The weak economy of the Zulu could not allow them to sustain the war against the Boers and this led to their defeat.
The Zulu were disunited and therefore they could not fight and win the battle against the more united and organized Boers.
The occurrence of natural calamities like famine, which killed many of the Zulu people, weakened them thus led to their defeat by the Boers.
The poor leadership of the Zulu warriors as provided by Chief Dingane who could not mobilize his warriors properly to fight the Boers hence their defeat.
The Boers had superior weapons during the war for example they had guns that the Zulu did not have and this made it possible for the Boers to defeat them.
The Boers were determined to take over the Zulu land at all cost that is why they fought a winning battle a gainst the Zulu at the banks of the Blood River.
The Boers were more organized and it was easy for them to fight the Zulu who seem to be disorganized hence their defeat by the Boers.
The Zulu people attacked by diseases like malaria, small pox, sleeping sickness, which weakened them thus led to their defeat by the Boers at the battle of the Blood River.
The flight and the subsequent death of their leader Dingane in Swaziland greatly demoralized many of the Zulu warriors hence their defeat by the Boers.
The coming of the British in the Zulu land interfered with the affairs of the Zulu and this made it easy for the Boers to defeat them.