Telling the Grass-Fed Beef Story

Dr. John Comerford
Associate Professor and Extension Beef Specialist
Department of Dairy and Animal Science
The Pennsylvania State University

Beef customers are being told many things about their food these days.  The advertisements for beef products shout this product is safer, this one is healthier, this one is better for the environment, and many other claims of value.  Mary Lou Quinlan, founder of the marketing company Just Ask a Woman, told attendees at the Food System Summit 2010 about research conducted from January to June indicating that the pressures of a bad economy, media stories about unsafe food, confusing and misleading labels and even friends questioning their food choices on Facebook all figure into beef purchase decisions. How can a customer sort all of this out and determine the real value they want in their beef ? Many of these attributes are placed on grass-fed compared to grain-fed beef.

The reality is there is no evidence whatsoever that grass-fed beef has any advantage for safety, human health, or impact on the environment than grain-fed beef. Both types of beef deliver the important factors of nutrition in the human diet of protein, iron, and zinc in equal proportions.

On the environmental front, studies by Yan et al (2009) in Ireland used growth chambers to evaluate the greenhouse gas emissions from cattle with varying levels of forage and grain in the diet.  Coupling these results with a 30% increase of harvest age of grass-fed cattle compared to grain-fed, it becomes clear there is a 500% increase in greenhouse gas emissions for each pound of beef produced from grass-fed compared to grain-fed cattle. Uncontrolled nitrogen and phosphate release to the environment, 35% more water use, and 30% more land use for grass-fed cattle compared to grain-fed increases the environmental impact of strictly grass feeding. A model reported by Canadian workers (Janzen et al, 2008) accounts for carbon loss from fossil fuels for corn production and other factors of production for both grass- and grain-fed cattle and shows the added efficiency of animal production and resource use from intensive grain feeding will reduce the collective environmental impact of grain-fed compared to grass-fed beef.

Two usual claims for grass-fed compared to grain-fed beef are that there is a greater content of conjugated linoleic acid or CLA, which was shown to decrease tumor growth in mice in laboratory studies, and that the grass-fed product is lower in cholesterol.  Cholesterol content has never been different in grass- or grain-fed beef.  That is just a convenient rumor that got started. Cholesterol does not follow fat content, and foods higher in cholesterol than beef, like shellfish, eggs, and venison, often have very little fat. There also are some legal issues for false labeling of cholesterol content that can get people in trouble.

The ‘potent anti-carcinogen’ CLA story may be one of the biggest hoaxes played on the consumer because the values used to differentiate grass-fed from grain-fed beef are from raw meat.  Samples of raw grass-fed beef consistently have twice the CLA content as a proportion of total fat than samples from raw grain-fed beef.  This means the typical grass-fed steak has the same CLA content as a Certified Angus Beef ®, heavily grain-fed steak because there would typically be twice as much total fat in the CAB steak. However, this is all irrelevant because studies show when the meat is cooked, there is no difference in CLA content because a large amount of the fat is lost in cooking.  Even if people ate the meat raw, you would have to eat 176 pounds of grass-fed beef daily to get the level fed to the mice in the original CLA study (Ha et al, 1987).  It also should be noted that in the original CLA study 16 of the 20 mice getting huge doses of CLA still got cancer. The dosage of CLA from this study would have to be increased 182,000 times for an equivalent dose to an average person. The whole CLA story has been based on these 4 mice, making this result irrelevant to human health.

Similarly, the Omega-6 to Omega-3 fatty acid ratio is an important feature of fat intake in humans. The recommended daily intakes of Omega-3  fatty acids from the World Health Organization of 1.1 to 1.6 grams/day show it would require a person to eat 4 1/2 pounds of cooked grass-fed beef daily to meet the minimum daily requirement.  Therefore, any speculation that eating grass-fed beef will enhance human health due to Omega-3 fatty acid consumption is clearly incomplete at best, and usually false.

Consumer science studies show food safety is important to consumers, and it is an important feature of food buying decisions.  The advertisements for grass-fed beef that claim there are no chances of E. coli infection in humans from grass-fed beef are scary and dangerous, and not because this is a threat to traditional beef products. It is dangerous because it gives consumers a false sense of security. In the case of E. coli, this contamination happens in a processing plant and has nothing to do with how or where the animal was raised.  Cattle in all types of environments- feedlots and pasture- have been shown to have the virulent form of E. coli in their digestive tract, and it requires the special care that is taken in beef processing plants to prevent meat contamination. It also requires consumers to use safe handling and cooking methods common to all foods for their safety, and these false claims do not diminish that need.

Grass-fed beef will usually be leaner with less fat in the edible portion than grain-fed beef, and this is due to less marbling, or the intramuscular flecks of fat measured in the ribeye steak.  The conflict for beef customers and producers is that consumer studies indicate the desirable factors of tenderness, juiciness, and flavor-generally described as “quality” by consumers-are highly related to marbling content.  One has to be careful what is described as ‘lean’ because leanness will be relative to marbling content in the edible portion of the meat. Consumers generally describe a steak as “fat” when it has a large amount of exterior or subcutaneous fat left on it. Since the consumer seldom eats this fat or it is cut off in the processing phase, little attention is given to the real source of fat in beef steaks-marbling. As the marbling content is increased, we increase the amount of saturated and other fats in the edible portion. Studies also show steaks can be too lean because it will not be as desirable to consumers. We walk a fine line between keeping the product lean and making it a desirable eating experience. Premium grain-fed beef such as Certified Angus Beef ® must meet a high standard of marbling content, and few grass-fed cattle can meet this standard.  We have no idea if the higher levels of marbling-resulting in high Choice and Prime quality grades-in grass-fed meat have a positive relationship to eating satisfaction. One small study showed it may actually be negative because of the influence on meat flavor.

It is very important that we have grass-fed beef as a choice for beef consumers because these are often consumers that do not buy other types of beef.  However, the enterprise cannot be sustainable and engage new customers if it is based on false and misleading information.  There are many other important factors for beef –buying decisions we can use to promote the grass-fed product.  Locally-produced, animals raised in a pasture environment, source verification, and others are very important features of beef that consumers value. Grass-fed beef can capitalize on many of these attributes without some of the deception going on now.

4 thoughts on “Telling the Grass-Fed Beef Story


    Happy feedlot (CAFO) cattle, eating to their heart’s content. Also for your information, cattle on feedlot diets never eat grain alone but Totally Mixed Rations (TMRs) that contain roughage, even on the final finishing diet. That manure you are bemoaning Brie is collected in lagoons that then are pumped to provide a natural source of fertilizer to neighboring fields. And yes, I’ve been through several feedlots, including large Texas feeders, during my education in veterinary medicine and I can assure you that the cattle there are very content. Very interesting article Dr. Comerford.

  2. You say: “However, this is all irrelevant because studies show when the meat is cooked, there is no difference in CLA content because a large amount of the fat is lost in cooking.”

    Yet I find that statement contradicted here: “The major changes in fatty acid composition, which implicated 16 out of 34 fatty acids, resulted in higher percentages in cooked beef of SFA and MUFA and lower proportions of PUFA, relative to raw meat, while conjugated linoleic acid (CLA) isomers revealed a great stability to thermal processes. Heating decreased the PUFA/SFA ratio of meat but did not change its n−6/n−3 index. Thermal procedures induced only slight oxidative changes in meat immediately after treatment but hardly affected the true retention values of its individual fatty acids (72–168%), including CLA isomers (81–128%).”

    Meat Science, Volume 84, Issue 4, April 2010, Pages 769-777

    I’m curious to hear your source for your statement about CLA.

    Also, you do not discuss the difference in the ratio of n-3 to n-6 fatty acids in grass-fed vs. grain-fed beef. We know that high intake of n-6 fatty acid (linoleic acid specifically) is linked to weight gain and cancers in animals and humans. Wouldn’t eating foods reflecting a more normal balance of n-3 to n-6 seem wise in light of that?

  3. There is no question the emissions data are true. This feature of the rumen has been recognized for a long time and is simply Nature in action. The Irish study was done to provide the actual measurements without bias since all the gas going in the chamber and all the gas produced by the animal in the chamber can be quantified. The point about carbon sequestration is well taken and was not a part of the discussion, except noting the Canadian work that is using a model to compare the systems on a unit of food produced. This is the only reasonable way to make such comparisons because absolute numbers are just used for propaganda. However, this is only one feature in a matrix of issues that influence the environment. The notion that carbon sequestration is the only important environmental issue for concern in agriculture is a narrow view of a much larger picture. Everyone, including the academic community, must start connecting all the dots so there is a way to meet the need to double food production in this country in the next 40 years.

    You should check your science on tenderness. Genoytpically, tenderness has a hertitability of about 0.3in most studies. However, phenotypically, tenderness can be skewed by a range of 100% or more by environmental effects. Animal age, chilling rate of the carcass, thawing methods of frozen meat, aging of carcasses, cooking methods, etc. etc. will influence meat tenderness at consumption. Secondly, the same piece of meat can have a tenderness rating with a variability of more than 20% from different consumers. I hope you are referring to shear value as the measure of tenderness. There are clear data to show diets high in forage compared to those high in grain will biologically reduce the inherent tenderness of meat based on shear value. Anibal and I have spoken on several occasions about how we and the folks in Argentina manage tenderness, and he and I have shared data on a number of occasions. I do not know what marbling study you are referring to, but he and I have not disagreed on this issue and we have both garnered important features of production from each other.

    Your mention of Certified Angus Beef includes a common misconception about this product. CAB has nothing to do with the Angus breed of cattle. “Angus” as labeled on meat is meat that meets a standard for marbling score, quality grade, and the coat color must be 75% black with no visible signs of Brahman influence. Purebred Simmental, Limousin, Gelbvieh (and many other breeds) and their crosses with other breeds are all eligible to be labeled CAB and are. Obviously, a Hereford/Angus steer can easily be labeled as CAB. The key is the standard of middle Choice or higher. This has been found to be a significant threshold grade for eating satisfaction of tenderness, juiciness, and flavor for consumers.

    I am not sure I understand your comment about finishing grain and grass-fed cattle. Grain fed cattle are always paid for by the content of the meat (quality and yield grade) and not by the weight. Fat is fat whether it is from grain or grass. As I noted the scientific scrutiny of these fats shows there is no difference in them or the actual amount is so minimal to be insignificant in the cooked product. The so called “healthier” aspects of grass-fed meat is simply dreaming. If one chooses to eat less fat in their beef, then the grade and marbling will necessarily be reduced. Sorry, but we can’t have it both ways.

    Please recall I am a preponent of this enterprise, but the enterprise has supported itself far too long with false and misleading information. There has for a long time been a void in the information for producers and consumers about grass-fed beef, and that void has been filled with something for sale. We now have many of the unbiased comparisons to rely on to make production and marketing decisions. It is time for the enterprise to embrace these facts, move forward with them, and make the enterprise sustainable for the future.

  4. It is very easy to espouse such claims as you make here and the Ireland study makes when you ignore many other studies. The Ireland study for instance ignores the ability of the land in use to sequester carbon. Even with the increase in emissions, it that is true, grassfed operations are still carbon positive and feedlot settings are carbon negative, meaning that there is a positive atmospheric result from grassfed operations and damage to the atmosphere from feedlots. Whether grassfed beef provides all that the WHO says we need for Omega-3’s or not doesn’t really matter. You will still consume more Omega-3’s from grassfed beef than from grain fed beef and study after study has born this to be true for those studies that use true empirical data instead of 27 subjects. I would think as a scientist you would want to know what is true and not just try to prove what you believe to be true. By the way, there is a study that clearly disproves your marbling hypothesis done by Dr. Anibal Pordomingo. Tenderness is an issue and is generally a result of genetics not grain or grass. I do agree with you thought that there are some producers out there that are claiming grassfed only for marketing sake and their product is inferior at best. These folks do need to start caring about the food they produce and not just the money they can make but you and I are not going to stop them, we just have to out educate them! Certified Angus by the way means nothing other than good advertising by the AAA (American Angus Assoc) although, Angus is a british breed and those breeds do tend to rank highest for tenderness but Angus is not the only british breed with this characteristic.

    One more thing, I don’t believe that grassfed beef should be much leaner than grain fed beef. First, grain fed beef is too fat but this is the result of a system that pays by the pound regarless of what that pound is made of, the fatter and heavier the better – which I don’t agree with. I know with proper genetics and education on finishing, grassfed cattle are every bit as fat as grain feed animals and yet will have a much healthier make up than grain fed.

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