The Cow-Calf Manager, September 2002

Livestock Update, September 2002

John B. Hall, Extension Animal Scientist, Beef, VA Tech

Commodity Feeds May Keep Cow-Calf Operations Going
The continued drought, limited hay supplies, and rising corn prices will make feeding the cowherd through the fall and winter a challenge. However, the continuing liquidation of cows in the West and movement of heifers into feedlots indicate that producers that can hold on to their herds will be rewarded with better calf prices in 2003 and 2004. The cowherd needs to be maintained with economical feedstuffs for the next 6 to 8 months.

Commodity feeds such as brewer's grains, corn gluten feed or soy hulls can offer economical options for cow-calf producers. These products are excellent cattle feed, but vary greatly in price, water content and nutrients. Because of this tremendous variability in several factors it is often difficult to compare different commodity feeds. Producers need to be careful to compare commodity feeds on an equal basis. The value of commodity feeds need to be on:

1. Amount of dry matter
2. Cost per pounds of nutrients
3. Animal intake factors
4. Handling and storage considerations

The first step is to obtain a nutrient analysis of the commodity from the supplier. This should include dry matter (DM), crude protein (CP), and total digestible nutrients (TDN). Information on mineral content is also helpful to the extension professionals or nutritionists that will help producers design a feeding program. Sometimes estimates of energy content or TDN are not given in the standard analysis instead fiber content will be listed. Because of the variable nature of some commodities estimates of TDN from fiber may not be entirely accurate. Ask for a minimum TDN level to be specified.

Secondly, compare commodities on a dry matter basis. Commodity feeds range from 79% water for wet brewer's grains to 10% water (90% DM) for corn gluten feed. To compare the price of commodities on a DM basis use the following formula:

Cost per ton on DM basis = Cost per ton as delivered ÷ (% DM/100)

For example, a producer can buy wet brewer's grains for $25 per ton delivered or dry corn gluten feed for $100 per ton delivered. Which is the better buy on a dry basis?

Cost of wet brewer's grain on a DM basis
= $ 25 ÷ (21/100)
= $25 ÷ .21
= $ 119.05

Cost of corn gluten on a DM basis
= $ 100 ÷ (90/100)
= $100 ÷ .9
= $111.11

In this case, corn gluten would be the better buy costing $ 8 less per ton than wet brewer's grain on a DM basis. But feeds need to supply nutrients not just dry matter.

Energy is the nutrient that is most needed by the cowherd after water. So, to supply energy to the cowherd is the main reason producers buy supplemental feeds. In addition, most commodity feeds contain levels of crude protein above the requirements of the cow, so for all practical purposes most commodity feeds are equal to each other in terms of protein. Simply comparing the cost of feeds on a DM basis would not be a fair comparison. Producers need to compare feeds on TDN content of the dry feed (DM basis). To do this, divide the cost of the feed on a DM basis by the % TDN of the feed (DM basis) as in the following formula:

Cost per ton of TDN (energy) = Cost per ton on a DM basis ÷ (% TDN/100)

Using the same feeds from the above example, wet brewer's grains contain 85% TDN whereas dry corn gluten feed contains 80% TDN. Which is the better buy on a dry basis?

Cost of wet brewer's grain per ton of TDN
= $ 119.05 ÷ (85/100)
= $119.05 ÷ .85
= $ 140.06

Cost of corn gluten per ton of TDN
= $ 111.11 ÷ (80/100)
= $111.11 ÷ .8
= $ 138.89

Because of the energy level of the brewer's grains these two feed are less than $2.00 per ton difference on an energy basis. However, all commodity feeds are variable in their nutrient content even from load to load from the same plant. If the brewer's grains in the above example were only 70% TDN, then the cost per ton of energy would be over $170.00. Over a $30 difference between the two feeds. The bottom line is test the feeds and buy them based on a dry energy basis.

Three, animal intake and digestion factors also must be considered. Brewer's grains are very high in water content and young cattle are not physically able to eat enough brewer's grains to meet their needs. Even for cows, very wet commodities should not make up more than 50 to 70% of the diet.

Fiber is also a very important consideration. Cows need sufficient fiber to keep the rumen working properly. Commodities such as soyhulls and corn gluten contain high levels of easily digestible fiber, so they can be fed as a high percentage of the diet. In comparison, brewer's grains, hominy and snack food by-products are lower in fiber, so producers need to be careful when feeding these commodities not to feed too much. In most cases, cows will still need 5 to 10 lbs of hay per day.

The true digestibility for some commodity feeds may be less than indicated by nutrient analysis. Research from NC State indicates that the performance of young growing cattle was only 84% to 88% of predicted performance when corn gluten was the primary energy supplement. Similarly, performance of calves fed brewer's grains was only 90% to 95% of expected gains. Producers need to keep these considerations in mind when selecting different commodity feeds.

Finally, transportation and storage of commodities may dictate which feeds can be used by a particular operation. Wet feeds have a very short storage life during warm weather, some only a few days. Large amounts of wet commodity feeds may not work for smaller operations, while large operations may need deliveries 2 to 3 times per week. Also, commodities can be bulky and not flow well in traditional grain storage structures and handling equipment. Often a bunker or covered commodity shed is needed. Visit with other producers that are using the commodity feed you are interested in to get information about storage and handling.

Commodity feeds will probably keep many operations in business this year. A careful comparison of these feeds on a dry nutrient basis with consideration to storage and handling is important. Work with your extension animal science agent or nutritionist on a feeding program for your herd. Tests for prussic acid are available through the state diagnostic labs or other laboratories. Forages should contain less than 50mg% on a dry basis to be safe to feed. Pasture samples need to be taken fresh and frozen. Remember summer annuals may also be high in nitrates. For more information on prussic acid poisoning in livestock or sampling procedures contact your county extension agent.

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