Zane Davis - Academia.edu (original) (raw)
Papers by Zane Davis
PLOS ONE
We previously reported that feeding Se-biofortified alfalfa hay to weaned beef calves in a precon... more We previously reported that feeding Se-biofortified alfalfa hay to weaned beef calves in a preconditioning program decreases morbidity and mortality during the feedlot period. To understand the mode of action by which supranutritional Se supplementation supports calf health, we examined the effect of agronomic Se-biofortification on nasal microbiome and fecal parasites. Recently weaned Angus-cross beef calves (n = 30) were randomly assigned to two groups and fed an alfalfa hay-based diet for 9 weeks in a preconditioning program. Alfalfa hay was harvested from fields fertilized with sodium selenate at a rate of 0 or 90 g Se/ha. Calculated Se intake from dietary sources was 1.09 and 27.45 mg Se/calf per day for calves consuming alfalfa hay with Se concentrations of 0.06 and 3.47 mg Se/kg dry matter, respectively. Feeding Se-biofortified alfalfa hay for 9 weeks was effective at increasing whole-blood Se concentrations (556 ± 11 vs 140 ± 11 ng/mL; P < 0.001) and increasing body weigh...
Genes, 2021
Selenium (Se) is an essential micronutrient for growth and immune function in beef cattle. We pre... more Selenium (Se) is an essential micronutrient for growth and immune function in beef cattle. We previously showed that supranutritional maternal organic Se supplementation during late pregnancy improves immune function in their newborn calves; however, the effects of maternal organic Se-supplementation on fetal programming during different pregnancy stages have yet to be elucidated. Herein, we investigated the effects of supranutritional maternal organic Se-supplementation in different pregnancy trimesters on their beef calf’s genome-wide transcriptome profiles. Within 12 to 48 h of birth, whole blood and Longissimus dorsi (LD) muscle biopsies were collected from calves born to 40 crossbred Angus cows that received, except for the control group (CTR), Se-yeast boluses (105 mg of Se/wk) during the first (TR1), second (TR2), or third (TR3) trimester of gestation. Whole-blood Se concentrations of newborn calves increased from CTR, TR1, TR2 to TR3, whereas muscle Se concentrations of newb...
Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn... more Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn antelope (Antilocapra americana) and whitetail deer (Odocoileus virginianus texanus) within several Texas counties in the United States. Clinically it presents as chronic liver disease with progressive hepatic necrosis and fibrosis, icterus and liver failure. The damaged livers are yellow and many have multiple firm, often gritty foci that are scattered throughout all lobes. Early investigations included feeding studies using potential toxic plants, climate and forage studies, infectious disease surveys and various mycotoxin studies and analyses. None have definitively reproduced the disease or identified the inciting cause. However, the problem continues and recent outbreaks have allowed the collection of additional frozen tissues, and numerous paraffin tissue blocks and slides for additional studies. The objectives for this work are to evaluate and compare the microscopic changes, special histochemical studies, microbial and fungal surveys and chemical assays for dehyro-pyrrolizidine alkaloid (DHPA) metabolites of these additional cases with historical reports. These bovine livers had a spectrum of lesions including lipid degeneration and necrosis, eosinophilic granulomatous hepatitis, focal follicular lymphoid proliferation and chronic fibrosing hepatitis with dystrophic mineralization. No pyrrolizidine alkaloid metabolites were detected in any of the livers and select special stains did not reveal any fungal, bacterial or parasitic etiologies. The lack of findings and mixed histologic presentation suggest that this syndrome is a collection of chronic diseases probably of various etiologies. Earlier animal surveillance work is needed in endemic areas to better understand the etiology and pathogenesis of this syndrome.
Veterinary Clinics of North America: Equine Practice, 2018
Most toxins are ingested and the gastrointestinal enterocytes are literally the first to be expos... more Most toxins are ingested and the gastrointestinal enterocytes are literally the first to be exposed and damaged. However, because many toxins cause extensive organspecific damage, the gastrointestinal lesions are lost in the shadows of other lesions that have been generally accepted as characteristic of poisoning. A typical example is the microcystin. The microcystins poison horses, cattle, and various other animals including man. They are potent hepatotoxins produced by Microcystis aeruginosa, M viridis, and M wesenbergii. They inhibit cellular serine and threonine protein phosphatases, resulting in excessive phosphorylation of cell regulatory proteins and cytoskeleton collapse. This damage is seen as massive hepatocellular degeneration and necrosis. The disrupted hepatic vascular plate results in hemorrhage and embolization of necrotic and degenerative hepatocytes to distant vessels. Microcystins target hepatocytes as they are absorbed from the portal circulation by bile acid-like receptors. Similar receptors are responsible for microcystin absorption in the ileum where enterocytes have similar receptors. Microcystin's effect in these enterocytes produces extensive degeneration, necrosis, and loss of structure including villous blunting and collapse. However, this damage is rarely identified in poisoned animals because Disclosure: The authors have no conflict of interest or commercial involvement with this information.
Veterinary Clinics of North America: Food Animal Practice, 2020
Often toxic plants affect reproductive function, but these reproductive changes are lost in the s... more Often toxic plants affect reproductive function, but these reproductive changes are lost in the shadows of more impressive disease and lesions. For example, locoweeds are primarily considered neurotoxins, as they often produce spectacular neurologic disease; however, under some conditions (dose, duration, and poisoning frequency) reproductive failure may be the initial sign of locoweed poisoning. Locoweeds are potent endocrine disrupters, and poisoning quickly alters spermatogenesis, spermatic maturation. They also impair libido resulting in male reproductive failure. 1 Female reproduction is similarly affected, as poisoning quickly produces cystic ovaries with altered estrus. Locoweed also is fetotoxic resulting in placental resorption, abortion, fetal myocardial dysfunction with placental damage, and hydrops amnii. Locoweed poisoned neonates are slow to stand and ambulate and some are unable to nurse. Locoweed-induced birth defects include small calves or lambs with phocomelia.
Veterinary Clinics of North America: Food Animal Practice, 2020
Veterinary Clinics of North America: Food Animal Practice, 2020
Locoweed poisoning, or locoism, is a neurologic disease that was historically considered to be th... more Locoweed poisoning, or locoism, is a neurologic disease that was historically considered to be the largest poisonous plant problem in the western United States. 1,2 Nearly a century ago, resources were first appropriated to provide livestock producers solutions to locoism. Despite huge advances in understanding and managing the disease, many problems persist and additional solutions to avoid poisoning are needed. Poisoning initially was described in horses, cattle, sheep, and goats. From this work, it became obvious that several plants were the cause of poisoning. These were commonly referred to as locoweeds and they included approximately 20 species of the Astragalus and Oxytropis genera. 1 The next 4 or 5 decades did little other than to map locoweed populations, characterize the extent of their toxicity, and educate livestock producers to avoid using contaminated ranges. In the 1960s and 1970s, more detailed publications were produced to better characterize both the clinical and histologic changes of poisoning. Extensive visceral and neuronal vacuolation of certain cell populations were identified. Additionally, this vacuolation was found to be similar to livestock poisoning caused by Australian Swainsona species.
Veterinary Clinics of North America: Food Animal Practice, 2020
Many toxic plants, ingested by livestock while grazing or eating contaminated processed feed, pro... more Many toxic plants, ingested by livestock while grazing or eating contaminated processed feed, produce myoskeletal or myocardial lesions that sometimes have irreversible consequences. Some myotoxic plants are lethal after ingestion of very small amounts whereas others require consumption for many days to several weeks to produce disease. Incorporation of field studies, clinical signs, gross and microscopic pathology, and chemical identification of plants, toxins, and metabolites in animal samples is essential for an accurate diagnosis. This review introduces toxic plants that cause myotoxicity, reviews toxins and lesions, discusses analyses for making an accurate diagnosis, and summarizes treatments and recommendations to avoid future poisonings.
Rangelands, 2020
On the Ground • Toxic larkspurs (Delphinium species) cause large economic losses from cattle deat... more On the Ground • Toxic larkspurs (Delphinium species) cause large economic losses from cattle deaths, increased management costs, and reduced utilization of pastures and rangelands. • Larkspur toxicity to cattle can vary by geographic location due to toxic alkaloid content. • Larkspur alkaloid chemistry can be used to predict plant toxicity. • Cattle breeds differ in their susceptibility to larkspur poisoning. • As cattle age from yearlings to 2-year olds, they become less susceptible to larkspur. • Heifers are three times more likely to be poisoned at the same dose of larkspur alkaloids than either bulls or steers, suggesting that they must be managed differently on rangelands where larkspur is present.
Toxicon: X, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Animal Science, 2019
Selenium (Se) is an essential element that is required by animals to maximize health and producti... more Selenium (Se) is an essential element that is required by animals to maximize health and production. Some western rangelands contain alkaline soils that are naturally high in Se while others have been contaminated with elevated concentrations of bioavailable Se. Anecdotal evidence of poor reproductive efficiency has been reported on some seleniferous ranges. In order to determine the effects of high Se feeds on spermatogenesis, mature rams were fed alfalfa pellets containing 0.1, 7.5, 15, or 25 ppm Se. Desired Se concentrations were achieved by mixing western aster containing approximately 3,000 ppm Se with alfalfa. Pellets were fed at 3% of body weight for twelve weeks during the breeding season. Semen and blood samples were collected weekly and semen viability, motility, and morphology were evaluated. After twelve weeks of being fed high Se pellets, one testicle from each ram was surgically removed for morphometric and histological evaluation. The rams were then fed a control alfa...
Toxicon: X, 2019
This research compared the cytotoxic actions of the benzofuran ketone, tremetone in B16 murine me... more This research compared the cytotoxic actions of the benzofuran ketone, tremetone in B16 murine melanoma cells to SH-SY5Y human neuroblastoma cells with an MTT assay. Tremetone was not cytotoxic in B16 cells. In SH-SY5Y cells, concentration-dependent tremetone cytotoxicity occurred without microsomal activation. No cytotoxicity was observed with 6-hydroxytremetone. This suggests that SH-SY5Y cells are a better model for the cytotoxic actions of tremetone and that tremetone is toxic without microsomal activation.
Journal of Animal Science, 2019
Larkspur (Delphinium spp.) poisoning is a long-term problem for cattle grazing on rangelands of w... more Larkspur (Delphinium spp.) poisoning is a long-term problem for cattle grazing on rangelands of western North America. Results from preliminary experiments have suggested that differences in larkspur toxicity may exist between heifers and bulls. The objective of this study was to compare the physiological responses of yearling Angus heifers, steers, and bulls with a standardized dose of Delphinium barbeyi and to test the hypothesis that the response is sex dependent. Clinical signs of intoxication, including muscle coordination and function, were measured 24 h after oral dosing with larkspur by walking the cattle at a pace of 5 to 6 km h −1 for up to 40 min on an oval dirt track. Due to the experimental methods used, the variation in susceptibility to larkspur was not quantifiable for walking times of 0 or 40 min or more. Larkspur susceptible animals that were not able to walk (0 min; 36% of the animals) or larkspur resistant animals that walked the entire test period of 40 min (9% of the animals) resulted in censored or truncated data. The statistical methods (censReg and lmec) were used to adjust for data truncation or censoring. The heifers were only able to walk −8.9 ± 3.9 min (65.5% censored on the left) compared with 13.2 ± 3.7 min for bulls and 15.9 ± 2.7 min for steers. When heifers were compared with bulls and steers together, heifers walked 23.4 ± 4.5 min less (P < 0.0001). Serum alkaloid concentrations were measured immediately before walking, and deltaline concentrations averaged 266 ± 28, 131 ± 20, and 219 ± 28 ng mL −1 for all heifers, steers, and bulls, respectively, and serum methyllycaconitine concentrations averaged 660 ± 46, 397 ± 32, and 612 ± 34 ng mL −1 for all heifers, steers, and bulls, respectively. The relative risk of a zero walk time for yearling heifers is 330% that of yearling bulls (P = 0.0008). These results suggest that yearling Angus heifers are more susceptible to larkspur intoxication and, when possible, heifers should be kept from grazing larkspur-infested rangelands as a simple management tool to reduce the risk of fatal poisoning.
Research in veterinary science, Jan 14, 2018
White snakeroot (Ageratina altissima) contains the putative toxin tremetone and can produce a dis... more White snakeroot (Ageratina altissima) contains the putative toxin tremetone and can produce a disease called "trembles" or "milk sickness". However the toxicity of tremetone has not been demonstrated in vivo. It has been reported that the plant is less toxic after drying and grinding. The objectives of these studies were to determine: 1) the toxic effect of grinding white snakeroot 4 months prior to dosing and, 2) the toxic effect of storing white snakeroot at ambient temperature for 5 years. Dried white snakeroot, ground 1 day, 1 month, and 4 months prior to dosing, was orally gavaged to goats at 2% of their body weight for up to 28 days or until they were minimally poisoned (minimal muscular weakness and increased serum creatine kinase (CK) activities). All four goats dosed with white snakeroot that had been ground 4 months previously and stored at room temperature were poisoned, became exercise intolerant, and had increased serum CK activities (>5600 U/ L)....
Toxicon : official journal of the International Society on Toxinology, Jan 3, 2018
Rayless goldenrod (RG; Isocoma pluriflora) poisons livestock in the southwestern U.S., west Texas... more Rayless goldenrod (RG; Isocoma pluriflora) poisons livestock in the southwestern U.S., west Texas, and northern Mexico. The putative toxin(s) have historically been thought to be benzofuran ketones. Goats have been used successfully as a model of RG poisoning. The transmammary transfer of toxicity to offspring from lactating goats has not been studied, thus the objective of this study was to determine if nursing kids would become poisoned via mother's milk when the dams were dosed with RG. Twelve lactating goats (6 controls and 6 treated; all with twin kids) were dosed via oral gavage with alfalfa or rayless goldenrod at 2% of BW per day for 14 days. Two kids showed overt clinical signs near the end of the study; however, no dams showed clinical signs, and none developed exercise intolerance or muscle weakness. After day 11 of treatment, the RG kids showed increased (P < 0.05) serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine kinase (CK) a...
Journal of applied toxicology : JAT, Jan 10, 2016
Selenium (Se) poisoning by different forms of Se occurs in the United States. However, the toxico... more Selenium (Se) poisoning by different forms of Se occurs in the United States. However, the toxicokinetics of different selenocompounds after oral ingestion is not well documented. In this study the toxicokinetics of Se absorption, distribution and elimination were determined in serum and whole blood of lambs that were orally dosed with increasing doses of Se as sodium selenite (inorganic Se) or selenomethionine (SeMet, organic Se). Thirty-two lambs were randomly assigned to eight treatment groups, with four animals per group. Se was administered at 1, 2 or 3 mg kg(-1) body weight, as either sodium selenite or SeMet with proper control groups. Blood and serum were collected at predetermined time points for 7 days post-dosing. Resulting Se concentrations in both serum and whole blood from SeMet treatment groups were significantly greater than those given equimolar doses of Se as sodium selenite. Se concentrations in serum and whole blood of lambs dosed with SeMet peaked at significant...
Toxicon : official journal of the International Society on Toxinology, Jan 2, 2015
Calves with congenital defects born to cows that have grazed teratogenic Lupinus spp. during preg... more Calves with congenital defects born to cows that have grazed teratogenic Lupinus spp. during pregnancy can suffer from what is termed crooked calf syndrome. Crooked calf syndrome defects include cleft palate, spinal column defects and limb malformations formed by alkaloid-induced inhibition of fetal movement. In this study, we tested the hypothesis that there are differences in fetal activity of fetuses carried by Holstein verses Angus heifers orally dosed with 1.1 g/kg dried ground Lupinus leucophyllus. Fetal activity was monitored via transrectal ultrasonography and maternal serum was analyzed for specific lupine alkaloids. There were more (P < 0.05) movements in fetuses of Holstein heifers than those in Angus heifers at eight and 12 h after oral dosing. In addition to serum alkaloid toxicokinetic differences, the Holstein heifers had significantly lower serum concentrations of anagyrine at 2, 4, and 8 h after oral dosing than Angus heifers. Holstein heifers also had significan...
PLOS ONE
We previously reported that feeding Se-biofortified alfalfa hay to weaned beef calves in a precon... more We previously reported that feeding Se-biofortified alfalfa hay to weaned beef calves in a preconditioning program decreases morbidity and mortality during the feedlot period. To understand the mode of action by which supranutritional Se supplementation supports calf health, we examined the effect of agronomic Se-biofortification on nasal microbiome and fecal parasites. Recently weaned Angus-cross beef calves (n = 30) were randomly assigned to two groups and fed an alfalfa hay-based diet for 9 weeks in a preconditioning program. Alfalfa hay was harvested from fields fertilized with sodium selenate at a rate of 0 or 90 g Se/ha. Calculated Se intake from dietary sources was 1.09 and 27.45 mg Se/calf per day for calves consuming alfalfa hay with Se concentrations of 0.06 and 3.47 mg Se/kg dry matter, respectively. Feeding Se-biofortified alfalfa hay for 9 weeks was effective at increasing whole-blood Se concentrations (556 ± 11 vs 140 ± 11 ng/mL; P < 0.001) and increasing body weigh...
Genes, 2021
Selenium (Se) is an essential micronutrient for growth and immune function in beef cattle. We pre... more Selenium (Se) is an essential micronutrient for growth and immune function in beef cattle. We previously showed that supranutritional maternal organic Se supplementation during late pregnancy improves immune function in their newborn calves; however, the effects of maternal organic Se-supplementation on fetal programming during different pregnancy stages have yet to be elucidated. Herein, we investigated the effects of supranutritional maternal organic Se-supplementation in different pregnancy trimesters on their beef calf’s genome-wide transcriptome profiles. Within 12 to 48 h of birth, whole blood and Longissimus dorsi (LD) muscle biopsies were collected from calves born to 40 crossbred Angus cows that received, except for the control group (CTR), Se-yeast boluses (105 mg of Se/wk) during the first (TR1), second (TR2), or third (TR3) trimester of gestation. Whole-blood Se concentrations of newborn calves increased from CTR, TR1, TR2 to TR3, whereas muscle Se concentrations of newb...
Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn... more Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn antelope (Antilocapra americana) and whitetail deer (Odocoileus virginianus texanus) within several Texas counties in the United States. Clinically it presents as chronic liver disease with progressive hepatic necrosis and fibrosis, icterus and liver failure. The damaged livers are yellow and many have multiple firm, often gritty foci that are scattered throughout all lobes. Early investigations included feeding studies using potential toxic plants, climate and forage studies, infectious disease surveys and various mycotoxin studies and analyses. None have definitively reproduced the disease or identified the inciting cause. However, the problem continues and recent outbreaks have allowed the collection of additional frozen tissues, and numerous paraffin tissue blocks and slides for additional studies. The objectives for this work are to evaluate and compare the microscopic changes, special histochemical studies, microbial and fungal surveys and chemical assays for dehyro-pyrrolizidine alkaloid (DHPA) metabolites of these additional cases with historical reports. These bovine livers had a spectrum of lesions including lipid degeneration and necrosis, eosinophilic granulomatous hepatitis, focal follicular lymphoid proliferation and chronic fibrosing hepatitis with dystrophic mineralization. No pyrrolizidine alkaloid metabolites were detected in any of the livers and select special stains did not reveal any fungal, bacterial or parasitic etiologies. The lack of findings and mixed histologic presentation suggest that this syndrome is a collection of chronic diseases probably of various etiologies. Earlier animal surveillance work is needed in endemic areas to better understand the etiology and pathogenesis of this syndrome.
Veterinary Clinics of North America: Equine Practice, 2018
Most toxins are ingested and the gastrointestinal enterocytes are literally the first to be expos... more Most toxins are ingested and the gastrointestinal enterocytes are literally the first to be exposed and damaged. However, because many toxins cause extensive organspecific damage, the gastrointestinal lesions are lost in the shadows of other lesions that have been generally accepted as characteristic of poisoning. A typical example is the microcystin. The microcystins poison horses, cattle, and various other animals including man. They are potent hepatotoxins produced by Microcystis aeruginosa, M viridis, and M wesenbergii. They inhibit cellular serine and threonine protein phosphatases, resulting in excessive phosphorylation of cell regulatory proteins and cytoskeleton collapse. This damage is seen as massive hepatocellular degeneration and necrosis. The disrupted hepatic vascular plate results in hemorrhage and embolization of necrotic and degenerative hepatocytes to distant vessels. Microcystins target hepatocytes as they are absorbed from the portal circulation by bile acid-like receptors. Similar receptors are responsible for microcystin absorption in the ileum where enterocytes have similar receptors. Microcystin's effect in these enterocytes produces extensive degeneration, necrosis, and loss of structure including villous blunting and collapse. However, this damage is rarely identified in poisoned animals because Disclosure: The authors have no conflict of interest or commercial involvement with this information.
Veterinary Clinics of North America: Food Animal Practice, 2020
Often toxic plants affect reproductive function, but these reproductive changes are lost in the s... more Often toxic plants affect reproductive function, but these reproductive changes are lost in the shadows of more impressive disease and lesions. For example, locoweeds are primarily considered neurotoxins, as they often produce spectacular neurologic disease; however, under some conditions (dose, duration, and poisoning frequency) reproductive failure may be the initial sign of locoweed poisoning. Locoweeds are potent endocrine disrupters, and poisoning quickly alters spermatogenesis, spermatic maturation. They also impair libido resulting in male reproductive failure. 1 Female reproduction is similarly affected, as poisoning quickly produces cystic ovaries with altered estrus. Locoweed also is fetotoxic resulting in placental resorption, abortion, fetal myocardial dysfunction with placental damage, and hydrops amnii. Locoweed poisoned neonates are slow to stand and ambulate and some are unable to nurse. Locoweed-induced birth defects include small calves or lambs with phocomelia.
Veterinary Clinics of North America: Food Animal Practice, 2020
Veterinary Clinics of North America: Food Animal Practice, 2020
Locoweed poisoning, or locoism, is a neurologic disease that was historically considered to be th... more Locoweed poisoning, or locoism, is a neurologic disease that was historically considered to be the largest poisonous plant problem in the western United States. 1,2 Nearly a century ago, resources were first appropriated to provide livestock producers solutions to locoism. Despite huge advances in understanding and managing the disease, many problems persist and additional solutions to avoid poisoning are needed. Poisoning initially was described in horses, cattle, sheep, and goats. From this work, it became obvious that several plants were the cause of poisoning. These were commonly referred to as locoweeds and they included approximately 20 species of the Astragalus and Oxytropis genera. 1 The next 4 or 5 decades did little other than to map locoweed populations, characterize the extent of their toxicity, and educate livestock producers to avoid using contaminated ranges. In the 1960s and 1970s, more detailed publications were produced to better characterize both the clinical and histologic changes of poisoning. Extensive visceral and neuronal vacuolation of certain cell populations were identified. Additionally, this vacuolation was found to be similar to livestock poisoning caused by Australian Swainsona species.
Veterinary Clinics of North America: Food Animal Practice, 2020
Many toxic plants, ingested by livestock while grazing or eating contaminated processed feed, pro... more Many toxic plants, ingested by livestock while grazing or eating contaminated processed feed, produce myoskeletal or myocardial lesions that sometimes have irreversible consequences. Some myotoxic plants are lethal after ingestion of very small amounts whereas others require consumption for many days to several weeks to produce disease. Incorporation of field studies, clinical signs, gross and microscopic pathology, and chemical identification of plants, toxins, and metabolites in animal samples is essential for an accurate diagnosis. This review introduces toxic plants that cause myotoxicity, reviews toxins and lesions, discusses analyses for making an accurate diagnosis, and summarizes treatments and recommendations to avoid future poisonings.
Rangelands, 2020
On the Ground • Toxic larkspurs (Delphinium species) cause large economic losses from cattle deat... more On the Ground • Toxic larkspurs (Delphinium species) cause large economic losses from cattle deaths, increased management costs, and reduced utilization of pastures and rangelands. • Larkspur toxicity to cattle can vary by geographic location due to toxic alkaloid content. • Larkspur alkaloid chemistry can be used to predict plant toxicity. • Cattle breeds differ in their susceptibility to larkspur poisoning. • As cattle age from yearlings to 2-year olds, they become less susceptible to larkspur. • Heifers are three times more likely to be poisoned at the same dose of larkspur alkaloids than either bulls or steers, suggesting that they must be managed differently on rangelands where larkspur is present.
Toxicon: X, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Animal Science, 2019
Selenium (Se) is an essential element that is required by animals to maximize health and producti... more Selenium (Se) is an essential element that is required by animals to maximize health and production. Some western rangelands contain alkaline soils that are naturally high in Se while others have been contaminated with elevated concentrations of bioavailable Se. Anecdotal evidence of poor reproductive efficiency has been reported on some seleniferous ranges. In order to determine the effects of high Se feeds on spermatogenesis, mature rams were fed alfalfa pellets containing 0.1, 7.5, 15, or 25 ppm Se. Desired Se concentrations were achieved by mixing western aster containing approximately 3,000 ppm Se with alfalfa. Pellets were fed at 3% of body weight for twelve weeks during the breeding season. Semen and blood samples were collected weekly and semen viability, motility, and morphology were evaluated. After twelve weeks of being fed high Se pellets, one testicle from each ram was surgically removed for morphometric and histological evaluation. The rams were then fed a control alfa...
Toxicon: X, 2019
This research compared the cytotoxic actions of the benzofuran ketone, tremetone in B16 murine me... more This research compared the cytotoxic actions of the benzofuran ketone, tremetone in B16 murine melanoma cells to SH-SY5Y human neuroblastoma cells with an MTT assay. Tremetone was not cytotoxic in B16 cells. In SH-SY5Y cells, concentration-dependent tremetone cytotoxicity occurred without microsomal activation. No cytotoxicity was observed with 6-hydroxytremetone. This suggests that SH-SY5Y cells are a better model for the cytotoxic actions of tremetone and that tremetone is toxic without microsomal activation.
Journal of Animal Science, 2019
Larkspur (Delphinium spp.) poisoning is a long-term problem for cattle grazing on rangelands of w... more Larkspur (Delphinium spp.) poisoning is a long-term problem for cattle grazing on rangelands of western North America. Results from preliminary experiments have suggested that differences in larkspur toxicity may exist between heifers and bulls. The objective of this study was to compare the physiological responses of yearling Angus heifers, steers, and bulls with a standardized dose of Delphinium barbeyi and to test the hypothesis that the response is sex dependent. Clinical signs of intoxication, including muscle coordination and function, were measured 24 h after oral dosing with larkspur by walking the cattle at a pace of 5 to 6 km h −1 for up to 40 min on an oval dirt track. Due to the experimental methods used, the variation in susceptibility to larkspur was not quantifiable for walking times of 0 or 40 min or more. Larkspur susceptible animals that were not able to walk (0 min; 36% of the animals) or larkspur resistant animals that walked the entire test period of 40 min (9% of the animals) resulted in censored or truncated data. The statistical methods (censReg and lmec) were used to adjust for data truncation or censoring. The heifers were only able to walk −8.9 ± 3.9 min (65.5% censored on the left) compared with 13.2 ± 3.7 min for bulls and 15.9 ± 2.7 min for steers. When heifers were compared with bulls and steers together, heifers walked 23.4 ± 4.5 min less (P < 0.0001). Serum alkaloid concentrations were measured immediately before walking, and deltaline concentrations averaged 266 ± 28, 131 ± 20, and 219 ± 28 ng mL −1 for all heifers, steers, and bulls, respectively, and serum methyllycaconitine concentrations averaged 660 ± 46, 397 ± 32, and 612 ± 34 ng mL −1 for all heifers, steers, and bulls, respectively. The relative risk of a zero walk time for yearling heifers is 330% that of yearling bulls (P = 0.0008). These results suggest that yearling Angus heifers are more susceptible to larkspur intoxication and, when possible, heifers should be kept from grazing larkspur-infested rangelands as a simple management tool to reduce the risk of fatal poisoning.
Research in veterinary science, Jan 14, 2018
White snakeroot (Ageratina altissima) contains the putative toxin tremetone and can produce a dis... more White snakeroot (Ageratina altissima) contains the putative toxin tremetone and can produce a disease called "trembles" or "milk sickness". However the toxicity of tremetone has not been demonstrated in vivo. It has been reported that the plant is less toxic after drying and grinding. The objectives of these studies were to determine: 1) the toxic effect of grinding white snakeroot 4 months prior to dosing and, 2) the toxic effect of storing white snakeroot at ambient temperature for 5 years. Dried white snakeroot, ground 1 day, 1 month, and 4 months prior to dosing, was orally gavaged to goats at 2% of their body weight for up to 28 days or until they were minimally poisoned (minimal muscular weakness and increased serum creatine kinase (CK) activities). All four goats dosed with white snakeroot that had been ground 4 months previously and stored at room temperature were poisoned, became exercise intolerant, and had increased serum CK activities (>5600 U/ L)....
Toxicon : official journal of the International Society on Toxinology, Jan 3, 2018
Rayless goldenrod (RG; Isocoma pluriflora) poisons livestock in the southwestern U.S., west Texas... more Rayless goldenrod (RG; Isocoma pluriflora) poisons livestock in the southwestern U.S., west Texas, and northern Mexico. The putative toxin(s) have historically been thought to be benzofuran ketones. Goats have been used successfully as a model of RG poisoning. The transmammary transfer of toxicity to offspring from lactating goats has not been studied, thus the objective of this study was to determine if nursing kids would become poisoned via mother's milk when the dams were dosed with RG. Twelve lactating goats (6 controls and 6 treated; all with twin kids) were dosed via oral gavage with alfalfa or rayless goldenrod at 2% of BW per day for 14 days. Two kids showed overt clinical signs near the end of the study; however, no dams showed clinical signs, and none developed exercise intolerance or muscle weakness. After day 11 of treatment, the RG kids showed increased (P < 0.05) serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine kinase (CK) a...
Journal of applied toxicology : JAT, Jan 10, 2016
Selenium (Se) poisoning by different forms of Se occurs in the United States. However, the toxico... more Selenium (Se) poisoning by different forms of Se occurs in the United States. However, the toxicokinetics of different selenocompounds after oral ingestion is not well documented. In this study the toxicokinetics of Se absorption, distribution and elimination were determined in serum and whole blood of lambs that were orally dosed with increasing doses of Se as sodium selenite (inorganic Se) or selenomethionine (SeMet, organic Se). Thirty-two lambs were randomly assigned to eight treatment groups, with four animals per group. Se was administered at 1, 2 or 3 mg kg(-1) body weight, as either sodium selenite or SeMet with proper control groups. Blood and serum were collected at predetermined time points for 7 days post-dosing. Resulting Se concentrations in both serum and whole blood from SeMet treatment groups were significantly greater than those given equimolar doses of Se as sodium selenite. Se concentrations in serum and whole blood of lambs dosed with SeMet peaked at significant...
Toxicon : official journal of the International Society on Toxinology, Jan 2, 2015
Calves with congenital defects born to cows that have grazed teratogenic Lupinus spp. during preg... more Calves with congenital defects born to cows that have grazed teratogenic Lupinus spp. during pregnancy can suffer from what is termed crooked calf syndrome. Crooked calf syndrome defects include cleft palate, spinal column defects and limb malformations formed by alkaloid-induced inhibition of fetal movement. In this study, we tested the hypothesis that there are differences in fetal activity of fetuses carried by Holstein verses Angus heifers orally dosed with 1.1 g/kg dried ground Lupinus leucophyllus. Fetal activity was monitored via transrectal ultrasonography and maternal serum was analyzed for specific lupine alkaloids. There were more (P < 0.05) movements in fetuses of Holstein heifers than those in Angus heifers at eight and 12 h after oral dosing. In addition to serum alkaloid toxicokinetic differences, the Holstein heifers had significantly lower serum concentrations of anagyrine at 2, 4, and 8 h after oral dosing than Angus heifers. Holstein heifers also had significan...