Rehydrated Corn Grain Silages with Different Rehydration Sources: Nutrient Utilization in Growing Goats and Ruminal Responses in Sheep

Ensiling ground corn after rehydration improves its conservation and increases starch susceptibility to ruminal degradation, potentially replacing costly chemical preservatives. Three complementary experiments were conducted. Intake, ingestive behavior, and blood parameters were evaluated in 32 growing goat kids; nutrient digestibility and N-balance were evaluated in 24 growing goats; and ruminal parameters and in situ degradability were assessed in four rumen-cannulated, castrated male Santa Inês sheep (30.4 ± 6.0 kg) using a 4 × 4 Latin square design, evaluating the replacement of ground corn (GC) with rehydrated GC silage using water (RCSwater), cactus pear cladode mucilage (RCSmucilage), or whey (RCSwhey). Dry matter intake was higher (p < 0.05) with RCSmucilage than with RCSwhey, whereas crude protein and neutral detergent fiber intakes were lower (p < 0.05) with RCSwhey than with GC and RCSmucilage. The proportion of ingested N excreted in urine was lower in goats fed GC and similar for rehydrated silages. RCSmucilage resulted in the highest N intake and lowest N-fecal/N-intake ratio and ruminal pH. RCSwhey also resulted in the lowest ruminal N-NH3 concentration. Overall, RCSmucilage showed potential to replace ground corn at 415 g/kg diet in growing goats based on nutrient intake, digestibility, and N-utilization responses. Ruminal measurements obtained in cannulated sheep provided complementary information on the evaluated corn sources and should not be directly extrapolated to growing goats. Future studies should validate these responses across animal species and production conditions and test other rehydrating additives.