March 12 2013 07:31 AM

We recognize groundwater as a valuable resource this week

This week, March 10 to 16, is recognized as National Groundwater Awareness week. Groundwater is one of our most valuable resources, needed by people, animals and crops every day. The National Ground Water Association (NGWA) estimates that 44 percent of the U.S. population depends on groundwater, either public supply or private wells, for their water needs. The association also says that irrigation is the number one use of groundwater with 53.3 billion gallons used each day to irrigate cropland.

Joe HarnerDairy farms use considerable amounts of water on a daily basis. Water usage on a dairy farm varies, of course, but last week at the Western Dairy Management Conference in Reno, Nev., Joe Harner of Kansas State University (at right) shared an average water budget for a lactating cow built using scientific data.

Based on his calculations, a cow drinks 28.8 gallons per day and consumes another 3.2 gallons in the ration. Approximately 18 gallons are used in the parlor and for deck washing, and 14.4 gallons per cow run through the plate cooler. Heat abatement varies based on time of year and location, but his figures showed that just under 5 gallons of water are used per cow per day for cooling systems.

This comes to a total of 71.2 gallons of clean water per cow per day. Most farms do a good job reusing some water, an average of 14.4 gallons per cow, so water usage per cow, on average, is 56.9 gallons per day.

Joe HarrisonAs dairy producers, we do not just use groundwater but also play a role in keeping it safe for consumption. Also at the Western Dairy Management Conference last week, Joe Harrison from Washington State University (at left) discussed the risk of antibiotics and hormones entering the environment and ultimately groundwater through livestock manure.

He explained that when producers think of antibiotic residues, they most often think of milk and meat but these residues can show up in the environment as well. He shared what he considered to be the best management practices to slow or stop the movement of pharmaceuticals from the point of excretion by the cow to surface and groundwater. Those management practices include:

Grass Filter Strips- Research has demonstrated that grass filter strips were effective in reducing the concentration of estradiol originating from poultry litter by 58, 81 and 94 percent after transporting through grass filters of 20, 40 and 60 feet (Nichols et al, 1997).

Composting- It has been found that windrow composting of poultry manure for 139 days resulted in a 84 percent drop in 17beta-estradiol content and a 90 percent decrease in testosterone content (Haak et al, 2005).

Identify Readily Available Alternatives- The ethanol industry has shifted towards the use of nonantibiotic antimicrobial products to avoid the issue of antibiotic residues in distillers grain.

Anaerobic Digestion- It was found that anaerobic digestion of manure and sewage sludge has been shown to result in reductions in pharmaceuticals (Zhao et al, 2008).