Clinical trial to determine the productivity impact of milk urea nitrogen reports

Abstract

A clinical trial was conducted to determine the perceived and actual utility of milk urea nitrogen (MUN) notification and interpretation as a tool for monitoring protein and energy imbalances in dairy cows. Based on MUN results during the summer of 2001, 50 farms with high MUN values and 30 with low values were randomly allocated to become either intervention or control farms. From January to November 2002 (the trial period), intervention included monthly notification of individual cow MUN results, interpretation of abnormal average MUN values in subgroups of cows based on parity and days-in-milk, and suggestion of possible nutritional reasons for the abnormal MUNs. Intervention farms responded to a survey regarding report utilization, subsequent feed changes and perceptions of MUN testing. Control farms received the individual cow MUN results, but no additional interpretation. No significant differences in average MUN or standardized milk production between intervention and control farms were seen during the last three months of the trial (the outcome period). However, in herds making a feed change in response to MUN notification and interpretation (71% of intervention herds), milk production increased 2.4 lb (1.1 kg)/cow per day in the month after the feed change when compared to randomly selected herds not making a feed change during the same time period. Most dairy producers receiving the MUN notification and interpretation reports felt they knew how to use MUN reports after the trial, and felt that MUN testing was at least somewhat useful as a nutritional tool.