Effects of recombinant granulocyte colony-stimulating factor on Staphylococcus aureus mastitis in lactating dairy cows.
The in vivo effects of recombinant human granulocyte colony-stimulating factor on blood and milk leukocytes in dairy cows was examined. A 2-fold increase in peripheral white blood cell counts was observed by d 5 of treatment and peaked on d 12 with values 3-fold those of controls. Counts remained elevated above pretreatment values during the treatment period, then returned to normal by d 23 of the trial. Differential white blood cell counts demonstrated that neutrophils predominated (73.8%) in treated cows versus controls (22.1%) during the treatment period. Immediately prior to experimental challenge with Staphylococcus aureus, milk SCC were 582 x 10(3) and 261 x 10(3)/ml, and percentages milk neutrophils were 64.4 and 45.3, respectively, in treated and control cows. After challenge, a 46.7% reduction in new infections was observed in quarters of treated cows compared with controls. Recombinant human granulocyte colony-stimulating factor was a granulopoietic growth and differentiation factor in the cow, and the resulting leukocytosis into the mammary gland may have been protective against experimental bacterial challenge.
Nickerson
S C
SC
Hill Farm Research Station, Louisiana State University Agricultural Center, Homer 71040.
Owens
W E
WE
Watts
J L
JL
D000818:Animals; D002417:Cattle; D002452:Cell Count / Q000662:veterinary; D003115:Colony-Stimulating Factors / Q000627:therapeutic use*; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor; D007774:Lactation; D007958:Leukocyte Count / Q000662:veterinary; D007962:Leukocytes / Q000276:immunology*; D008414:Mastitis, Bovine / Q000517:prevention & control*; D008892:Milk / Q000166:cytology; D011247:Pregnancy; D011994:Recombinant Proteins / Q000627:therapeutic use; D013203:Staphylococcal Infections / Q000517:prevention & control / Q000662:veterinary*
D003115:Colony-Stimulating Factors; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor