Animal feeds under ruminant production are a challenge, and ruminants are mostly fed on fibrous plants including high-moisture plant by-products (HMPBs). These HMPBs are available during the food processing periods and cannot be fed entirely in their fresh form. These resources are conserved in the form of silage for future feeding. Silage-making entails the anaerobic preservation of forages with the aid of additives that reduce the pH of the ensiled materials and preserve the forage. Most silage research work focuses mainly on the preservation of forages/plants, with less attention on HMPBs. This review focuses on the silage production from HMPBs (e.g., pulps/pomaces), challenges involved in the ensiling of these resources, use of additives (e.g., chemical additives), and growth performance of ruminants fed silage from these resources. This review will assist farmers from developing countries who rely on HMPBs as sources of animal feed.