Oak (Quercus rubor)poisoning in cattle.

: Two outbreaks of oak poisoning in cattle in the Republic of South Africa are described. In the first outbreak 22 out of 80 head of cattle were severely affected while 40 out of a herd of 135 cattle were affected in the second outbreak. Of these 40, only one survived after 9 months despite vigorous treatment. Only young cattle under 2 years were affected during both outbreaks in spite of an average herd age of approximately 6 years in the second group of cattle. Clinical signs included severe weakness with a swaying gait, diarrhoea and dehydration. Some were pot bellied while others were emaciated and remained stunted. The most prominent macroscopic and microscopic lesion present in 3 animals autopsied, was a non-suppurative interstitial nephritis which was accompanied by oedema and ulceration of the caecum and colon. Histochemical studies were carried out on pigment granules observed in kidney sections.