Measuring Waste on the Run

When you’re trying to capture urine from a playful lamb on the run, baby diapers just won’t work.

Animal scientist Kenneth E. Turner tried the toddler size. But these often fell off as lambs frolicked in their grassy pasture “playpen.” Turner, with the Agricultural Research Service, found a solution to this problem--but why was he even looking for one?

The answer centers on the nitrogen and other nutrients present in livestock urine and feces. Scientists need reliable ways to measure this nitrogen. Then they can figure out how thoroughly the animals digest their diet, and how much of the diet's plant protein is actually used in making lean muscle. Excreted protein, in a nitrogen form, can contaminate groundwater--and cost farmers money.

Scientists like Turner aim to control the nitrogen losses at the source--the animal’s diet. Knowing how much nutrients are in the urine and manure will also help farmers decide whether and how much commercial fertilizer a pasture needs. Or, when to move the animals to another pasture to avoid concentrating wastes.

Typically, measurements of waste compounds are made with livestock kept in indoor chambers 1 to 3 days. Using lambs free to roam mini-pastures is more challenging, but the results should be more realistic, according to Turner, at the ARS Appalachian Farming Systems Research Center, Beaver, W.Va. ARS is the U.S. Department of Agriculture's chief scientific arm.

Turner solved the sheep-diaper problem by attaching a urinary catheter bag to a canvas fecal collection bag, securely but comfortably strapped to the hindquarters of female lambs. They wear the bags only a few days, with frequent changes for comfort. Beef calves and goats are next to be fitted with collection bags.

A story on the research appears in the September Agricultural Research magazine and on the web at:

http://www.ars.usda.gov/is/AR/archive/sep99/diap0999.htm

Scientific contact: Kenneth E. Turner, ARS Appalachian Farming Systems Research Center, Beaver, W.Va., phone (304) 256-2843, fax (304) 256-2921, [email protected].