HIGH-LYSINE CORN AS A SOURCE OF PROTEIN AND ENERGY FOR FINISHING CALVES

Three trials evaluated the protein and energy value of high-lysine cor n for finishing calves. In Trial 1, 60 finishing steer calves were use d to evaluate corn source (high-lysine vs control) and protein source (urea, blood meal [BM], corn gluten meal [CGM]) and level(BM and CGM a ddition: low, medium, high). Calves were individually fed using Calan gates for 102 d, and then were pen-fed (two pens per corn treatment) t he remaining 83 d. During the initial 102 d, calves fed high-lysine co rn had similar gains but were 6% more efficient (P < .10) compared wit h calves fed control corn. Performance did not differ (P > .10) among sources or levels of protein supplementation. Over the entire feeding period (185 d), calves fed high-lysine corn were 10% more efficient (P < .10) than calves fed control corn. In the second study, in situ sta rch disappearance was faster (P < .10) and the proportion of CP degrad ed by 12 h was 27% greater (P < .10) for high-lysine corn than for con trol corn. In a metabolism trial, five steers fitted with ruminal, duo denal, and ileal cannulas were used in a randomized block design to ev aluate the effect of corn source on site and extent of digestion. Inta ke and ruminal and total tract digestibility of OM and N did not diffe r (P > .10) between corn sources. Steers fed high-lysine corn tended t o have greater ruminal (P = .23) and postruminal (P = .18) starch dige stion, resulting in greater (P < .10) total tract starch digestibility . Because protein source and level had no effect on performance and st arch digestibility was increased with high-lysine corn, the improved f eed efficiency observed with calves fed high-lysine corn was likely a result of improved energy utilization and not due to the additional ly sine content.