Effect of Replacing Alfalfa Hay with Common Vetch Hay in Sheep Diets on Growth Performance, Rumen Fermentation and Rumen Microbiota.

Simple Summary: Using homegrown forage instead of imported alfalfa hay (AH) improves animal productivity and reduces feed costs, but the benefits of feeding high-quality common vetch hay (CVH) to lambs are not clear. This study aimed to determine the effect of replacing alfalfa hay with common vetch hay on growth performance, rumen fermentation, and rumen microbiota of fattening lambs. The results showed that substitution of AH by CVH in ruminant diets result in improvements in fattening performance and economic efficiency and a reduction in the methane produced per unit of ADG, thereby resulting in advantageous in decreasing reliance on imported AH. The aim of this study was to determine whether the inclusion of 40% of common vetch (CV) hay as a feed ingredient in place of alfalfa hay (AH) would improve performance and ruminal fermentation and microbiota in fattening lambs. Twenty lambs were equally divided into two groups: control group (fed 40% AH with 20% rice straw) and CV group (fed 40% CV hay with 20% rice straw). Concerning hay quality, CV hay had greater in vitro digestibility of dry matter and neutral detergent fiber (p < 0.05) than AH. Lambs fed the CV diet had a higher average daily gain (ADG) and efficiency of feed and economy than lambs fed the control group. The NH₃-N content and estimated methane produced per unit of ADG of the CV diet group were significantly lower (p < 0.05) than control group. Multiple differential microbial genera were identified, with Prevotella being the most dominant genus and a tendency towards higher (p = 0.095) in lambs offered CV diet. The higher Ruminococcus abundance (p < 0.05) was found in animals of the CV group compared to the control group. In summary, CV can be incorporated into lamb diets as a low-cost forage alternative to AH to improve feed efficiency and animal performance and to reduce methane produced per unit of ADG. [ABSTRACT FROM AUTHOR]