Marbling and fats Most grass-fed beef is leaner than feedlot beef, lacking
marbling, which lowers the fat content and
caloric value of the meat. Meat from grass-fed cattle has higher levels of
conjugated linoleic acid (CLA) and the
omega-3 fatty acids,
ALA, EPA, and DHA. A study showed that tissue lipids of North American and African ruminants were similar to pasture-fed cattle, but dissimilar to grain-fed cattle. The lipid composition of wild ruminant tissues may serve as a model for dietary lipid recommendations in treating and preventing chronic disease.
Dairy In 2021, food management system expert
Sylvain Charlebois remarked on the industry's use of
palm oil, given as
palmitic acid supplements, to augment the output of milk product: they "are marketed as a way to increase milk output and boost fat content" but a "review by the Dairy Research and Extension Consortium of Alberta found that butter made from cows fed palm oil remains difficult to spread at room temperature." Charlebois noted that this was not beneficial to the consumer, who was surprised and had not been notified of the
social contract variation to his disadvantage.
Taste The cow's diet affects the flavor of the resultant meat and milk. A 2003
Colorado State University study found that 80% of consumers in the Denver-Colorado area preferred the taste of United States corn-fed beef to
Australian grass-fed beef, and negligible difference in taste preference compared to
Canadian barley-fed beef, though the cattle's food was not the only difference in the beef tested, nor is Denver a representative sample of the world beef market, so the results are inconclusive. Remarkably, in some circumstances, cattle are fed wine or beer. It is believed that this improves the taste of the beef. This technique has been used both in Japan and France.
Nutrition transportation Animal products for human consumption from animals raised on pasture have shown nutritional differences from those of animals raised on other feedstuffs.
Health E. coli Diet composition is thought to affect the level of
shigatoxigenic and verotoxigenic Escherichia coli but research up to 2017 is inconsistent and did not show clear trends. A June 2025 study indicated the safety implications were not yet fully understood, and found some additional evidence, though noting their limited sample and variability. FSNS, an industry safety lab, also argued that the evidence is inconclusive and that all meat should be cooked to a safe minimum internal temperature of .
Bovine spongiform encephalopathy Meat and bone meal can be a risk factor for
bovine spongiform encephalopathy (BSE), when healthy animals consume tainted tissues from infected animals. People concerned about
Creutzfeldt–Jakob disease (CJD), which is also a spongiform encephalopathy, may favor grass-fed cattle for this reason. In the United States, this risk is relatively low as feeding of protein sources from any ruminant to another ruminant has been banned since 1997. The problem becomes more complicated as other feedstuffs containing animal by-products are still allowed to be fed to other non-ruminants (chickens, cats, dogs, horses, pigs, etc.). Therefore, at a feed mill mixing feed for pigs, for instance, there is still the possibility of cross-contamination of feed going to cattle. Since only a tiny amount of the contaminating
prion begins the cascading brain disease, any amount of mixed feed could cause many animals to become infected. This was the only traceable link among the cattle with BSE in Canada that led to the recent US embargo of Canadian beef. No cases of BSE have been reported so far in Australia. This is largely due to Australia's strict quarantine and biosecurity rules that prohibit beef imports from countries known to be infected with BSE. However, according to a report filed in
The Australian on February 25, 2010, those rules were suddenly relaxed and the process to submit beef products from known BSE-infected countries was allowed (pending an application process). But less than a week later, Tony Burke, the Australian Minister For Agriculture, Fisheries and Forestry overturned the decision and placed a 'two year stop' on all fresh and chilled beef products destined for Australia from BSE known countries of origin, thereby relaxing fears held by Australians that contaminated US beef would find its way onto Australian supermarket shelves after a long absence. Soybean meal is cheap and plentiful in the United States. As a result, the use of animal byproduct feeds was never common, as it was in Europe. However, US regulations only partially prohibit the use of animal byproducts in feed. In 1997, regulations prohibited the feeding of mammalian byproducts to
ruminants such as cattle and goats. However, the byproducts of ruminants can still be legally fed to
pets or other livestock such as pigs and poultry such as chickens. In addition, it is legal for ruminants to be fed byproducts from some of these animals.
Campylobacter Campylobacter, a bacterium that can cause another
foodborne illness resulting in nausea, vomiting, fever, abdominal pain, headache and muscle pain, was found by Australian researchers to be carried by 58% of cattle raised in feedlots versus only 2% of pasture raised and finished cattle. ==Environmental concerns==