Relación entre el resultado de la prueba de California para mastitis y las características físico- químicas y microbiológicas de la leche en seis ganaderías lecheras en Sonsonate, El Salvador

Abstract

The study was conducted in the period from October to April 2015, on six dairy farms with milking, in the municipalities of Caluco and Sonsonate, Sonsonate, El Salvador. For research, were conducted in each of the farms, california two tests for mastitis (CMT) separated by two months, on all cows, categorizing them as negative and positive subclinical, each category three samples of milk taken meter milking more sample tank cooled during sampling. The samples were taken in sterile jars and transported at 4 ° C to the laboratory in the Faculty of Agricultural Science for analysis within 24 hours. Milk samples were analyzed for nutritional parameters: protein, fat, lactose and solids non-fat, made with the analyzer Lactostar® Gerber; physical parameters density, pH and titratable acidity; and microbiological parameters: somatic cells with DCC DeLaval® apparatus, plate count of colony forming units (CFU) for aerobic mesophilic bacteria and total coliforms test reductase test antibiotics and prevalence of mastitis by livestock. Statistical analysis was performed using the program INFOSTAT with the nonparametric method called Kruscal Wallis, comparing physical, chemical and microbiological parameters against the categorization of CMT. Differences were considered significant at a probability of less than 5% (P <0.05).The nutritional compositions milks cows with negative results, subclinical and positive CMT were 3.28, 3.15 and 3.09% for protein; 3.77, 3.76 and 3.56% for fat, 4.98, 4.81 and 4.72% for lactose and 8.95, 8.72 and 8.67 respectively for non-fat solids. No significant differences due CMT categories in these parameters were found, however a slight decrease was observed in the content of nutrients to the extent that more reaction CMT. In physical analyzes, density and acidity were similar between categories of CMT, while the pH increased significantly tending to be basic with increasing negative reaction to CMT (6.72), subclinical (6.78) and positive (6.86) respectively. In bacterial counts great variability among samples of the same category was CMT. highest total counts of aerobic mesophilic bacteria in cows with a CMT reaction, positive (594.583 cfu / ml), subclinical (311.333 cfu / ml) and negative (250,194 cfu / ml) was observed, but the differences were not significant; similarly in total coliform-positive CMT had higher counts (179,000 cfu / ml) that subclinical (21.792 cfu / ml) and negative (22.806 cfu / ml) and the differences were not significant. The somatic cell count increased from the positive was higher in cows (1,720,194 CS / ml) CMT degree in subclinical (673.333 CS / ml) and negative (137.028 CS / ml).It was concluded that the degree of mastitis negatively affected the quality of milk since in most cases the positive reaction decreased nutrient concentration, increased the count of aerobic mesophilic bacteria also increased the pH and the somatic cell count of significantly.