Prevalence of Pathogens Causing Subclinical
Mastitis in Argentinean Dairy Herds
Silvana Andrea Dieser, Claudina Vissio1,
Mirta Cristina Lasagno, Cristina Inés Bogni, Alejandro José
Larriestra1 and Liliana Mónica Odierno*
Departamento de Microbiología e Inmunología,
Facultad de Ciencias Exactas, Físico-Químicas y Naturales; 1Departamento
de Patología Animal, Facultad de Agronomía y Veterinaria,
Universidad Nacional de Río Cuarto, Ruta 36 Km 601, X5804ZAB Río
Cuarto, Córdoba, República Argentina *Corresponding author:
lodierno@exa.unrc.edu.ar
Abstract
The
objective of this study was to investigate the prevalence of different mastitis pathogens in Argentinean dairy
farms. Composite milk samples were collected of 2296 cows from 51 randomly
selected herds in Córdoba, Argentina. Somatic cell count was determined in all
samples and bacterial examination of the milk samples with a SCC exceeding
200,000 cells/mL was performed.
About
54%of cows were diagnosed with subclinical mastitis (SCC
≥200,000/mL). Bacteria were isolated in 83.1% of milk samples
subjected to bacteriological analysis. The most frequently isolated pathogen was coagulase-negative
staphylococci (CNS) (52.1%), followed by
Staphylococcus aureus (21.3%),
Corynebacterium spp. (5.2%),
Streptococcus agalactiae (4.4%) and
Streptococcus dysgalactiae (4.4%).
This
study demonstrates that among the major pathogens isolated, the contagious
bacteria caused most of the subclinical infections of dairy cows in Cordoba,
Argentina. Moreover, CNS was the most relevant group of minor pathogens causing
subclinical mastitis.