September 15, 2003
Agricultural Research Service News
More Tender Beef, Thanks to Vitamin D
Moderately increasing vitamin D fed to cattle prior to slaughter is a safe way of providing consumers with tender beef. Raising cattle?s blood calcium 20 to 30 percent by feeding the animals extra vitamin D3, beginning two to three days before slaughter, results in an increase in muscle calcium and more tender cuts of meat. Elevated calcium triggers the tenderizing process by activating postmortem muscle enzymes that can help degrade structural proteins that toughen meat. Vitamin D3, the form of vitamin found in humans and animals, helps people and animals build strong, healthy bones and teeth. A deficiency can cause bones to become thin, brittle or soft or misshapen, and can lead to metabolic diseases such as milk fever in dairy cattle and osteoporosis in people. The vitamin D tenderizing method is being tested by private firms within the United States.
Feedlots and the Environment
A feedlot in Bushland, Texas, is one of a very few fitted with devices that measure runoff flow from the cattle pens and sample it for nitrogen, phosphorus and pathogens. Commercial feedlots store runoff in holding ponds that normally prevent it from contaminating waterways. The study is aimed at finding ways to minimize the amounts of nutrients in runoff and eliminate pathogens. It involves monitoring how much nitrogen is escaping from manure into the air as ammonia gas. To study ammonia emissions from manure, ARS scientists simulate feedlot surfaces by packing manure in 8-inch-deep, 33-foot-diameter circles outdoors. A 10-foot-tall tower is placed in the center of each circle, with collectors at various heights to capture ammonia. Initial results show that decreasing the protein fed to cattle in feedlots from 13 to 11.5 percent might decrease daily ammonia emissions by about 20 percent.
New Method Speeds up Pesticide Residue Monitoring.
A new approach to analyzing diverse pesticide residues in fruits and vegetables makes it easier and less expensive for analytical chemists to do their jobs. QuEChERS (pronounced catchers), developed by ARS, stands for ?quick, easy, cheap, effective, rugged and safe.? It?s a streamlined approach for extracting pesticide residues from food samples and preparing them for analysis. Using QuEChERS, a single chemist can now prepare a batch of 10 previously chopped samples in about 30 minutes with $1 of materials per sample. This translates to at least 4-fold lower material costs than traditional methods. A single, easy-to-clean Teflon tube is the only item to be washed and reused, eliminating all of the glassware used in conventional methods. Less than 10 millimeters of solvent waste is generated ? much less than the 75-450 milliliters generated by other methods.
New Tester Fine-Tunes Irrigation Systems
To reach every thirsty plant in an orchard or field, water pressure has to be just right. Tomorrow?s farmers might choose to conveniently spot-check water pressure using a portable device invented by ARS engineers. The pressure-tester is designed for drip-irrigation systems that use thin-walled, flexible black tubing that?s either buried or above ground. The unit offers a practical way to determine whether an irrigation system is working properly. The tester weighs about one pound, is about the size of a pipe wrench and is accurate to within the accepted 5 percent. The tester isn?t intended to replace today?s permanently installed meters and gauges, but instead act as a handy option for special situations. It works somewhat like a giant clothespin that?s clamped around an irrigation tube and then released. A scale indicates pressure in the standard unit of measure -- pounds per square inch.