NUTRITIONAL EVALUATION OF CACTUS CLADODES AND OTHER SELECTED BROWSE SPECIES AND THE EFFECT OF SUPPLEMENTATION OF ACACIA SALIGNA AND CACTUS CLADODES ON PERFORMANCE OF GOATS IN EASTERN ZONE OF TIGRAY, NORTHERN ETHIOPIA

Abstract

This research, conducted across the eastern zone of Tigray, Ethiopia, integrated four interrelated activities to enhance local goat production. The primary objectives were to: (1) assess the goat production system, cactus (Opuntia ficus-indica) production, and its utilization; (2) evaluate the nutritive value of five cactus cultivars (Dekik, Korem, Lematse, Tsaeda, and Keyh) and selected browse species; (3) evaluate the effect of supplementing with cactus cladodes, Acacia saligna, wheat bran, and cottonseed cake on performance goats; and (4) To evaluate the influence of the concentrate substitution regime (using Acacia saligna and cactus cladodes) on semen quality, the meat composition, the semen quality and the physico-mechanical and chemical characteristics of leather derived from Central Highland goats. A survey of 151 households in four districts (Wukro-Kilte-Awlaelo, Atsbi-Womberta, Ganta-Afeshum, and Saesie-Tsaeda-Emba) confirmed that goats are the predominant and most valuable livestock, primarily raised for breeding and subsequently for income generation. The average household kept 12.78 goats and had 15 years of experience. Feed resources varied by season, with natural grasses and browse used in the wet season, and crop residues, cactus cladodes, and browse dominating the dry season. Key browse species included Acacia abyssinica, Carisa edulis, Acacia saligna, and Dodonaea viscosa. Constraints to goat production included land, water, and labor shortages. Cactus is cultivated mainly as a food source, but 68% of households also feed it to their animals, often as a supplement to crop residues. The Keyh cultivar was the most abundant, widely utilized for food and feed, and had the highest fruit production potential. However, bloating from cactus feeding, often treated with dissolved detergent, was a major concern. Nutritive analysis of five browse species and five cactus cultivars showed considerable differences. Among browse, D. viscosa was superior, recording the highest crude protein (CP) content (17.73\%) and highest in vitro dry matter digestibility (IVDMD) (70.47\%) during the wet season. Among cactus, the Keyh cultivar showed the highest IVDMD (70.59\%), while Lematse had the highest CP (11.17\%) in the wet season. A feeding trial with 24 goats tested the replacement of concentrate (cottonseed cake, CSC) with cactus and Acacia saligna (AS); Goats on Treatment 4 (T4), which involved a partial replacement of 35 gDM CSC with 40 gDM AS and 80 gDM cactus cladodes (CC), showed the highest dry matter intake, average daily body weight gain, feed conversion efficiency, hot carcass weight, and dressing percentage. In the final experiment, goats supplemented with Treatment 3 (T3) (45 gDM CSC + 80 gDM AS) produced the highest quality semen, characterized by larger testicle size, higher progressive and mass motility, and higher semen concentration. T3 also resulted in higher goat meat fat content. Regarding leather, partially replacing CSC with either Acacia saligna or a combination of AS and CC produced leathers with physico-mechanical and chemical properties (e.g., tensile strength and tear resistance) comparable to those of goats supplemented with sole concentrate(containing 80 gDM/dayCSC) in terms of meat composition and leather characteristics.