Mastitis Culturing

Bulk tank, individual cow, and bedding culturing for mastitis causing agents is a service that Minnesota DHIA is now offering to assist dairymen with mastitis management.  DHIA personnel offering these services have had training in sampling techniques developed by the University of Minnesota. Mastitis causes lower milk production, increased days open, loss of animals due to culling, and a lower milk price. It also affects the dairy industry with poorer fluid milk quality and less cheese production. Bulk tank and individual cow culturing can be valuable tools in assisting dairymen to produce high quality milk and reduce losses due to mastitis.  In managing the spread of mastitis, the University of Minnesota recommends bulk tank cultures, individual cow cultures, and bedding cultures to fully analyze where mastitis causing pathogens are coming from.

Bulk tank cultures

n Are used to determine if contagious organisms such as Staph Aureus, Strep Ag, or Mycoplasma are present in the herd.

n Help monitor the effectiveness of bedding management and milking procedures-high levels of environmental organisms on bulk tank cultures indicate problems in those areas.

n Instructions for proper methods of taking samples are available from your Field Rep. Sterile vials with no preservatives in them are needed and are usually available from the milk hauler, but can be provided by your Field Representative if needed. It is recommended that 5 days worth of milk be sampled for accurate detection of contagious organisms. In most cases the milk hauler can take samples for dairymen. It is important that samples are not taken from the milk port and that they are frozen immediately. Your Field Rep can pick up the samples on test date and send them to the lab for you.

Individual Cow Cultures

n Are used to identify what organism cows are infected with and can be checked for antibiotic sensitivities if the dairymen desires.

n The best time for taking samples is during milking, right after the cow has been prepped (before the unit is attached).

n DHIA personnel doing the sampling will have the supplies they need to ensure that high quality samples are taken.

n Samples can usually be taken on test date, however if a large portion of the herd is to be cultured it will be best to do so at a different milking.

n Composite samples can be used, but if possible it is best to use CMT to determine which quarters are infected and take samples from those quarters.

n A printed list of the cows and quarters sampled should be included with the sample vials to help lab personnel make sure samples are correctly identified.

Bedding Cultures

n Can be used to determine the "bacterial challenge" cows face from environmental organisms.

n Samples should be taken from a good representation of stalls in the area where cows' udders are when they are laying down.  Take the samples right before stalls are cleaned and re-bedded.

n Put samples in a ziplock bag, squeezing out excess air and freeze immediately.

Culture Results

Culture results can be sent to dairymen via regular mail, e-mail, or fax and can be recorded in Dairy Comp and Scout programs. Your Field Rep can record results for you if you do not have on-farm software. Copies can also be sent directly to your veterinarian if you desire.

A booklet with more information on dealing with specific organisms and other mastitis management information is available. Follow the link Interpreting Mastitis Culture Results.  Additional information on mastitis control and culturing can be found at the University website at http://mastitislab.tripod.com/index.htm.