They were lost; or perhaps they had felt the urgent need of trekking from Zululand back to a more peaceful country.

I sent all the hunters I had with me to look for them, only Scowl and I remaining at the wagons, which in those disturbed times I did not like to leave unguarded.
Four days went by, a week went by, and no sign of either hunters or oxen.

Then at last a message, which reached me in some roundabout fashion, to the effect that the hunters had found the oxen a long way off, but on trying to return to Nodwengu had been driven by some of the Usutu--that is, by Cetewayo's party--across the Tugela into Natal, whence they dared not attempt to return.
For once in my life I went into a rage and cursed that nondescript kind of messenger, sent by I know not whom, in language that I think he will not forget.

Then, realising the futility of swearing at a mere tool, I went up to the Great House and demanded an audience with Panda himself.
Presently the inceku, or household servant, to whom I gave my message, returned, saying that I was to be admitted at once, and on entering the enclosure I found the King sitting at the head of the kraal quite alone, except for a man who was holding a large shield over him in order to keep off the sun.
He greeted me warmly, and I told him my trouble about the oxen, whereon he sent away the shield-holder, leaving us two together.
"Watcher-by-Night," he said, "why do you blame me for these events, when you know that I am nobody in my own House?
I say that I am a dead man, whose sons fight for his inheritance.

I cannot tell you for certain who it was that drove away your oxen.