The effect of intramammary injection of recombinant bovine granulocyte-macrophage colony-stimulating factor (rboGM-CSF, 400 ug/10 ml control solution per quarter) on milk levels of chemiluminescence (CL) activity, somatic cell count (SCC) and Staphylococci count was investigated, using seven Holstein dairy cows with Staphylococci subclinical mastitis. The animals were divided into a short-term (short group; 3 cows) and a long-term mastitis group (long group; 4 cows). Injection of rboGM-CSF increased the milk CL activity significantly in both groups with maximum levels 6 h after the injection. The maximum level was higher in the short group than in the long group. In the short group, milk SCC had a considerable rise with a maximum level on day 1, and was followed by a gradual decline to a normal level (below 200,000 cells/ml) on day 7 after the injection. On the other hand, the SCC had a rise with a maximum level 6 h after the injection, and maintained high levels thereafter in the long group. The rboGM-CSF injection lowered the count of milk Staphylococci drastically in the short group. The lowering effect on the count of milk Staphylococci was also observed in the long group. However, the effect was small compared with that in the short group, and the bacterial count increased back to the previous level on day 7 after the cytokine injection. The present study in dicates that the rboGM-CSF has potential as a therapeutic agent of the Staphylococci subclinical mastitis of dairy cows, if the cytokine is applied at the initial stage of infection. (Pathophysiology Section, Department of Production Animal Diseases Tel +81-29-838-7810)
Reference:
- Takahashi et al. (1998) Proc. Jpn. Soc. Mastitis Res. 3:22-23.
- Takahashi et al. (1999) Jpn patent No.2995205, (2001) US patent No.6297045.
- Takahashi et al. (2001) JARQ 35:131-136.
