tissue debris in the lochia is normal, occurs day 5-10.
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| − | **** Due to sloughing of caruncular surfaces that leaves vascular 'stubs' that leak blood.
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| − | * Reduction of lochia in the uterus with myometrial contractions occuring for the first 7-10 days.
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| − | ** In dairy cows, up to 2000ml is expelled from the uterus in the first 2-3 days after parturition.
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| − | *** By 14-18 days, locial discharge is almost non-existent in most cows.
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| − |
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| − | ==Endometrial Repair==
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| − | === Vasoconstriction ===
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| − | * After separation of foetal '''cotyledons''' from maternal '''caruncles''' (within 8-12 hours of delivery of the neonate) vasoconstriction occurs at the base of the maternal caruncle.
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| − |
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| − | === Necrosis ===
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| − |
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| − | * Irreversible cell death that leads to sloughing of the caruncular mass leaving necrotic tissue in the lochial fluid inside the [[Uterus - Anatomy & Physiology|uterus]].
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| − | * Some blood is released from the caruncular stalk generating a blood-tinged fluid.
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| − |
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| − | === Sloughing ===
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| − |
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| − | * About 5 days after parturition.
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| − | * Caruncles lose cellular organization and integrity.
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| − | * Chunks of the caruncles detach from the surface.
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| − | * Remnants of blood vessels exposed on the surface.
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| − |
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| − | === Repair ===
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| − |
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| − | * After the decidual tissue of the caruncle has sloughed into the uterine lumen, the caruncle begins to undergo repair.
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| − | * Eventually covered again with endometrial epithelium.
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| − | * At the same time caruncular repair is taking place, the intercaruncular endometrial surfaces undergo repair.
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| − | * Epithelium of the intercaruncular area repairs at a faster rate than the caruncles.
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| − | ** Repair of intercaruncular endometrium is usually complete by day 8 post-partum.
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| − | * Delay in caruncular repair compared to intercaruncular epithelium is because a large mass of caruncular tissue must undergo necrosis and sloughing before surface epithelial repair can take place.
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| − |
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| − | === Species Differences ===
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| − | * Once again, the most significant example is in the dairy cow. This is the example shown above. However, there are significant species differences.
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| − |
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| − | '''''Time Required for Uterine Involution and Resumption of Ovarian Activity in Various Species'''''
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| − | {| style="width:75%; height:200px" border="1"
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| − | !'''Species'''
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| − | !'''Alpaca'''
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| − | !'''Beef Cow'''
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| − | !'''Bitch'''
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| − | !'''Camel'''
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| − | !'''Dairy Cow'''
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| − | !'''Ewe'''
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| − | !'''Llama'''
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| − | !'''Mare'''
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| − | !'''Queen'''
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| − | !'''Sow'''
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| − | |-
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| − | | '''Time Required for Complete Uterine Involution (days)'''
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| − | | 20
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| − | | 30
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| − | | 90
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| − | | 30-50
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| − | | 45-50
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| − | | 30
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| − | | 20
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| − | | 21-28
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| − | | 30
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| − | | 28-30
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| − | |-
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| − | | '''Time Required for Resumption of Ovarian Activity'''
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| − | | 5-10 days
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| − | | 50-60 days (inhibited by lactation)
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| − | | 150 days (long natural postpartum anoestrus)
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| − | | 25-40 days or up to 1 year (inhibited by lactation)
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| − | | 18-25 days
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| − | | 180 days (short day breeder)
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| − | | 5-10 days
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| − | | 5-12 days
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| − | | 30 days
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| − | | 7 days (inhibited by lactation)
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| − | |-
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| − | |}
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| − | ==Elimination of Bacterial Contamination of the Reproductive Tract==
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| − | Generally, parturition in domestic animals occurs in a non-sterile environment. As a result, bacterial contamination of the reproductive tract, especially the [[Uterus - Anatomy & Physiology|uterus]], is an inevitable sequela to parturition.
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| − |
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| − | * The postpartum tract containing lochia is an ideal environment for the growth of bacteria.
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| − | * Even though myometrial contractions remove the large volume of lochia, bacterial growth can continue.
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| − | * Bacterial contamination is not always associated with pathology.
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| − | * Normal post-partum events eliminate the bacterial flora within a reasonable time.
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| − | * Elevated oestrodiol promotes leukosis in the uterus and elsewhere in the tract.
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| − | * In some cases, high numbers of bacteria can overwhelm the natural defence mechanisms, resulting in [[Healing and Repair - Pathology#Female|postpartum uterine infection]].
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| − | * Conditions that predispose the uterus to infection are:
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| − | ** Retained foetal membranes
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| − | ** [[Dystocia]]
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| − | ** Delay in lochial expulsion due to weak myometrial contractions.
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| − | ==Factors Influencing the Puerperium==
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| − | === Uterine Involution ===
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| − | ==== Age ====
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| − | * More rapid in primiparia than pleuriparia
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| − | ==== Season ====
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| − | * More rapid in spring and summer months.
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| − | ==== Suckling vs Milking ====
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| − | * Results are contradictory
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| − | * May be a breed influence on the time taken to return to ovarian cyclicity
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| − | ==== Climate ====
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| − | * Heat stress can accelerate and inhibit the speed of involution.
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| − | ==== Periparturient Abnormalities ====
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| − | * Dystocia, retained placenta, hypocalcaemia, ketosis, twin calves and metritis delay involution.
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| − | * Periparturient problems cause a delay of the process of involution by ~5-8 days.
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| − | ==== Delayed Return to Ovarian Cyclicity ====
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| − | * Inhibits involution
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| − | === Restoration of the Endometrium ===
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| − |
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| − | * Retained foetal membranes and metritis inhibit healing.
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| − | * Return to ovarian cyclicity may have an influence.
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| − | === Return to Ovarian Cyclicity ===
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| − | This can be affected by; periparturient abnormalities, milk yield, nutrition, breed, parity, season, climate and suckling intensity and milking frequency.
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| − | ==Species Differences in the Puerperium==
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| − | ===[[Puerperium - Cow|Cow]] ===
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| − | ===[[Puerperium - Mare|Mare]] ===
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| − | ===[[Puerperium - Sheep and Goat|Ewe & Nanny Goat]] ===
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| − | ===[[Puerperium - Sow| Sow]] ===
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| − | ===[[Puerperium - Bitch| Bitch]]===
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| − |
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| − | ===[[Puerperium - Cat| Cat ]]===
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| − | [[Category:Pregnancy and Parturition]]
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| − | [[Category:Bullet Points]]
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