Maize silage for milk production - Part 1: Effect of the quality of maize silage on milk

Abstract

Ensiled forage maize is an alternative or complementary forage to grass silage and is the main source of forage for ruminant livestock in many European countries. The growing of maize for silage was tried unsuccessfully in Ireland in the 1970’s, was resumed in the late 1980’s and is now well established in suitable areas in the south and east of Ireland. However, variation in growing conditions and summer radiation can result in considerable variation in the yield, maturity and feeding value of the crop from year to year and between regions or locations within years. A series of experiments were conducted at Moorepark and at Johnstown Castle Research Centre to evaluate the role of maize silage in the diet of lactating dairy cows, the effect of variation in the quality (starch content and digestibility) of maize silage, the proportion of maize silage in the forage and the effect of harvesting date of immature maize silage on feed intake, milk production and milk composition compared with an all grass silage based diet. Grass silages of moderate or high digestibility were used. These studies were carried out with cows in early or mid lactation or at both stages of lactation. The forages were supplemented with concentrates at low to moderate levels of feeding (4-7 kg/cow/day). The concentrates generally contained a high level of crude protein (220- 250 g CP/kg fresh weight) to balance the low level of crude protein in maize silage. The experiments were conducted over periods of 7-9 weeks.