Partial Replacement of Corn with Jackfruit Silage Maintains Productive Performance and Carcass Characteristics of Feedlot Lambs

Dependence on corn may increase feed costs and supply vulnerability in tropical livestock systems. This study evaluated replacing corn with whole-fruit jackfruit (Artocarpus heterophyllus Lam.) silage in feedlot lamb diets. Sixteen castrated male Santa Inês crossbred lambs (26.2 ± 3.6 kg) received diets in which jackfruit silage replaced 0, 333, 666, or 1000 g/kg of corn dry matter in the concentrate. Jackfruit silage had lower non-fibrous carbohydrate gas volume (132.9 vs. 182.9 mL), degradation rate (0.081 vs. 0.096 h−1), and total carbohydrate gas volume (238.5 vs. 298.2 mL) than corn (p < 0.05). Dry matter intake increased linearly, whereas organic matter digestibility, final body weight, and total weight gain decreased linearly as replacement increased (p ≤ 0.011). Feed conversion ratio increased from 6.6 to 12.3 kg dry matter intake/kg gain. Nevertheless, 333 g/kg replacement maintained 98.5% of final body weight and 96.0% of total weight gain. Carcass yields and Longissimus muscle area were unaffected. One-third replacement reduced corn use by 26.2% per kilogram of gain while maintaining productive viability. Jackfruit silage is therefore a strategic partial, rather than complete, substitute for corn in tropical sheep diets.