Silage finishing systems have been developed for store lambs, the type and level of supplement required depending on the quality of forage available (Butler, 1985). Under the requirements laid down by the United Kingdom Register of Organic Food Standards (UKROFS), restrictions are made on both the total quantity of concentrates and the protein source fed. While some work has been carried out on alternative sources of protein in the diets of finishing lambs (Yilala and Bryant, 1985), little informantion is available on the use of beans under UK conditions.

The objective of this experiment was to assess the potential of beans as an alternative protein source for lambs fed to UKROFS standards on a basal ration of baled silage.

One hundred and forty four approximately six month old Scottish Blackface wether lambs (mean liveweight 33.6 kg, se = 0.23) were housed off silage aftermaths. Following an acclimatisation period of twelve days, these were randomly allocated in pens of 12 to one of four treatment groups depending on the type of concentrate fed - beans (B), 50/50 barley/beans (BB), barley/soya (BS) and barley/fishmeal (BF). A mineralised supplement of 400 g of concentrate was fed daily in each case. Moderate quality baled silage (dry matter (DM) 307 g/kg, metabolisable energy 9.4 MJ/kg DM, crude protein 129 g/kg DM) was available to appetite, with fresh material offered twice daily. The barley component of the rations was rolled: beans were fed whole.