Milk urea nitrogen is a strong indicator of the nutritional status of the heard - especially the protein and energy portions of the ration. The reason this is so important is because feed expenses account for over 50 percent of the cost of milk production. Underfeeding or overfeeding these two major portions of the ration mean lost income opportunities for the producer. In addition, excess nitrogen in the feces and urine may contribute to environmental problems.
Most producers group their cows into production strings.
A production string is any grouping of cows that are managed the same, especially in regards to feeding. Other terms for production strings are pens, corrals, or groups. DHIA typically tests all of the cows in a herd on a once a month basis. There are times, however, when a producer would like to know specific information more frequently. The information may or may not be necessary on an individual cow basis.