Red clover-grass, Persian clover, and common fetch that are generally grown for green manuring in organic cropping cycles, are also valuable forages for the feeding of pigs. They could substitute up to 30% of concentrates (on dry matter basis) in the feeding of growing pigs without negative impact on nitrogen (N) retention. This indicates that protein and amino acids of these legumes are well digested and utilised by the pigs. However, inclusion of roughage to pig diets shifts N utilisation so that N excretion to faeces is increased while N excretion to urine is decreased. Persian clover, in particular, is an intriguing roughage for pigs as its protein contains more amino acids that that of red clover-grass or common vetch. In addition, the digestibility of fibre is good in Persian clover, due to lower cellulose and lignin content in the fibre fraction. In practice, the voluntary feed intake of roughages remains lower, from 5% to 20% of pigs’ dry matter intake depending on the production phase
