Datura contamination of hay as the suspected cause of an extensive outbreak of impaction colic in horses : clinical communication

Abstract

atura poisoning of horses is extensively reviewed. An outbreak of intractable impaction colic affecting 18 of 83 horses was stopped by withdrawing dried tef hay contaminated with young Datura plants. The dried, botanically identified Datura stramonium and D. ferox contained respectively 0.15 % mass/mass (m/m) hyoscyamine as well as 0.16 % m/m hyoscine (scopolamine) and only hyoscine at a concentration of 0.11 % m/m. Immature, unidentifiable plants resembling D. stramonium, contained 0.14 % m/m and 0.12 % m/m of the 2 respective tropane alkaloids. The outbreak was characterised by protracted and repeated colic attacks due to impaction of the large colon and/or caecum without any other anti-muscarinic signs. Comparative analyses of single specimens of dried seed of the 2 species collected from both fertilised and waste areas revealed that young South African Datura spp. had levels of tropane alkaloids comparable to those in the well-known toxic seed and were, consequently, equally toxic. The inherent danger of tef hay being contaminated with Datura is emphasised. To our knowledge this is the 1st field case of poisoning in horses ascribed to the vegetative parts of Datura spp

Confirmed Datura poisoning in a horse most probably due to D. ferox in contaminated tef hay : clinical communication

“…The fact that atropine was only detected in the urine of the horse at a very low concentration and ratio in comparison to scopolamine (namely 1:170 on Day 1) (Table 1), is in accordance with the ratio of these 2 alkaloids present in the leaves (arguably the main vegetative component ingested) of the plant (1:113) ( Table 2). These levels are also in accordance with the data generated by Naudé et al 7 and that of de Kock, Naudé and Jonker (unpubl. data, 2002) on Datura ferox occurring in South Africa.…”

“…They contain antimuscarinic, tropane alkaloids of which atropine (dl-hyoscyamine) and scopolamine (hyoscine) are the most prominent. Both alkaloids are present in D. stramonium and mainly scopolamine in D. ferox 7 (S S de Kock and L Jonker, National Horseracing Authority, unpubl. data 2003).…”

“…Datura intoxication in horses was recently extensively reviewed by Naudé et al, who reported on an extensive outbreak of impaction colic attributed to tef hay contaminated by Datura spp. 7 . Locally, contamination of grain with Datura seed has also been responsible for fatal intoxication of horses 9 .…”

“…They have, consequently, in the past not been identified in contaminated hay despite strong evidence of suspected Datura-poisoning. The disintegrated plant material becomes intermingled with the hay and cannot be avoided if this is all feed that is available to the horse 7 . Tef poses problems in feed because it is annually sown, and with Datura also being an annual weed, such hay is particularly prone to Datura infestation.…”

“…Tef poses problems in feed because it is annually sown, and with Datura also being an annual weed, such hay is particularly prone to Datura infestation. Tef should, therefore, be sprayed with a broad-leaf herbicide before it is cut for hay 7 . In equine medicine, atropine is used routinely to control the muscarinic signs of organphosphoric and carbamate intoxication.…”