National Institute of Animal Health (NIAH)

Topics in Animal Health Research 2005

18. Therapeutic effect of the combined intramammary administration of rbGM-CSF and rbIL-8 on Staphylococcus aureus-induced subclinical mastitis in dairy cows

Japanese

  The effect of the combined intramammary administration of recombinant bovine granulocyte-macrophage colony-stimulating factor (rbGM-CSF, 400 μg/10ml control solution per quarter) and recombinant bovine interleukin 8 (rbIL-8, 1 mg/5 ml control solution per quarter) on levels of chemiluminescence (CL) activity in milk, the somatic cell count (SCC) and the Staphylococcus aureus (S. aureus) count was investigated using 15 Holstein dairy cows with S. aureus-induced subclinical mastitis. The animals were divided into an early-stage and a late-stage mastitis. Combined injection of rbGM-CSF and rbIL-8 significantly increased CL activity in the milk in both groups with maximum levels on day 1 after the injection. The CL activity decreased to less than pre-injected levels on days 7 and 14 after the injection in the early group, but the CL activity in the late group remained at high levels throughout the experiment. In both groups, the milk SCC underwent considerable increases, with maximum levels on days 1 and 2 after the injection. The SCC in the early group then declined gradually to a normal on day 14 after the injection. However, in the late group the SCC remained at high levels. The combined injection of the cytokines lowered the counts of total bacteria and S. aureus in the milk drastically in the early group. A lowering effect on bacteria counts was also observed in the late group, but this was small compared with the early group, and the bacterial count increased again on days 7 and 14 after the cytokine injection. The present study indicates that the combined intramammary administration of rbGM-CSF and rbIL-8 has potential as a therapeutic agent on S. aureus-induced subclinical mastitis in dairy cows if the cytokines are applied in an initial stage of infection.
(Research Team for Production Diseases, Tel +81-29-838-7780)

References:

  • Takahashi et al. (2004) Can. J. Vet. Res. 68: 182-187.
  • Takahashi et al. (2004) J. Anim. Feed Sci. 13: 563-566.
  • Takahashi et al. (2005) J. Vet. Med. B. 52: 32-37.

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