Effect of Mastitis on Milk Production and Composition in Dairy Cows

Abstract

Bovine mastitis is considered the leading cause of economic losses in dairy farms worldwide due to the associated treatment costs, reduced cow performance, milk quantity, and quality decline, as well as early culling. The purpose of this study was to examine the relationship between somatic cell count (SCC), and physicochemical milk parameters in Romanian Black and White spotted dairy cows. In the study conducted between March and September of 2022, on a farm from the Northeast Romania, a total of 62 cows, with ages ranging from 3 to 5 years, average days in milk (DIM) 75 +/- 35 days, and milk production 22+/- 1.8 kg (mean +/- SEM and clinical signs of mastitis were enrolled. Cows were clinically examined and milk samples were collected in order to evaluate milk SCC and physicochemical parameters such as fat, protein, lactose, casein, dry matter percentage, and density using the fluoro-optic method (Combiscope, Delta Instruments). Statistical analysis was carried out using Graphpad Prism software. A correlation matrix was computed to establish the relationship between the number of somatic cells, and the physicochemical parameters of milk. A very small significant negative relationship was observed between somatic cell score and lactose percentage (r= -0.56), as well as milk fat (r= -0.39) and protein (r= -0.37). In conclusion, bovine mastitis has a negative impact on both milk production and composition, however further studies involving both healthy and cows with mastitis are needed for a more robust evaluation of clinical mastitis effect on milk parameters.