Kenaf seeds as a potential supplement to sheep

Abstract

Kenaf, Hibiscus cannabinus L. is traditionally known as a fibre crop but it also produces seeds which may be a valuable protein supplement to livestock in rangelands. This study investigated the potential of kenaf seeds (KS) as a protein supplement to ruminants. Twelve merino wethers were assigned to two diets in a randomised complete block design forming two groups of six wethers each. The dietary treatments allocated to animals were mixed summer grass hay of low quality (LQH) and LQH supplemented with KS (LQHKS). Addition of KS to grass hay increased dietary dry matter intake (DMI) and organic matter intake (OMI). However, there were no differences in DM or organic matter (OM) digestibilities between dietary treatments (P>0.05). In contrast, nitrogen (N) digestibility of the LQHKS was almost twice that of LQH. There was inefficient use of N by the LQHKS animals and this was evidenced by high N excretion in urine. Even though LQHKS animals had high N excretion in urine, they retained 0.36 g/d of N compared to the LQH (–0.91 g/d). The excretion of N in faeces as a percent of N intake was significantly reduced in the LQHKS group compared to the LQH. The increased N digestion observed in LQHKS group implies that KS can be a good source of protein for ruminants but should be fed with an energy source.