Influence of Giving a Choice of Grazing or Maize Silage Offered in the Field Simultaneously on Diet Selection of Lactating Dairy Cows

Changing the times of access to grazing and to maize silage (MS) offered indoors affects the relative intake of each feed, but has little effect on dairy cow performance (Hernandez-Mendo & Leaver, 2000). Offering the MS in the grazing paddock as an instantaneous alternative to grazing should give an insight into the factors influencing feed intake, and may provide a means of alleviating the high rate of decline in milk yield of grazing dairy cows. The objective of this study was to examine the response in diet preferences and performance of lactating dairy cows when grazing a perennial ryegrass sward and having access to maize silage ad libitum simultaneously in spring, at two concentrate levels (CL) and two sward heights (SH)