When forage or hay quality is low it is important to supplement cattle to maintain performance and good immune function. Energy (commonly reported as TDN) and protein are the first priorities for supplementation and they are responsible for the big changes in cattle body condition and performance. When forage TDN is low or when increases in body condition are needed, supplements high in TDN should be selected and feed daily. Crude fiber is a good indicator of TDN in most sacked feeds and cubes. Select feeds that are 10-11% crude fiber or less; as crude fiber increases TDN values decrease.