The latest findings show that grazing dairy cows with low milk urea nitrogen breeding values (MUNBV) have a 28% reduction in the urinary urea nitrogen loading rate per urine patch than cows with higher MUNBVs. The lowest MUNBV animals in the study excreted 165.3 g less urinary urea nitrogen per day than the highest MUNBV animals. The research, completed by PhD student Cameron Marshall (recipient of the Lincoln University Doctoral Scholarship), also showed that the low MUNBV cows also yielded an increase in milk protein percentage. “Cameron’s work shows that the cows themselves are an important tool in helping to cut nitrate leaching and nitrous oxide emissions, and in helping farmers meet their regulatory reductions. “Most farmers’ herds will naturally comprise a mixture of low MUNBV cows and higher MUNBV cows, with the trait being identified through testing the milk.