For rumen animals such as cattle and sheep, use raw potatoes. One of the most successful methods of storing and feeding potatoes is to ensile them with a roughage source such as ground alfalfa or other hays. Choking has not been reported as a problem when potatoes are packed into bunker silos and allowed to ferment for two or more weeks. For desirable fermentation, the dry matter of the feeds in the silo should be 35-45 percent. Since potatoes are high in moisture, for proper fermentation add dried feeds to lower the dry matter level of the silo pack. Success has been reported with mixes of 400-500 pounds of dry hay and a ton of potatoes. The resulting mix will contain 33-38 percent dry matter. Dan Hinman of the University of Idaho suggests a blend of 80 percent potatoes, 16 percent dry ground hay (300 to 350 pounds per ton of potatoes), and 4 percent ground grain (80 pounds). The dry hay will soak up any excess moisture in the potatoes.
When this mix is ensiled, it will have about the same nutrient content as corn silage. Analysis of the mixture after ensiling would indicate how to use it most effectively in a total ration. Dry freezing will absorb most of the excess moisture in raw potatoes. For open-air drying by freezing, spread potatoes two to three inches deep in a field or pasture (Wilson, 1950). Potato tubers will shrivel to hard little lumps and keep indefinitely. Cattle readily eat them in the summer. To sun dry raw potatoes, chop tubers into one inch chunks or strips, spread in a thin layer and pick them up when dry.
Due to rapid fermentation in the rumen, higher levels of fiber in the diet may be advisable if high levels of potatoes are fed to ruminant animals. It is important that potatoes be introduced to ruminants gradually. Initially no more than eight pounds per head should be fed in a mixed ration and then increased only in four- to five-pound increments every other day until the desired level is reached. After the bacteria in the rumen have adapted to potato starch in the diet, the animals should be fed at a constant level (Aldrich, 1979). If potatoes are not fed for four to five days, they should be gradually reintroduced.
Potatoes should be cooked for monogastric animals such as swine.
SUPPLEMENTS for CATTLE and SHEEP
Supplements designed for corn diets may be used for diets containing potatoes. If high levels of potatoes are fed in moderate roughage diets, calcium may need to be supplemented. The most economic source of calcium would be calcium carbonate or feed-grade limestone. When phosphorus exceeds calcium in the diet, urinary calculi (water belly) may be a problem.
Feeding 60-70 pounds of potatoes provides less than half the daily protein requirement for cattle; therefore, one pound of a protein supplement containing 40-50 percent crude protein or three pounds of alfalfa needs to be added. Also, since potatoes are low in fiber, hay should be added for a source of roughage. Alfalfa hay would also be an excellent complimentary source of minerals, especially calcium. A suggested supplement for rations with high amounts of potatoes might contain molasses, urea, limestone, dicalcium phosphate, magnesium oxide, vitamins A, D and E, and/or a trace mineral pre-mix containing manganese, iron, zinc, copper, iodine, and cobalt. Ration guides are given for cattle in Table 3 and for sheep in Table 4. Protein supplement requirements decrease with better hay quality.
Note: A nutritionist can calculate specific rations based on ingredient analysis and livestock requirements.
Figure 2. Potatoes are ground for livestock feed and then emptied into a waiting truck.
Figure 3. Ground potatoes ready to be mixed and ensiled, depending on the final feed needed.
References:
- Aldrich, S. 1979. Potatoes (D.M.) compare with corn. Feedlot management Feb:52.
- Wilson, J. 1950. How to feed those low-grade spuds. Root Crops 5:37.
Using Potato as Livestock Feed