No abstract

As concerns for environmental damage instigated by agricultural processes increase, there is a greater need to develop more ecologically acceptable methods of producing agricultural products. Therefore, in beef production we have to minimise N excretion and maximise N retained. Urea recycling provides a mechanism by which N may be salvaged into bacterial matter that may be digested by the animal to supply amino acids for production purposes. According to Huntington and Archibeque (2000), the amount of recycled urea-N can be influenced by the ruminal ammonia concentration, the OM digestibility and the plasma concentration of urea. The objective of the present study was to examine the effect of different levels of ruminal degradable N (RDN) on nutrient digestion and N metabolism in double-muscled Belgian Blue (dm-BB) bulls fed maize silage based diet.