Submitted to: International Virtual Conference on Infectious Diseases of Animals
Publication Type: Abstract Only
Publication Acceptance Date: 4/20/1997
Publication Date: N/A
Technical Abstract: An experiment was conducted to determine the immunomodulatory activity of recombinant bovine granulocyte-macrophage colony stimulatory factor (rbGM-CSF) in lactating dairy cows. Administration of rbGM-CSF was via single daily subcutaneous injection on alternating sides of the lateral cervical region at 0, 0.5, or 2.5 micrograms/kg body weight for eight consecutive days. Control cows received a placebo saline injection. Cows were challenged in one mammary quarter with 41 colony forming units of Escherichia coli after receiving seven daily injections of rbGM-CSF to measure any effects on experimentally-induced mastitis. A dose-dependent febrile response developed upon repeated administration of rbGM-CSF. Increases in rectal temperatures in response to rbGM-CSF administration after the first day averaged 0.37 degrees C greater than control cows within 5 to 6 h. By 9 to 10 h after rbGM-CSF injection, increases in rectal temperatures averaged 0.59 degrees C over control cows. Rectal temperatures returned to control levels by 24 h after each injection. Associated with the febrile responses were increases in respiration and heart rates.