Livestock is a major component of agriculture, and a continuous supply of nutritious forage/fodder is necessary for sustainable livestock production. Zinc (Zn) deficiency is a global concern for human as well as animal health, but Zn fertilisation for productivity and biofortification of forages is not well understood. Therefore, a 2-year field study was conducted to investigate the influence of soil-applied ZnSO₄ on morphological traits, yield, nutritional quality and Zn biofortification in four forages. The grass forages (oat, barley, annual ryegrass and triticale) were factorially combined with four levels of soil-applied ZnSO₄ (0, 5, 10 and 15 kg ha^-1) and two harvesting stages (booting and 50% heading). The treatments were arranged in a triplicate randomised complete block design with a split–split plot arrangement where grass forage species were kept in main plots, ZnSO₄ application in subplots and harvest stage in subsub plots. ZnSO₄ fertilisation significantly improved morphological traits, dry-matter yield, crude protein, acid detergent fibre (ADF) and shoot Zn concentration in all grass forages at both harvesting stages. Best performance for yield, quality traits, and Zn contents across all crops was observed where ZnSO₄ was applied at 15 kg ha^-1 and harvested at 50% heading stage. The highest economic returns were provided by triticale and annual ryegrass with 15 kg ZnSO₄ ha^-1 harvested at 50% heading. In conclusion, for a profitable forage production with good nutritional quality and Zn biofortification, triticale and annual ryegrass may be recommended with a 15 kg ZnSO₄ ha^-1 fertilisation.