Cyanogenic poisoning by spontaneous ingestion of star grass (Cynodon nlemfuensis var. nlemfuensis cv. ‘Florico’) in cattle

Abstract

This study reports the epidemiological data and the clinical-pathological condition of five outbreaks of cyanogenic poisoning in cattle spontaneously ingesting star grass (Cynodon nlemfuensis Vanderyst var. nlemfuensis cv. ‘Florico’). In all outbreaks, the areas where the plant was previously fertilized with high concentrations of nitrogen and the properties adopted the silvipastoral system. The first clinical signs appeared between 10 and 15 minutes after the first introduction of cattle and were characterized by muscular tremors, dyspnea, moderate tympanism, staggering gait, forced breathing with open mouth, sternal recumbency followed by death after 15 to 30 minutes and/or recovery in a few hours after the signs started. In total, 43 cows have become ill and 18 died. Two necropsies were performed and no significant changes were found except for the presence of the plant near the esophageal sphincter region. No histological lesions were seen through microscopy. Green leaves of the star grass were collected from all properties where the outbreaks occurred and the test of the picro-sodium paper was performed, revealing red-brick coloration in 20 minutes after maceration of the leaves.

Experimental reproduction of cyanogenic poisoning by star grass (Cynodon nlemfuensis Vanderyst var. nlemfuensis cv. “Florico”) in cattle

“…Similarly, the paddocks in a shaded area with more fertilization resulted in a stronger reaction to the sodium picrate paper test. This is in accordance with what occurs in the spontaneous poisoning described by Molossi (2019). Vetter & Haraszti (1977), observed that the HCN production in Sorghum spp.…”

“…The use of cv. Florico star grass cultivated in the shade provided the accumulation of hydrocyanic acid in the plant and its consumption by the bovines resulted in cyanogenic poisoning (Molossi 2019).…”

Plants causing poisoning outbreaks of livestock in South America: A review

“…In Brazil, other cyanogenic plants such as Anadenanthera macrocarpa and Piptadenia viridiflora (Fabaceae) ( Tokarnia et al, 1999b , 2012 ), Cnidoscolus phyllacanthus (Euphorbiaceae) ( Oliveira et al, 2008 ), and Passiflora foetida (Passifloraceae) ( Carvalho et al, 2011 ) cause poisoning in the Northeast region; while Prunus sellowii (Rosaceae), Cynodon spp. (Poaceae), and Sorghum sudanense cause poisoning in the southern region ( Gava et al, 1992 ; Juffo et al, 2012 ; Molossi et al, 2019 ; Gris et al, 2021 ).…”