Constraints on PDFs from W and Z rapidity distributions at CDF

The rapidity distributions of W and Z bosons produced in proton anti-proton collisions at CDF are presented. The rapidity distribution of Z bosons, measured for the first time over the entire kinematic range, is better described by NLO QCD (and also by QCD with gluon resummation) than by leading order QCD. The W charge asymmetry data as a function of rapidity strongly constrain the ratio of d and u quark momentum distributions in the proton over the x range of 0.006 to 0.34. The W data are used to rule out recently proposed models for charge and flavor symmetry violation of the sea quark distributions in the nucleon