The mystery of the missing white dog poo

Back in the day, your pooch’s poo had a white hew after a day or two, but not anymore. Picture: Cup of Couple / Pexels

Back in the day, your pooch’s poo had a white hew after a day or two, but not anymore. Picture: Cup of Couple / Pexels

Published May 24, 2024


If you were a child or a dog owner right up until the early 2000s, you might remember seeing white, chalky dog poo on pavements or in parks. Today, such a sight is rare. This got me thinking, what changed? I spoke to a seasoned (pun intended) dog food scientist at a large pet food company who asked to remain anonymous for fear of reprisal by “Big Pet Food”.

“In past decades, dog poo often turned white after drying in the sun. This phenomenon was primarily due to the high calcium content in dog food at the time. Manufacturers commonly included bone meal, a source of calcium, in their formulas,” they said.

When dogs consumed this food, the excess calcium passed through their digestive systems and into their stools. As the faeces dried out, the calcium would give it a white, chalky appearance.

The significant shift occurred in the late 1980s and early 1990s. Veterinary nutritionists and pet food companies began to understand more about canine dietary needs and the potential health implications of excess calcium.

Too much calcium in a dog's diet could lead to skeletal issues and other health problems, especially in growing puppies. Pet food manufacturers gradually reduced the amount of bone meal and other calcium-rich ingredients in their products, opting for more balanced formulas.

This change improved the overall health of dogs and had an unexpected side effect: the disappearance of white dog poo.

“The key element here is the composition of modern dog food. Today’s commercial dog foods are formulated with carefully measured nutrients to ensure pets receive a balanced diet. Ingredients like meat by-products, grains, and vegetables are more common, and bone meal is used sparingly, if at all,” explained our mystery scientist.

When dog poo dries today, it retains more of its original colour and composition because it lacks the high levels of calcium that once caused it to bleach in the sun.

Additionally, the increased fibre content in modern dog diets can lead to softer, more quickly degrading stools, further reducing the likelihood of encountering those white, chalky remnants.