Effects of Piliostigma Thonningii (Schumach.) milne-rech essential oil supplementation on reproductive performance, semen quality, and fertility indices in bunaji bulls

This study examined the impact of camel’s foot essential oil, also known as Piliostigma thonningii seed essential oil (Milne–Rech seed essential oil, MSEO), on the reproductive performance of Bunaji bulls. Piliostigma thonningii was selected because its seeds are rich in bioactive phytochemicals, including phenolics, flavonoids, and terpenoids, which have demonstrated antioxidant, antimicrobial, and endocrine-modulating properties capable of enhancing testicular function, spermatogenesis, and semen quality. In addition, the plant is widely available in tropical savanna ecosystems, making it a cost-effective and sustainable phytogenic alternative to synthetic reproductive enhancers. A completely randomized design was used to allocate fifteen clinically healthy bulls (aged 22–24 months; average body weight: 160.55 ± 0.60 kg) to three dietary treatments. For 16 weeks, bulls were fed a common basal diet supplemented with 0 ml/kg MSEO (T1, control), 10 ml/kg MSEO (T2), or 20 ml/kg MSEO (T3). Dietary treatments did not affect semen pH or its creamy white coloration (P > 0.05). However, MSEO supplementation significantly increased (P < 0.05) sperm concentration and ejaculate volume, with T3 recording the highest values. Sperm motility, percentage of live sperm, and live-to-dead sperm ratio were significantly improved (P < 0.05) in T2 and T3 compared with the control. Conversely, bulls in T3 exhibited the lowest proportions of dead and morphologically abnormal sperm cells (P < 0.05). Percentages of normal sperm cells and certain sperm abnormalities, including midpiece droplet, coiled tail, detached head, free tail, and bent tail, were not significantly affected by dietary treatment (P > 0.05). Scrotal length and circumference increased significantly (P < 0.05) with MSEO inclusion, with the highest values observed in T3. In conclusion, dietary supplementation with 20 ml/kg MSEO enhanced testicular development and semen quality without adverse effects, supporting its potential use as a natural, sustainable phytogenic alternative to synthetic reproductive enhancers in bull production systems.