Palatability is the preference an animal has for a particular feed when offered a choice. Palatability only matters when there is a choice of food for the livestock. It is affected by texture, aroma, succulence, hairiness, leaf percentage, fertilization, sugar content, and other factors. Just as humans tend to eat more at a dinner of delectable specialties, livestock will eat more if the palatability is high. Animal performance is not solely based on palatability, even though it is a significant factor. As a basic rule, grass is more palatable to animals when young, tender, and leafy. As the flowering stems mature, the roughage becomes less palatable. Forage plants have two basic components: cell contents (protein, sugar, and starch) and structural components of cell walls (cellulose, hemicellulose, and lignin). Cell wall components govern the rate of digestion and therefore the rate of intake. The cell wall components are less palatable and livestock will choose the younger plants. This concept is important because young grass plants need enough time and growth to have enough leaves, the basic site for photosynthesis. Some have likened the surface area of leaves to the square footage of a warehouse. The more leaves, the more production. So livestock selectively nibbling off the new leaves can be detrimental. From the plant's perspective, grazing is least harmful at maturity. But from the animal's vantage point, grazing immature plants is favored since both palatability and digestibility are better. Wise forage-livestock managers plan their harvesting, grazing or mowing, to balance the best quality feed with the best regrowth opportunities of the plants.
Livestock will avoid plants near dung deposits, first because they are malodorous and later because the plants have had time to mature and are then less palatable. Plants in urine spots are not usually avoided because the urine is quickly volatilized (vaporized) or leached.
Managers help meet livestock demands by calendarizing their pasture systems using separate areas for cool and warm season species. Variation in seasonal productivity provides a source of high quality pasture for spring and mid-summer grazing.