共查询到20条相似文献，搜索用时 31 毫秒
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The changing concentrations and temporal relationships among a PGF2α metabolite (PGFM), progesterone (P4), LH, and estradiol-17β (E2) before, during, and after luteolysis were studied in 10 mares. Blood samples were collected every hour for ≥4 d beginning on day 12 after ovulation. The luteolytic period extended from a decrease in P4 at a common transitional hour (Hour 0) at the end of preluteolysis and beginning of luteolysis to a defined ending when P4 reached 1 ng/mL. The length of luteolysis was 22.9 ± 0.9 h, contrasting with 2 d in published P4 profiles from sampling every 6 to 24 h. In mares with complete data for Hours −40 to −2 (n = 6), PGFM concentrations remained below assay sensitivity (n = 2) or two or three small pulses (peak, 29 ± 4 pg/mL) occurred. During luteolysis, the pulses became more prominent (peak, 193 ± 36 pg/mL). Rhythmicity of PGFM pulses was not detected by a pulsatility program during preluteolysis but was detected in seven of nine mares during luteolysis and postluteolysis combined. The nadir-to-nadir interval for LH pulses and the peak-to-peak interval between adjacent pulses were longer (P < 0.05) during preluteolysis than during luteolysis (nadir to nadir, 5.2 ± 0.3 h vs 3.6 ± 0.4 h; peak to peak, 9.4 ± 1.0 h vs 4.7 ± 0.5 h). Unlike reported findings in cattle, concentrations of P4 decreased linearly within the hours of each PGFM pulse during luteolysis, and a positive effect of an LH pulse on P4 and E2 concentration was not detected. The reported balancing of P4 concentrations between a negative effect of PGF2α and a positive effect of LH in heifers was not detected in mares. 相似文献
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Heidrun Gehlen Sophie Twickel Sabita Stöckle Corinna Weber Claus P. Bartmann 《Journal of animal physiology and animal nutrition》2020,104(2):679-689
Pituitary pars intermedia dysfunction is the most prevalent endocrine disease in horses. Although donkeys and mules may also be affected, only a few data have been published. Reference values for diagnostic parameters, such as adrenocorticotropic hormone (ACTH), are especially scarce or even lacking. Therefore, in the present study, available data from the literature have been verified and completed to facilitate a reliable diagnosis. Clinical inspections and haematological and biochemical examinations were carried out four times in a three-month interval (February to November) in 44 donkeys and 31 mules. Data from clinically healthy animals were used as an orientation. Plasma ACTH concentrations showed seasonal changes in both animal groups. However, it was generally higher in donkeys than mules. Although blood glucose (EDTA plasma) showed no difference between groups, serum insulin concentrations were consistently higher in donkeys. Serum fructosamine levels were slightly higher in mules, whereas, in some cases, serum triglyceride levels were considerably higher in donkeys. Serum gamma-glutamyltransferase showed a striking peak in mules in August, whereas the remaining gamma-glutamyltransferase values were lower compared to donkeys. By comparing donkeys and mules, the present work reveals differences in various blood parameters which should be considered for diagnoses and future studies. 相似文献
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Different models are available to estimate species’ niche and distribution. Mechanistic and correlative models have different underlying conceptual bases, thus generating different estimates of a species’ niche and geographic extent. Hybrid models, which combining correlative and mechanistic approaches, are considered a promising strategy; however, no synthesis in the literature assessed their applicability for terrestrial vertebrates to allow best-choice model considering their strengths and trade-offs. Here, we provide a systematic review of studies that compared or integrated correlative and mechanistic models to estimate species’ niche for terrestrial vertebrates under climate change. Our goal was to understand their conceptual, methodological, and performance differences, and the applicability of each approach. The studies we reviewed directly compared mechanistic and correlative predictions in terms of accuracy or estimated suitable area, however, without any quantitative analysis to support comparisons. Contrastingly, many studies suggest that instead of comparing approaches, mechanistic and correlative methods should be integrated (hybrid models). However, we stress that the best approach is highly context-dependent. Indeed, the quality and effectiveness of the prediction depends on the study's objective, methodological design, and which type of species’ niche and geographic distribution estimated are more appropriate to answer the study's issue. 相似文献
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Cosinor analysis was used to evaluate whether pituitary and adrenal hormones exhibit circadian rhythmicity in horses. The effect of season and animal age on their respective rhythms was also determined. In addition, the usefulness of evaluating cortisol rhythmicity for the diagnosis of pituitary pars intermedia dysfunction (PPID) was assessed. Serum cortisol concentrations (P < 0.01), but not plasma ACTH or α-melanocyte-stimulating hormone (α-MSH), showed a significant circadian periodicity in horses. An effect of season on hormone concentration was observed with plasma ACTH and α-MSH concentration greater in the fall and cortisol concentration greater in the spring (P < 0.001). Age did not affect cortisol rhythm, but it did blunt the variation in cortisol concentration in horses, similar to what has been previously reported to occur in aged people and dogs. In addition, our results suggest that clinically and diagnostically normal, non–PPID-affected horses commonly have a loss of cortisol diurnal rhythm. Therefore, measurement of circadian rhythm is not an appropriate diagnostic test for PPID. 相似文献
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《Strength and Conditioning Journal》2005,58(2):135-147
We evaluated elk (Cervus elaphus), mule deer (Odocoileus hemionus), cattle (Bos taurus), and domestic sheep (Ovis aries) diet composition, diet overlap, and forage selection on aspen (Populus tremuloides Michaux)–sagebrush (Artemisia spp. L.) summer range in northeastern Nevada to understand potential for forage competition to provide better information for managing these communities. Diets were determined through microhistological fecal analysis from 1998 to 2000, and forage selection was evaluated at feeding sites in aspen and sagebrush communities in 1999 and 2000. Elk spring diets were the most diverse in composition; summer elk diets were dominated by forbs (59%–78%); deer consumed mostly woody browse (64%–72%); and cattle and sheep ate mostly graminoids. Lupines (Lupinus spp. L.) constituted ≥ 11% of elk, deer, and sheep diets in summer. Spurred lupine (Lupinus caudatus Kellogg) was the lupine typically selected in feeding sites and greatest consumption occurred in summer when total alkaloid levels were lowest. Highest diet overlap was between cattle and sheep in 1999 (68%) and lowest between deer and cattle in 2000 (3%). Summer elk and deer diets overlapped moderately (45%–59%). Diets did not differ between elk in spring with sheep, elk in summer with deer and sheep, or cattle with sheep. Cattle foraged selectively on forbs in aspen communities (68%) and on graminoids in sagebrush communities (88%), reflecting relative forage availabilities. We detected no differences among elk, cattle, and sheep for forage selection in aspen communities. Electivity indices indicated elk preferred forbs in aspen and sagebrush communities; cattle preferred graminoids in sagebrush; and foraging sheep preferred forbs in aspen. Our results suggest potential for forage competition among ungulates on aspen–sagebrush summer range is highest for forbs in aspen communities. Monitoring productivity and use of key forage species, particularly forbs in aspen communities, should complement management objectives on shared aspen–sagebrush summer range. 相似文献
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Raj Kumar Singh Kuldeep Dhama Muthannan Andavar Ramakrishnan Kumaragurubaran Karthik Ruchi Tiwari 《The Veterinary quarterly》2016,36(3):150-175
This review converses the Zika virus which has attained global concern due to its rapid pandemic potential and impact on humans. Though Zika virus was first isolated in 1947, till the recent large-scale outbreak which occurred in Micronesia, in 2007, the virus was placed into the innocuous pathogen category. The World Health Organization on 1 February 2016 declared it as a ‘Public Health Emergency of International Concern.’ Of the note, American as well as Pacific Island strains/isolates is relatively closer to Asian lineage strains. The African and American strains share more than 87.5% and 95% homologies with Asian strains/isolates, respectively. Asian strains form independent clusters, except those isolated from China, suggesting relatively more diversity than African strains. Prevention and control are mainly aimed at the vector population (mosquitoes) with Aedes aegypti being the main species. Surveys in Africa and Asia indicated seropositivity in various animal species. However, so far its natural reservoir is unknown. There is an urgent need to understand why Zika virus has shifted from being a virus that caused mild illness to unforeseen birth defects as well as autoimmune-neurological problems. Unfortunately, an effective vaccine is not available yet. Availability of cryo-electron microscopy based on 3.8 Å resolution revealing mature Zika virus structure and the probable virus attachment site to host cell would provide critical insights into the development of antiviral treatments and vaccines. 相似文献
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Gary Wobeser G. Douglas Campbell André Dallaire Scott McBurney 《The Canadian veterinary journal. La revue veterinaire canadienne》2009,50(12):1251-1256
Information related to infection of wild rodents or lagomorphs in Canada by Francisella tularensis, Yersinia pestis, other Yersinia spp., and Clostridium piliforme was searched for this study. Reports on tularemia in humans linked to these species came from diagnostic databases, literature, wildlife health specialists, and public health agencies. Tularemia has been diagnosed in 8 species of wild rodent and 2 species in the genus Lepus in Canada. Tularemia occurred in wild animals, or in humans associated with these species, in all jurisdictions except the Yukon and Nunavut. Tularemia was diagnosed most frequently in beaver, muskrats, and snowshoe hares, and although tularemia is closely linked to cottontail rabbits in the USA, it has not been reported in cottontails in Canada. Tularemia in humans was associated with muskrats and hares more commonly than with beaver. Plague was diagnosed in bushy-tailed woodrats in British Columbia in 1988. Based on surveys, Y. pestis may occur enzootically in southern Alberta, Saskatchewan, and British Columbia. Infection with Yersinia pseudotuberculosis and Y. enterocolitica has been diagnosed in beaver, muskrats, and snowshoe hares in many provinces. Tyzzer’s disease has been diagnosed in muskrats in British Columbia, Saskatchewan, Ontario, and Quebec and in snowshoe hares in Ontario. Infection with these bacteria is likely much more frequent than indicated by diagnostic records. 相似文献
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《The Professional Animal Scientist》1999,15(1):1-6
Restricted and programmed feeding are two commonly used approaches to manage feed intake by cattle. Restricted feeding, which is most often applied to starting cattle on feed and to finishing cattle, takes various forms but generally includes any method of feed intake management with which intake is restricted relative to actual or anticipated ad libitum intake. Conversely, programmed feeding, which is most frequently used in growing programs, is a method in which net energy equations are used to calculate the quantities of feed required to meet the needs for maintenance and a specific rate of gain. Both restricted and programmed feeding have been shown to improve feed efficiency, perhaps in part because recent research data suggest that body energy gain by cattle increases in a diminishing manner with increasing energy intake. Nonetheless, commercial application of restricted and(or) programmed feeding is limited by concerns related to application in large vs small pens and potential negative effects of restriction and(or) programming on daily gain and carcass quality grade. Research findings suggest consistent improvements in feed efficiency, generally decreased daily gain, and generally lower carcass quality grade when intake is restricted from 5 to 15% relative to pair-fed ad libitum controls in finishing cattle. Application of restricted and(or) programmed feeding during growing periods followed by ad libitum feeding, however, seems to have little effect on subsequent performance and carcass quality grade. Although restricted feeding offers the advantages of simplified feed bunk management, advanced knowledge of feed milling needs, and potential environmental benefits, additional research and field-level fine tuning will be needed before widespread commercial application is likely. 相似文献
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《The Professional Animal Scientist》2000,16(3):159-163
Transportation conditions of slaughter horses for human consumption have become a visible issue in the media during the last decade. Animal protection groups successfully lobbied Congress during the 1996 Farm Bill to establish regulations governing the care of slaughter horses during transport. These regulations were based partially on funded research projects initiated in 1997 examining types of transport vehicles, fitness of horses for travel, types of injuries, length of transit, dehydration and water management, and stocking density. Using the results of these independent research studies along with public input, a comprehensive set of regulations was drafted and published for public comment in 1999. In the proposed regulations, conveyances with two or more stacked levels will be prohibited from transporting equines 5 yr after the publication of the final rule. Additionally, the maximum transit length will be 28 h, and no electrical prods can be used on equines in commercial transport for any purpose, including loading and unloading. Each horse must have a completed owner-shipper certificate with a statement of fitness to travel as defined by the ability to bear weight on all four limbs, the ability to walk unassisted, and not being blind in both eyes. The shipper must present the owner-shipper certificates to a USDA representative and not leave the slaughter facility until equines have been examined by a USDA representative. Civil penalties of up to $5000 US may be assessed for any violation of the final rule. 相似文献
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Transmissible spongiform encephalopathies affect a number of mammalian species. The most common spongiform encephalopathies are scrapie in sheep and Bovine Spongiform Encephalopathy (BSE) in cattle. Feline Spongiform Encephalopathy (FSE) is a related disorder in domestic cats. Because of the link between BSE and FSE, cats are put on a par with cattle, in terms of politics and regulations. In the Netherlands, when a case of BSE is found on a farm, not only the ruminants, but also the cats are taken away for post-mortem examination. So far, the cats examined have always been negative for FSE. There are no scientific reasons for destroying the cats on farms where BSE has been found. 相似文献
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Raj Kumar Singh Ruchi Tiwari Senthilkumar Natesan Rekha Khandia 《The Veterinary quarterly》2019,39(1):26-55
Nipah (Nee-pa) viral disease is a zoonotic infection caused by Nipah virus (NiV), a paramyxovirus belonging to the genus Henipavirus of the family Paramyxoviridae. It is a biosafety level-4 pathogen, which is transmitted by specific types of fruit bats, mainly Pteropus spp. which are natural reservoir host. The disease was reported for the first time from the Kampung Sungai Nipah village of Malaysia in 1998. Human-to-human transmission also occurs. Outbreaks have been reported also from other countries in South and Southeast Asia. Phylogenetic analysis affirmed the circulation of two major clades of NiV as based on currently available complete N and G gene sequences. NiV isolates from Malaysia and Cambodia clustered together in NiV-MY clade, whereas isolates from Bangladesh and India clusterered within NiV-BD clade. NiV isolates from Thailand harboured mixed population of sequences. In humans, the virus is responsible for causing rapidly progressing severe illness which might be characterized by severe respiratory illness and/or deadly encephalitis. In pigs below six months of age, respiratory illness along with nervous symptoms may develop. Different types of enzyme-linked immunosorbent assays along with molecular methods based on polymerase chain reaction have been developed for diagnostic purposes. Due to the expensive nature of the antibody drugs, identification of broad-spectrum antivirals is essential along with focusing on small interfering RNAs (siRNAs). High pathogenicity of NiV in humans, and lack of vaccines or therapeutics to counter this disease have attracted attention of researchers worldwide for developing effective NiV vaccine and treatment regimens. 相似文献
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J. F. M. Nouws T. B. Vree M. Baakman F. Driessens L. Vellenga D. J. Mevius 《The Veterinary quarterly》2013,33(2):123-135
Summary Pharmacokinetics and tissue distribution experiments were conducted in pigs to which sulphadimidine (SDM) was administered intravenously, orally, and intramuscularly at a dosage of 20 mg SDM/kg. SDM was acetylated extensively, but neither hydroxy metabolites nor their derivatives could be detected in plasma, edible tissues or urine. Following i.v. and two oral routes of administration, the N4‐acetylsulphadimidine (N4‐SDM) concentration‐time curve runs parallel to that of SDM. The percentage of N4‐SDM in plasma was in the range between 7 and 13.5% of the total sulphonamide concentration. The bioavailability of SDM administered in a drench was 88.9 ± 5.4 % and administered mixed with pelleted feed for 3 consecutive days it was 48.0 ± 11.5 %. The renal clearance of unbound SDM, which was urine flow related, was 1/7 of that of creatinine, indicating reabsorption of the parent drug. The unbound N4SDM was eliminated three times faster than creatinine, indicating that tubular secretion was the predominant mechanism of excretion. After i.v. administration, 51.9 % of the administered dose was recovered in urine within 72 h p.i., one quarter of which as SDM and three quarters as N4‐SDM. Tissue distribution data obtained at 26, 74, 168, and 218 h after i.m. injection revealed that the highest SDM concentration was found in plasma. The SDM concentration in muscle, liver, and kidney ranged from one third to one fifth of that in plasma. The N4‐SDM formed a minor part of the sulphonamide content in edible tissues, in which the SDM as well as the N4‐SDM concentration parallelled the plasma concentrations. Negative results obtained with a semi‐quantitative bioassay method, based on monitoring of urine or plasma, revealed that the SDM concentration levels in edible tissues were in that case below 0. 1μ/g tissue. 相似文献
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Hamscher G 《DTW. Deutsche tier?rztliche Wochenschrift》2004,111(7):288-291
Within the European Union, food safety and consumer protection are topics of highest priority. The evaluation of the safety of contaminants and residues in food is usually based on the determination of the acceptable daily intake (ADI), which in turn is the basis for maximum residue levels (MRLs). As this procedure depends on animal testing, a safety factor of 100 is usually applied to provide a margin of safety. This paper discusses the occurrence of relevant contaminants (e.g. dioxins, acrylamide) and residues (e.g. antibiotics, antiparasitic agents) in food and provides a brief assessment of the risks resulting from the consumption of food containing these substances. 相似文献
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Tina Rødgaard Jan Stagsted Berit Ø. Christoffersen Susanna Cirera Sophia G. Moesgaard Michael Sturek Mouhamad Alloosh Peter M.H. Heegaard 《Veterinary immunology and immunopathology》2013,151(3-4):325-330
The acute phase protein orosomucoid (ORM) has anti-inflammatory and immunomodulatory effects, and may play an important role in the maintenance of metabolic homeostasis in obesity-induced low-grade inflammation. Even though the pig is a widely used model for obesity related metabolic symptoms, the expression of ORM has not yet been characterized in such pig models. The objective of this study was to investigate the expression of ORM1 mRNA in liver, visceral adipose tissue, subcutaneous adipose tissue (SAT) from the abdomen or retroperitoneal abdominal adipose tissue (RPAT) and SAT from the neck, as well as the serum concentration of ORM protein in three porcine obesity models; the domestic pig, Göttingen minipigs and Ossabaw minipigs.No changes in ORM1 mRNA expression were observed in obese pigs compared to lean pigs in the four types of tissues. However, obese Ossabaw minipigs, but none of the other breeds, showed significantly elevated ORM serum concentrations compared to their lean counterparts. Studies in humans have shown that the expression of ORM was unchanged in adipose tissue depots in obese humans with an increased serum concentration of ORM. Thus in this respect, obese Ossabaw minipigs behave more similarly to obese humans than the other two pig breeds investigated. 相似文献