Iron(III) oxide, often referred to as rust, is a compound that forms when iron reacts with oxygen in the presence of water or moisture. The ionic formula for this compound is Fe₂O₃. In this formula, "Fe" represents iron, and "O" represents oxygen. The subscript numbers indicate the number of atoms present for each element in the molecule. Iron has a +3 charge (Fe³⁺) in this instance, which is balanced by the presence of three oxygen atoms, each carrying a -2 charge (O²⁻). This balance ensures the overall charge neutrality of the compound, making Fe₂O₃ stable. Iron(III) oxide is widely used in various industries, including as a pigment in paints and in the production of magnets due to its reddish-brown color and magnetic properties.

Fiber, essential for a healthy digestive system, is found in a variety of foods. Plant-based foods are key sources, such as fruits (berries, apples), vegetables (broccoli, carrots), legumes (lentils, beans), whole grains (oats, whole wheat pasta), nuts, and seeds. There are two types of dietary fiber: soluble, which dissolves in water and can help decrease glucose and cholesterol levels, and insoluble, which does not dissolve, aiding in the movement through the digestive system. Including a mix of these fibers by consuming a diverse range of whole foods can support gut health, enhance satiety, and contribute to a balanced diet.

Most livestock, including ruminants like cows, sheep, and goats, possess specialized stomach compartments to break down cellulose, a complex carbohydrate found in plant cell walls. However, monogastric (single-stomached) animals such as pigs, chickens, and horses lack the ability to effectively digest cellulose due to the absence of microbes that produce cellulase, the enzyme required for cellulose breakdown in their digestive tracts. While horses and other hindgut fermenters can partially digest cellulose through fermentation in the cecum and large intestine, the efficiency is significantly lower compared to ruminants. Monogastric animals rely more on easily digestible carbohydrates found in grains and processed feeds for their energy needs, highlighting the importance of dietary selection based on the digestive capabilities of each livestock species.