Physical and microbiological quality of raw milk affected by subclinic mastitis

This thesis work was carried out in a livestock production unit in northern Veracruz. The California Test (CMT) was performed to 38 Cows Swiss breed x Cebu, with a free grazingfeed. Of which 18 samples were taken control of raw milk, 21 samples with grade 1 subclinical mastitis, 18 samples with grade 2 subclinical mastitis and 18 samples with grade 3 subclinical mastitis, all samples were collected directly from the affected room. The samples were evaluated in the ultrasonic milk analyzer (Lactoscan LA, Milkotronic Ltd, Bulgaria). The results were compared to NOM-155-SCFI2012. The statistical analysis was performed in the IBM SPSS Statistics version 21 program. In the results obtained, no difference in fat concentration was found according to the mastitis levels observed (P-0.363), the observed average was 3.03x0.17%. Difference in protein concentration was found according to observed mastitis levels (0.006). It is concluded that the physicochemical characteristics of raw milk are affected by the presence of subclinical Mastitis, especially by mishandling during mechanical milking.