ABSTRACT


Carlos Pedraza G.1, Joaquín García E.1, Claudio Ciudad B.2, Rosa Palma V.2, Gastón Alegría R.3 y Livio Zurita A.3
 
The California Mastitis Test (CMT) was applied to fore milk samples from 1.088 quarters corresponding to 272 cows from six dairy farms of the province of Santiago, Chile. The results indicated 84.2% of reacting cows and 61.76% quarters with mastitis. Five milk groups according to the degree CMT were determined and these were submitted to chemical and bacteriological examinations.Results for analytical dataare presented ranging from milk derived from glands without subclinical mastiti (CMTn)up to milk with mastitis grade 3 (CMT3), and the corresponding range ofvalues determined for the various parameters were: pH 6,70 to 6,88; acidity 17,03 a 14,69° Dornic; total protein 3,13 a 3,19%; casein 2,30 to 2,10%; density 1,031 to 1,028 gr/ml; methilene Blue test 36,84 a 27,5 h.
Differences for all parameters except total protein were significant (P ≤ 0,05).Incidence of pathogenic bacteria in udders increased with increment in grade of subclinical mastitis. The main pathological flora was represented by Staphylococcus aureus (75,65% of samples possitive to pathogenic bacteries) andStreptococcus agalactiae(24,35% of samples).
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1Méds. Vets., Programa Producción de Leche, Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias (INIA), Casilla 5427, Santiago, Chile.
2Bioquímicos, Laboratorio Central. Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias, Casilla 5427, Santiago, Chile.
3Méds. Veterinarios, Escuela de Medicina Veterinaria, Universidad de Chile.