Navegando por Autor "SCHILD, Ana Lucia"

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Conditioned food aversion to Ipomoea carnea var. fistulosa induced by Baccharis coridifolia in goats
(2013-08) ADRIEN DELGADO, María de Lourdes; CORREA, Gabriela Riet; OLIVEIRA JÚNIOR, Carlos Alberto de; PFISTER, James A.; COOK, Daniel; SOUZA, Elda Ely Gomes de; CORREA, Franklin Riet; SCHILD, Ana Lucia
Baccharis coridifolia is a plant that induces strong conditioned food aversion in ruminants. This research aimed to induce a conditioned food aversion to Ipomoea carnea var. fistulosa in goats, using B. coridifolia as an aversive agent, and to compare the aversion induced by this plant with the aversion induced by lithium chloride (LiCl). Thirteen goats were allotted into two groups: Group 1 with six goats was averted with 175mg/kg of body weight of LiCl and Group 2 with seven goats was averted with 0,25g/kg of bw of dried B. coridifolia. All goats were averted on day 1 after the ingestion of I. carnea. The aversion procedure with LiCl or B. coridifolia in goats from Groups 1 and 2, respectively, was repeated in those goats that again consumed the plant during tests on days 2, 3, and 7. The goats of both groups were challenged in pens on 23 and 38 days after the last day of aversion and challenged in the pasture on days 11, 15, 18, 20, 22, 25, 27 and 29 after the last day of aversion. After this period goats were challenged every 15 days on pasture until the 330º day after the last day of aversion (7th day). Two goats from Group 1 ingested I. carnea on the first day of the pasture challenge, 4 days after the last day of aversive conditioning in the pen. In addition, another goat in Group 1 started to consume the plant on day 18, and other two goats ate it on day 20. One goat in Group 1 that had never eaten I. carnea died on day 155. One goat from Group 2 started to ingest I. carnea on the first day of the pasture challenge, and a second goat started to consume this plant on day 182. At the end of the experiment, on day 330, the other five goats averted with B. coridifolia remained averted. These results suggest that B. coridifolia or an active compound from the plant could be used to induce aversion to toxic plants. Using B. coridifolia would be cheaper and, particularly in flocks with large number of animals, possibly easier than using LiCl, which requires the use of oral gavage and qualified personnel for its implementation.
Acesso aberto (Open Access)
Evolução e reversibilidade das lesões neurológicas e cardíacas em ovinos intoxicados experimentalmente por Ateleia glazioviana e Tetrapterys multiglandulosa
(2008-03) ALMEIDA, Milton Begeres de; PRIEBE, Amanda Pantaleão da Silva; RIVERO, Beatriz Riet Correa; CORREA, Gabriela Riet; FISS, Letícia; RAFFI, Margarida Buss; SCHILD, Ana Lucia
To determine the reversibility of neurological and cardiac lesions in Ateleia glazioviana and Tetrapterys multiglandulosa poisoning, 3 groups of four sheep each were fed orally with the plants. In Group 1, 2 and 3, when sheep with nervous signs showed considerable increase of symptoms and risk of death, the plant administration was suspended. Group 4 with two sheep was used as control. Sheep from Group 1, fed 10g/kg during 6 days of fresh A. glazioviana collected in autumn were euthanized 8, 11, 16, and 21 days after the start of the experiment; they had shown regression of nervous signs, but had progressive cardiac lesions. Sheep from Group 2, fed during 8 days the same dose of fresh A. glazioviana collected in spring, were euthanized on days 9, 23, 38 and 68; they had shown regression of nervous signs and had no cardiac lesions. This suggests that the plant is less toxic in spring. Sheep from Group 3, fed 10g/kg during 11 days dry and ground T. multiglandulosa mixed with concentrated food, were euthanized on days 33, 33, 92 and 92; they had shown regression of nervous signs, and cardiac lesions were less severe on day 33 than on day 92. These results indicate that nervous lesions are reversible after the end of feeding, but cardiac lesions are progressive after discontinuation of the plant administration; these can be afterwards reversible if the animals do not anymore show clinical signs or die as a consequence of the poisoning. Results of those and previous experiments show that lesions of the nervous system are induced by lower doses than cardiac lesions and occur within a shorter period, what suggests that in spontaneous cases cardiac signs are always preceded by nervous signs, and that nervous signs can occur in the absence of cardiac lesions.
Acesso aberto (Open Access)
Intoxicação experimental por Tetrapterys multiglandulosa (Malpighiaceae) em ovinos
(2005-06) CORREA, Gabriela Riet; TERRA, Fabiano Fonseca; SCHILD, Ana Lucia; CORREA, Franklin Riet; BARROS, Severo Sales de
Cardiac fibrosis was observed in a calf showing dullness, weakening and respiratory insufficiency in a farm in the state of São Paulo, where cardiac insufficiency, abortion and nervous signs in cattle were associated with the ingestion of Tetrapterys multiglandulosa. The objectives of this paper were to determine the susceptibility of sheep to the intoxication by T. multiglandulosa, to describe the clinical and pathological characteristics of the intoxication, and to evaluate the possibility of using sheep as an experimental species for toxicological studies with this plant. In a previous experiment to determine the toxicity of T. multiglandulosa to be used in sheep, the green plant was given to a steer at the dose of 22g per kg body weight (g/kg/bw), daily, during 9 days. After 9 days the steer showed nervous signs, and on the 12thday was euthanatized. No gross lesions were observed at necropsy. Status spongiosus was observed on the deeper layers of the cerebral cortex and subcortical white matter. Six male sheep were divided in three groups of two sheep each. Group 1 (Sheep 1 and 2) received daily doses of 6 g/kg/bw of the dry plant, during 30 days; Group 2 (Sheep 3 and 4) received daily doses of 3 g/kg/bw, during 60 days; and Group 3 was the control group. Sheep 1 was euthanatized 30 days after the start of the ingestion. Only cardiac arrhythmia was observed clinically, and no lesions were observed at necropsy. Sheep 2, 3 and 4 had also cardiac arrhythmia from day 9, 12 and 18, respectively. From day 52 they started to show depression, reluctance to move and incoordination. Clinical signs got gradually worst and the sheep were euthanatized on days 60, 70 and 80, when clinical signs were marked, and the animals will die at any moment. Hydrothorax, hydropericardium, ascites, nutmeg appearance of the liver and hard whitish myocardium, mainly in the interventricular septum and left ventricle, were observed at necropsy. Histologically, the heart of Sheep 2, 3 and 4 had areas of fibrosis associated with mononuclear cell infiltration. No lesions were found in the heart of Sheep 1. The 4 treated sheep had status spongiosus in different areas of the cerebrum and brain stem, mainly of the deep layers of the cerebral cortex and subcortical white matter. Status spongiosus were also observed in the cerebellar white matter and cervical medulla. In the later the vacuolization was moderate in the white matter and mild in the grey matter. Status spongiosus were mild in Sheep 1 and moderate to severe in Sheep 2, 3 and 4. On electron microscopy it was observed that the status spongiosus is due to an intramyelinic edema. No gross or histologic lesions were observed on the two control sheep, which were euthanized on day 80 after the start of the experiment.
Acesso aberto (Open Access)
Methods of inducing conditioned food aversion to Baccharis coridifolia (mio-mio) in cattle
(2013-10) ALMEIDA, Milton Begeres de; SCHILD, Ana Lucia; PFISTER, James A.; PIMENTEL, Marcelo; FORSTER, Karine Maciel; CORREA, Franklin Riet
Three experiments were performed to determine the efficacy of various methods of averting naïve cattle to prevent Baccharis coridifolia poisoning: forced oral administration of 0.5g kg-1 body weight of fresh B. coridifolia; forced inhalation of the smoke from burning B. coridifolia and rubbing the plant on the animals' muzzles and mouths; and introducing the animals into paddocks with low invasion by B. coridifolia. Results demonstrated that cattle forced to ingest low doses become strongly averted if introduced into paddocks 23-26 hours after the aversion. In contrast, cattle introduced into the paddocks between 1-10 hours were not fully averted. Inhalation of B. coridifolia smoke, and rubbing the plant on the animals' muzzles and mouths were not efficient to induce an aversion. The introduction of cattle into paddocks with approximately 1% of B. coridifolia was efficient if the animals remained 5 months in the area, but not if they only remained for 60 hours, as cattle required sufficient time to learn to avoid the plant.