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Milk Leukocyte Differential (MLD) Allows New Test 
to “See” Subclinical Mastitis, Early and Accurately

Advanced Animal Diagnostics founder shares new technology 
at 2014 National Mastitis Council

FORT WORTH, Texas — January 29, 2014 — The dairy cow’s immune system provides much more data than current mastitis tests are able to capture, said the founder of Advanced Animal Diagnostics at the 2014 National Mastitis Council conference in Fort Worth, Texas, this week. But a new rapid on-farm test, released by the company last fall, now offers dairy producers a reliable technology that “sees” hidden mastitis in individual quarters long before symptoms appear – by performing a milk leukocyte differential (MLD).

Modeled after the blood leukocyte differential used in humans and companion animals for decades, the QScout™ MLD test is the only on-farm test that provides a differential cell count of infection-fighting leukocytes, or white blood cells.
“One number simply doesn’t tell the whole story,” said Rudy Rodriguez, chief scientific officer of Durham, N.C.-based Advanced Animal Diagnostics. Rather than simply looking at somatic cell count (SCC) – the sum of all body cells and inflammatory cells found in milk – he recommends looking at the differential cell count, a separate count and proportion of each type of white blood cell, including macrophages, lymphocytes and neutrophils.


“By counting, measuring and assessing the ‘first responders’ of the cow’s immune system, it is possible to more accurately detect infection,” he said. “Composite milk samples can blend away subclinical mastitis hiding in a quarter, but QScout MLD looks at each quarter individually for elevated neutrophil levels that signal infection.”

During the featured symposium, “New and Not-So-New Technologies for Detection and Management of Mastitis,” Rodriguez shared a powerful example in which a composite SCC score of 123,000 would have otherwise deemed the cow negative, but the differential cell count provided by QScout MLD revealed high neutrophils in the left rear quarter, indicating a hidden infection – and a positive result for mastitis. Culture results later confirmed the infection.

Rodriguez, who brings more than 30 years of experience in human and companion animal medical devices development to the dairy industry, told attendees that white blood cell differential has “long been a tool used in human and companion animal medicine.”


Reviewing more than three decades of milk quality research, Rodriguez said a better understanding of the dynamics of mastitis could be accomplished by specifically measuring the rise and fall of the types of white blood cells in the milk.

Accompanying Rodriguez was Dr. Mitch Hockett, Advanced Animal Diagnostics’ director of farm trials and technical marketing, who shared the results of a selective dry cow trial in which cows diagnosed with QScout MLD at dry off were treated with antibiotics only if at least one quarter was infected. When this group was compared with cows that were blanket treated with antibiotics in all quarters, no statistical difference existed between the two groups in culture positive infection rates or SCCs 10 days after calving or in clinical events, culls or other health events through 150 days in milk.

About QScout MLD

QScout MLD is the only rapid, on-farm test that measures and assesses the cow’s immune response to infection, providing a positive or negative diagnosis for subclinical mastitis in each quarter – in three minutes per cow, on average. Click here for a video demonstration.

About Advanced Animal Diagnostics

Advanced Animal Diagnostics (AAD), Durham, N.C., provides livestock producers with diagnostics that improve profitability and empower more precise care of animals so they live healthier, more productive lives. AAD is committed to researching, developing and commercializing the industry’s most reliable, on-farm diagnostic tests, such as QScout™ MLD for early detection of subclinical mastitis in dairy cows. With its diagnostic offerings, the company aims to empower real-time management decisions that increase productivity, prevent losses, improve animal welfare and protect the food supply.

For more information, visit or 
call 1-855 Q2COUNT.

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