Journal of Animal Research: v.6 n.2, p. 113-116. April 2016 DOI: 10.5958/2277-940X.2015.00177.1 Assessment of Lactate Dehydrogenase Enzyme Activity in Milk as a Marker for Detection of Subclinical Mastitis Mahavir Singh 1 , Anshu Sharma 1 *, Dinesh Mittal 1 , Poonam Yadav 2 and Gaurav Charaya 3 1 College Central Laboratory, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, INDIA 2 Centre for Radioecology, GJUS & T, Hisar, Haryana, INDIA 3 Department of Veterinary Medicine, LUVAS, Hisar, Haryana, INDIA *Corresponding author: A Sharma; Email: anshusharma_dr@yahoo.com Received: 13 February, 2016 Accepted: 04 March, 2016 ABSTRACT Sub clinical mastitis is responsible for heavy economic losses throughout the world in dairy sector. The objective of present study was to investigate lactate dehydrogenase (LDH) enzyme activity in milk for detection of subclinical mastitis in buffaloes Milk samples from 60 buffaloes, including 40 subclinical infected and 20 healthy were subjected to the estimation of LDH using a LDH activity assay kit. LDH concentration in milk of buffaloes having subclinical mastitis was reported to be high (1.88±0.91 µmole/ml/min) as compared to healthy animals (0.26±0.10 µmole/ml/min). The receiver operating characteristics analysis at cut off value of 0.44 µmole/ml/min for LDH activity exhibited sensitivity and specifcity of 95% each and area under curve was 0.959. Results of the correlation matrix revealed signifcantly strong positive interdependence of somatic cell count with enzyme LDH (r = 0.722**; P <0.01). Measuring LDH activity in milk was found both easy and cost effective with high sensitivity and specifcity indicating that LDH activity has great potential as a diagnostic tool for detection of sub clinical mastitis in buffaloes. Keywords: Buffalo, subclinical mastitis, lactate dehydrogenase enzyme, somatic cell count Mastitis is most costly disease of dairy animals and responsible for huge economic losses in India (Sharma et al. 2012). Majority of intramammary infections result in subclinical mastitis (SCM), which shows no infammatory signs in udder and no abnormalities in udder secretions. However, compositional quality of milk is severely impacted by subclinical infection. Animals with subclinical mastitis should be considered as a constant risk of infection within and between herds (Charaya et al. 2013). Therefore, early detection of sub clinical mastitis is of utmost importance in order to take appropriate measures toward cure and prevention of transmission of infection to other healthy buffaloes in herd. Although several diagnostic techniques have been used for detection of SCM, they are of little importance because of less sensitivity and specifcity. Advance tests like real time PCR and estimation of acute phase proteins are costly and their use as routine tests will take time. Therefore, other infammatory markers with high diagnostic value and faster turnaround times are required for early diagnosis of SCM. For many years there has been an interest in using different enzymes in milk as biomarkers for mastitis. The present study intended to investigate the possibility of optimizing the determination of enzyme Lactate dehydrogenase (LDH, EC 1.1.1.27) activity in milk in order to evaluate its use as a potential marker for detection of subclinical mastitis. MATERIALS AND METHODS Sample collection and bacteriological examination Milk samples were collected aseptically from all the four quarters from apparently healthy buffaloes of an organized buffalo farm. Hands were properly washed with soap and water and teat apices swabbed with 70% alcohol. The frst