Aplicación de la prueba de CMT y somatic cell counter® para evaluar calidad de leche de vaca en tanque

Objective: evaluate whether California mastitis test (CMT) values for bulk milk depend on its somatic cell content. Evaluate if the composition of the milk changes as a function of the number of somatic cells.Design/methodology/approach: 48 samples of bulk milk from different dairy farms and cheese factories in Tabasco, Mexico were taken randomly. Measured parameters were: California Mastitis Test (CMT), the somatic cell count (CCS), fat, protein, non-fat solids, lactose. The values of CCS were grouped in 3 intervals: (500,000), (500,000-1,000,000), (1,000,000) to be compared with qualitative data of CMT (0, 1, 2) in a two-way contingency table. Milk samples were also grouped in 4 categories according to their number of somatic cells A (0-250,000), B (251,000-500,000), C (500,000-750,000) y D (750,000) to compare fat, protein, non-fat solids, lactose by one-way ANOVA and Tukey test at a 5% confidence level.Results: the CMT values were dependent on its somatic cells content intervals; (x288.1, p0.05). A lower amount of non-fat solids, lactose and protein was observed in the group D, with highest category of somatic cells (p0.05). Limitations on study/implications: the CMT test depend on the somatic cell content in cow’s bulk milk. Milk with high somatic cell content had less non-fat solids, and less lactose. Findings/conclusions: the CMT have been traditionally used to assess the udder’s health of individual cows; in this research, we validate to use CMT to assess bulk milk samples. Samples with high somatic cell content had less non-fat solids, less lactose and less protein.