Table 2.
Composition and nutrient profile of bloat-provocative diets offered to heifers during a 28-d experimental period
| Day of the experimental period | |||||
|---|---|---|---|---|---|
| Item | 0 to 2 | 3 to 5 | 6 to 8 | 9 to 11 | 11 to 28 |
| Ingredients, % (as-fed basis) | |||||
| Grass hay (chopped) | 75 | 50 | 25 | 15 | 0 |
| Pellet2 | 25 | 50 | 75 | 85 | 100 |
| Nutrient profile1 (dry matter basis) | |||||
| Dry matter, % | 92.9 | 91.8 | 90.6 | 90.1 | 89.4 |
| Crude protein, % | 11.4 | 14.1 | 17.0 | 18.1 | 19.9 |
| Neutral detergent fiber, % | 58.7 | 44.6 | 30.2 | 24.3 | 15.4 |
| Acid detergent fiber, % | 36.7 | 28.7 | 20.4 | 17.0 | 11.9 |
| Starch, % | 16.6 | 24.3 | 32.2 | 35.5 | 40.4 |
| Net energy for maintenance, Mcal/kg | 1.24 | 1.50 | 1.77 | 1.88 | 2.04 |
| Net energy for growth, Mcal/kg | 0.669 | 0.902 | 1.143 | 1.241 | 1.39 |
| Ca, % | 0.670 | 0.731 | 0.795 | 0.821 | 0.860 |
| P, % | 0.283 | 0.399 | 0.518 | 0.566 | 0.640 |
| Mg, % | 0.149 | 0.169 | 0.189 | 0.197 | 0.210 |
| K, % | 1.70 | 1.53 | 1.35 | 1.28 | 1.17 |
| Na, % | 0.149 | 0.236 | 0.326 | 0.363 | 0.418 |
| Fe, mg/kg | 246 | 272 | 298 | 309 | 325 |
| Zn, mg/kg | 48.3 | 67.0 | 86.2 | 94.1 | 106 |
| Cu, mg/kg | 14.7 | 21.6 | 28.7 | 31.6 | 36 |
| Mn, mg/kg | 73.7 | 75.4 | 77.2 | 77.9 | 79 |
| Mo, mg/kg | 1.32 | 1.35 | 1.37 | 1.38 | 1.40 |
| Co, mg/kg | 0.639 | 0.925 | 1.218 | 1.338 | 1.52 |
| Se, mg/kg | 0.183 | 0.299 | 0.418 | 0.466 | 0.540 |
1Containing (as-fed basis) 58.1% of cracked sorghum (Sorghum bicolor L.) grain, 21.4% of dehydrated alfalfa hay, 15.5% of soybean meal, 2.5% liquid molasses, 2% mineral mix, and 0.5% pellet binder. The mineral mix contained 14% Ca, 7% P, 13% NaCl, 0.27% K, 0.4% Mg, 0.25% Cu, 0.003% Se, 0.99% Zn, 90.91 IU/kg of vitamin A, 9.09 IU/kg of vitamin D3, and 0.045 IU/kg of vitamin E (Purina Animal Nutrition, Shoreview, MN).
2Analyzed via wet chemistry procedures by a commercial laboratory (Dairy One Forage Laboratory, Ithaca, NY). Calculations for net energy for maintenance and growth used the equations proposed by the NRC (2000).
3Calculated with the following equations (NRC, 2000): net energy for maintenance = (1.37 × ME) – (0.138 × ME2) + (0.0105 × ME3) – (1.12); net energy for gain = (1.42 × ME) – (0.174 × ME2) + (0.0122 × ME3) – (0.165); ME = (0.82 × DE); 1 kg of TDN = 4.4 Mcal of DE. Given that ME = metabolizable energy, DE = digestible energy, TDN = total digestible nutrients calculated based on the study by Weiss et al. (1992).