Crop destruction caused by uncontrolled cattle grazing remains a major challenge for farmers in Nigeria. Unauthorized grazing by Fulani herdsmen and the due disapproval by the farmers has led to the murder of thousands innocent farmers in Nigeria for more than two decades. Conventional approaches such as fencing, physical confrontation, and lethal control methods often escalate tensions between farmers and pastoralists. This study presents the design and development of a stealth ultrasonic cattle repellent device capable of deterring cattle from entering cultivated farmland. The device named Stealth Transmitting Repellent Oscillator for Livestock Zones (STROZ) broadcasts high frequency acoustic signals in the range of 20 to 35 kHz, which are audible to cattle but largely inaudible to humans. The sound played is a loud screeching sound. The system exploits bovine neophobic behaviour, where animals tend to avoid unfamiliar stimuli. The device consists of a microcontroller based ultrasonic signal generator, a power amplification stage, and directional ultrasonic transducers. Experimental evaluations were conducted in controlled field conditions to evaluate the effectiveness of the system in repelling cattle. Results show that the system achieved an average deterrence effectiveness of 85% within a 15meter radius. The proposed device provides a non violent technological solution for reducing crop damage and mitigating farmer-herder conflicts.