Vol. 9, Issue 9, Part A (2025)

The study was conducted in the laboratories of Razi University in Kermanshah Governorate and Al-Qasim Green University laboratories in Babylon Governorate during the period from 1/11/2024 to 4/5/2025. The aim was to evaluate the effect of gradually replacing alfalfa (AF) with Panicum maximum (PM) at two levels of concentrate feed on gas production. Increasing proportions of PM (100%, 75%, 50%, 25%, 0%) were used to replace AF and mixed with concentrate feed. The concentrate feed proportion in the first five treatments was 60%, while in the remaining treatments it was 70%. The oat hay and PM were mixed with the concentrate feed as a total mixed ration (TMR). Laboratory experiments were then conducted to Parameters estimated included methane production (CH₄), Metabolizable energy (ME), net energy (NE), microbial protein (MP), and short-chain fatty acids (SCFA). The results revealed that the inclusion of PM at 100% of the roughage portion with concentrate-to-forage ratios of 60:40 and 70:30 led to a decline in ME, NE, MP, SCFA, and CH₄. In contrast, increasing the concentrate level to 70% with 30% roughage improved ME, NE, MP, SCFA, and CH₄ values. Furthermore, replacing AF with 75% PM at both concentrate levels enhanced the studied parameters compared to other substitution levels.