Influence of Subclinical Mastitis on Milk Quality, Quantity, and Composition in Jersey Crossbred Cows in Tropical Climate

Abstract

Aims: Subclinical mastitis (SCM) is a persistent challenge in the dairy sector, responsible for huge economic losses in terms of production and productivity per animal. The present study was conducted to understand the impact of SCM on milk quality, milk yield, and composition. Methodology: A total of 65 lactating animals were screened for subclinical mastitis and from the screened animals, 24 animals of the same age and parity were selected. These animals were categorized into two groups: Healthy (n=12) and SCM positive (n=12). The quality of milk was assessed by Methylene blue reduction test (MBRT), Total bacterial count (TBC), California mastitis test (CMT), and Somatic cell count (SCC). Morning milk yield, Evening milk yield, and total milk yield were recorded to monitor the milk yield in both groups, and milk fat percent, total protein (TP), Solid non-fat (SNF), and Total solids (TS) were analyzed to study the milk composition difference in both healthy and SCM-positive animals. The animals under study were Jersey crossbred. Animals in lactation were screened for SCM by direct microscopic somatic cell count (DMSCC). Place of Study: The research work was carried out in the cattle yard at ICAR-National Dairy Research Institute, Eastern Regional Station, Kalyani, West Bengal, India. The ICAR-NDRI, ERS is located in the city of Kalyani, West Bengal. The region has a tropical climate with an average temperature of at least 18 degrees centigrade and high humidity, receiving abundant rainfall throughout the year. Results: In this study, we found a significant difference (P<0.01) in log10TBC and MBRT between the healthy and the SCM-positive groups and a significant difference (P<0.05) in log10 SCC, CMT, Milk yield, milk fat percentage, and total solids between the healthy and the SCM-positive groups. No significant difference was observed in the total protein and solid non-fat between the groups.  Conclusion: The cause for SCM is multi-factorial in nature, and considering proper management practices, including hygiene and sanitation, can serve as a booster to maintain better udder health in dairy animals.