Only one battle of the jihad, the December 1804 defeat at Tsuntua, carries a specifically sourced casualty figure, and no historian has reconciled or extended that single data point into a war-wide total across the four years of campaigning that followed against Kebbi, Katsina, Daura, Kano and Gobir.
What would resolve this A study working systematically from surviving Arabic-language chronicles of the jihad, including Muhammad Bello's own history of his father's campaigns, cross-checked against Hausa oral and written tradition, to build a reconciled casualty estimate across the war's major engagements and its civilian displacement.
OpenWest African Islamic history; Hausa and Fulani chronicle sourcesMervyn Hiskett, The Sword of Truth: The Life and Times of the Shehu Usuman dan Fodio