Mastitis caused by Streptococcus uberis

Diagnosis and treatment of Mastitis caused by Streptococcus uberis Translated From PLM, France

For many years, the main cause for mastitis in dairy cows was identified as the Streptococcus species , S. agalactiae and S. dysgalactiae. The presence of these two germ species is, however, on a continuous downturn, most probably due to the progress of hygiene in milking and dry cow routines. Regrettably, another pernicious germ shows up with increasing frequency in mastitis infections, Streptococcus uberis.

Diagnosis of a S. uberis mastitis

The S. uberis is found in the udder, in the intestine, and on the cow’s skin and teats, which is where most Streptococcus germs tend to be. The particularity of the S. uberis is its extraordinary ability to develop in an external environment, i.e. in the bedding or anywhere on the animals. The contamination can take place during milking or in the environment. Consequently, the S. uberis belongs to the environmental as well as to the mammary reservoir germ strains. When checking up cases of mastitis, one should have the following points in mind:

Cows during the lactation phase (milk cows):

  • With certain cows, numerous subclinical infections (absence of symptoms) with very high cell count throughout the lactation. Any treatment in this category of dairy cows during the lactation phase is bound to produce poor results;
  • More rarely, non-obvious cases of clinical mastitis, typically during the first three months after calving on cows with an individual cell count >300,000 cells/ml prior to the mastitis outbreak. These often remain with very high cell counts after clinical recovery;
  • The clinical mastitis episodes look much like streptococcus infections: low-key general symptoms. Pre-milking jets sometimes reveals blood-stained curd whilst the bulk of the milk remains normal;

Young stock:

The number of mastitis infections typically increases around calving time.

The fight against S. uberis

The particular ecology of S. uberis makes it particularly difficult to fight against this germ. It is necessary to practice very strict milking routines and to take all possible measures to keep the germ away from the environment. Previous issues of PLM describe what priority measures to apply. We would like to draw our attention to a few perticular aspects:

When intiating the dry phase:

S. uberis causes increased numbers of mastitis infections around calving time. The cattle are often contaminated during the dry period. Consequently, it is important to be vigilant and inspect the dry cows’ udders once or twice per week. The objective is to diagnose an infection at the earliest possible stage (preferrably by palpation). The treatment during the dry period is fundamental. When carried out, it will be possible to check on the S. uberis incidence throughout the lactation. The intra-udder treatment prescribed by the vet is a speciality that will maintain a high level of concentration throughout the dry period.

The housing:

The ideal is to have cubicles (stalls) as a protection against environmentally transmitted S. uberis infections. If the cows are on deep straw in a loose-housing area, the bedding must be completely replaced as often as possible. With regard to the increased risk of infection during the dry phase, we recommend keeping a close eye on the young stock and dry cow housing area: limited number of cattle, adequate bedding.

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