By: Heather Smith Thomas
Most cows “clean” soon after calving, shedding placental membranes within 2 to 12 hours. If it takes longer than 24 hours, it is called a retained placenta. Dr. George Barrington of Washington State University says the cause involves malfunction in normal “turning loose” of tissue attachments between the maternal and fetal sides of the placenta.
“The neutrophils (white blood cells) normally go into these attachment sites and release enzymes that help digest the maternal side and the fetal side so it can release,” he says. The tissues have to soften up and let go.
Risk factors that increase the chances for retained placenta include premature calving, abortion, twins, inducing parturition early, a hard birth, C-sections, etc. “Low calcium, vitamin E and/or selenium, deficiency in trace minerals, negative energy balance, etc. may also create risk for retained placenta,” says Barrington.
Ranchers often assume that if a cow retains her placenta she has an infection, but all cows have a contaminated uterus after calving. There is a big difference between infection and disease. The main reason a cow doesn’t clear this infection within a week or so is because her immune system is hindered.
“Having the placenta in there provides a great habitat for pathogens to thrive. Some of these cows start to run a fever. But trying to remove the placenta is a bad idea. If it tears, the portion remaining and the trauma caused by pulling on tissues that are not ready to come out slows healing and impairs the cow’s capability to return to heat and rebreed,” he says.
The most common treatment for cows with retained placenta and uterine infection is antibiotics. It’s better to use systemic antibiotics rather than put anything into the uterus. “A study done years ago by a student here at WSU looked at neutrophil migration to the uterus. He found that even putting buffered sterile saline into the uterus slowed down this migration. Putting anything into the uterus or infusing it with medication could be counterproductive,” says Barrington.
Systemic antibiotics are more beneficial. “Ceftiofur is a good choice due to its wide spectrum but Excenel, Naxcel and Exceed are all prescription antibiotics. If you can’t get hold of a veterinarian, regular procaine penicillin G works. Stick with label dosage unless you can talk with a veterinarian to figure out what the withdrawal time would be if he/she suggests a higher dose,” says Barrington.
“Some people use oxytocin because it enhances uterine contractions, but there is no evidence that it works. The body’s own immune system (and the cells within the uterus that digest the attachments binding placental tissues to the uterine lining) isn’t functioning properly.”
If a cow retains her placenta, monitor her closely to make sure she doesn’t develop a fever, go off feed and get sick. If she’s doing fine just give her time and let nature take its course. “A high percentage of cows with retained placenta don’t have a problem, but the spectrum ranges in severity from no problems to killing them,” he says.
“Many cows have a retained placenta and are not sick. Some take longer than normal to breed back. Others get sick and get over it and a small proportion get sick and die no matter what we do,” he says.
The best way to prevent retained placenta is to make sure cows are healthy, with a strong immune system. This involves a good nutrition program with adequate trace minerals/vitamins. “Try to prevent prolonged dystocias, being there to assist a calving cow when appropriate. A cow might have a retained placenta after a breech birth, however, and that’s just an accident.” You’d be suspicious of a herd health or nutrition problem, however, if you see more than just an occasional retained placenta.