Comparing feed costs
It is getting increasingly expensive to feed sheep, goats, and other livestock. Even if you grow your own feed, there can be significant costs, including opportunity costs (i.e. selling the feed vs. feeding it). All producers should know how to compare feed costs and balance least-cost rations for their livestock.
Feedstuffs are priced according to different units of measure: bushels, tons, pounds, or bales. Bales come in many different sizes. Thus, the first step in comparing feed costs is to convert prices to an equivalent unit, usually pounds, ton or hundred weight (cwt). For example, barley that sells for $3 per bushel has a price equivalent of $0.0625 per pound ($3/bu ÷ 48 lbs/bu). Hay that costs $5 per bale costs $0.125 per pound ($5/bale ÷ 40 lbs/bale), assuming the bales average 40 lbs. Lighter bales will increase the per pound cost of the hay. For this reason, hay should always be purchased by weight (ton) -- not volume (bale).
Livestock feed rations are balanced on a "dry matter" basis, whereas feedstuffs are priced “as-is,” meaning that a portion of the weight of the feedstuff is moisture (water). Because the dry matter content of feedstuffs can vary significantly, prices must be converted to a dry matter (DM) basis. This is especially important when you are comparing relatively dry feeds (hays and grains) with high moisture feedstuffs, such as silage, haylage, green fodder, and various by-products.
To the determine the dry matter cost of a feed, all you have to do is divide the price of the feedstuff by its dry matter content (% DM). Barley (grain) is 89% dry matter, so its dry matter cost is $0.071 per pound ($0.063/lb ÷ 89% DM). Conversely, hydroponic fodder contains only 12% dry matter. At a cost of $0.05 per pound (as-is), its dry matter cost is $0.417 per pound ($0.05/lb ÷ 12% DM), making it a quite expensive feedstuff, though its initial per lb. cost was low (0.05/lb).
Livestock do not require certain feedstuffs; they require nutrients (protein, energy, minerals, and vitamins) in specified amounts. Feedstuffs vary considerably in the amount of protein, energy, and other nutrients that they contain. For this reason, the cost of providing a certain nutrient is the basis on which feedstuffs are compared.
To determine the cost of a nutrient, you divide the feed's dry matter cost by the percent nutrient in the feed. Continuing with our barley example, barley (grain) provides TDN (energy) at a cost of $0.085 per pound ($0.071/lb ÷ 84% TDN) whereas the cost of TDN in alfalfa hay is $0.245 per pound ($0.142 ÷ 58% TDN) and $0.587 per pound ($0.417 ÷ 71% TDN) for the more expensive hydroponic fodder.
Similar calculations can be made for protein and other nutrients. Soybean meal is usually the most economical source of protein. In this example, soybean meal provides protein at a cost of $0.45 per pound (0.219 ÷ 0.49).
The cost of a feedstuff needs to include its delivery cost to the farm. Another factor which will affect the cost of different feedstuffs is the degree of feed wastage. Some feeds have practically no wastage, whereas others can have signficant feed loss. Feeding method can have a large effect on feed wastage. Feeds that are improperly stored can lose substantial nutritive value.
In these examples, grains (barley and corn) and silage are the most economical sources of energy (TDN) for sheep and goats. Soybean meal is the most economical source of protein. This will not be the case for every geographic location or farm. Different feedstuffs are available at different prices at different locations. To determine which are the most economical sources of nutrients for your farm, similar calculuations need to be made with available feedstuffs and their prices.
In order to compare the cost of nutrients of some feedstuffs, you should have them analyzed to determine their nutritive content. While grains and oilseeds have fairly consistent nutrient levels ("book" values can be used in calculations), forages and by-product feeds can vary signficantly in their nutritive values. For example, alfalfa hay can vary anywhere from 10 percent to more than 20 percent protein, depending upon when it was harvested for hay.
You can use this Excel spreadsheet to compare the nutrient costs of different feedstuffs: http://www.sheepandgoat.com/spreadsheets/CompareNutrientCosts.xlsx.
Cost is not the only factor to consider when evaluating feedstuffs. There may be limitations as to how much of a feedstuff can be fed. For example, corn silage is a very economical source of nutrients, but a high-producing animal may not be able to eat enough of it to meet its nutritional requirements -- due to its high moisture content.
Feedstuffs need to be combined to create a ration that is 100 percent nutritionally balanced for the livestock being fed. Care must be taken not to create any dangerous imbalances.
Some feedstuffs contain high levels of certain minerals, which limits their inclusion in diets. For example, dried distiller's grains contain high levels of sulfur. Sulfur binds with copper and limits its absorption. Urea can only replace a portion of the protein in the diet.
There may be other factors to consider when evaluating feedstuffs. Some feedstuffs are more costly on a per pound basis, but may have other advantages that are difficult to put an economic value on. Nutritional tubs are a perfect example. Their direct cost of nutrients is very expensive, but they are great labor-savers.
Hydroponic fodder is also a very expensive source of nutrients, but it is a means of providing green forage year-round. Commercial feeds are expensive, but 100% nutritionally-balanced and available in convenient 50-lb. bags.
While feed costs in this article are realistic, they are for example purposes only. Feed prices and their relationships to each other are constantly changing. One may be a more economical feedstuff now might be a more expensive option at another time. They are also different at different locations (county, state, or country).
References
Table 15-11. Composition of Common Feedstuffs. Nutrient Requirements of Small Ruminants (NRC 2007)
Table 12. Feed Composition Guide. Sheep Production Handbook (2002).
Forage reports (barley fodder). Fodder Pro (FarmTek)
This article was updated in 2015 by Susan Schoenian.