AN INNOVATIVE APPROACH TO IMPROVE NITROGEN UTILIZATION IN RUMINANTS

Currently, only about30%of the dietary nitrogen is retained as milk or meat by ruminants, including dairy cows, beef cattle, and sheep. The excretion and waste of most of the dietary nitrogen not only increases production cost but also creates pollution of the environment.Improvement of NUE in ruminants without depressing animal performance is critical tothe sustainability of secure supplies of high-quality meat (lamb and beef) and milk.Predation and subsequent degradation of rumen bacteria, which are the major protein source available to cows and sheep, by rumen protozoa is one of the major causes of the low nitrogen utilization efficiency.?Our long-termgoal is to understand the metabolism, physiology, and ecology of rumen protozoa, especially thegenus Entodinium, to inform future development of new strategies to improve NUE in ruminantsby specifically inhibiting rumen protozoa and decreasing protozoa-mediated intraruminal Nrecycling without adversely affecting the ruminants or their rumen microbiome.