Performing a milk culture

​A milk culture can be used to confirm the presence of bacterial mastitis. Culturing the milk can allow identification of the bacteria, this will help aid understanding of the cause of mastitis, that is is the mastitis is the result of environmental factors or is it a species that can be contagious (Staphlococcus aureus, mycoplasma). Milk culture will help direct treatment of mastitis by checking to see which antibiotic will work best to treat the specific bacteria
  1. Wear gloves and clean the udder
  2. Before taking the sample, remove foremilk from the teat by stripping 4-5 squirts 
  3. Clean the teat end with an alcohol wipe. Allow it to air dry 30 to 45 seconds.
  4. place small amount of milk in a sterile container (sterile vial or Whirl-Pak bag)  
  5. label  container with goat ID, which half of the udder, and the date.
  6.  freeze the sample. .
  7. Submit the frozen sample for culture and sensitivity to your veterinarian or state diagnostic lab - request aerobic culture and mycoplasma culture - mycoplasma is commonly missed on routine cultures.
On farm monitoring of somatic cell count
Somatic cells in milk are primarily white blood cells produced to fight infection in the udder. Increased somatic cell count can be an indicator of mastitis. Goats have higher somatic cell counts compared to cows as measured by the machines used to screen milk, this is because goats have some natural particles that register as a cell on a machine count. Factors other than infection can influence the SCC in goats, for example when does are cycling and at different phases of lactation. 
Because subclinical mastitis occurs without obvious signs it is ideal to monitor SCC once a month by either performing Dairy Herd Improvement testing or performing a monthly test at the farm such as a California Mastitis Test (CMT) or using a PortaCheck goat test. 
The California Mastitis Test (CMT) is an indirect test that uses an anionic detergent that reacts with the DNA in the somatic cells in the milk sample to form a gel. High viscosity of the gel is indicative of high SCC and, thus, also indicative of subclinical mastitis. The CMT is easy and fast to run, it is a doe side test so its use can easily be incorporated into the milking routine. If a doe shows increased SCC on the CMT it is suggested that a milk culture be submitted. ​