Consumers’ reasons for buying beef from “grass-fed” cattle vary and are based mainly on perceptions, including promotion of animal health and well-being, environmental sustainability, and/or production of meat products with a changed nutritional profile.
Reducing the external carcass fat of beef has been one of the most important breeding goals for the U.S. beef industry during the last 30 years. The studies show that beef fat deposition is highly heritable. As such, the total fat content may differ significantly among breeds.
As a result, the total fat content of beef is affected not only by the feeding regime but also genetic variability between cattle breeds, harvest age, carcass grade, and beef cut. However, the way cows are fed can considerably affect the nutrient composition of their beef.
The term grass-fed isn’t clearly defined.
That said, grass-fed cows eat (mainly) grass, while grain-fed cows eat (mainly) an unnatural diet based on corn and soy during the latter part of their lives.
Many studies have shown that cattle finished on pasture produce higher quantities of Vitamin E in the final meat product than cattle fed high concentrate diets.
Antioxidants such as vitamin E protect cells against the effects of free radicals. Free radicals are potentially damaging by-products of metabolism that may contribute to the development of chronic diseases such as cancer and cardiovascular disease.
Cattle produced under extensive grass-based production methods usually have carcass fat which is more yellow than their concentrate-fed counterparts caused by carotenoids from the lush green forages. Although yellow carcass fat is negatively regarded in many countries worldwide, it has been related to a healthier fatty acid composition and increased antioxidant content.
Carotenes (mainly β-carotene) are precursors of retinol (Vitamin A), a critical fat-soluble vitamin that is important for normal vision, bone growth, reproduction, cell division, and cell differentiation.
Researchers studied the effects of grass-feeding on the beta-carotene content of beef. They discovered that pasture-fed steers incorporated significantly higher amounts of beta-carotene into muscle tissues as compared to grain-fed animals.
Grass-fed beef may contain less total fat than grain-fed beef, but a lot more omega-3 fatty acids and CLA are linked to health benefits.
In human nutrition, there are two important fatty acids: -linolenic acid (LA), which is an omega-3 fatty acid, and linoleic acid (LA), which is an omega-6 fatty acid. Essential fatty acids cannot be synthesized by the human body, despite their importance to human health; therefore, essential fatty acids must be acquired through food.
There have been several studies with livestock that have found similar results. For example, cattle fed mostly grass significantly boosted the omega-3 content of the meat. Also, they produced a more favorable omega-6 to omega-3 ratio than grain-fed beef.
Growing consumer interest in grass-fed beef products has sparked a number of debates about the perceived differences in nutritional quality between grass-fed and grain-fed cattle.
With respect to palatability, grass-fed beef has traditionally been less well accepted in markets where grain-fed products are predominant. But the taste isn’t the only thing keeping the grain-fed and grass-fed camps apart. Grass-fed meat may be the best option if you want super-lean meat.
References:
https://www.sciencedirect.com/science/article/pii/S0309174013004944
https://pubmed.ncbi.nlm.nih.gov/16500874/
https://pubmed.ncbi.nlm.nih.gov/31829294/
https://pubmed.ncbi.nlm.nih.gov/35028571/
https://pubmed.ncbi.nlm.nih.gov/22061397/
https://www.sciencedirect.com/science/article/pii/S0309174013004944?via%3Dihub