For the average dairy herd, mastitis can be a challenge. Infected cows may have milk that has to be discarded, or get clinical signs that take them out of the herd completely. A new blood test being developed at Oregon State University may help prevent these problems.

Bovine clinical mastitis is the most prevalent and costly disease in the dairy industry. The disease is usually diagnosed shortly after calving, and it can strike nearly 17% of U.S. dairy cows in the first 30 days of lactation. The disease costs the industry millions of dollars in lost milk income, and loss of cows.

The new OSU test can assist with the prevention and early treatment intervention actions against clinical mastitis. That’s according to Gerd Bobe, lead author of the study and an animal scientist at OSU’s College of Agricultural Sciences and Linus Pauling Institute.

The researchers found biomarkers in the cows’ blood that can indicate which animals are at increased risk for a specific disease, Bobe explains. “After giving birth, all cows are highly vulnerable to serious infection and metabolic diseases,” he says. “Long before they acquire the disease, these cows have a metabolic profile that indicates if they are at increased risk.”

Early warning system
The blood test can act as an early warning system for cows. In nearly all cases, clinical mastitis develops when the cow’s immune system can’t defend against exposure to pathogenic bacteria at the end of the teat. Most of the time symptoms are mild, with some milk-quality issues; but the disease can become serious, causing a cow to get a fever and stop her from eating.

The OSU test allows a dairy farmer to determine which cows are at risk for infection before it occurs, Bobe says. Knowing this, a producer could ramp up the use of nutritional supplements that boost the animal’s immune system ahead of calving.

In the study, 161 healthy pregnant Holstein cows from a 1,000-head dairy farm in Oregon’s Willamette Valley were followed. Blood samples were collected weekly during the last three weeks before calving, and at calving. After calving, researchers selected blood samples of eight cows diagnosed with clinical mastitis but no other diseases after calving. Those samples were compared with nine cows that remained healthy after calving.

Using a form of analytical chemistry called ultra-performance liquid chromatography high-resolution mass spectrometry, the researchers analyzed the blood samples for lipids and other circulating metabolites.

Bobe says at some point before calving, the cows got infected. “This method allows us to determine when those cows were infected and needed to be treated.”

This research offers the potential to manage mastitis more precisely in the herd, matching nutritional supplements to the cows that need it most. This is research work only, and it was published in the Journal of Dairy Science.

Source: Oregon State University