How can retained placenta problems be prevented?
Since there are many causes of retained placenta, there is no simple answer. Some of the obvious answers include: (1) don’t allow cows to get too thin or too fat before calving, (2) reduce stress near calving as much as possible, (3) prevent exposure to pine needles, juniper trees, and pine trees (particularly ponderosa pines) before calving, (4) make sure your trace mineral and vitamin supplementation program is adequate, (5) prevent foothill abortion problems, and (6) maintain a sound vaccination program to minimize the chance of viral or bacterial abortions.
Because calving problems often result in retained placenta, it is important to consider the appropriate selection of genetics for your herd as a part of prevention. One of the useful tools is birth weight Expected Progency Differences (EPDs). Lower birth weights will decrease calving problems if all other factors are equal. However, it is also important to remember that big cows with big pelvic canals can have big calves easily. So select bulls with birth weight EPDs in keeping with your herd.
Also, remember to look at the bull’s actual birth weight data and remember that the birth weight EPD numbers are not the same between breeds. One breed can have a bull calf with a birth weight of 100 pounds and a birth weight EPD of 1.0 while another breed can have a bull calf with a birth weight of 80 pounds and a birth weight EPD of 5.0. Obviously, the second bull will tend to have calves with lower birth weights if all other factors are equal.
Another tool available is pelvic measurements in yearling heifers. The value of this tool is to cull replacement heifers with small pelvic canals before breeding for the first time. Regarding birth weights, it is important to remember that the cow or heifer has 60 percent of the "input" into how large the calf is going to be. Therefore, genetic selection of the cowherd has more impact than the one time selection of the bulls.
If you don’t have problems with retained placenta, that is excellent. If you do, there are a number of important items you will need to consider and discuss with your veterinarian. — John Maas, Extension veterinarian, University of California-Davis