Efficient utilization of silage diets depends upon the nutritional value of the forage and the amount eaten by the animals. However, even good quality silage is usually supplemented with energy concentrates (principally cereal based) to provide sufficient dietary energy for a high producing dairy cow. This experiment was therefore designed to examine two concentrate energy sources (starch and sugar) at two levels of crude protein on animal production, using the sugar based concentrate (molaferm 20) as a true silage supplement.

A 3 x 4 week changeover design based on Latin squares, the experiment was conducted with 18 individually fed Autumn calving dairy cows, on average 77 days calved. The animals were second lactation or more and commenced their experimental period at least six weeks postpartum, with the preceding 2 weeks being used as a covariance period. Cows were blocked according to current milk yield, liveweight and lactation number and from these randomly assigned to 6 treatment groups.