Effects of form of leftover khat (Catha edulis) on feed intake, digestion, and growth performance of Hararghe Highland goats

Khat (Catha edulis) is a lucrative cash crop in many African countries and other areas of the world. Leftover khat can be used as a feedstuff for ruminants, although seasonal production limits the extent of utilization. Practical methods of feed conservation to preserve nutritional value would be beneficial. Thus, a study was conducted to investigate effects of feeding different forms of leftover khat on intake, digestion, and growth performance of a tropically adapted indigenous goat genotype of eastern Ethiopia. Twenty-four (six per treatment) individually housed Hararghe Highland yearling male goats with an initial body weight of 18 ± 0.4 kg were used in an on-station experiment, and 32 similar yearlings with an initial body weight of 19 ± 0.4 kg were employed under on-farm conditions. The on-farm experiment occurred at two villages, with four farmer groups (two farmers per group co-managing animals) per village. Four animals in each farmer group were subjected to each of the four different treatments. Experiments were 90 days in length, with inclusion of a subsequent 10-day period on-station to determine digestibility. Khat in fresh, dry, and silage forms was fed at 1.5% body weight (dry matter; DM), whereas control animals did not receive khat. Animals on-station consumed grass hay ad libitum and those on-farm grazed/browsed surrounding areas. Grass hay DM intake on-station was greater (P < 0.05) without than with khat (528, 358, 387, and 368 g/day; SE = 20.3), although total DM intake was increased by feeding khat regardless of form (528, 649, 622, and 639 g/day for control, fresh, dry, and silage, respectively; SE = 22.9). Digestibility of organic matter was increased (P < 0.05) by feeding each form of khat (62.3%, 75.7%, 75.2%, and 72.4% for control, fresh, dry, and silage, respectively; SE = 1.63). Nitrogen balance was increased by fresh and ensiled khat (P < 0.05) (−0.54, 2.07, 0.80, and 0.86 g/day for control, fresh, dry, and silage, respectively). Average daily gain (ADG) was increased by khat regardless of form on-station (13, 49, 33, and 39 g; SE = 4.6), and on-farm ADG was less for control than for fresh and dry forms (P < 0.05) (32, 56, 47, and 42 g for control, fresh, dry, and silage, respectively SE = 2.0). The ratio of ADG:DM intake on-station was lower for control than for fresh (P < 0.05) and silage (P < 0.05) (26, 76, 54, and 61 g/kg for control, fresh, dry, and silage, respectively; SE = 7.6). In conclusion, feeding leftover khat to Highland goats consuming low to moderate quality forage-based diets can increase growth performance. Khat can be preserved for use as a feedstuff throughout the year by drying or ensiling without marked effect on performance.