lnterest of multi-species swards for pasture-based milk production systems

The objective of this 2-year study was to determine the potential ofmulti-species swards (MSS) for making secure forage availability in grazing dairy systems, and for increasing milk production on a per-ha basis. Four types of sward with increasing number of sward species (fi-om pure perennial ryegrass to a mixture of five species including perennial ryegrass, two clovers, chicory and tall fescue) were compared with four block replicates. Treatments within blocks were simultaneously grazed by four homogeneous dairy herds at the same pasture allowance. Total grazing days per season or per year were unaffected by treatment, but milk output per ha was greater for grass-legume mixtures and MSS compared to pure perennial ryegrass swards. This was related to greater milk production per cow and per day. It is concluded that, under favourable weather conditions particularly in late spring and early summer, advantages of MSS on milk output on a per-ha basis are main! y due to an improved per-cow production rather than to increased pasture herbage production and grazing days/ ha