COMPARISON OF AMMONIUM, POTASSIUM, SODIUM, CHLORIDE AND HYDROXYL IONS ON INVITRO DRY-MATTER DISAPPEARANCE OF MILO STALKS

Effects and some interactions of cations and anions on in vitro dry matter disappearance (IVDMD) of milo stalks were studied in 5 experiments. From 1-5% (of dry matter) of NaOH or KOH were added as pretreatment to milo stalks. NaOH and KOH treatments increased IVDMD over the control; NaOH increased IVDMD more than KOH, especially at higher treatment levels. In exp. [experiment] II NH4Cl, NH4OH, KCl KOH, NaCl and NaOH were used in 3 levels each (on a molar basis) as pretreatment of milo stalks. All hydroxide treatments improved IVDMD but NaOH and KOH were superior to NH4OH as pretreatments of milo stalks with 56.2, 55.0 and 46.4% IVDMD, respectively. Hydroxide compounds increased IVDMD but chloride compounds reduced IVDMD slightly with increasing increments of the chloride ion. In exp. III NaCl replaced NaHCO3 as part of artificial rumen fluid (ARF) and IVDMD of milo stalks declined from 48 to 46% when chloride concentration reached 100 meq. Above 100 meq of chloride ion IVDMD declined more rapidly to < 30% with 165 meq chloride in ARF. Stalks were pretreated with 10 levels of NH4OH varying from 0-4.5% of dry matter in exp. IV. Addition of < 2% of NH4OH resulted in higher IVDMD (43-49%) but IVDMD did not increase much > 50% when more NH4OH was added. In a final experiment NaOH was replaced (on a molar basis) in increments of 10% by NH4OH as a pretreatment for milo stalks. The IVDMD percentage declined linearly from 52.3 to 43.4% as NH4OH constituted a greater proportion of chemical treatment. Pretreatment with hydroxyl ion elevated IVDMD of low quality forage but interactions with cations, dissociation constants of the specific chemicals and levels of chemical affected extent of improvement. [Chemical treatment of forages and roughages is used to improve digestion of low quality forage by ruminants.].