Twenty-three percent of pork producers (those working more than six years and more than two hours per day) have one or more documented respiratory problems.

That's the report from Kelley Donham, DVM, and professor of occupational and environmental health at the University of Iowa's (UI) College of Public Health, Iowa City.

Donham also serves as director of Iowa's Center for Agricultural Safety and Health (I-CASH), and has monitored worker health and safety at more than 600 farms in Iowa and Nebraska as lead researcher in the Certified Safe Farm (CSF) project.

Respiratory Problems

The most prevalent respiratory problems include chronic bronchitis and asthma-like wheezing symptoms, which can result from exposure to dust, endotoxins and ammonia.

“The best defense is to decrease the source of exposure to dust,” Donham explains. Feed, microbes, dried manure and pig skin cells in the air are main culprits, he says.

Using an extra 1% of oil or fat in the diet and reducing the distance between feed drops and feeders can also help reduce feed dust. Added fat also reduces the amount of debris sloughing off the pigs, he says.

Slotted floors should allow manure to quickly flow into the pit without collecting or drying. Oil sprinkling systems and power washing every 3-4 weeks have also proven effective for cutting dust levels.

In addition to reducing dust, Donham says respirators (disposable masks, half-faced masks or powered air-purifying respirators [PAPR]) should be used by the following persons:

  • Anyone who works more than two hours/day in a swine barn;

  • Operators who experience chest tightness, wheezing, cough or a feeling of constant cold or flu-like symptoms;

  • Those working in rooms where dust levels over 2.5 mg/cubic meter and ammonia greater than 7 ppm, or engaged in heavy dust exposure activities such as loading, feeding or power washing.

Disposable masks filter inhaled air so long as they create a tight seal around the person's nose and mouth, he says. Half-faced masks may be more effective for those whose symptoms aren't controlled by disposable masks.

Manure Gas Exposure

PAPR use a battery-powered blower to force air through a filter into a plastic helmet with a face shield. These are recommended for persons with difficulty getting a good seal with other masks (due to scars, beards or size), or for those with preexisting heart or respiratory problems who require stronger protection or have trouble breathing through a disposable or half-faced mask. The cost is about $600/unit, but Donham says they are a job-saver for some people. “We have kept some people with health problems in business for years by fitting them with a PAPR,” Donham says.

A study in Canada suggests that approximately 10% of producers who leave hog production do so because of respiratory problems.

Keep in mind that wearing a dust mask is not a cure-all. “Never rely on a mask to replace doing things in the environment to reduce dust exposure,” Donham says.

Accidental Needle Sticks

When manure stored in pits deeper than 2-3 ft. for long periods of time is agitated, a dangerous gas called hydrogen sulfide is rapidly released. “It is like a champagne bottle being shaken,” Donham says.

Move outside of the building (even if doors and windows are opened) during agitation and for at least 30 minutes afterwards to avoid toxic exposure, he suggests.

If you detect a problem when agitating or pumping is started, one option is to raise the pH of manure by adding hydrated (also called slaked) lime. This can help keep hydrogen sulfide from escaping from the pit. Emptying the pit frequently — three or four times per year, if possible — also helps suppress gas build-up.

Accidental Needle Sticks

Avoid jabbing yourself or a co-worker with a needle when treating animals. Veterinary products for large animals are more concentrated than human medicine, so even small inoculations can cause severe reactions, he reminds. The trauma itself can be nasty because of the large, multi-use needles commonly used in livestock facilities.

Infection is always a concern, and many vaccines contain additives that can be extremely irritating and inflammatory, Donham notes. Certain live vaccines can also cause illness in humans.

Women of child-bearing age should not handle hormones, such as prostoglandins or oxytocin. “If a pregnant woman happens to get inoculated with either of those products, it may have an adverse effect on the fetus,” he warns.

Donham lists these preventative measures:

  • Use single-dose syringes (if practical);

  • Keep needles covered until use;

  • Do not carry loaded syringes in your pocket or mouth; and

  • Change needles frequently.

Training employees on safe inoculation procedures and sharps handling is essential, as is having plenty of help on hand during treatments to help prevent accidents. Larger animals, especially sows or boars, should be restrained in chutes or pens for treatment. Needleless injection technology is another promising option.

Noise Exposure

Anyone who visits a hog facility knows they can be noisy places. Michael Humann, also of the UI department of occupational health and environment, has studied noise exposure and hearing loss among workers on hog farms. He ranks power washing, heat checking, processing or bleeding pigs, loading pigs and feeding time among the noisiest jobs.

It is not uncommon for sound to average above 90 decibels during these tasks. (See Table 1).

There are also episodes when, “noise can get so intense, so quick, there is a risk of people damaging their hearing instantly,” Humann says. This is especially true during piglet processing when sound can hit 140 decibels.

But Humann says noise-induced hearing loss usually happens gradually from routine exposure to decibel levels of 85 or higher. Signs you might be suffering include difficulty hearing women's voices, understanding conversations in noisy rooms and being told the TV is too loud.

Humann urges workers to wear hearing protection, such as muffs or formable ear plugs. Also plan your work to avoid exposure as much as possible. For example, do not enter the barn during feeding time, rotate between noisy jobs and quiet jobs and perform recordkeeping or other mobile tasks away from the barn. Sound engineering in hog facilities is difficult because of the dust and rugged conditions.

Other Injuries

Injuries can happen in a split second — anything from getting your finger pinched in a gate to having a sow back up and put your knee out of joint. “There are so many opportunities for trauma,” Donham remarks.

Operator safety should be a high priority in designing facilities, equipment maintenance, development of animal care practices and ongoing employee training.

For more information, visit www.public-health.uiowa.edu/ICASH or call I-CASH at 319-335-4065.

Table 1. Noisiest Tasks in Sow Units and Finishing Facilities

Sow Units
Task Decibels (dB)
Heat checking 92
Processing pigs 91
Moving pigs 84
Feeding pigs 83
Cleaning pens 82
Ultrasound monitoring 82
Inoculating 81
Inseminating 78
(Humann, University of Iowa)
Finishing Facilities
Task Decibels (dB)
Power washing 97
Bleeding 96.8
Truck washing 88.9
Vaccination 89.5
Loading 92.5
(Miller, University of Iowa)