Receiver operating characteristic analysis of milk lactosefor identification of mastitis in buffaloes

Abstract

Receiver operating characteristic (ROC) analysis is a simple statistical tool used to classify a diagnostic indicator in terms of area under a ROC curve (AUC) and to develop potential threshold values of a diagnostic indicator. Milk lactose was analyzed by ROC analysis to see its accuracy to discriminate infected and healthy udder quarters, and to develope an optimum threshold value along with corresponding sensitivity (Se), specificity (Sp) and positive likelihood ratio (LR+) value. Data for the present study comprised of 1516 milk samples collected from Jaffrabadi buffaloes. Milk lactose was estimated by milk analyzer 'LACTOSCAN' and further samples were checked for sub-clinical mastitis by California mastitis test (CMT). The threshold values of milk lactose for identification of moderate and severe infection were found to be 5.31g% (Se, 58.82%; Sp, 58.28%) and 5.23g% (Se, 70.97%; Sp, 64.41%), respectively by ROC analysis. Milk samples with lactose content below 5.31g% were 1.41 times more likely come from moderately infected quarters (LR+ = 1.41); whereas, below 5.23g% were 1.99 times more likely come from severely infected quarters (LR+ = 1.99). The overall accuracy of milk lactose for discrimination of normal quarters from moderately infected quarters was 64% (AUC=0.64) and from severely infected quarters was 72% (AUC=0.72) (P<0.001). Thus, the present study indicated that milk lactose classified mastitic and healthy udder quarters in Jaffrabadi buffaloes with moderate accuracy.

Evaluation of the Udders Health Status through Somatic Cell Count and the Californian Mastitis Test in Algerian Dairy Farms

“…However, Patbandha et al (2016) indicated that milk lactose decreased with increase in severity of infection. Milk (Faroult et al, 2003).…”

Nutritional and hygienic quality of raw milk intended for consumption in the region of Guelma, Algeria

“…Physicochemical parameters (freezing point, conductivity, fat content, protein content, lactose content, mineral content and vitamins) were measured by a "Lactoscan" (Milkotronic LTD Europe) according to the manufacturer's instructions (Patbandha et al 2016) Samples preparation and dilutions for microbiological analysis were performed according to the recommendations of the International Dairy Federation (IDF, 1991).…”