Retained Placenta

What is Retained Placenta?

Retained placenta (RP) is defined as the failure to expel the fetal membranes (afterbirth) within 12 hours of calving. Normally, the placenta is expelled within 1–6 hours after calving. RP affects 5–10% of dairy cows, with higher rates in first-calf heifers and cows that experience dystocia (difficult calving).

The placenta normally separates from the uterine wall through enzymatic breakdown of the caruncular-cotyledon connections and contraction of the uterus. RP occurs when this process is disrupted — by hormonal imbalances, uterine inertia, nutritional deficiencies (vitamin E, selenium), or physical trauma during difficult calving.

RP significantly increases the risk of metritis (uterine infection) — cows with RP are 3–5 times more likely to develop metritis. It also delays return to cyclicity, reduces conception rates by 15–25%, and increases culling risk. The economic cost per case is $100–$300 in treatment, lost production, and reduced fertility.

Prevention strategies include: ensuring adequate vitamin E and selenium status, minimizing dystocis through proper nutrition and bull selection, ensuring clean calving environments, and avoiding premature manipulation of the placenta. Treatment options include manual removal (increasingly discouraged due to endometritis risk), intrauterine antibiotics, and systemic antibiotics if infection develops.

Why Retained Placenta Happens

Normal placenta expulsion occurs within 1–6 hours after calving through enzymatic breakdown of the caruncular-cotyledon connections and uterine contractions. Retained placenta (RP) occurs when this process is disrupted. Dystocia (difficult calving) causes physical trauma to the placenta and uterine wall, damaging the connections and delaying separation. Hormonal imbalances — particularly low estrogen or high progesterone at calving — prevent the enzymatic breakdown. Vitamin E and selenium deficiency impairs neutrophil function and uterine involution, both essential for placental release. Twin pregnancies stretch the uterus beyond normal capacity, weakening contractions. Premature calving (before 270 days) means the placental connections haven't fully matured for separation. Stress (heat, transport, overcrowding) at calving elevates cortisol, which inhibits oxytocin release needed for uterine contractions. First-calf heifers have higher RP rates (8–12%) than mature cows (3–6%) due to smaller pelvic dimensions and less experienced uterine musculature.

Prevention Through Nutrition

Vitamin E: supplement 1,000–2,000 IU/day during the last 60 days of gestation. Vitamin E is an antioxidant that supports immune function and uterine health. Feed vitamin E through the ration (premix or commercial pre-fresh supplement) or injectable (2,000 IU 30 days pre-calving). Selenium: target 0.3 ppm in the total ration dry matter (or 3 mg injectable 30 days before calving). Selenium is essential for neutrophil function and glutathione peroxidase activity. Avoid excess iron in the ration — iron interferes with selenium absorption; maintain Fe:Se ratio below 2:1. The combination of vitamin E + selenium is more effective than either alone — research shows RP incidence drops from 10–15% to 3–5% with proper supplementation. Cost: $2–$5/cow for the supplementation program vs $100–$300 per RP case. Additional nutritional factors: adequate energy in late gestation (avoid over-conditioning), balanced mineral program (Zn, Cu, Mn support tissue healing), and clean, dry calving environment to reduce bacterial contamination.

Treatment and Follow-up

Do NOT pull or manually remove the retained placenta — this causes endometritis, uterine perforation, and hemorrhage. The placenta will detach naturally as the uterus involutes; pulling disrupts this process and introduces infection. Instead, administer intrauterine antibiotics: ceftiofur (5g in 50 mL sterile water) or ampicillin (2g in 50 mL) infused directly into the uterus. Systemic antibiotics (oxytetracycline, ceftiofur) are indicated if the cow develops fever (>103.5°F), foul-smelling vaginal discharge, or reduced appetite — signs of metritis. Monitor the cow closely for 7–14 days post-calving: check rectal temperature daily (normal 101–102.5°F), observe vaginal discharge (should diminish and become less foul), and monitor feed intake and milk production. Recheck at 14 days post-calving — perform rectal palpation or ultrasound to assess uterine involution and check for pyometra (pus accumulation in the uterus). Cows with RP that develop metritis have 25–40% lower conception rates and may require 1–2 additional services. Plan to breed these cows later in lactation and consider culling if reproductive performance doesn't recover.