18. Evaluation of Spineless Cactus (Opuntia ficus-indicus) as an Alternative Feed and Water Source for Animals During Dry Season in Eritrea

Throughout East Africa, animal feed resources fluctuate seasonally and are often of limited availability. Finding alternative feed resources that can sustain animal production during the long dry season is an essential need. Cactus is a drought tolerant and succulent feed resource available throughout the year in Eritrea. This study was conducted to evaluate the effect of increasing levels of spineless cactus inclusion in the diet of sheep fed urea-treated barley straw. Twenty-four fat-tailed Highland male sheep with a mean live weight of 21.1 kg were randomly assigned into four treatments (T1–T4). Animals in T1 received ad libitum amount of urea (5%) treated barley straw (UTBS) alone, while those in T2, T3 and T4 received ad libitum UTBS supplemented with 175 g, 350 g and 525 g of spineless cactus (dry matter basis), respectively. With increasing level of cactus, there were significant increases in DMI (p < 0.001) and body weight performance (p < 0.05), while water consumption decreased (p < 0.001). The highest DMI was found in the last two treatments (101.8 and 96.5 g/kgBW^0.75d, respectively) as compared to the first two treatments (94.4 and 87.6 g/kgBW^0.75d). The water intake was significantly decreased with the progressive increase in cactus. The highest body weight gain (51.9 g/day) was found when sheep received 350 g dry matter (DM) of cactus (T3), while the lowest was in the control diet (26.8 g/day). The metabolism trial demonstrated that available energy intake was directly related to performance in the feeding trial. In conclusion, feeding cactus with UTBS can significantly increase animal performance and feed intake, and reduced water intake.