153 Trop. Agric. (Trinidad) Vol. 90 No. 3 July 2013 0041-3216/2013/030153-07 © 2013 Trop. Agric. (Trinidad) Correlation of California mastitis test and somatic cell count on milk of water buffalo cows in the Philippines Roderick T. Salvador, DVSM, MPH 1,§ , Agnes Alexandria A. Garcia, DVM 1,§ , Nancy S. Abes, DVM, MS and Claro N. Mingala, DVSM, MVSt, PhD 2, * §: Both authors contributed equally to this work. 1 College of Veterinary Science and Medicine, Central Luzon State University, Science City of Muñoz 3120, Nueva Ecija, Philippines 2 Animal Health Unit, Philippine Carabao Center, Science City of Muñoz 3120, Nueva Ecija, Philippines *Corresponding Author: Dr. Claro N. Mingala Philippine Carabao Center National Headquarters and Gene Pool, Science City of Munoz, 3120 Nueva Ecija, Philippines Tel. No.: (63) 44-456-0731 to 34; Fax No.: (63) 44-456-0730; Email: cnmingala@hotmail.com The objective of the study was to determine the correlation of California Mastitis Test (CMT) and somatic cells count (SCC) on milk of Murrah buffalo cows. It aimed to calculate the prevalence of subclinical mastitis (SCM), sensitivity and specificity of CMT using SCC as the basis, determine the predictive values of CMT, calculate the true prevalence of subclinical mastitis based on sensitivity and specificity established, and determine the variations on the correlation of SCC and CMT against several factors: age of animal, parity number and length of lactation. Pearson’s correlation analysis and Kappa statistics were used for statistical analysis. Results showed that Correlation and Kappa statistics had a 23.37% (p <.0001) and 20.20% (p <.0001) respective agreement between the results of SCC and CMT. SCM prevalence were 30.29% and 23.46% based on CMT and SCC, respectively. The CMT has 54.43% sensitivity and 77.10% specificity. The positive predictive value of CMT was 42.11% while the negative predictive value was 84.67%. The calculated true prevalence of the test was 23.33%. Test agreement may change from slight to fair depending on the factors considered such as the age of the animal, parity number and length of lactation. Keywords: CMT; SCC; Water Buffalo, Philippines Mastitis is an infectious disease that causes major economic losses in the dairy industry worldwide. Losses are related to the reduction of milk production, and expenses related to the additional inputs to reduce the level of mastitis (Halasa et al. 2007). Around 10% or more decrease in milk production is related to clinical mastitis (Dijkhuizen and Renkema 1978). On the other hand, subclinical mastitis (SCM) can cause two third losses on the total milk production due to infected quarters (Radostits et al. 2007). The US dairy industry is losing approximately $2 billion annually. Similar impact is observed in Europe and other countries (Donovan et al. 2005; Denis et al. 2009). According to Khan and Khan (2006) as cited by Ali et al. (2011), losses are also related to earlier culling of animals and replacements. While clinical mastitis is easy to detect, SCM requires reliable laboratory tests. Undiagnosed SCM might lead to poor herd udder health as a consequence of pathogen shedding. The common form of diagnosis is through the measurement of the somatic cells present in the milk. Somatic cells are markers of inflammation. California mastitis test (CMT) is an indirect method to measure the somatic cells in the milk sample. The main advantages with CMT are that it is quick, cheap, and simple and that it is an “animal side test” (Sharma et al. 2010). Other indirect diagnostic tests for SCM for cattle and buffaloes are the White Side Test (WST), White Side + Dye (WSTD), Surf Test and the Surf + Dye Test. Among these indirect tests, CMT was found to have the highest sensitivity followed by WST/WSTD and Surf