Health, safety, and environmental concerns of farm animal waste

Modern animal husbandry has been concerned with increasing efficiency by increasing the number of animals raised per unit area; decreasing labor costs by automated animal feeding, watering, and housing; and using antibiotics to increase animal growth rates. These changes in animal production practices have resulted in reduced disease risks in some cases, but also have introduced new risks and challenges to the animal handler. Topics covered here include exposure pathways and health hazards associated with animal excreta, birthing wastes, and carcasses, with emphasis on infectious microbes (e.g., bacterial, viral, and protozoan pathogens) and airborne hazards (e.g., gases, dust particles, aerosols, and odors). Measures for reducing risks to animal handlers, including the use of waste management and treatment techniques, are reviewed.