Prevalence of Staphylococcus aureus intramammary infection in automatic milking systems and association with cow udder health in Finnish dairy herds

Abstract

Intramammary infection (IMI) is one of the major health problems in dairy herds worldwide causing economic losses and significantly decreasing milk production and quality. Staphylococcus aureus (Staph. aureus) is one of the most prevalent udder pathogens causing IMI. The aim of this study was to evaluate the prevalence of Staph. aureus IMI and its association to cow somatic cell count (SCC), and daily milk yield (DMY). Data about cow composite milk SCC and DMY was recorded once from 253 dairy cows from two Finnish dairy herds. The data about mastitis causing bacteria in the cows’ udder quarter milk samples was collected from a three-month period before the SCC record. The within-herd prevalence of Staph. aureus IMI was 3.3% (95 % CI 1.3-7.4) and 5.5% (95 % CI 1.6-14.2) in the study herds 1 and 2 during the three-month period, respectively. There was no significant association between the presence of the Staph. aureus and cow SCC or DMY according to a linear regression model. In conclusion, the prevalence of Staph. aureus IMI was low in the study herds and no significant effect on DMY or milk SCC was identified in this study. Further studies should evaluate the prevalence of Staph. aureus in dairy herds with automatic milking systems for longer time period and with larger sample size.

Veise udaranakkused on üheks peamiseks teguriks, mis halvendavad karjades piimakvaliteeti, vähendavad piimatoodangut ning põhjustavad majanduslikku kahju. Staphylococcus aureus (Staph. aureus) on peamistest udarapatogeenidest, mis põhjustab udaranakkuseid. Käesoleva uurimistöö eesmärgiks oli hinnata Staph.aureus põhjustatud udaranakkuse levimust ja selle mõju lehma üldpiima somaatiliste rakkude arvule (SRA) ja päevatoodangule. Lehma üldpiima SRA ja päevatoodang registreeriti kahes soome lüpsikarjas peetaval 253 lehmal. Mastiidipatogeenide esinemus määrati udaraveerandite piimast kolme kuu jooksul enne SRA analüüsi. Karjasisene Staph. aureus`e põhjustatud udaranakkuste levimus oli ühes karjas 3.3% (95 % CI 1.3-7.4) ja teises karjas 5.5 (95 % CI 1.6-14.2). Lehma piimatoodangu ja üldpiima SRA ning Staph. aureus esinemuse vahel ei leitud regresioonianalüüsiga statistiliselt olulist seost. Staph. aureus levimus oli uurimisalustes karjades madal ja sellel ei olnud mõju lehma päevatoodangule ega SRAle. Järgnevate uuringutega peab hindama robotlüpsikarjades Staph. aureus levimust pikema perioodi vältel ja suurema proovide arvu juures.