Megacal System of Measuring Cattle Performance

Introduction

Texas Beef has a cattle performance measuring system that is a superior alternative to the feed conversion system in establishing a uniform and accurate yardstick for measuring cattle performance. This system, designed in 1982 by W.H. O'Brien and Dr. E.S. Erwin, established a relative energy value for each ingredient in the ration based on established proven feed values. The sum of these values determines a ration energy value on an as fed basis. Units of energy accrue to each lot in direct proportion to the pounds of feed posted to the lot. When the cattle are closed out and the net gain established, the total megacalories (units of energy fed to the cattle) is divided by the gain to offer the new performance standard. Mega/# gained. This system is not to be confused with the NEm and NEg method of computing gain from consumption.

Finding the Energy Value of the Feed

Using N.C.R. tables for each ingredient for the NEm and NEg, the energy of the complete ration is determined on an "as fed" basis. This illiminates the need for moisture conversion calculations at a later point. To arrive at the relative energy value of the ration, we used the mean of the NEm and NEg. This value closely approximates the "therm" system in establishing a relative energy value to the ration. If a top ration has an NEm of 77 and NEg of 50, then the energy value would be 63.5 megacalories for each 100 pounds of feed.

Putting the Megacalorie System to Work

These energy units accrue to a lot of cattle and for each 100 pounds of feed that is fed to the cattle, 63.5 megacalories are added to the megacalorie record in the computer. During the course of a lot history in the feedyard, the total megacalories are accumulated until the final shipment. The total megacalories is then divided by the net pounds gained to determine the megacalories per pound gained. This figure will be stored in history to be available for industry or historical comparisons. Moreover, this barometer will be available for future projections of performance of similar cattle at similar times of the year.

Megacalories Versus Conversion

Why change? The conversion method is an old and accepted method and will probably continue to be used by some people. Conversion would be an ideal system is one could be assured that all feeders would use the same ration from year to year. The fault with the conversion system is the inability to differentiate between the relative feed and energy values of different ingredients. If we compare our performance this year, feeding wheat and alfalfa to last year feeding milo and cotton burrs, it would appear from conversion that we have significantly improved performance. In the same way a ration showing a very poor conversion result can be made to look very good with 4% fat. The conversion figure does show the energy value of the feed, but does not give the management the ability to put all criteria back to a common ground so the management can be measured. Conversion measures cattle performance, the magacalorie system offers a systematic method for gauging your current performance to the industry and to your own history, without being affected by changing ration energies.

Experience

We are now entering our fourteenth year of megacalorie history. We have found this system to offer the best and most accurate means for evaluating performance and expressing reliable performance predictions.

Beginning in the fall of 1984 we started predicting performance based on breed, background, and the historic number of megacalories that particular class of cattle to put on one pound of feed. By taking that figure and multiplying by the current cost per megacalorie we arrived at cost of gain. An example of the sytem at work is shown below.

ASSUMPTIONS:

FEED COST		$100.00/TON
FEED VALUE		63.5 MEGACALORIES
HISTORICAL MEG REQ	5.3MEG/LB.GN.1
COST/MEGA		.0782
NO.1 X STEER		700 LB
MONTH PLACED 		OCTOBER
CALCULATION  		5.3 X .O78 = .4133

**NOTE: Based on our history, (1) a 700lb. steer requires 5.3 megacalories for each pound gained, (2) a ration costing $5.00 cwt divided by 63.5 megacalories = .078 cents/megacalorie, and (3) the 5.3 is the megacalorie required times .078, the cost per megacalorie to arrive at a projected cost gain of .413.

 

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