Causes and treatment of retained placenta in cows

Retained placenta is one of the complications associated with delivery in dairy cows and other livestock species such as pigs, goats, sheep, horses and donkeys. Under normal circumstances, the placenta should be expelled within 24 hours of giving birth, especially in
dairy cows. There is reduced uterine contraction (the reduced force to push it out) 24 hours after calving, which results in retained placenta. It may take several days before the placenta attachment to the uterus decomposes to allow it to drop.

In a herd of dairy cows, cases of retained placenta should not exceed 10% of all calving cows; figures above that indicate that there is a serious problem within the herd. A farmer with one cow may experience the problem of retained placenta after his cow has calved up to ten times. The condition is easy to recognize since part of the placenta can be seen hanging from the birth canal after a cow gives birth. In some cases, the whole placenta may remain inside the uterus thereby making it difficult to notice the problem. However, a keen farmer who observes their cow well during calving would know that the cow has not dropped the placenta.

Danger posed by retained placenta

In dairy cows, retained placenta may be the cause of serious economic loss to the farmers due to the following reasons:

• Cows with retained placenta may develop bacterial infection and become ill and thus reduce production. Some may even die.
• Milk from cows with retained placenta is unfit for human consumption and therefore cannot be sold. The fertility of dairy cows is affected when most cows in the herd suffer from retained placenta. This causes a direct loss to the farmer due to delayed calving leading to a lengthy period between births (calving intervals) and hence low milk production. It is unhygienic to milk a cow with a decomposing afterbirth hanging on it

Causes of retained placenta

The problem is caused by the following factors:

• Abortions and premature calvings. The birth may occur normal but the placenta may not detach itself from the uterus lining thereby causing the problem of retained afterbirth.
• When the cow produces twin calves, the uterus becomes weak, causing retained afterbirth.
• In cases of milk fever, the lack of muscle power can weaken the animal and reduce its ability to push out or expel the placenta.
• Difficult calving may also stress the uterus after the calf has been delivered.
• Dirty cattle shed may lead to early infection of the placenta that may cause inflammation and hence delay or reduced chances of placental separation and expulsion. It is important
  to note that it is unnecessary to assist a calving cow before it is confirmed that the cow cannot give birth on its own.
• Lack of Vitamin E or selenium deficiency may lead to reduced muscle power in the uterus during calving.
• Other conditions such as poor feeding, liver flukes and copper deficiency may lead to general weakness and hence retained placenta.
• Over-conditioned cows; excessive corn silage fed to dry cows (over 50% of forage dry matter intake).
• Overfeeding grain to dry cows (greater than 0.5% of bodyweight).
• Excessive calcium from too much legume forage fed to dry cows (over 25-30% of forage dry matter intake).
• Calcium and phosphorus deficiency; inadequate supplementation for dry cows.
• Excessive vitamin D (over 50,000 to 100,000 units daily).

Treatment requires a qualified vet

A farmer should always bear in mind that the uterus should always be hygienic since it is the house of a future calf and determines the future milk yield. Therefore whenever there is a problem of retained afterbirth, the affected cow should be attended to by a qualified veterinary doctor.

• The vet first removes the placenta, then administers the right treatment.

When removing the placenta, care should be taken not to tear the placenta or leave pieces in the uterus. Most vets would leave the animal for three to four days without treatment to allow the placenta to decompose. However, this would depend on the health of the cow.

• Antibiotic tablets are inserted through the birth canal into the uterus to stop infection.
• Depending on the level of sickness and the presence of a large volume of stinking fluid, a veterinary surgeon may drain the uterus using a length of tubing with warm saline water.
• Full treatment with the use of injectable antibiotic may help the animal to recover quickly.
• However, for effective control, proper recording of all calvings would assist he farmers to establish the cause of high incidences of retained afterbirth in their animal herds.

Suggestions

• Minimize stressful conditions during dry period and at calving.
• Prevent milk fever.
• Evaluate dry cow ration.
• Provide 0.3 part per million selenium in total ration dry matter for both milking and dry cows. If the problem affects the entire herd, submit blood samples from six to 12 dry cows for calcium, phosphorus, magnesium, selenium (glutathione peroxidase), vitamins A and E, carotene and BUN analysis.
• If special supplementation is not used for dry cows, administer 50 mg of selenium and 680 units of vitamin E as an injection about three weeks before calving.
• Ensure adequate vitamins A and E equivalent intake:
  1. Provide about 135,000 total units of vitamin A for dry cows and 150,000 for milk cows; 2,000 to 3,000 units of vitamin E for dry cows and 1,000 to 1,500 units for milk cows total daily from all sources (natural and supplemental) with 1 mg of carotene equivalent to 400 units of vitamin A.
  2. Provide cows with fresh forage as green- chop or pasture for at least four to six weeks each year.
• If there are numerous abortions, test the herd for brucellosis, neosporosis, IBR, BVD, leptospirosis and non-specific infections.
• Prevent cows from becoming over-conditioned.

Dairy cow management after birth

Apart from the problem of retained placenta, dairy cows that have just given birth could develop infections. About 90 per cent of the animals have some form of bacterial infections during the first week of delivery.

Some animals with a strong immune system can resist bacterial infections of the uterus after delivery. Others require antibiotic treatment. Although the use of antibiotics can solve the problem in some animals, studies show that some animals can still overcome the problem without treatment through proper diets that restore their health. Milk from animals under treatment should not be consumed for a period of up to 72 hours. Some antibiotics such as oxytetracycline can persist in the animal’s body for longer periods.