Growth Performance, Carcass Characteristics and Economic Viability of Nguni Cattle Fed Diets Containing Graded Levels of <em>Opuntia ficus-indica</em>

Abstract

Given the severe droughts caused by global warming, smallholder beef cattle farmers are faced with serious forage and feed scarcity. This becomes worse for resource-poor farmers who cannot afford commercial feeds. It is therefore crucial to assess the use of low-cost alternative feed resources to supplement free-range beef cattle and ensure sustainable livestock production in ways that stimulate free-range beef farmers’ participation in mainstream beef market. In an attempt to improve free-range beef cattle herds and explore the economic viability of utilizing Opuntia ficus-indica (spineless cactus) cladodes as a supplementary feed, we investigated the impact of cactus diets on animal growth performance and carcass characteristics of Nguni cattle heifers. Four dietary treatments were randomly assigned to thirty-two heifers aged 24 months, weighing, on average, 172.20 ± 27.10 kg, with each dietary treatment replicated to eight individually penned heifers for 90 days. The dietary treatments were control diet (pasture-based energy + protein sources), 10% cactus diet, 20% cactus diet and commercial diet (crop-based energy and commercial protein source). The energy concentration of the control diet was 9.35 MJ/Kg DM and the cactus was included on dry matter basis during formulation of compound diets. Thus, cactus was administered in a dry rather than wet form. The animals were confined in feeding pens 24/7 without access to pasture, with feed and water provided ad libitum. The heifers fed commercial and control diets attained significantly (p 45min and 24h were comparable (p > 0.05) between heifers fed cactus diets and those fed commercial and control diets. The 10 and 20% cactus diets had greater gross margins (p < 0.05) of $17.47 and $18.62, respectively, than the other diets, due largely to reduced total variable costs. The comparability of carcass traits of heifers fed cactus diets and those fed non-cactus diets as well as higher economic returns from cactus inclusion warrants the use of cactus diets, particularly during drought when commercial feed prices rise.

Keywords

• animal growth performance
• carcass traits
• economic returns
• Nguni cattle heifers
• spineless cactus diets