Fact Sheet: Other than Streptococcus agalactiae

The Disease

The Strep organisms that cause mastitis are commonly divided into Streptococcus agalactiae and Streps other than Strep ag. These bacteria include Streps Uberis and dysgalactiae as well as a host of species including S. acidominimus, S. alactolyticus, S. canis S. equi, S. equinus and S. parauberis. The significance of these other Streps is their means of entering the udder. All of these organisms may be contracted by the cow from the environment and not just from another cow, thus they are called environmental streps. These bacteria are found in bedding, soil, walkways or any surface the cow is in contact with. Environmental Streptococcal mastitis may be apparent (clinical) or inapparent (subclinical). The significance of these pathogens is greater in well managed herds with low somatic cell counts and fewer infections with the contagious mastitis organisms. Environmental Streps can add substantially to the bulk tank SCC. Among these bacteria are many that are difficult to treat effectively during lactation. And to top this all off the environmental streps cause a high percentage of dry cow infections. Culturing clinical mastitis cases and conducting antibiotic sensitivity trials will provide a data base that will guide the most effective treatment.

The Consequences

Many environmental Strep infections are acquired during the dry period, carried into lactation and represent early clinical cases of mastitis. This is also true of heifers at first calving. Rates of new infections are greatest in the first 2-5 months in milk but Strep infections can occur through out lactation. While environmental streps are less affected than coliformes by season of the year and weather conditions hot and rainy weather still are times of increased rates of infection. With environmental streptococcal mastitis abnormal milk is the most common symptom. Occasionally there will be swelling of the quarter and less often the cow will have a fever and/or go “off feed”. This is not to say that this organism cannot cause life threatening illness. Most Environmental streps are eliminated from the cow in under 30 days by the use of effective antibiotics or the cow clearing the infection on her own. During the period of infection there is lost production, reduction in milk quality and medical costs. Also infections that recur damage the udder tissue resulting in permanent loss of the cows capability for production.

Control or Elimination

As is often the case their are two ways of looking at prevention for this or most any environmental mastitis pathogen.

Increase the cows ability to resist the bacteria or at least don’t interfere with the ability she has.

  • Reduce or eliminate damage to teat ends due to improper milking machine function.

  • Stalls should be designed to provide a comfortable resting place that minimizes stress and the chances for injury.

  • Proper nutrition to provide adequate amounts of Vitamin E and Selenium and to avoid metabolic problems such as milk fever.

Keep the population of infectious organisms reduced to prevent overwhelming the cows defenses.

  • Clean and DRY! Important for all ages
  • Inorganic bedding is associated with fewer pathogens.
  • Predipping has been very useful in some herds
  • Milking hygiene, milk clean and dry teats and udders.

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