Epidemiological aspects of field intoxication by Amorimia pubiflora (Malpighiaceae) in cattle in Mato Grosso and experimental reproduction of intoxication in cattle and sheep

Authors: BECKER, M - Universidade Federal De Mato Grosso; CALDEIRA, F - Universidade Federal De Mato Grosso; CARNEIRO, F - Universidade Federal De Mato Grosso; OLIVEIRA, L - Universidade Federal De Mato Grosso; TOKARNIA, C - Universidade Federal Do Rio De Janeiro; RIET-CORREA, F - Federal University Of Campina Grande; Lee, Stephen; COLODEL, E - Universidade Federal De Mato Grosso

Submitted to: Pesquisa Veterinaria Brasileira
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2013
Publication Date: 9/1/2013
Publication URL: http://handle.nal.usda.gov/10113/5498093
Citation: Becker, M., Caldeira, F.H., Carneiro, F.M., Oliveira, L.P., Tokarnia, C.H., Riet-Correa, F., Lee, S.T., Colodel, E.M. 2013. Epidemiological aspects of field intoxication by Amorimia pubiflora (Malpighiaceae) in cattle in Mato Grosso and experimental reproduction of intoxication in cattle and sheep. Pesquisa Veterinaria Brasileira. 33(9):1049-1056.

Interpretive Summary: In the county of Colniza, Mato Gross, Brazil the main limitation for livestock production is the occurrence of "sudden death" in cattle, which affects up to 50% of the livestock on some farms. In monitoring the farms over the last 10 years the presence of Amorimia pubiflora on the farm pastures has been associated with "sudden deaths" in cattle. Although cattle deaths occurred throughout the year, deaths occurred moost frequently at the beginning of the rainy season when A. pubiflora sprouts in the pastures. "Sudden Death Poisoning" was experimentally reproduced in sheep and cattle by administration of young leaves, mature leaves and fruits of A. pubiflora. In the sheep that died, the first clinical signs occurred between 34 min. and 17 hrs, 34 min. Several clinical signs were observed including engorgement of the jugular veins, muscle trembling, apathy and reluctance to move. Clinical signs in the final phase was characterized by generalized tremors and muscle contractions of the limbs, head and neck, respiratory distress, sternal and lateral recumbence or falling to the ground with peddling movements followed by death. In this study the young leaves contained 0.015% monofluoroacetate and were more toxic than mature leaves.

Technical Abstract: In the county of Colniza, Mato Grosso, the main limitation for livestock production is the occurrence of "sudden death" in cattle, which affects in some farms up to 50% of the herd. In visits to some of the farms where the problem occurred, in 2004, 2011 and 2012, the presence of Amorimia pubiflora on the pastures was associated with the occurrence of "sudden deaths" in cattle. The deaths occurred throughout the year, however more frequently at beginning of the rainy season, when A. pubiflora sprouts in the grazing areas. The poisoning was experimentally reproduced in sheep and cattle by the administration of young leaves of the plant collected during two seasons, and in sheep by the administration of mature leaves and fruits. In the sheep that died, the first clinical signs were observed between 34min and 17h34min after the administration of the plant, and the clinical course varied from 3min to 15h20min, with a final peracute phase of 3 to 21 minutes. The main clinical signs were tachycardia, engorgement of the jugular veins, muscle trembling, apathy and reluctance to move, which were more evident when the animals were moved. The peracute final phase was characterized by generalized tremors and muscle contractions mainly of limbs, head and neck, respiratory distress and abdominal respiration, sternal and quick lateral recumbence or falling to the ground with peddling movements, opisthotonus, nystagmus, nystagmus and cyanosis of the oral mucosa, followed by death. The young leaves of A. pubiflora, independent of the collection period, were more toxic and caused death of sheep and cattle after ingestion of 2g/kg and 3g/kg respectively. Mature leaves caused death at the dose of 20g/kg, and the fruits at 5g/kg. The young leaves contained 0.015% of sodium monofluoracetate which is responsible for clinical signs of the "sudden death". These findings show the importance of Amorimia pubiflora for cattle raising in Midwestern Brazil. The plant is toxic also for sheep causing a clinical picture similar to that reported in cattle poisoned by monofluoracetate-containing plants.