Vicia sativa as a grazed forage for lactating ewes in a temperate grassland production system

Here, we present research to overcome a current limitation of temperate grassland systems to provide home-grown, early season protein for lactating ewes—a period of high protein demand in these systems. Traditionally used as a forage crop, there is renewed interest in common vetch (Vicia sativa) due to its ability to grow during low temperatures over-winter compared to other legumes. We hypothesised that vetch would support the sustainable development of lamb production by reducing reliance on purchased protein typically used in grass-only systems. A grazing study determined the performance of early lactation ewes and their twin lambs grazing either an Italian ryegrass (IRG) sward or a vetch/IRG (V/IRG) mix over a six-week period. The experiment comprised replicate plots of two treatments, with 8 ewes, each rearing twin lambs, grazing each plot. Plots were divided into sub-plots using electric fencing and rotationally grazed. Findings showed i) ewes selectively grazed vetch as evidenced by a drop in vetch percentage by, on average, 10% units between the start and end of grazing; ii) vetch re-grew when rotationally grazed with a 21– 28-d rest period, with vetch percentage of the sward increasing 10% units; and iii) grazing lactating ewes on V/IRG improved combined ewe and lamb weights by five weeks post-lambing but longer term effects were limited by vetch availability. Furthermore, there was a tendency for lamb live-weight gains to be higher for lambs whose dams grazed on vetch/IRG compared to IRG swards (573 versus 563 g ewe−1 d−1, respectively, p = 0.056). As the need for alternatives to imported protein feed increases, this research demonstrates how vegetative common vetch, as part of a mixed sward, has the potential to provide a home-produced winter-grown protein feed in temperate grasslands.