Subclinical mastitis effects in some dairy herds in the Upper Chicamocha River (Boyacá Department)

Abstract

The purpose of this work was to carry out a study about the effects of subclinical mastitis in cows of 34 dairy farms in the Upper Chicamocha region (Boyacá department).The farms are registered in the livestock farmers association of Boyacá (FABEGAN). This study was done with the aim to know about the infection status of cows and establish which are the principal etiologic agents associated with the disease and its relation with the milking routine. To this aim, applied comparison even tests for the productive variables to relate with the California Mastitis Test (CMT) and the microbiological characterization, a blocks design under factorial 2 x 4 array to analyze the existence of significant differences between the mastitis grades, the sample season and its interaction, and blocks design under factorial 2 x 4 array to analyze the existence of significant differences among the mastitis subclinical grades, the sampling season and its interaction. 6616 quarters were submitted to the California Mastitis Test (CMT) in two times and different season. The results did not show any significant differences between the two times of sampling. The positive samples according with CMT (CMT-2 and CMT-3) were submitted to microbiological tests where, in the most of the cases of mastitis, the presence of Streptococcus agalactiae and Staphylococcus aureus was detected. They are the main etiologic agents in the disease. The results indicate the close relation between the milking routine and mastitis. The deficient practices in the milking process are the cause of dissemination and prevalence of mastitis in farms.