Partial replacement of corn grain with levels of crude glycerin on feed intake, digestibility, ruminal fermentation, nitrogen utilization, and performance of feedlot lambs

This study aimed to evaluate the effects of replacing corn grain with increasing levels (0, 50, 100, 200 g kg⁻¹ of dry matter) of crude glycerin (GLY) on feed intake, digestibility, ruminal fermentation, nitrogen utilization, blood glucose and performance of male lambs fed a high-concentrate diet. Five castrated adult rumen-cannulated male lambs (30.3 ± 3.12 body weight) were used in a 5 × 5 Latin square design to evaluate metabolism parameters. Forty lambs (22.3 ± 3.8 kg body weight) were used in a randomized block design for performance evaluation. Diets contained 25 g kg⁻¹ sugarcane bagasse (Saccharum officinarum L.) and 75 g kg⁻¹ concentrate. There was a quadratic effect (P = 0.03) of GLY on the intakes of DM and neutral detergent fiber (P = 0.01). Increasing GLY levels did not affect (P > 0.05) nutrient digestibility and decreased linearly (P < 0.01) the ruminal acetate. Ruminal propionate, acetate: propionate ratio, and the efficiency of microbial protein synthesis were quadratically affected (P < 0.05) by GLY levels. Feeding GLY at 150 g kg⁻¹ DM increased microbial efficiency but did not affect lamb performance and feed conversion (P > 0.05). The partial replacement of corn grain with crude glycerin at 150 g kg⁻¹ DM did not adversely affect the intake and digestibility of nutrients and nitrogen utilization, nor did it impact body weight gains. Therefore, it can be considered as an alternative method to optimize feed costs while maintaining performance in finishing lambs fed a high-concentrate diet.