"Gross" Conversion Efficiency of: (a) energy intake into milk energy and (b) N intake into Milk N
The Figures below present the efficiency of conversion of gross energy intake into milk energy and the efficiency of conversion of N intake into milk protein N (commonly referred to as Nitrogen Use Efficiency, or NUE). The energy graph was constructed based on NRC (2001) prediction but the N graph was constructed with data of the literature. Each point is the treatment average (n~ 72) of approximately 12 studies.
- Explain the increase in efficiency of utilization of dietary energy with increase multiple of maintenance.
- Explain the NRC system predicts that efficiency of utilization of dietary energy no longer increases for cows producing more that approximately 45-50 kg of milk.
- Why doesn't the conversion of dietary N into milk N follow the same pattern as for the energy?
Source: E graph from VandeHaar (unpublished); N graph from Wattiaux (unpublished).