Effect of feeding treated or untreated corn cob as grass basal diet replacement on nutrient digestibility, N utilization, and rumen fermentation of lambs

Abstract

The aim of the study was to assess the effect of substituting a grass basal diet with either untreated or treated corn cobs on nutrient digestibility, nitrogen utilization, and rumen fermentation in lambs. The research utilized 20 lambs aged of 6 months, with an average initial body weight of 17.29 ± 2.05 kg. These lambs were divided into six groups based body weight, each lamb in each group received one of basal diet treatment: fresh chopped grass (FG), ground corn cob (GC), ensiled corn cob (EC), and urea-treated corn cob (UC). The basal diet was provided ad libitum and supplemented with 350 g/head/day of concentrate. The concentrate was formulated to contain 18% crude protein and 73% TDN (total digestible nutrients). Results of the study indicated that the various basal diets influenced fibre digestibility (NDF, ADF, and cellulose). Among the diets, the highest fibre digestibility was observed in the lambs fed the urea-treated corn cob basal diet. The basal diet treatment also affected the excretion of nitrogen through faeces and urine. Lambs fed the urea-treated corn cob basal diet exhibited the highest urinary nitrogen excretion, whereas nitrogen absorption was most efficient in the grass basal diet. Conversely, nitrogen retention was similar across all diets, averaging 2.32 g/head/day. Rumen fermentation parameters, including ruminal pH, NH3-N, and total VFA, exhibited similarity across the different diet treatments. In conclusion, this study suggests that both untreated and treated corn cobs is potential as fibre sources to replace grass basal diet for lambs.