CHANGES IN BOVINE MAMMARY-SECRETION COMPOSITION DURING EARLY INVOLUTION FOLLOWING INTRAMAMMARY INFUSION OF RECOMBINANT BOVINE CYTOKINES

This study was designed to determine whether intramammary infusion of recombinant bovine interleulin-1 beta or interleukin-2 had any adverse influence on bovine mammary function during the early non-lactating p eriod. Mammary glands of eight Jersey cows were infused with either 10 mu g of interleukin-1 beta or 1.0 mg of interleukin-2 following abrup t cessation of milking. Mammary secretions from each gland were collec ted from cows frequently during early involution and evaluated for cha nges in secretion composition. percentage of milk fat and solids-not-f at during the experimental period was variable for all treatments. Per centage of protein increased throughout the study for all treatments, but mammary glands treated with interleukin-1 beta had higher protein percentages. All interleukin-treated mammary glands had lower concentr ations of lactose than controls. Mammary secretions from interleukin-1 beta treated glands had higher concentrations of lactoferrin at 7 and 14 days of involution. Similarly, mammary secretions from interleukin -2 treated glands had higher concentrations of serum albumin on day 3 of involution and throughout the remainder of the study. Concentration of citrate and the citrate:lactoferrin molar ratio generally decrease d throughout the study for all treatment groups. Concentration of alph a-tactalbumin in mammary secretions decreased throughout the study and was not different between treatment groups. Though significant change s in mammary secretion composition due to the presence of cytokines we re observed in this study, resulting in an apparent acceleration of in volution, there was no indication that these changes adversely affecte d normal bovine mammary function during the early non-lactating period .