Evaluation of an electrical conductivity portable device as an alternative for subclinical mastitis detection

Abstract

The use of efficient methods for the early diagnosis of subclinical mastitis is of great importance in milk production. By using an electrical conductivity meter (EC), the efficiency of subclinical mastitis diagnosis was evaluated in dairy farms in northern Parana, Brazil, and the results were compared with those obtained by using the California Mastitis Test and the Somatic Cell Count (SCC). Samples from 941 quarters of 259 cows of the Holstein and Jersey breeds were analyzed in four dairy farms between June and July 2014. The EC method correctly evaluated 54.8% of the samples (264 samples with subclinical mastitis) and 250 without infection when compared with the diagnosis by CMT. Of the 445 samples diagnosed as positive by EC, 19.7% were classified by CMT with score 2 and 24.7% with score 3. Of the samples with negative results (496), most of them had scores 0 and 1 (50.4% and 21.4 %). The correlations between EC and SCC (r = 0.14) and EC and CMT (r = 0.17) were positive but low, which generated false positive and false negative results of subclinical mastitis in the herd.

Key words: California Mastitis Test, Somatic Cell Count, milk