Cows and cow farms were a common sight during Third World War, mainly showing up in the various American farmlands that were invaded by the Soviets. They were one of many species of animal to sustain losses during the conflict.
The common cow (Bos primigenius) was a widespread domesticated farm animal by the advent of Third World War, and had held such a position for over a hundred years prior. Cows were typically farmed for their milk and their meat, though some were occasionally domesticated for entertainment purposes, such as rodeo breeding and vacation "dude" ranches. Cows could be found all over America, but were mostly seen in the outer states of the main North American continent, usually in locations with standard seasonal changes.
The Soviet invasion of North America was a devastating blow to farming in general, including cow farms. Many farmers were forced to flee from the oncoming assault and leave their cattle behind in the process; unmanned farms brimming with helpless, quietly grazing cattle were a common sight during the homeland battles of the war. Usually the animals were ignored by both sides of the conflict, but often the farm buildings themselves would be garrisoned by foot soldiers and subsequently destroyed in combat, killing the hapless bovines within. Sometimes, during the slow hours between battles, soldiers on both sides would simply grow bored and open fire on the dim witted creatures to pass the time. Finally, during the Psychic Dominator disaster, Yuri clones would sometimes amuse themselves by mind controlling cows and forcing them to do ridiculous things, sometimes resulting in their death. Whatever the various causes, the damage to the meat and milk market of America was devastating, and after the war had ended it took many years to fully recover.
Cows typically had next to no combat use, with one major exception. For some freak reason, perhaps a malfunction of some sort, whenever a cow was placed inside an IFV an upper level security code was bypassed and the IFV would gain a Prism weapon even more powerful than a Prism Tower. Why this happened remains a huge mystery to this day. Cows could usually only be controlled with mind control, and even then the mind-controlled unit was not able to be loaded into a vehicle. This combo was thus almost impossible to achieve during normal gameplay.