Draught Animal Pumping

  The  gross  energy  expenditure  of a working  bullock can be 
  calculated as the energy consumed daily as food by the animal, 
  minus the energy in its dung. This method gives a daily gross 
  energy input for a bullock as about 97,200 kJ. If this energy 
  is supplied to the animal as cereal,it will need approximately 
  6.7 kg/day.  Useful work production of a bullock is estimated 
  at  7,920 kJ/day, which  puts the  efficiency of an animal at 
  around 8 per cent.