Udder health and immunosuppression during the transition period in dairy cows under pastured-based systems of milk production

Objective 1 Characterize the effect of parity on cytokine-mediated innate immune response during the transition period of dairy cows. Objective 2 Evaluate the use of an immune stimulant cytokine (polyethylene glycolated form of recombinant bovine granulocyte colony-stimulating factor; PEG rbG-CSF) under field conditions in commercial dairy herds. Specific objectives a. To evaluate the effects of use PEG rbG-CSF in the udder health and other health disorders in primiparous and multiparous Holstein dairy cows b. To evaluate the effects of use PEG rbG-CSF on fertility in primiparous and multiparous Holstein dairy cows. c. To evaluate the effects of use PEG rbG-CSF on metabolic status of primiparous and multiparous Holstein dairy cows. d. To evaluate the effects of use PEG rbG-CSF in immune system in primiparous and multiparous Holstein dairy cows. e. To make an economic evaluation of the use of PEG rbG-CSF in primiparous and multiparous Holstein dairy cows.