feedlot

feedlot, a plot of land on which livestock are fattened for market. A feedlot intensively manages cattle or other animals in a relatively small area and feeds them primarily grains until they are ready for processing for human consumption.

Feedlots are categorized according to size: small feedlots have a capacity of 1,000 to 7,999 head of cattle, whereas large feedlots can hold 8,000 or more. Large feedlot operations are referred to as concentrated animal feeding operations (CAFOs). In 2018 there were roughly 27,000 feedlots in the United States, accounting for about 25 million animals. Although the majority of North American feedlots manage fewer than 100 head of cattle, more than 75 percent of all cattle come from feedlots that house 1,000 or more animals.

Beef production has become highly scientific and efficient because of the high cost of labour, land, and feed. Feedlots support maximal growth and weight gain through a high-energy diet of grains and legumes, such as corn and soy. The confines of the feedlot discourage foraging activity to lower stress and energy expenditure, reduce the health issues and risks associated with open grazing, and maximize profits. In the United States more than 75 percent of beef cattle are born on pasture and moved to feedlots after weaning. Cattle may be shipped to feedlots from multiple locations, and, upon arrival, they are examined, vaccinated, dewormed, and given identification tags. An animal may spend several months to a year in a feedlot, depending on its weight at arrival. When the cattle reach slaughter weight, they are sent to a nearby slaughterhouse for processing.

Grain, often fortified with legumes, is critical to weight gain in the feedlot industry. In the 1800s, farmers in the United States discovered they could feed surplus grain to cattle, which produced heavily marbled beef that commanded higher prices. Advancements in irrigation enabled grain harvests with larger yields, and feedlots and soon slaughterhouses were built in many grain-producing areas. Since the 1970s, outdoor feedlots in the United States have been concentrated in the dry climate of the High Plains of Texas, Oklahoma, Kansas, Nebraska, and Colorado, which was found to be ideal for fattening cattle.

However, the grain provided in feedlots is not the optimal diet for cattle as they are ruminants that evolved to eat grass. Cattle have a four-chambered gut designed to digest fibrous grass forage with the aid of microbes that ferment the vegetative matter. Grass-fed cattle ruminate, or regurgitate, their food for rechewing, passing it from the digestive tract back to the mouth to aid in the breakdown of the insoluble fibres. The repeated addition of saliva increases the slipperiness of the food, helps balance the pH, and reduces bloat (gas buildup in the digestive tract). For grass-fed cattle, digestion is a slow process. Because feedlot cattle eat more grains than forage, their guts perform differently. They do not ruminate as much because the structural components of grains are simpler than those found in leaf cell walls, resulting in the rapid conversion of grains to nutrients. The consumption of grain also changes the pH and the composition of the microflora in the gut, which can cause ulcers, liver abscesses from the bacteria Fusobacterium necrophorum, and overcolonization by the bacteria Clostridium perfringens or Escherichia coli. Animals affected by liver abscesses do not gain weight as well as healthy cattle, and severe cases can progress to involve heart and lung problems, including sudden death. Given the challenges posed by grain-based feeds, the digestive health of feedlot cattle must be closely monitored.

Antibiotic drugs (often called antimicrobial drugs) are widely used to support the health of feedlot cattle. Given the density of the animals, the bacterial growth associated with grain-based feed, and the constant accumulation of urine and feces, feedlot conditions are ideal breeding grounds for a number of pathogenic bacteria. Antibiotic drugs, such as macrolides, are often given prophylactically for a variety of potential diseases and are also known to help cattle gain weight; they are frequently administered in feed or water. It is also common to administer an antibiotic injection to new feedlot animals to control and manage bovine respiratory disease. However, there are concerns that such casual and widespread antibacterial use is an important driver of antibiotic resistance, which threatens the continued efficacy of antibiotics used in human and veterinary medicine. The World Health Organization (WHO) estimates that the animal sector consumes about 80 percent of the medically important antibiotics in some countries, much of which is used for growth promotion in healthy animals. Antibiotic-resistant bacteria can spread beyond feedlots in manure, which is widely used to augment soil fertility. Farms that utilize feedlot manures have significantly higher levels of antibiotic-resistant bacteria in the soil compared with untreated farm soils. Recognizing the threat of antibiotic resistance to modern medicine, the WHO recommends heavily restricting the use of medically important antibiotics in food animals and avoiding the use of antibiotics to promote animal weight gain or to treat animals that have not been clinically diagnosed with a bacterial disease.

Feedlots can present environmental issues, including air and water pollution and excess dust, because of the large numbers of animals they contain. A steer can produce 30 kg (65 pounds) of manure per day (roughly a ton per year), and about 90 percent of that is water weight. Water contaminated with feces and urine must be managed to prevent runoff into local water sources. Best practices include constructing pens and other structures so that any water will run to a central collection pond to hold waste material. The waste can then be treated and used to water crops that are not intended for human consumption. The solid component of manure is scraped from pens twice per year or when the cattle have been removed from the pen and is offered to crop farmers as fertilizer. In the arid conditions of the High Plains, manure dries out quickly and produces dust that blows freely, which is exacerbated by the lack vegetation caused by the continual presence of cattle. Farmers can combat this dust by using sprinklers and cleaning pens on a regular basis.

Excess rainfall can lead to muddy pens, which affects the animals’ overall cleanliness and health and interferes with weight gain. Proper drainage can move the water away from the pens quickly, and elevated mounds can be constructed for cattle to lie on to stay out of the mud. Heat stress, which can kill animals, results from high temperatures combined with a lack of shade at feedlots and the animals’ heavy weights and dark hides. To reduce heat stress, sunshades can be installed to provide a respite from the sun.