Table 1. Changes in 24 hr mean ruminal pH, duration of time <5.6 and 5.8, total VFA, individual VFA proportions, acetic acid-to-propionic acid ratio, and LPS activity in weaning calves during weaning transition.
| Items | Weaning group (n=7) | SEM | ||||
|---|---|---|---|---|---|---|
| Week −1 | Week 0 | Week 1 | Week 3 | |||
| 24 hr mean ruminal pH | ||||||
| Minimum | 5.76 | 5.78 | 5.96A) | 6.16a) | 0.17 | |
| Mean | 5.36 | 5.38 | 5.70a) | 5.73a) | 0.10 | |
| Maximum | 6.42 | 6.23 | 6.43 | 6.58 | 0.24 | |
| Duration of ruminal pH | ||||||
| pH<5.6, min/d | 72.4 | 60.4 | 40.6 | 28.1 | 22.6 | |
| pH<5.8, min/d | 154.0 | 167.6 | 103.0 | 67.0a) | 66.6 | |
| Total VFA (mmol/dl) | 10.36 | 9.9 | 10.67 | 11.72 | 1.51 | |
| Individual VFA (%) | ||||||
| Acetic acid | 56.9 | 56.3 | 58.0 | 57.2 | 2.97 | |
| Propionic acid | 28.9 | 29.4 | 28.2 | 27.9 | 3.61 | |
| Butyric acid | 9.8 | 9.3 | 8.4 | 9.8 | 1.11 | |
| Others1) | 4.5 | 5.1 | 5.4 | 5.1 | 0.51 | |
| A/P ratio | 2.3 | 2.1 | 2.4 | 2.4 | 0.41 | |
| LPS (EU ×104/ml) | 13.0 | 14.0 | 14.8 | 16.0 | 7.71 | |
1) Volatile fatty acid (VFA) components that exclude acetate, propionate, and butyrate from total VFA. a, A) denotes significant difference (P<0.05 and 0.10, respectively) compared with the Week −1.