Haptoglobin and lactate dehydrogenase measurements in milk for the identification of subclinically diseased udder quarters
2007
Hiss, S.,University of Bonn (Germany). Inst. of Animal Science | Mueller, U.,University of Bonn (Germany). Inst. of Animal Science | Neu-Zahren, A.,University of Bonn (Germany). Inst. of Animal Science | Sauerwein, H.,University of Bonn (Germany). Inst. of Animal Science
The present paper describes the quantification of haptoglobin (Hp) and lactate dehydrogenase (LDH) in milk samples from healthy and subclinically diseased udder quarters in a herd of German Holstein cows. Hp was analysed in the laboratory using an ELISA. The activity of LDH was measured in raw milk directly in the milking parlor. Both parameters were suitable to distinguish between sterile samples and bacteriologically positive samples. The ability to differentiate between minor and major pathogens was better for Hp in skim milk than for LDH in raw milk. Hp and somatic cell count (SCC) as well as LDH and SCC were positively correlated (r=0.8 and r=0.76, respectively). Subclinical mastitis was defined as follows: SCC more than 100,000 cells/mL and bacteriologically positive findings in two out of three weekly samples. Sensitivity and specificity were above 85% for Hp and above 81% for LDH. Using a less rigid classification to define mastitis, i.e. SCC less than 200,000 cells/mL and two out of three weekly samples bacteriologically positive, sensitivity for Hp improved (89%) and remained unchanged for LDH. Both variables were useful for the diagnosis of subclinical mastitis. LDH activity in raw milk was less sensitive and specific than Hp but the method described herein offers the opportunity to measure LDH activity directly in the milking parlor.
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