Evaluation of Mastitis Related Measures & Their Applications to Classify Buffalo Milk in Chitwan, Nepal

Abstract

A study was performed to evaluate the epidemiological aspects of buffalo mastitis in the District Chitwan, Nepal for characterizing the California mastitis test (CMT), somatic cell count (SCC), electrical conductivity (EC) values and bacteriological analysis for defining buffalo milk. The CMT was performed by mixing equal volume of milk and 3% sodium lauryl sulphate. The SCC was determined by staining milk film with New Man’s Lampert Stain and EC values were measured by manual digital mastitis detector and expressed as mS/cm. Bacteriological analysis was done on the basis of Gram’s stain, morphological findings, colony characteristics and biochemical tests. The maximum number (16%) of clinical cases of mastitis was observed in the month of July and lowest in the month of April (1.6%). When the temperature and humidity increased, it indicates that there is need for better care of lactating buffaloes during this month. On a quarter basis, 16% of the foremilk samples in buffaloes were diagnosed as having subclinical mastitis and 11% were diagnosed as having clinical mastitis. The results of CMT scores and SCC showed the evidence that subclinical and clinical mastitic milk was having CMT positive scores (+1~+3) with ≥ 200 × 10 cells/mL. The mean pH of clinically normal buffalo milk was 6.75 (range 6.39 to 7.08) and subclinical mastitic and clinical mastitic milk was 6.85 (range 6.37 to 7.10) and 6.88 (range 6.41 to 7.20), respectively. Analysis of EC value in the milk revealed the presence of mastitis in buffaloes and the cut-off values was 3.7 mS/cm. The coagulase negative Staphylococcus (CNS), such as S. albus and S. epidermidis were the predominant organisms associated with subclinical mastitis, and CNS and coliforms in clinical mastitis. This information suggests that environmental mastitis was prevalent in buffaloes of Chitwan District. In this study, 9.5% of the quarters were having bacterial count (BC) more than 250 cfu/mL. The proposed criteria for normal milk are absence of clinical signs, CMT negative, SCC < 200 × 10 cells/mL, EC < 3.7 mS/cm and < 250 cfu/mL bacteria. The parameters for defining subclinically mastitic milk are absence of clinical signs, CMT positive, SCC ≥ 200 × 10 cells/mL, EC > 3.7 mS/cm and > 250 cfu/mL bacteria. Similarly, clinical mastitic milk was defined as milk having presence of clinical signs, CMT positive, SCC ≥ 200 × 10 cells /mL, EC > 3.7 mS/cm and BC > 250 cfu/mL.