Farm Description: 80 lactating cows that are housed in a tie stall barn that has water bed mattresses topped with sawdust. The cows are milked twice a day by family members. The ambient temperature is 68F (20C). All cows are treated with intramammary antibiotics at dry off. The bulk tank SCC of the farm is 289,000 cells/ml.
Cow Description: 2 year old Holstein. She was purchased from a neighboring farm 1 week after she calved. She has been milking 6 weeks and has not yet been bred. She is producing 86 lb (39 kg) of milk per day and has a BCS of 3.00. Her first test SCC was performed when she was about 30 days in milk and was 439,000 cells/mL. Today at the morning milking, abnormal milk was observed in the foremilk of the right front quarter, however there is no swelling in any of the quarters. After observing abnormal milk, the owner performed a CMT test on milk from the other 3 quarters. The CMT results were +1, +2, and negative for the left front, right rear and left rear, respectively. This cow is eating well and has good rumen contractions. Her body temperature is 101.5F (38.6C). This farm has never performed a bulk tank culture.
The bulk tank SCC of the farm that she was purchased from is 389,000 cells/mL and before the heifer was purchased, the owner of her original farm provided the following information:
BACTERIOLOGY RESULTS: MASTITIS BULK TANK
SAMPLE TYPE: BULK MILK 3/26, 3/28, 3/29
STAPH AUREUS: 30 CFU/ML
STAPH NON AUREUS: 300 CFU/ML
STREP AGALACTIAE: 100 CFU/ML
STREP – ENVIRONMENTAL: 350 CFU/ML
COLIFORMS: 25 CFU/ML
DISCLAIMER: These cases are teaching examples and do not represent all outcomes of individual cases. The treatments assume that the cow is in the United States and that the FDA rules for use of drugs are applicable. Individual cases in real cows should receive treatment protocols that have been discussed and developed with the local veterinarian.