Buying Supplements

February 2012

pregnant cows in pasture Questions seem to arise that go something like the following: I (the producer) know my cows that are in late gestation and grazing dormant native range are deficient in protein, what protein source is my best buy?

One of the challenges is that supplement costs, when priced on a ton basis, may look a lot alike price-wise, but the supplements under consideration may differ in protein content and that's where part of the confusion comes from. In addition, another confusing aspect many times is the protein supplements being considered differ in moisture content, so that throws another wrench into the pricing process.

To make direct comparisons of these supplements, purchase the supplements on a per pound of nutrient basis. If the cows are deficient in protein, then protein supplements can be purchased on a cost per pound of protein basis. The same thought process can be used if energy (TDN), or phosphorus, or any nutrient for that matter is needed to supplement the base diet.

Accounting for the differences in moisture content of different supplements may seem, at first, difficult to account for. As an example, what are the steps to take to compare two protein supplements if the protein supplement options are a 30% crude protein cube that is 90% dry matter and 10% water and wet distillers grains that is 30% crude protein and is 35% dry matter and 65% water. The easiest way to account for the differences in moisture content is to convert both feeds to 100% dry matter basis.

In this example, if both protein supplements are priced on a ton basis, determine the pounds of actual feed, not water, being purchased. The amount of actual feed of the 30% protein cube that is being purchased per ton is 1,800 pounds. This is calculated by multiplying 2,000 pounds times the dry matter content of the cube (2000 lb x 0.90 = 1,800 pounds).

To determine the amount of wet distillers grains being purchased, the same calculations can be used. If the wet distillers grains is priced on a ton basis, then 700 pounds of distillers grains (excluding the water) on a dry matter basis is purchased (2,000 lb x 0.35 = 700 pounds).

The next step is to determine the amount of actual protein in each of these feeds that could be used as a protein supplement. Both supplements are 30% crude protein on a dry matter basis. The amount of protein purchased for the 30% cube is 540 pounds and is calculated by multiplying the amount of dry matter times the protein content (1,800 pounds x 0.30 = 540 pounds).

The same procedure can be used to determine the amount protein in wet distillers grains that is purchased and is 210 pounds of protein (700 pounds x 0.30 = 210 pounds of protein).

After the amount of actual protein purchased is determined, calculating the price per pound of protein is relatively simple. In this example, if the 30% protein cube is priced at $200 per ton, divide price per ton by pounds of protein purchased in a ton on a 100% dry matter basis. For the 30% protein cube, the price per pound of protein is $0.37 per pound of protein ($200/540 lb = $0.3703). If wet distillers grains is priced at $78 per ton, then the price per pound of protein is $0.37 per pound of protein ($78/210 lb = 0.3714). In this example, there is really no difference in price per pound of protein for these supplements.

The price of both supplements was priced delivered to your ranch. It is assumed that the ranch has the equipment to deliver both supplements to the cows. This is an important consideration for the supplements selected as the ranch has to have the ability to deliver it to the herd.

Feed Cost Calculator

The University of Nebraska has developed an Excel Spreadsheet to help producers determine the cost of feeds on a price per nutrient basis. The "Feed Cost Cow-Q-Lator" is available on the West Central Research and Extension Center Ag Economics Decision Aids page.

Again, Microsoft Excel is needed to open the spreadsheet. The spreadsheet has instructions and they can be accessed by clicking on the "Instructions" tab at the bottom of the spreadsheet. Feeds are entered one at a time. To enter the first feed, click on tab "F1". To enter the second feed, click on "F2" to open up a new spreadsheet and to enter information on the second feed. More feeds can be entered by clicking on the "F" tabs at the bottom of the spreadsheet. Inputs for the spreadsheet include:

  • Price of the feed or supplement
  • The price is for how many pounds
  • What is the dry matter content
  • Nutrient (percent protein or energy) content on a dry matter basis

The spreadsheet asks for other items that help in determining true costs on a nutrient basis and include:

  • How far is the feed being transported
  • What is the cost per loaded mile
  • Estimate the percentage of the feed that will be lost during hauling
  • Is there any cost to store the feed
  • Storage loss (percentage)
  • Cost to feed this feed
  • Feeding losses (percentage

When the inputs have been entered into the spreadsheet, it will calculate:

  • Purchase Cost of Nutrient
  • Delivered Cost of Nutrient
  • Feed Cost of Nutrient
  • Consumed Cost of Nutrient

Dr. Rick Rasby Dr. Rick Rasby, Professor of Animal Science
Animal Science, University of Nebraska–Lincoln, Lincoln, NE