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Serum elimination profiles of methyllycaconitine and deltaline in cattle following oral administration of larkspur (Delphinium barbeyi)
2009
Green, Benedict T. | Welch, Kevin D. | Gardner, Dale R. | Stegelmeier, Bryan L. | Davis, T Zane | Cook, Daniel | Lee, Stephen T. | Pfister, James A. | Panter, Kip E.
Objective--To describe the simple elimination kinetics of methyllycaconitine (MLA) and deltaline and evaluate the heart rate response in cattle following oral administration of larkspur. Animals--5 healthy Angus steers that were habituated to metabolism crates. Procedures--Tall larkspur (Delphinium barbeyi) in the early flowering stage was collected, dried, and ground. Each steer received a single dose of larkspur that was equivalent to 10.4 mg of MLA/kg and 11.0 mg of deltaline/kg via oral administration. Steers were housed in metabolism crates during a 96-hour period following larkspur administration; heart rate was monitored continuously, and blood samples were collected periodically for analysis of serum MLA and deltaline concentrations as well as assessment of pharmacokinetic parameters. Results--No overt clinical signs of poisoning developed in any steer during the experiment. Mean ± SE heart rate reached a maximum of 79.0 ± 5.0 beats/min at 17 hours after larkspur administration. Serum MLA concentration was correlated directly with heart rate. Mean times to maximal serum concentration of MLA and deltaline were 8.8 ± 1.2 hours and 5.0 ± 0.6 hours, respectively. Mean elimination half-life values for MLA and deltaline were 20.5 ± 4.1 hours and 8.2 ± 0.6 hours, respectively. Conclusions and Clinical Relevance--Following larkspur administration in 5 healthy steers, maximum serum concentrations of MLA and deltaline were detected within 10 hours, and changes in serum MLA concentration and heart rate were correlated. Results indicated that cattle that have consumed larkspur will eliminate 99% of MLA and deltaline from serum within 144 hours.
Показать больше [+] Меньше [-]Effects of larkspur (Delphinium barbeyi) on heart rate and electrically evoked electromyographic response of the external anal sphincter in cattle
2009
Green, Benedict T. | Pfister, James A. | Cook, Daniel | Welch, Kevin D. | Stegelmeier, Bryan L. | Lee, Stephen T. | Gardner, Dale R. | Knoppel, Edward L. | Panter, Kip E.
Objective--To determine whether larkspur-derived N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids alter heart rate and electrically evoked electromyographic (eEMG) response of the external anal sphincter (EAS) in cattle and whether these effects can be reversed by acetylcholinesterase inhibitors. Animals--12 beef heifers and 4 cows. Procedures--3 or 4 heifers were used in 1 or 2 of 7 dose-response experiments; heart rate and EAS eEMG response were assessed before and 24 hours after oral treatment with larkspur (doses equivalent to 0.5 to 15 mg of MSAL-type alkaloids/kg). In 3 subsequent experiments, 3 heifers (1 of which was replaced with another heifer in the control experiment) each received 10 mg of MSAL-type alkaloids/kg and were injected IV with physostigmine (0.04 mg/kg), neostigmine (0.04 mg/kg), or saline (0.9% NaCl) solution 24 hours later, prior to assessment. Additionally, EAS eEMG response was measured in 4 cows before and after epidural administration of 2% lidocaine hydrochloride. Results--Larkspur-treated heifers developed dose-related increases in heart rate and decreases in EAS eEMG response. Twenty-four hours after administration of MSAL-type alkaloids, neostigmine decreased heart rate but did not affect eEMG response, whereas physostigmine did not affect heart rate but caused a 2-fold increase in eEMG response. In cows, epidural anesthesia did not alter eEMG response, suggesting that transdermal stimulation of the EAS pudendal innervation did not occur. Conclusions and Clinical Relevance--In cattle, cardiac effects and muscle weakness or loss of EAS eEMG response induced by larkspur-derived MSAL-type alkaloids were reversed by neostigmine or physostigmine, respectively. Treatment with anticholinesterase inhibitors may alter the clinical effects of larkspur poisoning in cattle.
Показать больше [+] Меньше [-]Evaluation of immunohistochemical detection of prion protein in rectoanal mucosa-associated lymphoid tissue for diagnosis of scrapie in sheep
2009
Dennis, Michelle M. | Thomsen, Bruce V. | Marshall, Katherine L. | Hall, S Mark | Wagner, Bruce A. | Salman, Mo D. | Norden, Dianne K. | Gaiser, Charles | Sutton, Diane L.
To determine the suitability and estimate the sensitivity of an immunohistochemical (IHC) test for disease-associated prion protein (PrP(Sc)) in biopsy specimens of rectoanal mucosa-associated lymphoid tissue (RAMALT) for diagnosis of scrapie in sheep. 762 sheep at high risk for having scrapie and indemnified by the National Scrapie Eradication Program. The IHC test for PrP(Sc) was applied to 2 RAMALT and 2 third-eyelid biopsy specimens and a postmortem RAMALT specimen from each sheep. Results were compared with those of a reference test in which results for tissues from obex and retropharyngeal lymph nodes, tonsil, or both were considered in parallel. The reference test identified 139 sheep as having scrapie. Biopsy-related complications occurred in 3 sheep. Sensitivity of the IHC test in RAMALT ranged from 85.3% to 89.4%, depending on the anatomic location from which RAMALT was obtained. Results for the test applied to 1 RAMALT specimen were similar to results interpreted in parallel for 2 third-eyelid specimens (sensitivity, 87.0%). The proportion of inconclusive test results attributable to insufficient lymphoid follicles in biopsy specimens was lower when considering results for 2 RAMALT specimens in parallel (10.1%) than when considering results for 2 third-eyelid specimens in parallel (23.7%). Specimens of RAMALT that were inappropriately collected from an area caudal to the rectoanal interface yielded a high proportion of inconclusive results (33.3% to 50.0%). The IHC test for PrP(Sc) in RAMALT was an effective means of detecting subclinical scrapie in live, high-risk sheep.
Показать больше [+] Меньше [-]Evaluation of economic effects and the health and performance of the general cattle population after exposure to cattle persistently infected with bovine viral diarrhea virus in a starter feedlot
2009
To evaluate economic effects and health and performance of the general cattle population after exposure to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) in a feedlot. 21,743 high-risk calves from the southeastern United States. PI status was determined by use of an antigen-capture ELISA (ACE) and confirmed by use of a second ACE, reverse transcriptase-PCR assay of sera, immunohistochemical analysis, and virus isolation from sera. Groups with various amounts of exposure to BVDV PI cattle were used. After being placed in the feedlot, identified PI cattle were removed from 1 section, but PI cattle remained in another section of the feedlot. Exposure groups for cattle lots arriving without PI animals were determined by spatial association to cattle lots, with PI animals remaining or removed from the lot. 15,348 cattle maintained their exposure group. Performance outcomes improved slightly among the 5 exposure groups as the risk for exposure to BVDV PI cattle decreased. Health outcomes had an association with exposure risk that depended on the exposure group. Comparing cattle lots with direct exposure with those without direct exposure revealed significant improvements in all performance outcomes and in first relapse percentage and mortality percentage in the health outcomes. Economic analysis revealed that fatalities accounted for losses of $5.26/animal and performance losses were $88.26/animal. This study provided evidence that exposure of the general population of feedlot cattle to BVDV PI animals resulted in substantial costs attributable to negative effects on performance and increased fatalities.
Показать больше [+] Меньше [-]Evaluation of the control of pathogen load by an anti-Salmonella bacterium in a herd of cattle with persistent Salmonella infection
2009
Patton, Toni G. | Sharma, Vijay K. | Carlson, Steve A.
To determine whether an anti-Salmonella bacterium is involved in control of pathogen load in persistently infected cattle herds. 24 Holstein calves experimentally infected and 39 Holstein cows naturally infected with Salmonella spp. An Escherichia coli (designated as P8E5) that possessed anti-Salmonella activity was isolated from Salmonella-negative bovine feces obtained from a herd with endemic Salmonella infection. In vitro analysis involved enumerating Salmonella enterica serovar Typhimurium coincubated with E coli P8E5. In vivo analysis involved coadministration of Salmonella spp and E coli P8E5 or an E coli control strain to neonatal Holstein calves. Fecal samples were collected on multiple days after inoculation, and quantitative PCR assay was performed by use of Salmonella-specific primers. E coli P8E5 reduced viability of Salmonella spp in vitro. Shedding of Salmonella organisms was diminished in calves administered E coli P8E5, whereas the control strain of E coli had no effect on shedding of Salmonella organisms. In this study, an E coli strain was identified that possessed bacteriocin-like activity and was able to decrease viability of Salmonella organisms in vitro and in vivo. Therefore, it is possible that this organism could be representative of native microbiota that dampen Salmonella spp in persistently infected cattle herds.
Показать больше [+] Меньше [-]Inquérito sorológico para toxoplasmose e leptospirose em mamíferos selvagens neotropicais do Zoológico de Aracaju, Sergipe | Serological survey of toxoplasmosis and leptospirosis in neotropical wild mammals from Aracaju Zoo, Sergipe, Brazil
2009
Modern zoological gardens are institutions to wildlife maintenance, aiming its conservation, the performance of scientific research and leisure, recreation and environmental education activities. The variety of wild species living in conditions different from the one found in its natural habitats represents a propitious environment for diseases spread, specially the zoonotic ones. Due to data shortage and wild mammals' epidemiological relevance both for toxoplasmosis as for leptospirosis, this study aimed to determine the serological survey of toxoplasmosis and leptospirosis in Neotropical wild mammals, from Zoo of Aracaju, Sergipe, Brazil. Blood samples were collected from 32 wild mammals, adults and from both sexes: 14 wild bearded capuchins (Cebus libidinosus), four goldenbellied capuchins (Cebus xanthosternus), three pumas (Puma concolor), one jaguar (Panthera onca), one crab-eating fox (Cerdocyon thous), six crab-eating raccoons (Procyon cancrivorus), two South American coatis (Nasua nasua), and one tayra (Eira barbara). Sera were tested to Toxoplasma gondii antibodies by the modified agglutination test (MAT e"1:25), and by the microscopic seroaglutination test (cut-off e”1:100) using 24 serovar of pathogenic leptospiras and two serovar of saprophyte leptospiras. Antibodies to T. gondii were found in 17 of 32 (53.1%) wild mammals, and antibodies to Leptospira spp. were found in 4 of 32 (12.5%) wild mammals. In relation to gender, 9 of 15 (60%) males, and 8 of 17 (47.1%) females had antibodies to Toxoplasma gondii, and 4 of 15 (26.7%) males had antibodies to Leptospira spp. Considering the origin of the seropositive animals to T. gondii, 8 of 17 (47%) were born in the zoo, 7 of 17 (41.2%) were from other zoos, and 2 (11.8%) were from the wild. Three of 4 (75%) mammals seropositive to Leptospira spp. were born in zoo, and 1 of 4 (25%) was from the wild. This is the first serological survey of Leptospira spp. in Neotropical primates and carnivores from Northeast zoo of Brazil, and the first time that antibodies to T. gondii and Leptospira spp. (serovar Copenhageni) were observed in the threaten specie of primate golden-bellied capuchins (Cebus xanthosternus) in Aracaju, SE.
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