Table 3.
Effect of diet composition investigated in 3 experiments on the rumen pool size before and after feeding determined by rumen evacuation
| Experiment | Prefeeding | Postfeeding | SEM | P-value Time1 |
|---|---|---|---|---|
| 1: Fiber2 | ||||
| Rumen pool, kg | ||||
| DM | 19.9 | 25.5 | 1.5 | <0.001 |
| NDF | 13.6 | 16.5 | 1.0 | <0.001 |
| iNDF1203 | 7.9 | 8.5 | 0.6 | 0.02 |
| ADF | 7.2 | 8.5 | 0.5 | <0.001 |
| Starch | 2.2 | 3.4 | 0.2 | <0.001 |
| Lignin | 1.5 | 1.7 | 0.1 | <0.001 |
| Rumen composition, % | ||||
| NDF | 69.5 | 64.7 | 0.9 | <0.001 |
| iNDF120 | 39.6 | 33.7 | 0.7 | <0.001 |
| ADF | 36.5 | 33.4 | 0.4 | <0.001 |
| Starch | 10.9 | 13.3 | 0.4 | <0.001 |
| Lignin | 7.5 | 6.8 | 0.1 | <0.001 |
| 2: Starch4 | ||||
| Rumen pool, kg | ||||
| DM | 17.5 | 23.4 | 1.0 | <0.001 |
| NDF | 10.3 | 12.4 | 0.7 | <0.001 |
| iNDF120 | 6.3 | 7.2 | 0.4 | <0.001 |
| Starch | 0.9 | 2.0 | 0.1 | <0.001 |
| Rumen composition, % | ||||
| NDF | 58.9 | 52.8 | 1.3 | <0.001 |
| iNDF120 | 36.3 | 30.8 | 1.1 | <0.001 |
| Starch | 4.7 | 8.4 | 0.3 | <0.001 |
| 3: Fatty acids5 | 4.7 | 8.4 | 0.3 | <0.001 |
| Rumen pool, kg | ||||
| DM | 12.2 | 15.6 | 0.53 | <0.001 |
| NDF | 6.8 | 7.9 | 0.25 | <0.001 |
| iNDF2406 | 3.5 | 3.9 | 0.15 | 0.02 |
| ADF | 4.5 | 5.2 | 0.17 | <0.001 |
| Starch | 0.6 | 1.5 | 0.08 | <0.001 |
| Lignin | 1.1 | 1.2 | 0.05 | <0.001 |
| Rumen composition, % | ||||
| NDF | 57.0 | 51.2 | 0.41 | <0.001 |
| iNDF240 | 29.6 | 25.1 | 0.82 | <0.001 |
| ADF | 37.6 | 33.8 | 0.45 | <0.001 |
| Starch | 4.8 | 9.1 | 0.37 | <0.001 |
| Lignin | 8.9 | 7.8 | 0.23 | <0.001 |
Treatment effects have been previously published in Oba and Allen (2000) for experiment 1, Oba and Allen (2003) for experiment 2, and Harvatine and Allen (2006) for experiment 3. No treatment by time interactions occurred for any responses (P > 0.05).
A 2 × 2 factorial design of brown midrib (BMR) and isogenic conventional (CONV) corn silage in a high- (38%) or low-NDF (29%) diet. Rumen evacuations were preformed 2 h before and 2 h after feeding at 1200 h.
iNDF120 = indigestible NDF, estimated as fiber remaining after 120 h of in vitro ruminal fermentation.
A 2 × 2 factorial design of dry ground (DG) and high-moisture ground (HM) corn in a high- (32%) and low-starch (21%) diet. Rumen evacuations were preformed 4 h before and 4 h after feeding at 1400 h.
CON = no-supplement fat control; SFA = prilled saturated fatty acid supplement (Energy Booster-100, Milk Specialties Inc., Eden Prairie, MN) at 2.5% of diet DM; UFA = calcium salts of unsaturated fatty acids (Megalac-R, Church and Dwight Co. Inc., Ewing, NJ) at 2.5% of diet DM; MIX = 50:50 mixture of SFA and UFA at 2.5% of diet DM. Rumen evacuations were preformed 2 h before and 4.5 h after feeding at 0900 h.
Indigestible NDF, estimated as fiber remaining after 240 h of in vitro ruminal fermentation.