Early weaned lambs have been successfully reared to slaughter on ad libitum concentrate diets for many years, mainly in systems involving out of season lamb production where high market prices offset the comparatively high feed costs. In these systems maximum growth rates are required to enable lambs to reach acceptable slaughter weights before market prices fall.

Feeding systems may be based on whole cereals supplemented with small, high protein pellets, a technique developed from Rowett studies (Orskov et al, 1974) or home made blends of processed cereals and by-products or proprietary concentrates. Component selection Is a common problem with diets based on whole grains and although this can largely be overcome by correct feeder design this incurs considerable expense. Diet selection can be reduced by processing grain (eg on farm rolling) or by pelleting. Cereal processing and pelleting however can have deleterious effects on rumen function as described by Orskov (1973), the effects being attributed to both inadequate saliva production and reduced rumen surface stimulation by roughage.