Staphylococcus aureus and Streptococcus dysgalactiae in Norwegian herds after introduction of selective dry cow therapy and teat dipping

Abstract

The objective was to promote a reduction in the prevalence of Staphylococcus aureus and Streptococcus dysgalactiae after 2 years of selective dry cow therapies and teat dipping/external teat sealant implementation. Three different dry cow treatments, one long-acting and two short-acting penicillin-based products were tested at herd level together with a negative control teat dipping group, an iodine teat dipping group and DryFlextrade mark, an external teat sealant. The regimes were independently randomly allocated to 178 dairy herds. Yearly bacteriological quarter milk samples were collected from all cows at the beginning of the trial, after 1 year and 2 years. At herd level, a total of 15% of the herds showed no Staphylococcus aureus isolates after 2 years, compared with 5% at the beginning. The distribution of Streptococcus dysgalactiae infected herds remained the same after 2 years. At cow level, there were no significant differences in the reduction of Staph. aureus between the different dry cow therapies and teat dipping regimes. But there was a significant reduction of Str. dysgalactiae in the iodine teat dipping group compared with Dryflextrade mark and the negative control group. The proportional rate of Staph. aureus positive quarters was reduced from 65.9% to 54.9% after 2 years. As for Str. dysgalactiae, an increase was observed from 14.2% to 15.2%.

The influence of iodine teat dipping and an external teat sealant in heifers on bacterial isolation from quarter milk culture obtained post-calving

“…In the current study, iodine PMTD significantly increased the risk of getting clinical affected quarters post-calving and the biological reason for this is unknown. However, this will also be in accordance with Whist et al (2007).…”

“…Lack of positive results in this study could be explained by the fact that many of these bacteria have already been established in the quarter pre calving according to Compton et al (2007a). It is not expected that teat dipping would have any effect on already established infections which is shown by Whist et al (2007) who identified higher somatic cell count in older S. aureus positive cows dipped with iodine PMTD. In the current study, iodine PMTD significantly increased the risk of getting clinical affected quarters post-calving and the biological reason for this is unknown.…”

“…Further details are described by Whist et al (2007). The teat dipping protocol consisted of 3 groups, a negative control group (n = 71 herds), a 0.15% iodine PMTD group (n = 52 herds), and an ETS group (DryFlex™) (n = 55 herds).…”

Norwegian mastitis control programme

“…Cows with high CMSCC (above 600-700,000 cells/ml) and with major pathogens should be culled at the most economically advantageous time during their lactation. The programme is scientifically based on the estimated probability of success or failure according to Østerås et al [12-14], and Østerås and Edge [28,29]. At present about 0.05% of Norwegian cows receive dry cow therapy.…”

Are Bacteriocins Underexploited? NOVEL Applications for OLD Antimicrobials

“…The efficacy of lacticin 3147 has been confirmed in vivo [158]. Besides teat seal, teat dipping has also proven to be a good strategy in the treatment of mastitis [159] and a lacticin 3147-producer strain culture used as a teat dip solution showed a high rate of elimination against S. aureus and S. dysgalactiae. Nisin has also been tested in teat dip and has shown a lower effect than lacticin 3147 due to partial inactivation at physiological pH, causing only a reduction in S. aureus [160][161][162].…”