Effects of feeding crude glycerin on feedlot performance and carcass characteristics in finishing goats

Twenty-four crossbred male (Thai Native × Anglo Nubian) weaned goats (17.4 ± 2.8 kg of initial BW) were used to assess the effect of the dietary supplementation of crude glycerin (CG) for corn grain on performance, carcass traits, muscle chemical composition, fatty acid profile, and blood metabolites. Four isocaloric and isonitrogenous diets were offered to the experimental animals (6 goats per treatment) for 91 days using randomized completely block design. The goats individually received dietary treatments containing 0, 5, 10, and 20% of CG (87.61% pure) on a DM basis. The diets were offered ad libitum as total mixed rations twice daily. Weight gain and concentrations of blood metabolites were determined. At the end of the experimental period, the harvest data and carcass characteristics of the goats were recorded, and muscular longissimus dorsi (LD) composition was determined. No significant effect of CG inclusion was observed in any of the growth performance, carcass, and meat quality traits studied. Likewise, mean serum glucose and BHBA concentrations were not affected (P > 0.05) by dietary treatments whereas serum insulin concentration linearly increased (L, P = 0.02) with increasing the amount of CGLY supplementation. Also, no apparent effects on FA composition were detected, except for C15:0, C16:0, C16:1, and C22:5n-3 were affected (P < 0.05) by CG level. We conclude that crude glycerin can be used as substitution for corn grain up to the level of approximately 20% of dry matter in the diets of finishing goats, and this study was a good approach in exploiting the use of biodiesel production for goat production.