Combine yeast and warm water in a cup or small bowl; set aside.
In a saucepan, heat the milk over medium heat until bubbles begin to appear around the edges.
Pour the hot milk over shortening, salt, and molasses. Stir until shortening melts. Cool the mixture until it is lukewarm and then stir in 1 cup of the flour, the yeast mixture, and the oats. Stir in enough additional flour to make a soft dough.
Turn the dough out onto a lightly floured surface and knead until smooth and elastic, about 10 minutes. If it is sticky, incorporate extra flour. Shape the dough into a ball and place it in a large buttered bowl; turn the dough over to grease both sides with the butter.
Cover the bowl with a kitchen towel and let it rise in a warm place until nearly doubled in size, about 1 hour. Punch down; cover and let rest 10 minutes. form into two loaves. Place in greased 9-by-5-by-3-inch loaf pans. Brush tops with melted butter.
Cover the pans with a kitchen towel and let the dough rise for about 45 minutes to 1 hour, or until nearly double in size.
Bake the bread at 375 F for 35 to 40 minutes. Remove from pans immediately and cool on racks.
Brush with more melted butter while hot for a softer crust.