Another factor worthy of consideration in balancing NFFS diets for protein content is the digestibility of protein, especially from dried sources. Survey information on digestibility of NFFS is limited. However, Kleinschmit et al. (2007) analyzed 6 commercial DGS products using a 2-step procedure (ruminal incubation followed by pepsin and pancreatin digestion) to estimate both RUP supply and digestibility. Estimated total-tract CP digestibility ranged from 85.3% to as low as 70.7%, and all DGS products had significantly lower estimated CP digestibility than soybean meal (Kleinschmit et al., 2007). Three of the dried DGS products had digestibility estimates equivalent to the wet DGS product evaluated, but 2 others were significantly less digestible, suggesting that drying does not necessarily impair protein digestibility, but it might if the process if not carefully controlled.