Greater farmer investment in well-formulated diets can increase liveweight gain and smallholder gross margins from cattle fattening

Abstract To improve the productivity of smallholder cattle fattening, farmers will need to invest in higher quality concentrate-based diets which provide a return greater than the additional feed costs. This research assessed two formulations of elephant grass, cassava bagasse, palm kernel cake and copra meal mixes for average daily liveweight gain (ADG) and income over feed cost (IOFC), compared to a forage diet in a pen experiment; and then evaluated the best performing diet as a supplement to existing smallholder bull fattening diets in villages in East Java, Indonesia. In the pen experiment, 24 Ongole bulls were allocated to three treatment diets fed at 25 g DM/kg liveweight.day in a 12-week randomised block experiment: 1) Elephant grass only; 2) a simplified feedlot diet (elephant grass, cassava bagasse, palm kernel cake and copra meal at 4.9, 9.8, 4.9 and 4.9 g DM/kg liveweight.day, respectively); and 3) a high cassava bagasse inclusion diet (elephant grass, cassava bagasse, palm kernel cake and copra meal at 4.9, 17.1, 1.2 and 1.2 g DM/kg liveweight.day, respectively). Intake and ADG were recorded. In the village experiment, 46 smallholder-managed Ongole crossbred bulls were randomly allocated to a control or intervention treatment group. Intervention group farmers fed their bulls 4 kg DM/day of the concentrate mix from the simplified feedlot diet in addition to normal feeding. Costs and returns, ADG and feeding were recorded. IOFC was calculated for both experiments and sensitivity-tested for variation in cattle price and opportunity cost of labour for harvesting home-grown feeds. In the pen experiment, the simplified feedlot diet yielded the highest ADG at 1.00 kg/day, with high cassava and elephant grass both yielding 0.23 kg/day. The purchased feed cost of gain was lowest for elephant grass (nil), followed by the simplified feedlot and the high cassava diets (9831 and 26708 IDR/kg liveweight, respectively). However, the high ADG in the simplified feedlot diet made that the most profitable diet, with an IOFC of IDR 27673, compared to IDR 2603 and IDR 8156 for the high cassava and elephant grass diets respectively. Including opportunity cost of labour for harvesting grass made simplified feedlot even more advantageous. When the concentrate from the simplified feedlot diet was fed to village bulls, ADG and daily feed cost doubled from 0.6 kg/day and IDR 6523/day, respectively, for control group bulls to 1.2 kg/day and IDR 11069/day for intervention bulls. However, IOFC did not improve with the intervention supplement when growth rates were already high, for example, when cattle were already fed high amounts of rice-bran or forage tree legumes. When opportunity cost of household labour for harvesting forages was included, most grass-based village diets became unprofitable. Even when the return per kg of liveweight gain is reduced by higher feed costs, if this results in higher ADG, then the IOFC of this strategy can far exceed least-cost feeding strategies for fattening cattle.