Spontaneous and experimental poisoning by Froelichia humboldtiana in cattle

Abstract

The aim of this work was to describe the epidemiological, clinical and pathological aspects of two outbreaks of spontaneous poisoning caused by Froelichia humboldtiana in cattle in Pernambuco, northeastern Brazil and reproduce experimentally this poisoning in cattle. Spontaneous poisonings of primary photosensitization occurred in two farms at the municipalities of Cachoeirinha and São Caetano and affected twenty-two adult bovines and two suckling calves after the rainy season. All bovines have recovered 21 days after they were removed from the pasture. To reproduce experimental poisoning, three cows and a calf were maintained in a pasture with 1ha composed by F. humboldtiana during 14 days. Clinical signs and skin lesions were similar in both spontaneous and experimental poisoning and consisted of cutaneous itching and hyperemia of non-pigmented areas of skin that evolved into edema, exudative dermatitis and extensive areas of skin necrosis. Serum levels of aspartate aminotransferase (AST), gamma glutamyltransferase (GGT), total, direct and indirect bilirubin were normal in all cattle examined. Histologically, lesions consisted of epidermal necrosis, hyperkeratosis with large amounts of degenerate neutrophils and acanthosis. In the dermis, edema and inflammatory infiltrate composed of eosinophils, lymphocytes and plasma cells mainly around the blood vessels were observed. In the experimental group, clinical signs of photosensitization were observed after the third day of F. humboldtiana consumption. The suckling calf displayed mild clinical signs of photodermatitis on the 8th day of the experiment. It was estimated that the average consumption of F. humboldtiana necessary to initiate clinical signs in each adult bovine was 78kg.

Primary Photosensitization by Chamaecrista serpens in Santa Inês Sheep

“…In this research, serial biochemical evaluations (liver function) did not show any liver damage, which, added to the absence of macroscopic and histological liver changes, ruled out the initial suspicion of hepatogenous photosensitization. Similar findings are described in cases of primary photosensitization caused by Froelichia humboldtiana [ 8 , 12 , 13 ], Malachra fasciata [ 14 ], Ammi majus [ 15 ] and Heterophyllaea pustulata [ 16 ].…”

“…Recently [ 14 ], it was demonstrated that the exclusive consumption of Malachra fasciata also caused signs of photosensitization in sheep, seven days after the beginning of ingestion of the plant. The photosensitizing effect of F. humboldtiana was reproduced in sheep and cattle, respectively, 10 and 3 days after the animals were introduced to pastures invaded by the plant [ 8 , 9 , 10 , 11 , 12 , 13 ].…”

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

“…3 C) and Chamaecrista serpens (Fabaceae, subfamily Caesalpinioideae) ( Fig. 3 D) affecting ruminants and equid ( Pimentel et al, 2007a ; ; Knupp et al, 2014 ; Silva-Filho et al, 2020 ; Mendonça et al, 2022 ), and Malachra fasciata (Malvaceae) ( Fig. 3 E) affecting sheep ( Araújo et al, 2017 ).…”