With the introduction of milk quotas, a greater emphasis was placed on reducing input costs in milk production systems. This has led to a reduction in compound feed usage and a greater dependance on home produced forage. The objective of this trial was to examine the effects upon silage intake, milk yield, milk quality and cow performance of feeding a flat rate of 3 or 6 kg of a 160 g/kg crude protein, cereal based compound feed to October calving Friesian dairy cows receiving ad libitum grass silage harvested either during mid May or early June.

In each of two years, forty multiparous, October calving Friesian dairy cows were used in a 2 x 2 factorial design experiment to examine the effects of feeding two levels of compound feed as a supplement to grass silage harvested at two cutting dates.

In each year silage was made from primary growths of late flowering perennial ryegrass swards harvested from the same fields either during mid May (H) or about fourteen days later in early June (L). The herbage was cut using a disc mower/conditioner, and left in the swath for about 24 hours prior to harvesting with a precision chop forage harvester.