CAFO is the official US EPA term for: 1. Animal Feeding Operations (AFOs) with more than 1000 animal units (an animal unit is defined as an animal equivalent of 1000 pounds live weight and equates to 1000 head of beef cattle, 700 dairy cows, 2500 swine weighing more than 55 lbs, 125 thousand broiler chickens, or 82 thousand laying hens or pullets) confined on site for more than 45 days during the year. and, 2. Any size AFO that discharges manure or wastewater into a natural or man-made ditch, stream or other waterway, regardless of size.