Approaches to the Level and Quality of Forage in Feedlot Diets for Lambs

Diets with low forage concentration may depress feed intake and average daily gain, while diets with high forage concentration may limit feed intake due to rumen filling. Adequate forage level may range from 7% to 14% in ration for feedlot lambs, depending on forage source and ingredient composition. Small amounts of good quality forage may improve growth performance of sheep in the first stage of fattening; however, higher energy efficiency can be obtained in feedlot lambs fed diets with low-quality roughage. Forages are required in low percentages in fattening diets for ruminants, mainly as functional ingredients, since they contribute by stimulating rumination and saliva production that reduce acidosis-related digestive disorders. The functionality of forage is influenced by its neutral detergent fiber (NDF) concentration. Feedlot cattle may have different productive performance when fed diets with constant levels of forages of different quality. These differences can be reduced when diets are formulated to contain similar NDF levels from forage. Diets for feedlot cattle formulated at 15% of NDF from forage can moderate ruminal upsets without altering feed intake; however, the optimal level might be between 4% and 8% of NDF from forage. In feedlot lambs there is limited information. Approximately 6% of NDF from forage may be included in the ration for maximum feed efficiency. At these NDF levels from forage, the forage source may have minimal influence on growth performance of feedlot animals. There are few reports on lambs on intensive feeding indicating maximum and minimum levels of NDF from forage in diets for better growth performance. This is an important scientific topic that must be considered in feedlot lambs to improve their productive performance.