Ive recently started baking with whole wheat flour and oat bran. Found some good reading here Farmer Direct Foods - Bread Recipes
Also they had this recipe for Whole Wheat Bread, just maybe for comparison about the recipe you are using...
Whole Wheat Bread
2 packages active dry yeast
1 cup water, warm, 105°F-115°F
1 cup milk, warm, 105°F-115°F
1/3 cup honey
6 ½ cups Natural s’ Wheat Whole White Wheat Flour
¼ cup shortening
2 tablespoons salt
Dissolve yeast in warm water in large mixing bowl. Add milk and honey. Beat in 3 cups of the flour and eggs. Beat 100 strokes or 2-3 minutes on medium mixer speed. Cover bowl and allow sponge to rest 20-30 minutes.
Mix in salt and flour, ½ cup at a time, until dough can be turned out on lightly floured surface to knead. If using a dough hook, add shortening and complete by kneading on dough hook 8 minutes. If kneading by hand, knead 10-15 minutes, gradually kneading in shortening.
Let dough rise in greased and covered bowl until double. Punch dough and divide in half. Let dough rest while greasing two 8 1/2 x 4 1/2 inch bread pans. Shape, place in pans and let rise until double. Bake at 375°F for 20 minutes. Makes two loaves.