Farm Animals - Hogs And Pigs

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Hogs and pigs are domesticated swine. A pig is a young swine that is not yet sexually mature. A young female hog is called a gilt. A female adult hog is called a sow. The generic term "hog" is generally used to refer to all hogs. Hogs are curious and intelligent animals, supposedly smarter than dogs. They have very sensitive noses, which they use to root around the ground for their food and explore their surroundings. Pregnant sows like to build nests of grass. Under natural conditions, sows give birth to (or farrow) a litter of piglets twice a year. Each litter includes eight piglets, on average, that suckle for about three months. The normal life expectancy of a hog is twelve to fifteen years.

The Modern Hog Industry

Hogs have been popular farm animals for centuries. According to the USDA, the 1850 agricultural census showed an inventory of around thirty million hogs. This number doubled to sixty million by 1900. At that time, 76% of American farms produced hogs. Hogs were favored because hog meat and fat were so versatile. Pork could be canned, smoked, or cured to provide food for long periods of time. Lard—the fat produced from hogs—was widely used as cooking oil and in making candles.

In 2002 the USDA agricultural census found that hogs were raised on 78,895 farms that year. The total inventory was put at 60.4 million. The total number of hogs on U.S. farms has remained virtually constant for more than a century, although the number of farms raising hogs has declined dramatically. In 2002 only 3% of farms raised hogs, as shown in Figure 4.3. This means that the number of hogs per farm has grown substantially. Figure 4.13 shows that in 2002 more than half of all hogs (53%) lived on farms that included at least 5,000 hogs each.

Hog production takes place mostly in the Midwest and South. Iowa was, by far, the top-producing state in 2002, with 15.5 million hogs. It was followed by North Carolina (9.9 million), Minnesota (6.4 million), Illinois (4.1 million), Indiana (3.5 million), Nebraska (2.9 million), and Missouri (2.9 million). Together these seven states accounted for 75% of the country's total hog population.

The hog industry has undergone tremendous consolidation, and only a handful of companies control most of the market. Smithfield Foods was the world's largest hog and pork producer in 2004, with sales of $9.3 billion. Other industry leaders included Tyson Industries and ConAgra Foods. The vast majority of hogs raised in the United States are concentrated on a few massive CAFOs. These facilities not only finish the hogs, as is done in the cattle industry, but actually raise them. Major pork producers operate farrowing complexes, nurseries, and growing-feeding units.

As shown in Figure 4.1 annual per capita consumption of pork products in the United States has changed little over the past century. In 1909 annual consumption FIGURE 4.13
Hog inventory breakdown, by number per farm, 2002
SOURCE: Adapted from "Table 21. Hogs and Pigs Herd Size by Inventory and Sales: 2002" in 2002 Census of Agriculture, U.S. Department of Agriculture, National Agricultural Statistics Service, 2004, (accessed March 17, 2005)
was 41.2 pounds per person. In 2003 it was 48.5 pounds per person.

Hog-Raising Practices

Confinement buildings for hogs can be hundreds of feet long and contain up to 12,000 hogs. They typically feature concrete or slatted floors—concrete floors can be easily cleaned and slatted floors allow manure and urine to fall into pits below. Hogs are kept on short tethers or confined in cages and pens to prevent them from getting exercise, which might build muscle instead of fat and toughen the meat. Crowded conditions can lead to aggressive behavior among the hogs, including tail chewing, biting, and fighting. Tail docking and teeth clipping are commonly practiced to help prevent injuries from these behaviors. Antibiotics, hormones, and other drugs are routinely administered to speed growth and prevent deadly diseases.


Breeding sows are often kept in individual stalls or confined with tethers until they are ready to farrow. Gestation crates, as they are called, are typically around seven feet long and just wide enough for the sow to lie down but not turn around (about two feet). The sow eats, urinates, and defecates where she stands. When she is ready to give birth, the sow may be moved to a farrowing pen in which she and her piglets will be kept tightly confined.

The USDA's National Animal Health Monitoring System (NAHMS) conducts a national swine survey every five years. The most recent report, Swine 2000, reported that 83.4% of sows on U.S. farms are farrowed in total confinement facilities, and 81.8% of pigs are raised in total confinement nurseries.

Industry officials defend the use of gestation crates, saying that the crates are necessary to keep aggressive sows from fighting with each other over food. Fighting can cause injuries that lead to miscarried fetuses. Pork producers believe that caged sows receive beneficial individual attention to their health and nutrition needs. The National Pork Producers Council says that hogs are better off raised indoors because they are protected from "extreme changes in temperature, snow, rain, mud and parasites."

The use of gestation crates has been banned in the United Kingdom and Sweden. The European Union plans to phase out use of the crates by 2013. In November 2002 Florida voters passed an amendment to the state constitution to outlaw the use of gestation crates. The move is largely symbolic, as the state is not a major hog producer. Following the vote, the Florida Farm Bureau reported that only two small hog farms in the state used gestation crates, and that one of them had already shut down and the other was phasing out of business.


Pork producers increasingly use artificial insemination and early separation of piglets from their mothers to produce more piglets each year. Early separation is possible because piglets can be bottle-fed by machines. Pork producers call it segregated early weaning (SEW). In an undated publication from the late 1990s (How Can We Price Early-Weaned Pigs? National Pork Producers Council,, Steve Meyer and Bill Lazarus called SEW an "exciting breakthrough" for improving profits in the industry.

The document recommended that SEW be done before the piglets reach nineteen days old. The primary advantage of SEW is that young nursing piglets receive high levels of natural antibodies from the sow's milk. This protection only lasts for about three weeks. After that, the piglets are more susceptible to diseases and can catch them from their mothers. SEW gives the piglets a better chance of remaining disease-free later, in the growing-feeding units where they are often susceptible to respiratory problems.


Generally, week-old pigs are subjected to teeth clipping, tail docking, and ear notching. The males are castrated at this time. These procedures are done without anesthesia. Once the piglets reach around fifty-five pounds, they are moved to indoor finishing pens. Piglets are raised to slaughter weight, typically 250 pounds, at around four to six months of age. Spent breeding sows are usually slaughtered at around two to three years of age.

According to the USDA's Swine 2000 report, nearly 18% of sows and gilts were culled during the first five months of 2000. The primary reasons were age (42%), reproductive failure (21%), and lameness (16%). Respiratory disease was also a cause of mortality, accounting for 28.9% of nursery deaths and 39.1% of deaths in grower/finisher pigs.

Animal welfarists are critical of hog-raising practices in the United States. They consider the intense confinement too stressful for intelligent and social animals like hogs. They also condemn early weaning as cruel to sows and piglets. Factory-farmed hogs not only suffer from excessive crowding, stress, and boredom but also experience serious breathing disorders because of high concentrations of ammonia from their waste materials. Critics also say that hogs experience feet and leg deformities from standing on floors made of improper materials.

Hog Slaughter

Hogs are generally killed via electrocution or by stunning followed by bleeding out. Electrocution is accomplished by stunning the hog with a wand with sufficient shock to stop its heart. This is called cardiac arrest stunning and is the technique most large hog slaughter plants use. Hogs can also be given an electrical shock to the head to render them unconscious. Next, the animals are hoisted up by their back feet and bled via a small incision in the chest. Fully electrocuted hogs are also bled out in this manner. The dead hogs are then lowered into vats of scalding water to remove hair. The meat can then be processed. (See Figure 4.14.)

According to Dr. Temple Grandin's instructions for electrical stunning, a hog stunned with sufficient amperage in the correct location will feel no pain. Insufficient amperage and an improper current path will cause the animal pain. Dr. Grandin recommends that head-stunned hogs be bled out within thirty seconds of being stunned to prevent them from regaining consciousness.

In 2003 Grandin conducted or oversaw audits conducted for McDonald's and Wendy's restaurants at twenty-seven pork processing plants. She reported her findings in the "2003 Restaurant Welfare Audits of Stunning and Handling in Federally Inspected Beef and Pork Slaughter Plants." Twenty-two of the plants audited used electrical stunning on their hogs, while the other five plants used carbon dioxide gas.

According to Grandin, the plants showed "excellent" performance during the audits. She reported that 91% of FIGURE 4.14
Hogs being processed at a meat-packing plant. The Library of Congress.
the pork plants passed the stunning audit and rendered 100% of their hogs insensible prior to the bleedline. These plants achieved correct wand placement on 99 to 100% of the hogs wanded. Two plants showed serious problems, with only 95 to 98% of the hogs wanded correctly.

"Hot wanding" is the term used to describe an improper wanding procedure in which the wand is energized before it fully contacts the pig. Auditors assume that hogs that squeal when the wand is applied are experiencing pain from being "hot-wanded." The auditors found that twenty-one of the twenty-two electrical stunning plants hot-wanded 0 to 1% of their hogs. One plant hot-wanded 2 to 3% of its hogs, which was considered unacceptable.

Grandin's auditing procedure also called for examination of use of electric prodding to move hogs through the processing plants. The audits found that only four hog plants used no electric prodding. Seventeen of the plants electrically prodded 1 to 25% of their hogs. Four plants used the electric prod on more than 26% of hogs. This was considered unacceptable. Serious problems were noted at two pork plants, where auditors observed workers poking hogs in the anus with sticks to get them to move.

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