Often Labeled Polluters, Dairy Cows Also Big Recyclers
GAINESVILLE—They produce mountains of manure and stinky, ozone- depleting (some scientists contend), methane gas. They also supply the nation with sweet, fresh milk. It’s a real public relations quandary for the nation’s dairy cattle.
But a survey of the state’s dairy industry conducted by University of Florida scientists brings “moo-ving” news for the bucolic bovines, often condemned as environmental criminals. Cattle are also major-league recyclers who eat about 600,000 cubic yards of by-products that otherwise would end up as waste in a landfill.
Need a visual?
“If you added up the volume of by-products made in Florida and consumed by Florida dairy cattle each year, you’d fill an area the size of a football field to 120 yards deep,” said Mary Beth Hall, an assistant professor of dairy nutrition at UF’s Institute of Food and Agricultural Sciences.
The 3,000 dairy cattle that reside on 1,700 acres at Alliance Dairies in Trenton eat their share of landfill-bound vittles. Dairy owner Ron St. John supplements his herd’s diet with several Florida-produced by-products. In addition to forage, corn silage and hay, each of St. John’s cows dines daily on 15 pounds of wet brewer’s grains that were used to make beer, seven pounds of whole cotton seeds leftover from cotton plants, four and a half pounds of citrus pulp delivered from the state’s citrus processing plants, and one and a half pounds of distiller’s grains that were used to make whisky.
These high-fiber throwaways are used not only in Florida, but in dairies all over the nation to supply energy and protein for the cows who seem to enjoy the additional chow. “They ask for more,” St. John said, laughing.
Because they are fibrous, the leftover grains, seeds and pulp are not foods that people could digest, Hall points out. But they are perfect for ruminants like cattle, who have four stomachs and unique digestive tracts filled with special microbes that easily break down the fibers, Hall said.
This environmental good news is important for the state’s 275 dairies and approximately 175,000 cows, who, along with their counterparts in other states, have taken public heat for groundwater pollution and odor.
True, dairies can be smelly, acknowledges, St. John. And the manure does contain nitrogen and phosphorus which can run off and foul the water system.
“The dairy cow does take a bad rap for polluting, but so have golf courses,” he said. “It’s just that they are recreationally friendly. We’re not.”
Hall said it is important for people to understand, that while dairies will always have their issues — “there’s no way you can get a cow to excrete nothing” — through this recycling effort, many are doing their part to help the environment as well.
“This is a good example of how animals and people fit together to get rid of waste,” Hall said. “People talk about sustainable agriculture, but what we need to talk about is a sustainable society where the agricultural community and the human community fit together to support each other.”