(Click here for a state-by-state list of injuries, with links to original accident reports and investigations)

Around 40 years ago, most American dairies were fairly small operations, according to a report co-authored by Jim MacDonald, a U.S. Department of Agriculture economist. They kept an average of 19 cows that ate grass from nearby pastures and were milked once or twice a day by family members or locals. These days, technological advancements such as more sophisticated automated milking systems have allowed dairies to vastly increase in size and to lower their costs per pound of milk produced. Consumers have been the primary beneficiaries of these advancements, as the changes have kept the cost of milk and dairy products low.

Nowhere in the country has it been easier for dairies to expand than in the West, with its relatively cheap rural land. As of 2007, the average Western dairy had 550 cows — about five times the national average. And around 80 dairies in the West each have at least 5,000 cows, according to MacDonald. To increase milk production and make it easier to get that many cows in and out of milking parlors two or three times a day, most Western dairies now keep the animals in huge pens or sprawling open-air sheds and feed them a high-protein diet of corn, soybeans, grain and alfalfa, much of it purchased instead of grown at the farm. California, not Wisconsin, is now the biggest milk producer in the country. And Idaho, New Mexico and Washington have drawn new dairies like manure draws flies; today, the three are also among the nation's top 10 states for milk production. Nowadays, with 39 percent of the country's 9.1 million milking cows, the West produces 41 percent of America's milk, which is then processed to make various kinds of milk, cheese and other dairy products. And immigrants, who are willing to work for less money than locals, now make up a large proportion of the staff.

All 14 of the employees where Gustavo works are immigrants; Gustavo says only three of them are documented. The dairy's 750 cows sleep and eat outside on hard dirt in six outdoor corrals that stretch the length of seven city blocks. Their large brown-and-white bodies bump against the metal bars, creating an eerie and arrhythmic melody.

Before his injury, Gustavo and a coworker would open one of the corrals and whack the cows on their backs to funnel them into the concrete milking parlor. Once inside, Gustavo would douse each cow's udders with disinfectant iodine and fit rubber hoses onto its teats, connecting them to the air-sucking milking machine. After 10 or 11 hours on his feet, Gustavo says he tended to feel less agile and less able to watch for the kicking back leg of a touchy cow. His face was often just six inches from the animal's rear, and then as now there were no bars to protect the workers from the cows.

Now, Gustavo is afraid to milk, so he feeds and tends to the dairy's calves. The pay is slightly better, but Gustavo says he still doesn't get rest breaks. He eats lunch while working, removing a manure-laden glove to shove a taco into his mouth. When he feels tired, which is every day, he thinks about his three kids.

Like most dairy workers, Gustavo is salaried, which sounds good until you consider his schedule. Gustavo pulls his neatly folded pay stub from his wallet. He makes $1,175 every two weeks. He works 10- to 12-hour days, with one day off every five days, and receives no overtime pay. That pencils out to about $8 to $10 per hour, which is around the national average for dairy workers, according to industry reports. When Gustavo first arrived in the area 11 years ago, he and his boss discussed only pay, not hours, and he was too happy to have a job to ask any questions. But now he feels he's at his boss's mercy, and he is all too aware that long hours make a dangerous job even more dangerous.

This is all perfectly legal. Even though dairies have modernized, some of the key labor laws governing the industry remain unchanged, still geared to the days when dairies had few employees beyond family members.

Dairy workers, like all agricultural employees, are exempt from the provisions for overtime pay in the Fair Labor Standards Act. Though dairy operators are required to pay at least minimum wage, they are exempt from another federal law that requires employers to report hours on employee pay-stubs. That makes it tough to enforce the law or prove wage violations, says Oregon Law Center labor lawyer Mark Wilk, who over the past decade has represented several hundred Oregon dairy workers who didn't make minimum wage.

As a final slash in the safety net of federal labor law, dairy workers, like all agricultural workers, are exempt from the National Labor Relations Act, which requires employers to negotiate with labor unions over salaries and work conditions and protects workers who try to form unions from being punished. Without this law — the Magna Carta of American labor — dairy workers cannot form a union unless their boss is willing to recognize it and they have little legal recourse if they get fired for trying to organize.

"Dairy folks are legally in the worst of all worlds. There really is no federal law at all to protect them," says Wilk. "This is the last bastion of feudalism. The ugly reality of the world that my clients live in is shocking."