Performance and carcass characteristics of finishing goat kids fed diets containing crude glycerin
The crude glycerin (co-product of biodiesel) has the potential to partially replace corn, because glycerol (an 80% constituent of crude glycerin) is converted to propionate in the rumen and acts as a precursor for hepatic glucose synthesis. However, most studies focus on the sheep and beef cattle, while limited research exists evaluating crude glycerin in the diet of goat kids. Therefore, the objectives of this trial were to determine the effects of partial replacement of corn by crude glycerin on performance and carcass characteristics of goat kids. Twenty crossbred Boer goat kids (initial BW of 17.08 ± 2.1 kg and 110 d old) were used in a randomized complete block design according to initial BW and age. Kids were penned individually during 51 d and fed an isonitrogenous (14.0 ± 0.2 CP, DM basis) diet composed of 70% of concentrate and 30% of forage (coastcross hay). Increasing levels of crude glycerin (80.0% glycerol, DM basis) were 0, 4, 8, or 12% corresponding to the experimental diets G0, G4, G8 and G12, respectively. Orthogonal polynomials for treatment responses were determined by linear, quadratic, and cubic effects. Effects were declared significant at P < 0.05 and trends are discussed between P > 0.05 and P < 0.10. Body weight (BW), average daily gain (ADG), G:F, dry matter intake, protein intake and ether extract intake were not affected by glycerin as a replacement for ground corn. Dry matter intake was 0.58, 0.65, 0.54 and 0.59 kg/d while ADG was 106, 106, 90 and 94 g for G0, G4, G8 and G12, respectively. The NDF intake tended (P = 0.08) to decrease linearly. Carcass characteristics (hot carcass weight, hot carcass yield and subcutaneous fat thickness) were unaffected by crude glycerin addition. Adding up to 12% crude glycerin to finishing kids does not affect the performance and carcass characteristics.
Keywords: Boer, cost of production, growth