Studies with readily degradable fiber sources as energy supplements for grazing and forage-fed ruminants have yielded different responses than research with grains (Caton and Dhuyvetter, 1997). Soybean hulls result in only a small decrease in forage intake (Martin and Hibberd, 1990; Grigsby et al., 1992). Other sources of readily degraded fiber such as wheat midds, beet pulp, and corn gluten feed have generally not decreased forage intake as much as grain-based supplements (Caton and Dhuyvetter, 1997).
Many fibrous feeds also have high energy values. A list of fibrous feeds that offer potential for replacing hay or traditional grain sources is presented in Table 14. Research suggests that these products may actually perform better than these numbers would indicate.
| Table 14. Protein, Fiber, and Energy Values of Selected Feedstuffs. | ||||
|---|---|---|---|---|
| Feed | CPa (%) |
NDFb (%) |
NEmc (Mcal/lb) |
NEd (Mcal/lb) |
| Corn | 9.8 | 10 | 1.02 | 0.70 |
| Beet Pulp | 9.7 | 54 | 0.79 | 0.52 |
| Citrus Pulp | 6.7 | 23 | 0.91 | 0.61 |
| Corn Gluten Feed | 25.6 | 45 | 0.92 | 0.62 |
| Cottonseed, Whole | 23.0 | 44 | 1.09 | 0.77 |
| Dried Brewers Grains | 25.4 | 46 | 0.68 | 0.41 |
| Soybean Hulls | 12.1 | 67 | 0.65 | 0.39 |
| Wheat Middlings | 18.4 | 37 | 0.73 | 0.45 |
| a Crude Protein b Neutral Detergent Fiber c Net Energy Maintenance d Net Energy Gain | ||||
Replacing Hay With a Digestible Fiber Various researchers have conducted winter feeding experiments to determine the feasibility of using digestible fiber in lieu of hay as a winter feed. In one study, cows were grazed on stockpiled tall fescue and fed hay (tall fescue) ad-libitum when pasture became limiting. Feeding four pounds of soybean hulls from December through March saved approximately 625 pounds of hay per cow and resulted in less body weight loss (13 pounds) than feeding hay only (86 pounds). Estimating hay costs at $80 per ton and soybean hull costs (delivered) at $80 per ton, more than $6 per cow was saved by feeding soybean hulls.
Cottonseed hulls are very palatable but are low in nutrient content. Cottonseed hulls should be considered a source of roughage rather than a supplemental source of energy or protein.
Replacing Corn With a Digestible Fiber Other work has been done using digestible fibers as a replacement for corn. In one study steers were maintained on tall fescue. One set of steers was fed four pounds of soybean hulls and another set was fed four pounds of corn while on grass. A third set of steers received no supplement. The steers gained similarly on soybean hulls and corn (two-pounds-per-day gain), with both being greater than the gain of steers that were not supplemented (1.5-pounds-per-day gain). Digestible fibers appear to be beneficial as a supplement for growing animals that are grazing or fed hay, compared with high-energy feedlot diets.