President Eisenhower signed the bill into law with an effective date of June 30, 1960. The Act covered 80% of US plants by requiring that humane methods be used by all packing companies selling meat to the federal government. In 1978, Senator Robert Dole of Kansas and Congressman George E. Brown, Jr. of California sponsored legislation that expanded the coverage of the Act to include livestock at all plants that are federally inspected. The legislation intended to proved more effective enforcement by allowing federal inspectors to stop processing lines until any unacceptable methods are corrected. However, the economic impact of stopping a processing line is so great that inspectors are rarely able to do so. An additional requirement of the 1978 law was that any meat imported into the US must be derived from animals slaughtered in a manner that accords with the Human Slaughter Act. Final regulations under the Humane Slaughter Act were published in 1979.


Since animals whose meat will be sold or treaded must be slaughtered under an inspector’s supervision, most slaughtering is performed off the farm at slaughterhouses. Three big companies (IBP, Cargill’s Excel Corp. and Con-Agra’s Monfort Inc.) control 80% of all beef production.

For animals other than poultry and ritually-slaughtered animals, it is a requirement of The Humane Slaughter Act that livestock must be stunned into unconsciousness before they are killed. The stunning of livestock is normally accomplished by an electrical device or a gun.

There are several types of guns employed:

FREE FIRE CARTRIDGE: A bullet is shot into the head of the animal. Use of this technique is rare, and only occurs in facilities where the head meat is condemned as unfit for consumption.

PENETRATING BOLT STUNNER: Either an exploding cartridge, in a pneumatic stun gun, a blast of air from an air line, drives forward a piston and an attached penetrating rod that enters the skull and brain of the animal and then retracts into the gun.

CONCUSSION STUNNER: This device operates like a penetrating bolt stunner, but a short, mushroom shaped knob strikes the skull producing unconsciousness without entering the brain.

Penetrating the bolt or concussion stunners are normally used, at both small and large slaughterhouses, to stun cattle. These stunner, also, are usually used when goats and sheep are slaughtered at small slaughterhouses, while the larger plants more often use electric devices on these smaller species.

One type of electrical stunner takes the form of large tongs with round disks on the ends, which carry an electrical charge through the brain when placed on either side of the head.