Commercial Pet Food
Commercial pet food had been around since the late 19th century but in the fifties it really took off. With better manufacturing and utilising bi-products from the human food industry; packaged pet food became the norm.
But something else happened at the same time. Dogs and cats started to get ill with diseases that had not previously been common such as, obesity, diabetes and pancreatitis as well as degenerative conditions such as heart, lung, and liver disease. Diarrhea, allergies, skin conditions and gingivitis became more common too.
Although more commercial pet foods today are now offering better ingredients (dump the junk section) processing requires them to be cooked to high temperatures, destroying much of the goodness found in raw food.