Abstract
<title>Abstract</title> <p> The use of unconventional feed resources offers a practical strategy for mitigating feed shortages and reducing feeding costs in small-ruminant production systems. This study evaluated the effects of replacing commercial concentrate with water hyacinth ( <italic>Eichhornia crassipes</italic> ) on nutrient utilization, growth performance, and economic returns in Doyogena sheep and Woyito-Guji goats. Twenty-four yearling intact males (12 sheep and 12 goats) were assigned to a 2 × 4 × 4 randomized crossover design comprising two species, four dietary treatments, and four feeding periods. Treatments consisted of natural grass hay offered <italic>ad libitum</italic> and commercial concentrate replaced by water hyacinth at 0% (T1), 25% (T2), 50% (T3), and 75% (T4) on a dry matter basis. Species and dietary treatment significantly affected nutrient intake, digestibility, and growth performance (P < 0.05). Sheep consumed more dry matter, organic matter, digestible crude protein, and metabolizable energy than goats (P < 0.001), resulting in greater average daily gain (ADG) and body weight gain (P < 0.05). Conversely, goats exhibited higher apparent digestibility coefficients of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber (P < 0.001). Increasing water hyacinth inclusion significantly reduced nutrient intake, digestibility, ADG, and feed conversion efficiency (P < 0.05). ADG declined from 88.1 to 58.7 g/day in sheep and from 75.4 to 36.1 g/day in goats across treatments. Economic analysis showed that increasing water hyacinth inclusion reduced feed costs and improved net income, with the highest returns at 75% replacement (1,323.7 ETB/head for sheep and 1,067.4 ETB/head for goats). Water hyacinth can replace up to 75% of commercial concentrate, although replacement levels of 25–50% are preferable when maximizing animal performance. </p>