Question: Why were beef butchered?
About the article "Fajita", section "Popularity".

Candidate passages:
Iliff had become established as a leading commercial cattle rancher in his holdings along the Platte river, and sold beef to mining camps, railroad workers and government agents working on Indian reservations.
In February 1868, he began to drive slaughter herds to Cheyenne, Wyoming to be butchered and both marketed locally and shipped by railroad to markets in Chicago.
Over the next decade, cattle ranches stocked with Texas Longhorn brought up along were established across Wyoming.
Several Texas companies relocated or started subsidiaries in Wyoming and Montana.
Cheyenne became a hub for the local cattle business, with its Union Pacific railroad connection. 
The first culinary evidence of the fajitas with the cut of meat, the cooking style (directly on a campfire or on a grill), and the Spanish nickname going back as far as the 1930s in the ranch lands of South and West Texas.
During cattle roundups, beef were butchered regularly to feed the hands.
Throwaway items such as the hide, the head, the entrails, and meat trimmings such as skirt were given to the Mexican cowboys called vaqueros as part of their pay.
Hearty border dishes like barbacoa de cabeza (head barbecue), menudo (tripe stew), and fajitas or arracheras (grilled skirt steak) have their roots in this practice.
Considering the limited number of skirts per carcass and the fact the meat wasn't available commercially, the fajita tradition remained regional and relatively obscure for many years, probably only familiar to vaqueros, butchers, and their families. 
 2000: "Bamboozled" 2004: "Beef II" 2004: "The MC: Why We Do It"  
American era (1898-1946).
Veterinary functions.
American occupation of the Philippines began in 1898.
During the American period in Philippine history (1898-1946), the American government established the a veterinary department in 1899, a part of the Board of Health, the office that was in-charge of public health and safety.
The government of the United States sent groups of American veterinary doctors to the Philippines to function as inspectors of cattle imported through Manila, as inspectors of both locally-butchered and imported beef, as caretakers of the health of animals owned by the government (including the horses of American soldiers), and as sanitary inspectors of public and private stables.
In 1899, 60 civilian American veterinarians were working hand-in-hand with the United States Army's Veterinary Corps.
In 1905, the veterinary department was placed under the management of the Bureau of Agriculture (known at present as the Bureau of Animal Industry). 
Meat in Korean cuisine has highly detailed classifications regarding freshness, quality, and part differentiation for specific cooking methods.
Since "yukhoe" uses raw beef, freshness is the most important criterion, and for this typical dish's beef it is recommended to use no more than one day after defrosting, and traditionally should not be aged more than one day after slaughtering.
Regular Korean "yukhoe" customers often patronize trusted restaurants or butcher's shops which have well-known, high-quality beef distributors.
Since 2004, the Korean Government has run the Beef Traceability System This system requires ID numbers with the age of the beef animal of origin, supplier, distributor, the beef's grade, and butchering date and originating butchery.
Most of the good beef restaurants in Korea list their beef's information on the wall.
Also, butcher shops post signs saying, "New beef coming day ( Hangul : 소 들어오는 날 )": These words have become a well-known idiom in Korea.
and it means newly butchered beef supplied at the day.
Raw beef can be contaminated with pathogenic bacteria, with enterohemorrhagic "E. coli" (O111 or O157:H7) being of particular concern.
But only by freshness of beef, the risk can be reduced.