Effect of winter closing date and spring opening date on the DM yield of perennial ryegrass cultivars

摘要

Grazed grass is continually being proven to be the cheapest feed available ( Shalloo et al.,2004).Therefore, increasing its proportion in the diet is one of the key objectives of Irish dairy production.However,due to climatic variation grass growth in Ireland is extremely seasonal thus cultivars with improved winter growth,such as those presently used in New Zealand,would be extremely beneficial in any extended grazing system as they would allow sufficient herbage availability for early turnout to pasture of cows in spring.The objective of this study was to investigate the effect of winter closing date and spring opening date on the DM production of ten different cultivars.