Bog asphodel (Narthecium ossifragum) as a cause of photosensitisation in lambs in Norway

Abstract

In a five year experiment, 195 lambs and their dam were kept on four plots of wet moorland rich in the plant Narthecium ossifragum. The plots were top-dressed with calcium and, or, phosphorus, or given no treatment. After three years, the plant disappeared from the plots to which phosphorus had been applied, but remained where calcium only had been used. The saponin content of the plant appeared to be uninfluenced by the type of top-dressing or time of year. Photosensitisation (alveld) occurred on all plots during the first three years. During the fourth year the disease occurred only where the plant persisted. In the fifth year the disease did not occur on any plot. Alveld was produced in two lambs by the repeated administration of large quantities of saponin preparations from N ossifragum. Lambs of haemoglobin type AA were significantly more resistant to the disease than lambs with type BB. In nearly half the cases, the bromsulphthalein liver function test indicated a susceptibility to alveld up to seven days before the appearance of clinical signs. Increased bromsulphthalein retention was more common amongst AA lambs than BB lambs, but nearly all the BB lambs developed alveld, and only a few of the AA lambs. The differences were significant.

Suspected bog asphodel (Narthecium ossifragum) toxicity in cattle in North Wales

“…Non‐fatal toxicosis has also been recorded in Norway causing photosensitisation in lambs grazing pasture containing bog asphodel, the clinical signs resolving when the animals were moved to land without the plant (Laksesvela and Dishington 1983).…”

Fungi onNarthecium ossifragum leaves and their possible involvement in alveld disease of Norwegian lambs

“…Slagsvold (Ender, 1955) established that it occurred only on pastures in which N. ossifragum was present and not on similar pastures from which N. ossifragum had been removed. Laksesvela and Dishington (1983) similarly found that alveld did not occur on plots from which N. ossifragum had disappeared after phosphate applications but did on plots which had not received phosphate and in which N. ossifragum persisted. The incidence of alveld outbreaks is unpredictable and can vary from year to year at a single site, as on the untreated grazing plot of Laksesvela and Dishington (1983).…”

“…The large saponin doses needed to reproduce alveld experimentally, together with yearly and regional variations in morbidity in lambs at risk (Laksesvela and Dishington, 1983), caused speculation that saponins might not be the sole causative agent. Geeldikkop, a photosensitization of sheep grazing Tribulus terrestris L. pastures was produced experimentally by giving small doses of cultures of Pithomyces chartarum (Berk.…”

Genomic Tools for the Identification of Loci Associated with Facial Eczema in New Zealand Sheep

“…In crossbred ewes, Hb-A has been associated with beneficial effects for several health-related traits, including mastitis and parasite resistance, whereas Hb-B was associated with increased fertility [71]. In Norway, Hb-A lambs have been reported to be significantly more resistant to hepatogenous photosensitisation (alveld) as a result of ingestion of Nathercium ossifragum than Hb-B animals [72]. Hepatogenous photosensitisation, known as geeldikkop, also occurs in small ruminants grazing Tribulus terrestris in South Africa.…”