Effects of Dietary Sunflower Hulls on Performance and Rumen Fermentation of Pregnant Naemi Ewes: A Sustainable Fiber...

(1) Background: In arid regions, limited forage availability increases feeding costs for small ruminants. Sunflower hulls (SFH), a low-cost agro-industrial by-product, may serve as an alternative fiber source, yet their effects on pregnant Naemi ewes remain unclear. This study aimed to evaluate how graded levels of SFH affect intake, digestibility, rumen fermentation, and metabolic responses during gestation and early lactation. (2) Methods: Eighty-four ewes were assigned to diets containing 0%, 12%, 20%, or 28% SFH in a total mixed ration and monitored across early gestation, late gestation, and lactation. (3) Results: Increasing SFH significantly increased dry matter intake, with the highest intake in the 28% SFH group (p < 0.05). Body weight remained unaffected, whereas body condition score varied by physiological stage. Digestibility of major nutrients was unchanged; however, acid detergent lignin digestibility increased at 28% SFH (p < 0.05). Higher SFH levels (20-28%) reduced total volatile fatty acids by approximately 12-18% and lowered acetate and propionate concentrations, especially in late gestation. Blood metabolites differed among treatments but remained within physiological reference ranges, confirming metabolic safety. (4) Conclusions: SFH can be safely included at up to 28% of diet dry matter; however, 12-20% SFH appears most practical, supporting adequate fiber intake without compromising rumen fermentation efficiency. This provides a cost-effective strategy for ewe feeding under forage-limited arid conditions.