Ammonia treatment of corn plant residues: digestibilities and growth rates

Two lamb digestion trials and two steer growth trials were conducted to evaluate NH3 treatment of cornstalks and cobs. In digestion trial 1, cornstalks were treated to contain 0, 2, 3 or 4 g NH3/100 g dry matter (DM); DM intake of lambs increased (P greater than .05) with increasing levels of NH3 (from 398 to 997 g). DM digestibility (DMD) increased (p greater than .05) from 36.8 to 47.0% with 2% NH3 but did not increase further with 3 or 4% NH3. In digestion trial 2, 3% NH3-treated cornstalks produced higher (P greater than .01) DMD, DM intake and cell wall digestibility than untreated cornstalks. No positive associative effects on DMD were observed from the addition of 50% alfalfa to treated stalks, but DM intake showed positive associative effects (P greater than .01). Steers fed stalklage harvested shortly after the harvest of high moisture grain gained more weight per day (P greater than .05) but were not more efficient (P less than .10) than steers fed stalklage harvested 1 month after grain harvest. NH3 treatment of stalklage did not improve rate or efficiency of gain over that obtained with the corresponding untreated stalklage (P less than .10). Steers fed 3% NH3-treated corn cobs gained .72 kg/day, compared with .39 kg/day for steers fed untreated cobs. DM intake increased (P greater than .05) from 4.22 kg/day for steers fed untreated cobs to 7.17 kg/day for steers fed 3% NH3 cobs.