Effects of addition of alfalfa hay as an absorbant on fermentation quality and effluent loss in corn silage

The objectives were to investigate the effects of addition of alfalfa hay as an absorbent on fermentation quality and effluent production of corn silage. Three levels of corn forage with dry matter (DM) contents of 18. 3، 21. 7 and 25. 5 percent were supplemented with 0، 5، 10، and 20 percent alfalfa hay، on as fed basis، and ensiled in three replicates in polyvinyl chloride mini-silos in a completely randomized design. Concentrations of ash and total nitrogen increased and that of neutral detergent fiber decreased significantly as the level of absorbent increased (P< 0. 05). Increasing the level of absorbent significantly increased the DM of silage where the higher levels of DM were observed in silages with 1 and 20 percent absorbent. The pH values were within the optimum range of corn silage (ranging from 3. 79 to 4. 33); however، silage pH was affected by the interaction between DM and level of absorbent (P<0. 05). The pH increased as the level of absorbent increased، however، the effect was less observed in silages with 26 percent DM. Also، there was an interaction between the DM and absorbent in the concentration of residual water-soluble carbohydrate of silage where the differences in water-soluble carbohydrates in silages with 18 percent initial DM were lower than those in silages with 22 and 26 percent DM. As the level of absorbent increased، aerobic stability was improved with the effects becoming less pronounced as the level of DM increased. Effluent production was markedly reduced as the level of absorbent increased so that it dropped to 0 ml at 20 percent alfalfa hay addition at all DM levels (P<0. 05). The concentrations of DM and nitrogen were higher in effluent produced from silages treated with higher level of absorbent; however، total DM and nitrogen losses were lower due to considerably lower effluent production. Results showed that using a minimum of 10 percent alfalfa hay could effectively reduce effluent production and improve aerobic stability of corn silage while maintaining its optimal pH.