The effects of forage supplements on the ingestive behaviour and production of dairy cows grazing ryegrass only or mixed ryegrass and white clover pastures

The effects on milk yield and feeding behaviour of offering ryegrass silage (r), ryegrass and white clover silage (c), or grass hay (h) supplements we re examined for cows grazing a ryegrass pasture (R) or a ryegrass and white clover pasture (C). The chemical composition oft he two silages was simila r brit the hay contained less crude protein. Cows grazing R pasture spent l onger feeding on c than r silages, and those consuming the c silage spent l ess time grazing than those consuming r silage. The cows grazing the C past ure spent longer feeding on r than c silages, and those consuming the r sil age spent less time grazing than those consuming c silage. The cows' intake of hay dry matter (DM) was less than silage DM and it was taken into the m outh at a slower rate, masticated more and swallowed less frequently than s ilage. Milk yield and composition were not affected by the type of suppleme ntary forage or pasture type. Thus cows grazing pastures of the two sward t ypes spent longer feeding on forages with dissimilar botanical composition if given the option. However, as this reduced the time that they spend graz ing there was no effect on milk production.