Three primary factors that affect forage quality include species, maturity, and temperature. As a general rule, annual forages will be higher in quality than perennial forages and cool-season forages will be higher in quality than warm-season forages. For example, replacement heifers grazing ryegrass may gain 2.0 to 2.75 pounds per day while replacement heifers grazing bermudagrass may only gain 0.75 to 1.0 pounds per day. These gains assume pastures are not overgrazed. As forages mature quality decreases, this is especially important to keep in mind when making hay. Hotter temperatures during the summer (regardless of rainfall) also reduce forage quality.