1675
Crude Glycerin as an Energy Source in Finishing Beef Diets
The objective of this study was to evaluate the effects of replacing dry ground corn with crude glycerin (CG) on DMI, digestibility, performance, and carcass characteristics of finishing beef bulls. An experiment in a completely randomized design with 25 d for adaptation and 95 d for sample collection was conducted, in which 3,640 Nellore bulls (367 ± 37 kg) were blocked by BW and assigned to 20 pens. Animals were randomly assigned to one of four treatments: 0, 5, 10, and 15% (DM basis) CG in diet. All diets contained 85% concentrate and were formulated to meet NRC (2000) recommendations. Diets were isocaloric, isonitrogenous, and allowed 1.4 kg/d BW gain. Initially, 20 animals were slaughtered to serve as reference to estimate initial empty BW, which allowed carcass gain calculation. Bulls were weighted at the beginning and end of the experiment for performance calculation. Measurements of ribeye area (RA), back fat (BF) and rump fat (RF) were obtained by ultrasound. Data were analyzed using the mixed procedures in SAS, and results are reported in the Table 1. Intake of DM decreased linearly (P < 0.01) with CG inclusion. A quadratic effect was observed (P < 0.01) for DM and TDN digestibility. However, CG inclusion did not change (P > 0.10) ADG, final BW, carcass gain, carcass dressing, feed:gain ratio, RA, BF, and RF. These results suggest that CG may be included in finishing beef cattle diets without affecting performance and carcass characteristics.
Keywords: Glycerin, Feedlot, Performance
Table 1. Effects of replacing dry ground corn with crude glycerin on DMI, digestibility, performance, and carcass characteristics in finishing beef bulls.
|
Crude Glycerin (%) |
SEM |
P-value |
||||
0 |
5 |
10 |
15 |
L |
Q |
||
DMI, kg/d |
10.5 |
10.1 |
10.2 |
9.6 |
0.15 |
< 0.01 |
0.60 |
DMI, % BW/d |
2.4 |
2.4 |
2.3 |
2.22 |
0.14 |
< 0.01 |
0.42 |
DM Digest., % |
62.6 |
60.2 |
64.1 |
69.7 |
0.86 |
- |
< 0.01 |
TDN Digest., % |
69.9 |
67.2 |
71.1 |
75.8 |
0.78 |
- |
< 0.01 |
ADG, kg/d |
1.41 |
1.37 |
1.35 |
1.34 |
0.02 |
0.20 |
0.77 |
Final BW, kg |
510.1 |
498.7 |
503.8 |
497.1 |
2.18 |
0.19 |
0.45 |
Carcass gain, kg |
89.2 |
84.2 |
82.7 |
83.1 |
1.41 |
0.33 |
0.07 |
Carcass dressing, % |
56.9 |
56.7 |
56.6 |
56.5 |
0.33 |
0.64 |
0.92 |
Feed:gain |
7.5 |
7.5 |
7.6 |
7.2 |
0.11 |
0.47 |
0.42 |
RA, cm3 |
83.0 |
82.2 |
82.1 |
80.9 |
0.40 |
0.06 |
0.88 |
BF, mm |
4.6 |
4.4 |
4.4 |
4.5 |
0.08 |
0.04 |
0.04 |
RF, mm |
6.6 |
6.4 |
6.4 |
6.4 |
0.06 |
0.09 |
0.25 |