Grass-Fed Beef Summary

On October 8^th and 10^th, 2002, seven half-Mashona steers from Weaver Ranch near Causey, New Mexico, were harvested at Texas Tech University’s Meat Sciences Laboratory at Lubbock, Texas. The steers had been on native grass pasture with no supplemental feed. 

Five of the steers were approximately 30 months old, and the other two were approximately 24 months old. The older steers averaged 1191 lb. live weight, and 685 lb. hot carcass weight, for a dressing percentage of 57.5%, with a ribeye area of 11.7 in² and a final yield grade of 2.16. The two younger steers were somewhat smaller at 948 lb. live weight and 549 lb. hot carcass weight, for a dressing percentage of 57.9 %. The younger steers averaged 9.25 in² ribeye area and brought in a final yield grade of 2.12. Four of the steers were quality graded as Standard Plus, two were graded as Select Plus, and one was graded Choice.

The sides of beef were aged for 21 days at the Texas Tech Meat Lab before being processed into the various cuts. The carcasses were cut to maximize the “value added cuts”, allowing more tender and valuable cutlets to be separated from ordinarily “tough” cuts such as chuck or round.

The five older steers averaged almost 306 lbs. of boneless steaks and roasts, with another 168 lbs. of lean trim and 38 lbs. of trimmed fat. The younger steers averaged 245 lbs. of boneless cuts, 128 lbs. of lean trim and 24 lbs. of fat. Part of the lean trim was packaged as fajita or stew meat, and the remainder was mixed with a portion of the fat for ground beef.

Texas Tech Meat Lab staff kept a ribeye steak from each animal for analysis. A trained Sensory Panel was assembled and given samples of each steak in a blind taste test. Panel members rated each sample on the basis of: Initial Juiciness, Sustained Juiciness, Initial Tenderness, Sustained Tenderness, Flavor Intensity, Beef Flavor, Overall Mouth-feel and Off Flavor. All categories are rated from 1 to 8. Eight is the best in all categories, except Off Flavor in which 1 is the best rating.

These results were a little lower than we had gotten from a test of feedlot grain-fed half-Mashona steers in the Spring 2002, except for the categories of Flavor Intensity and Beef Flavor, where the grass-fed steers scored significantly higher, achieving .2 to .3 points more than their grain-fed brothers.

The Texas Tech Meat Lab staff also performed the Warner/Bratzler Shear Test (WBS) for tenderness. In this test, uniform cores of cooked meat are removed from each sample, and subjected to a measured shear force. The kilograms of force required to shear the sample are recorded. Six lean meat cores from each steak are tested, and those results are averaged to make the WBS score for each animal. A reading of 3.0 kg or lower has been found to be 100% acceptable to the consumer on the basis of tenderness.

We believe our results on the grass-fed beef to be very good. The seven samples averaged 2.81 kg. Our highest (toughest) sample had a score of 3.3 kg, while our best sample had a score of only 2.2 kg. The highest reading from any of the individual shear tests was 4.4 kg, and our lowest individual reading was 1.3 kg.

Following these pleasing findings, we began to search the Internet for comparable beef studies.
At http://ansci.colostate.edu/ran/beef/2002/pdf/mrg02.pdf, we found “Comparison of the Palatability of Five Different Beef Product Lines” by M.R. Genho, K.E. Belk, J.A. Scanga and G.C. Smith.

In this study, the authors compared USDA commodity Choice and Select loin steaks to:
  Brand A – an upper 2/3 Choice branded beef line,
  Brand B – a lean branded beef line, and
  Brand C – a guaranteed tender branded beef line.
Comparisons were made on the basis of Warner/Bratzler Shear tests and taste tests by a trained Sensory Panel. For the purposes of this report, we have converted their WBS scores from pounds into kilograms.

The Sensory Panel used in the study rated the following categories on the basis of 1 to 8 (8 is the best reading): Juiciness, Fiber Tenderness, amount of Connective Tissue, Overall Tenderness and Flavor Intensity.

• In Juiciness, the panel rated the samples from 5.6 to 6.1. The average for our grass-fed samples’ readings for Initial Juiciness and Sustained Juiciness was almost 5.9.

• In Overall Tenderness, the panel from this study rated their samples from 5.8 to 6.5. The average from our grass-fed animals’ readings for Initial Tenderness and Sustained Tenderness was just over 5.8.

• In Flavor Intensity, this panel rated their samples from 5.4 to 5.8. Our Sensory Panel result for Flavor Intensity on our grass-fed beef was 6.48.

In the Warner/Bratzler Shear tests, the study reported Mean WBS scores ranging from 2.7 kg for Brand A to 3.4 kg for Brand B. We feel that our score of 2.81 kg, from cattle fattened on native grass, is very good.

The minimum WBS scores from the study ranged from 1.9 kg to 2.2 kg, with our lowest grass-fed result being the sample with a 2.2 kg reading. On the tougher end, however, our results were outstanding. The highest WBS scores from the study ranged from 4.3 kg all the way up to 5.1 kg. The highest score by any of our grass-fed samples was only 3.3 kg. In fact, in all of the individual tests on our samples, the highest single reading on any grass-fed core was only 4.4 kg.

As a part of our on-going research into grass-feeding, in March 2003, we had a Fatty Acid Profile run on each of the seven grass-fed carcasses at the University of Wyoming’s Department of Animal Sciences. Staff there prepared a lean meat core sample out of ribeye steaks we sent to them. Each sample was analyzed to determine which fatty acids were present in the samples, and in what amount.

When we scheduled these tests, we were most interested in the levels of Conjugated Linoleic Acid (CLA) and fatty acids Omega-6 (18:2) and Omega-3 (18:3). Current research is confirming the health benefits of CLA in the diet, and of the beneficial effects of getting a diet with the proper balance of Omega-6 to Omega-3, i.e. a ratio ranging from 4:1 to 1:1, rather than the imbalance provided by grain-fed beef, in which the ratio can be 20:1.

We were encouraged by finding our ratios of Omega-6:Omega-3 in the 3:1 to 4:1 range, but also a little surprised by another of the findings of the fatty acid profile. The staff at the laboratory told us that they had found unusually high readings for the fatty acids created by the animal as marbling (16:0, 18:0, and 18:1c9). They had not expected readings this high from grass-fed cattle with no supplemental feed. The staff also reported seeing substantial marbling in the steaks during sample preparation.

Mashona bulls from Weaver Ranch sired each of the seven steers. The dams were mostly Angus or Brangus commercial cows. The Mashona is a sanga type of Bos indicus from southern Africa. Our seed stock was imported as embryos from a carefully selected group of donors in Zimbabwe beginning in 1995. The Mashona were reported in Zimbabwe to be known to put on marbling before back fat. This would help to explain our outstanding results, first in grain-fed half-Mashona feedlot steers, and now in grass-fed half-Mashona steers.

As we approach another harvest season for grass-fed beef, we continue to enjoy the wonderful product we have, even while we research ways to make it better.

For more information on the health benefits of grass-fed beef we suggest you look at www.eatwild.com. For more information on Mashona cattle, visit www.AmericanMashona.com. For more background information on grass-fed beef, visit www.MilnesandGrassfedBeef.com. For pricing and availability of individually vacuum-packed and frozen USDA inspected beef packages or to reserve a full or partial beef to be processed to your specifications visit our link Prices & Products.

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