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United States Department of Agriculture

Agricultural Research Service

Title: Fetotoxic Effects of Locoweed (Astragalus lentiginosus) in Pregnant Goats

Authors
item Furlan, S - UNIV. SAO PAULO
item PANTER, KIP
item PFISTER, JAMES
item STEGELMEIER, BRYAN

Submitted to: Poisonous Plant Global Research and Solutions
Publication Type: Book / Chapter
Publication Acceptance Date: May 31, 2006
Publication Date: June 20, 2007
Citation: Furlani, S., Panter, K.E., Pfister, J.A., Stegelmeier, B.L. 2007. Fetotoxic Effects of Locoweed (Astragalus lentiginosus) in Pregnant Goats. Poisonous Plants Global Research and Solutions, Chpt. 22, pp. 130 - 135.

Interpretive Summary: There has been a substantial amount of research in sheep given locoweed from 60 to 130 days of gestation. Even so, there has been no research on fetotoxic effects of locoweed during gestation days 30-60, and little has been done to describe the effect of poisoning in pregnant goats. Thus the purpose of this study was to describe the clinical and fetal effects of locoweed poisoning in pregnant goats. Ten hand-mated pregnant goats were dosed with finely ground specklepod locoweed (Astragalus lentiginosus) for 30 days beginning on day 30 of gestation. Blood was collected periodically and analyzed for swainsonine, the locoweed toxin. Fetal movement was measured using ultrasound every 5 days. Locoweed poisoned goats developed clinical signs (impaired movement) within 9 to 10 days of treatment. These clinical signs became more severe with poisoned animals becoming lethargic and hesitant to move. Several animals developed severe rear limb weakness and paralysis. All pregnant goats, including treatment and controls, had viable fetuses on day 30 when the treatments began, and embryonic vesicles appeared normal between days 30-32. Fetal movement was detected in most animals by day 36. All fetuses where killed by locoweed dosing. By treatment day 5 (day 35 of gestation) one fetus had no visible fetal heartbeat and it was presumed dead. The other four goats developed similar fetal death on treatment days 10, 15 (2 animals), and 20. Locoweed dosing to pregnant goats killed every fetus; the same result could be expected under grazing conditions if pregnant goats consume locoweeds with high concentrations of toxic alkaloids.

Technical Abstract: There has beena substantial amount of research in sheep given locoweed from 60 to 130 days of gestation. Even so, there has been no research on fetotoxic effects of locoweed during gestation days 30-60, and little has been done to describe the effect of poisoning in pregnant goats. Thus the purpose of this study was to describe the clinical and ultrasonographic effects of locoweed poisoning in pregnant goats. Ten hand-mated, pregnant goats were dosed with finely ground Astragalus lentiginosus via gavage for 30 days beginning on day 30 of gestation. The dose was adjusted to deliver 8 mg swainsonine/kg body weight. Five similaly-bred goats were dosed with similar volumes of ground alfalfa hay as negative controls. Serum was collected periodically and analyzed for swainsonine. Fetal movement was measured using ultrasound every 5 days. Locoweed poisoned goats developed mild proprioceptive dficits with 9 to 10 days of treatment. These clinical signs became more severe with poisoned animals becoming lethargic, hesitant to move, prominent intention tremors and proprioceptive deficits. Several animals developed severe rear limb weakness and partial paresis. Serum swainsonine was rapidly elevated in treated goats, reaching concentrations of > 400 ng/ml after one day. All pregnant goats, including treatment and controls, had viable fetuses on day 30 when the treatments beta, and embryonic vesicles appeared normal between days 30-32. Fetal movement was detected in most animals by day 36. All fetuses were fatally impacted by locoweed dosing. By treatment day 5 (day 35 of gestation) one fetus had no visible fetal heartbeat and it was presumed dead. The other four goats developed similar fetal death on treatment days 10, 15 (2 animals), and 20. Histologically, fetuses were autolytic with no histologic vacuolation suggestive of locoweed poisoning. All of the poisoned does had neurovisceral vacuolation characteristic of locoweed poisoning.

Last Modified: 9/29/2014
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