Table 7.
Effects of adding polyethylene glycol (PEG) to steer ration containing high sorghum tannins on urinary nitrogenous components.
| Item | PEG, g/kg DM |
SEM |
P-value |
|||||
|---|---|---|---|---|---|---|---|---|
| 0.00 | 1.75 | 3.50 | 7.00 | T | L | Q | ||
| Urea, mmol/d | 1,333.7b | 1,399.5ab | 1,620.4a | 1,635.4a | 84.35 | 0.044 | 0.010 | 0.783 |
| Urea N:urinary N ratio, % | 59.0 | 60.6 | 70.1 | 68.9 | 3.57 | 0.073 | 0.028 | 0.723 |
| Uric acid, mmol/d | 2.5 | 2.7 | 2.7 | 3.3 | 0.36 | 0.501 | 0.407 | 0.698 |
| Uric acid N:urinary N ratio, % | 0.2 | 0.2 | 0.2 | 0.3 | 0.03 | 0.664 | 0.514 | 0.751 |
| Allantoin, mmol/d | 66.3 | 73.2 | 65.1 | 78.5 | 4.54 | 0.163 | 0.249 | 0.557 |
| Allantoin N/urinary N ratio, % | 5.9 | 6.3 | 5.7 | 6.6 | 0.40 | 0.343 | 0.469 | 0.517 |
| Creatinine, mmol/d | 78.5 | 87.8 | 77.4 | 91.3 | 5.21 | 0.176 | 0.242 | 0.664 |
| Creatinine N/urinary N ratio | 5.2 | 5.7 | 5.0 | 5.8 | 0.35 | 0.353 | 0.540 | 0.684 |
| Hippuric acid, mmol/d | 144.3 | 145.8 | 147.7 | 146.7 | 20.46 | 0.999 | 0.927 | 0.955 |
| Hippuric acid N:urinary N ratio, % | 3.2 | 3.1 | 3.2 | 3.1 | 0.43 | 0.999 | 0.969 | 0.997 |
| PD, mmol/d | 68.8 | 75.9 | 67.7 | 81.8 | 4.70 | 0.158 | 0.217 | 0.531 |
| Estimated rumen microbial N, g/d | 29.6 | 35.7 | 28.5 | 36.9 | 3.68 | 0.299 | 0.446 | 0.786 |
SEM = standard error of the mean; N = nitrogen; PD = purine derivatives; T = treatment; L = linear; Q = quadratic.
a, b Within a row, means without a common superscript differ significantly (P < 0.05).