Retention of Placenta RFM

• Morrow

• 02.03.10

Pathogenesis of Retained Placenta

• In 80% animals placenta is expelled within 2-3 h after delivery

– Get septic if retained for 12 h

• Incidences in non-infected cattle (7%)

• Retention of placenta is a clinical symptom of

– Premature parturition

– Nutritional deficiency

– Metabolic diseases

– Infections• Abortions; IBR

• Brucellosis carrier (20-50%)

– Post obstetrical handling

• Duration of pregnancy and Placental retention

– Earlier abortion placenta come along

– Late abortion placenta retained

– Premature birth placenta retained

Loosening process in Placentomes

• Preparatory changes in the last month of gestation

• Placental connective tissues collagenized • Flattening of the maternal crypts • Appearance of binuclear giant cells

– Resorptive phagocytic activities

• At onset of parturition the placentome tissues become loose

• Microscopic Structure of the Ruminant Placenta 

• A prominent feature of the ruminant placenta is the presence of large numbers of binucleate cells.  

• These cells arise early as part of the foetal trophoblast from cells that fail to undergo cytokinesis following nuclear division.  

• They invade and fuse with caruncular epithelial cells to form small syncytia.  

• Binucleate cells secrete the hormone placental lactogen.  

• Ruminants basically have an epitheliochorial placenta, but because the uterine epithelium is modified by invasion and fusion of binucleate cells, its structure is generally referred to as synepitheliochorial.  

• Prior to detailed study of these structures, it was thought that the maternal epithelium was eroded away, leaving trophoblast in contact with maternal connective tissue.  

• Constantly changing uterine pressure leading – Alternating ischemic & hyperemic conditions– Changes in the surface area of the fetal

chorionic villi.• Caruncles are pressed against the fetus (uterine

contractions)

– After fetal expulsion; • Umblical cord ruptures

– Surface area of chorionic villi reduces bec. of ischemia of the fetal villi

• Postpartum uterine contractions completes the detachment process

Factors affecting loosening Process of placentomes

• Biochemical factors (Selinium or PGF2 in placentomes)

• Histological factors– Infectious (placentitis)

– Noninfectious

» Immature placentomes Advanced involution

» Uterine atony Edema of the chrionic villi

» Necrosis of the villi hyperemia of the placentomes

Disturbance of the loosening process

• Immature placentome– Fetal expulsion

• Days before 120 no placental retention

• Days 121-150 placenta retained in 15%

• Days 240 – 265 placenta retained in 50%

Cont…

• Inadequate estrogen – No swelling of the collagen tissue fiber and

maternal crypts – Maturity of placento-uterine junctions occur

2-5 days before parturition– Weaker uterine contractions

• Noninflamatory edema of Chorionic villi

• Necrotic area in placentomes

Cont…

• Advanced involution of the placentome

• Hyperemia of placentome bec. of early closure of umblical blood vessels

• Placentitis and cotyledonitis

• Uterine atony

• Symptoms:– Digestive: Anorexia, constipation, low milk prod.

Rapid wt. Loss, inability to rise

– Nervous: depression, trembling, nervousness

• Treatment:– Gentl try to pull without breaking placenta – Milk animal or let calf suckle as early as possible– Oxytocin 10 IU 4 times after every 4 hours (during 24 h

after calving) – Glucose 25% (iv) or sodium propionate or propylene

glycol – Antibiotics for 5 to 7 days – Protease or collagenase enzyme (umbilical vains) 1 U / 3

gm tissue

Prevention

– Screen animals for brucellosis – Selenium and vitamin A supplementation – High intake of carbohydrates after calving– Palatable rations for propionic acid production – Addition of sodium propionate to feed or

(Gurr)