Mastitis, an infection of the mammary gland, affects more than half of all U.S. dairy cows and costs the dairy industry more than $180 per cow annually.
Marcus E. Kehrli, Jr., an Agricultural Research Service veterinary medical officer at the National Animal Disease Center at Ames, Iowa, has discovered that giving cows a natural compound helps them ward off mastitis. The cows already make this protein--cytokine G-CSF--in skin and other body cells. It stimulates bone marrow to produce white blood cells that help the immune system fight infections.
In recent studies, Kehrli injected cows with the compound daily from days 3 through 7 after calving. On the 6th day, the cows were challenged with a bacterium, and their response was monitored for several more days.
The good news is that one-half of the cows receiving G-CSF did not become infected when challenged with the bacteria. The other half of the G-CSF-injected cows had shorter and less severe infections than cows in the control group. All of the control group cows became infected and developed mastitis.
"Besides protecting a good number of cows, we were able to reduce the severity of infections by using this compound," Kehrli says. Cows receiving G-CSF had good appetites and gave more milk than those not receiving it. The benefit of using G-CSF as a preventative: less use of antibiotics in cows to treat mastitis.
Over the past decade, Kehrli and A.E. Freeman, an Iowa State University (ISU) professor of animal science, have been developing a way to identify the genetic source of resistance to mastitis. So far, they have identified a few cows that are naturally more resistant to mastitis infections.
The ARS and ISU researchers are currently collaborating with 21st Century Genetics-CRI, a bull stud company in Shawano, Wisconsin. As a result of this collaboration, producers may someday be able to purchase cows that have been bred for mastitis resistance.--By Linda Cooke McGraw, Agricultural Research Service Information Staff.
"Cytokine Protein Helps Cows Fight Mastitis" was published in the September 1998 issue of Agricultural Research magazine. Click here to see this issue's table of contents.