Bridged Phenolic Acids in Forage Cell Walls and their Effect on Cell Wall Digestibility

Some range grasses, range legumes and fodder tree leaves were evaluated for their phenolic acids content consisting ferulic (FA), p-coumeric (p-CA) and 0-coumeric (0-CA) acids to study their ultimate effect on cell wall (CW) digestibility at different stages of growth. Phenolic acids varied in the range of 0.113–5.13 mg/g, 0.185–2.91 mg/g and 0.894–4.33 mg/g of CW for range grasses, range legumes and fodder tree leaves respectively, taking various stages of growth into consideration. FA and p-CA were the major phenolic acids involved in the bridge formation, while 0-CA was observed In non-significant amounts. In case of range legumes sand fodder tree leaves, FA was the major factor responsible for lowering the digestibility (r=-0.74 & -0.78 respectively), while in case of range grasses the lower digestibility was due to p-CA. However; the p-CA content in range grasses did not affect the digestibility significantly (r=-0.43).