Microorganisms are ubiquitous in the environment. Microorganism can be found in soil, water, plants, decaying organic matter, exudates of animals or within contaminated treatment preparations on any dairy farm. These microorganisms can be isolated from an infected udder, respiratory, reproductive, and digestive tracts. The potential always exists for these microorganisms to gain access to the mammary gland during favorable conditions. When these isolates are present, it is possible that the samples were not collected in an aseptic technique. Care should be taken when deciding if these isolates were the true cause of an infection or if they are indicative of contamination. Therefore, it is important to evaluate the bulk tank milk (BTM) culture results using all available information.
File: CL-Res-60-Bulk-Tank-Milk-Microorganisms-1.pdf
Milk samples may be collected individually from each affected quarter (quarter milk samples) or combined from multiple quarters of a cow into one sample tube (composite milk samples). Composite milk samples are not recommended however, as cultures usually reveal growth of numerous different bacterial species, making it difficult, if not impossible, to determine which pathogens are causing mastitis and which are environmental contaminants. Isolation of contagious organisms, such as Staphylococcus aureus, Streptococcus agalactiae, or Mycoplasma sp., are indicators of true infections of the udder. Environmental organisms, such as Streptococcus spp., coliforms, Staphylococcus spp., (coagulase negative Staph.), Pseudomonas sp., Corynebacterium sp., yeast, and fungi, may be contaminants or true infections. Unless only screening for contagious pathogens, composite milk samples should be avoided.
Milk samples may become contaminated with bacteria from the hands of the sample collector, the environment, and the teat, skin or teat canal of the cow. It is important that proper sample collection techniques are used in order to avoid contamination of the milk sample.
File: CL-Res-59-milk-sample-collection-1.pdf
Klebsiella species are Gram-negative coliform bacteria that can cause mastitis, leading to significant economic losses on dairy farms. K. oxytoca and K. pneumoniae are the species that are responsible for causing clinical mastitis.
File: CL-Res-58-Klebsiella-1.pdf
Streptococcus dysgalactiae – This gram positive, beta-haemolytic, coccal bacterium can be spread from cow-to-cow or acquired from the environment. Good hygiene and mastitis control programs including post-milking teat disinfection, antibiotic dry cow therapy and maintaining a clean, dry environment will reduce infections caused by this pathogen.
Streptococcus uberis – This gram-positive bacterium is the most frequent cause of mastitis in lactating cows. It can be isolated from the udder, skin, lips, and genital area of dairy cows, but infections are typically acquired from the environment. This bacterium causes mastitis during the dry period and are isolated frequently from cows with clinical mastitis during early lactation. Good hygiene and mastitis control programs including post-milking teat disinfection, antibiotic dry cow therapy and maintaining a clean, dry environment will reduce infections caused by this pathogen.
Other Streptococcus species isolated less frequently include the following:
S. acidominimus, S. alactolyticus, S. canis, S. zooepidemicus, S. equi, S. equinus (formally S. bovis), and S. parauberis.
Enterococcus species – Enterococcus species are a gram-positive cocci and lactic acid bacteria. Species include E. durans, E. faecalis, E. faecium, and E. saccharoluticus. These bacteria cause clinical and subclinical mastitis infrequently. Cows are infected from environmental contamination. Effective mastitis control procedures as mentioned above will control these mastitis-causing pathogens.
File: CL-Res-57-Environmental-Streptococcus-species-15-05-06-1.pdf
The Wisconsin Veterinary Diagnostic Laboratory provides diagnostic testing for Equine Infectious Anemia (EIA) at its location in Barron, WI. This document provides information in regards to testing services.
File: CL-Res-54-Equine-Infectious-Anemia-EIA-Services-and-Submissions.pdf
Leptospirosis is an important infectious disease of dogs. In the Midwest, Leptospirosis is usually
diagnosed in the late summer to fall time period especially if there is a sustained period of above
normal precipitation 1–3 months earlier. It is important to remember that all breeds and life
styles (city vs. rural) dogs are at risk of contracting Leptospirosis, but adult male dogs that spend
a considerable amount of time outdoors are at greatest risk
File: CL-Res-49-LeptoDogs.pdf
Highly pathogenic avian influenza (Bird Flu) has been found in wild birds in North America. This virus can also infect poultry commonly found in backyard flocks. The strains were identified as H5N8 and H5N2 and typically do not cause disease in most wild birds but will cause severe disease in gallinaceous birds (domestic poultry and game birds). The strains are described as highly pathogenic because of rapid spread and high mortality in domesticated poultry
File: CL-Res-48-BirdFluinBackyardFlocks11-5-15-1.pdf
The Microscopic Agglutination Test (MAT) is the standard serological test used in the United States for diagnosis of Leptospirosis. The following six serovars are used in the assay: L. bratislava, L. canicola, L. grippotyphosa, L. hardjo-bovis, L. icterohaemorrhagiae and L. pomona. Generally, the serovar with the highest titer is the infecting serovar but cross-reactions do occur albeit at a lower level. Titers should be interpreted in the context of clinical findings, laboratory data and Leptospirosis vaccination history
File: CL-Res-47-LEPTOMATLARGEANIMAL.pdf
The ideal samples for investigation of respiratory diseases are those that are collected within 4-8
hours of death, however, any sample is better than none, and the lab does not charge based on
the number of samples submitted. Both fresh and formalin fixed tissues from 2-4 different sections
of lung including the junction between normal and diseased tissue.
File: CL-Res-37-Diagnostic-Submission-Guidelines.Resp_.pdf
The ideal samples are those that are collected within 8-12 hours of fetal expulsion although
samples collected 1-2 days after abortion may still yield useful information. Submit either the
entire fetus and placenta or both fresh and formalin fixed tissues as outlined.
File: CL-Res-30-Diagnostic-Submission-Guidelines-Large-and-Small-Ruminant-Abortion.pdf