As mentioned here, most beef cattle spend the first months of their lives in similar circumstances, growing up on small or midsized farms and living off grass. The vast majority of these calves are then moved into feedlots, whereas a small number of these calves are kept on smaller farms to be finished as grass-fed beef. Though it is cheaper to finish beef in a feedlot, there are some very serious problems with feedlots for people, the environment, and the cows themselves.
A cattle feedlot is essentially a factory for producing beef, with all the processes optimized for the greatest efficiency. There is one driving goal that supersedes all others, to produce beef at the lowest possible price. So the animals are packed tightly into small fenced areas, often many thousands of cattle all being kept together. Instead of eating grass, they are fed corn and other grains because cattle will put on weight (and especially fat) much more quickly than they would on grass. Under these conditions cattle will reach slaughter weight in about six months, making the total life span of these cattle only a bit over a year. While efficiency is generally a good thing, in the case of feedlots there are a lot of negative side effects that come alongside that reduced cost.
The big sustainability problems of feedlots have to do with the logistics of having thousands of animals packed into a tight space. Bringing all of these animals together concentrates the wastes of the cattle in the ground, the water, and the air. When living on pasture, there is enough biological action to process and absorb the wastes that cattle produce, but this is impossible when there are hundreds of times more animals packed into the same amount of space. It becomes necessary to construct massive and toxic dung holding ponds, there are smells that carry for miles, and water quality becomes a huge concern. Much of this waste is eventually spread to where it can be absorbed into the land, but even so it is a very polluting way of raising animals. Then there is all of the feed. For pastures and hay, there is relatively little need for inputs, the grasses grow with little help and well maintained pastures can be healthy and biodiverse ecosystems. Further, the soils of grasslands can act as a carbon sink for CO2 emissions rather than a source. Corn, however, is a very intensive crop, requiring massive inputs of fuel, fertilizers, and pesticides. And like most monoculture crops, growing corn creates biological deserts where almost nothing lives except for that single farmed plant.
Cattle don’t easily adapt to their crowded life of eating corn. Cows are adapted to live in herds, but not in the tens of thousands, and not where they can’t escape their own wastes. Cows also have evolved to mostly eat grasses and even have a special chamber of the stomach known as the rumen that helps them to digest grass. They will put on weight faster by eating corn, grain and sugar, but they quickly begin to have problems with their digestion and their livers. These conditions make illness a constant concern for growers, so cattle are often dosed with antibiotics during their entire stay at the feedlot. To pump their growth further, they are sometimes also supplemented with growth hormones. While it is difficult to know exactly how cows feel about their time in feedlots, everyone can agree that this is a vastly lower quality of life for a cow than wandering pastures and eating grass.
Grass finished beef
Grass fed beef is just that, cattle that spend all of their lives eating grasses, with little to no other grains being provided to them. Grass finishing isn’t really scalable in the same way as feedlots are, so it tends to be on smaller farms and providing for only local markets. Cattle that will end up as grass-fed beef continue on a trajectory very similar to what they experienced as calves, sometimes even staying on the same farm for their entire lives. These cattle live at least one extra year on a farm where they eat hay through the winter and pasture grasses through the summer. In Canada, a very typical harvest time is at the end of the fall, so that farmers don’t have to cut hay for these animals to stay around through another winter. At the very least, this is a much better life for the cattle than they would have had by spending their last six months on a feedlot.
So as mentioned above, grass finishing beef is less economically efficient in the short run if one simply looks at how many dollars and how much time is needed to produce a pound of beef. But at the same time, raising cattle on well managed grasslands is much better for the environment, people, and for the cattle themselves.