Yes, now is a good time to cut those branches.  Here is information from page 13 of Penn State's Pruning Ornamental Plants:

"Some deciduous trees have an exceptionally heavy sap flow—commonly called “bleeding”—in the early spring. If cuts are made then, the trees will “bleed.” While this sap loss does not injure the tree, it can be objectionable aesthetically and cause problems for pedestrians, automobiles, and so forth passing underneath. Excessive sap flow from pruning wounds can be avoided by pruning in midsummer or late fall. Maple, beech, birch, dogwood, elm, honeylocust, Kentucky coffeetree, magnolia, walnut, and yellow- wood are examples of trees best treated this way."