In Southland lambs are processed from November to May, resultmg in inefficient use of processing facilities and an inability to meet some market requirements for a continuous supply of product. However, spreading of lamb slaughter is hindered by the seasonal pattern of pasture growth and climatic conditions in Southland. Grasslands Diviston DSIR, Mervyn Dillon and Challenge Meats Ltd are now co-operating in a programme to overcome the pasture growth and cllmatlc constraints to extend the period of lamb slaughter in Southland. In the first part of the study silage alone or m various combmatlons wth gram was fed to lambs in wmter. Silage-fed lambs wth a high proportion of grain grew at the best and most consistent rates. Silage-fed lambs without grain supplements had inconsistent weight gams and a growth response so vanable that treatments ended early. Weight gains for grass-fed lambs were affected by preconditioning on to silage and reduction in the feed supply during wmter. However, pasture-fed lambs still produced the heaviest carcasses and greatest returns. Carcass grades had to be monitored closely to achieve maximum returns. Keywords: Southland, out-of-season lamb. lamb production. writer feeding