Research Article
Continuous and Long-Term Measurement of Reticuloruminal pH in Grazing Dairy Cows by an Indwelling and Wireless Data Transmitting Unit
Table 1
Mean reticuloruminal pH during feed changeover (phases 1–7), feed intake, and nutrient contents.
| | Mean | | | | Phases | | | | P-value | SEM1 | | | Phase 1 | Phase 2 | Phase 3 | Phase 4 | Phase 5 | Phase 6 | Phase 7 |
| Mean pH value | 6.43 | 6.58a | 6.54ab | 6.49ab | 6.46ab | 6.40abc |
6.34bc | 6.19c | 0.006 | 0.15 | 68.98 | SEM1 | 0.19 | 0.15a | 0.17a | 0.24b | 0.21ab | 0.19ab | 0.18ab | 0.19ab | 0.502 | 0.07 | 29.95 | 24-h minimum pH | 6.01 | 6.23 | 6.19 | 5.93 | 5.99 | 6.00 | 5.93 | 5.75 | 0.054 | 0.202 | 56.89 | t < pH 6.3 (min/d) | 491 | 258 | 321 | 417 | 448 | 436 | 675 | 884 | 0.053 | 308 | 56.89 | t < pH 6.0 (min/d) | 89 | 6a | 6a | 148a | 71ab | 55ab | 68ab | 261b | 0.226 | 165.98 | 43.62 | t < pH 5.8 (min/d) | 28 | 0a | 0a | 53b | 23ab | 10ab | 11ab | 96b | 0.688 | 97.6 | 29.89 | t < pH 5.5 (min/d) | 2 | 0a | 0a | 1a | 5a | 0a | 0a | 6a | 0.848 | 8.28 | 23.74 |
| Feed intake | | | | | | | | | | | | Hay (kg DM/d) | 3.6 | 3.9 | 3.7 | 3.7 | 3.7 | 3.7 | 3.7 | 2.7 | 0 | 0.09 | 99.14 | Grass Silage (kg DM/d) | 3.7 | 7.8 | 3.6 | 4.1 | 3.1 | 3.7 | 3.6 | 0 | 0 | 1.60 | 81.74 | Concentrate (g/kg DM) | 1.8 | 2.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.3 | 0 | 0.08 | 98.26 | Pasture (g/kg DM) | 9.7 | 0 | 10.1 | 9.9 | 11.0 | 10.3 | 10.6 | 15.9 | 0 | 1.46 | 95.1 | Daily DMI (kg DM) | 18.8 | 14.4 | 19.2 | 19.5 | 19.6 | 19.5 | 19.6 | 19.9 | 0 | 0.77 | 94.75 |
| Nutrient contents | | | | | | | | | | | | Crude protein (g/kg DM) | 147 | 133 | 150 | 146 | 148 | 147 | 146 | 158 | 0 | 1.33 | 98.39 | Fiber (g/kg DM) | 211 | 240 | 210 | 212 | 206 | 209 | 208 | 188 | 0 | 7.42 | 91.96 | Energy (MJ NEL/kg) | 6.41 | 5.99 | 6.44 | 6.41 | 6.48 | 6.43 | 6.44 | 6.67 | 0 | 0.09 | 92.58 | NDF (g/kg DM) | 414 | 454 | 405 | 415 | 407 | 413 | 416 | 391 | 0.130 | 8.55 | 93.08 | ADF (g/kg DM) | 234 | 275 | 231 | 235 | 227 | 232 | 231 | 208 | 0 | 10.12 | 91.31 | ADL (g/kg DM) | 30 | 34 | 29 | 30 | 29 | 30 | 30 | 27 | 0 | 0.72 | 95.98 |
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a–cLeast squares means within a row without a common superscript differ significantly ().
1SE of least squares means.
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