Nutritional effects of using cactus cladodes (Opuntia stricta Haw Haw) to replace sorghum silage in sheep diet

The aim of the present study was to evaluate the effects of replacing the sorghum silage in sheep diet with cactus cladodes [CC - Opuntia stricta (Haw) Haw] on dry matter and its compound intake and digestibility, feeding behavior, and nitrogen balance. The diets consisted of five replacement levels [0, 200, 400, 600, and 800 g/kg on a dry matter (DM) basis] and were formulated to be isonitrogenous [140 g/kg crude protein [CP], considering the ingredients' composition, with a roughage/concentrate ratio of 65:35, on a DM basis. Five uncastrated crossbred sheep, with an average body weight of 52.9 ± 6.0 kg, were assigned to a 5 × 5 Latin square. The trial lasted for 105 days with five consecutive 21-day periods, divided into 14-day adaptation and 7-day sampling periods. Dry matter (DM), organic matter, non-fiber carbohydrate (NFC), total digestible nutrient intake, and DM and NFC digestibility, increased (P ≤ 0.04) with the replacement of sorghum silage by CC. However, the time spent feeding and ruminating decreased, while idle time increased (P ≤ 0.03). Only feeding and rumination efficiency of DM improved (P ≤ 0.01) with the replacement, whereas feeding and rumination efficiency of neutral detergent fiber corrected to ash and protein did not. Nitrogen intake and nitrogen balance were not influenced, and urinary volume increased (P ≤ 0.01) with the addition of CC in the diet. In conclusion, we recommend replacing 80% of the sorghum silage with CC in sheep diets (with 35% concentrate), as CC was found to substantially increase the intake of nutrients, primarily energy.