TA-DA! I found you some!!! 
Here's some recipes I found for you that are low potein... at least they are listed as low protein.
Beef Jerky Pup Cake
Beef flavoured cake.
• 1 1/2 cups all-purpose flour
• 1 1/2 teaspoons baking powder
• 1/2 cup soft butter
• 1/2 cup corn oil
• 1 jar strained beef baby food
• 4 eggs
• 2-3 strips of beef jerky
Preheat oven to 325°. Grease and flour an 8x5x3 inch loaf pan. Cream butter until smooth. Add corn oil, baby food, and eggs. Mix until smooth.
Mix dry ingredients into beef mixture until batter is smooth. Crumble beef jerky and fold into batter. Pour batter into loaf pan. Bake 1 hour and 10 minutes. Cool on wire rack 15 minutes. Frost with plain yogurt, cream cheese or cottage cheese. Crumble another strip of beef jerky and sprinkle on top of icing. Store in refrigerator.
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Bacon Chicken Layer Cake
This recipe makes a real layer cake! Chicken, bacon and yogurt provide aromas that drive dogs crazy for this cake.
• 3 cups flour
• 1 T. baking powder
• 1/2 cup margarine, softened
• 6 eggs, beaten
• 1/2 cup corn oil
• 2 jars strained chicken baby food
• 2 cups finely shredded carrots
• plain or vanilla yogurt
• 2 or 3 strips of bacon, fried crisp, then crumbled, or use bacon-flavored jerky strips, cut into bits.
Generously grease and flour two 8" round cake pans; set aside. Combine flour and baking powder; set aside. In a mixing bowl, beat softened margarine until smooth. Add eggs and corn oil; mix well. Add strained chicken, and shredded carrots and mix until smooth. Add flour mixture and mix thoroughly. Pour batter into the 2 prepared 8" cake pans. Bake at 325° for 60 minutes. Let cool for a few minutes before removing from pans. Cool completely on wire racks.
Place one layer on a serving plate and spread yogurt over top. Place second layer on top, then spread yogurt on top and sides of entire cake. Sprinkle crumbled bacon or bits of jerky strips over top. Use "Pupperoni" sticks for candles.
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Peanut Butter Carrot Cake
Naturally sweet, colorful and flavorful, this cake is simple and easy to make. Great for Fall.
• 1 cup flour
• 1tsp baking soda
• 1/4 cup peanut butter
• 1/4 cup vegetable oil
• 1 cup shredded carrots
• 1 tsp. vanilla
• 1/3 cup honey
• 1 egg
Mix flour and baking soda. Add remaining ingredients. Pour into greased 8" round cake pan and bake at 350° for 30 minutes. Let cool. Puree cottage cheese in blender for icing. Decorate with more peanut butter and carrots.
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Bow Wow Cake (For Dogs) Recipe
8 ounces low-fat cream cheese, at room temperature
1/4 cup honey
1 tablespoon cornstarch
2 eggs
1 1/2 teaspoon vanilla
1/2 cup sliced almonds
Beat cream cheese with a mixer until smooth. Beat in honey. Sprinkle in cornstarch while beating on low speed. Beat in eggs and vanilla until well blended.
Pour into a greased, 8-inch springform pan. Bake at 350 degrees for 35 minutes, or until edges of cake are lightly browned and center is almost firm. Cool to room temperature. Remove sides of cake pan. Garnish cake with sliced almonds. Store in refidgerator.
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Apple Crunch Pupcakes Recipe
2 3/4 cups water
1/4 cup unsweetened applesauce
1/4 teaspoon vanilla
4 cups whole wheat flour
1 cup dried apple chips
1 tablespoon baking powder
1 egg -- lightly beaten
4 tablespoons honey
Preheat oven to 350F. Spray muffin tin with cooking spray. Mix all wet ingredients thoroughly. Combine dry ingredients in a separate bowl. Add wet to dry slowly, scraping well to make sure no dry mixture is left. Pour mixture into muffin tins. Bake 1 hour and 15 minutes, or until a toothpick inserted into the center comes out dry. Store in a sealed container.
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The peanut butter carrot cake one sounds the best to me, I think I'm gonna have a go at that myself cuz it sounds really easy.