Interactions of an introduced shrub and introduced earthworms in an Illinois urban woodland: Impact on leaf litter decomposition     

Liam Heneghan  James Steffen  Kristen Fagen 《Pedobiologia》2007,50(6):543-551

This study examined an ‘invasional meltdown’, where the invasion of a Midwestern woodland by an exotic shrub (Rhamnus cathartica L.P. Mill) and the invasion by Eurasian earthworms facilitated one another. Using a litterbag approach, we examined mass loss of four substrates (R. cathartica, Acer saccharum, Quercus rubra, and Quercus alba) along a gradient of Eurasian earthworm density and biomass throughout a 40.5 ha oak woodland in Glencoe, Illinois. Earthworm densities and biomass were greatest in patches where R. cathartica prevailed, and populations were lowest in an upland forest subcommunity within the woodland. At each of three points along this earthworm gradient, we placed replicated litterbags constructed either to permit or to deny access to the litter by earthworms. The treatments were, therefore, plot treatments (low, medium and high earthworm density and biomass) and litterbag treatments (earthworm access and earthworm excluded). We found that earthworms promoted a very rapid loss of litter from R. cathartica bags. Within 3 months greater than 90% of this litter was lost from the litterbags. Earthworm impacts on other substrates followed the sequence A. saccharum>Q. alba=Q. rubra. Effects of both litterbag and plot treatments were found within 3 months for A. saccharum but Quercus species were affected only after a year. We propose that the impact of earthworms on litter breakdown creates conditions that promote and sustain invasion by R. cathartica. Previous work has demonstrated that R. cathartica may alter soil properties in a way that promotes and sustains invasion by earthworms. These findings have implications for the restoration management of these systems, since the legacy of R. cathartica on soil properties and earthworm populations may persist even after the plant has been physically removed.  相似文献   

Evaluation of an enzyme-linked immunosorbent assay for serological surveillance of infection with Actinobacillus pleuropneumoniae serotype 5 in pig herds     

Klausen J  Andresen LO  Barfod K  Sørensen V 《Veterinary microbiology》2002,88(3):223-232

An indirect enzyme-linked immunoassay for serological surveillance of infection of pigs with Actinobacillus pleuropneumoniae (Ap) serotype 5 was developed. The antigen used was prepared from Ap serotype 5b strain L20. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the antigen contained high molecular weight lipopolysaccharide (LPS) and presumably also capsular polysaccharide (CP). The Ap serotype 5 ELISA was tested using sera from pigs experimentally infected with the 12 different Ap serotypes of biotype 1 and with sera from herds naturally infected with Ap serotypes 5, 6, 7 and 12. Cross-reactions were shown in one pig from a herd naturally infected with Ap serotype 7 and in one pig from a herd naturally infected with Ap serotype 12. The herd sensitivities of the Ap5 ELISA and a complement fixation test (CFT) were both estimated to 1.0, on the basis of serum samples from six herds naturally infected with Ap serotype 5. The herd specificities of both tests were estimated to 0.98, based on serum samples from 123 pig herds (10 samples from each herd) from the Danish specific pathogen-free (SPF) programme for pig production.  相似文献   

Have you had your pet spayed or neutered?     

Contributed by Julie L. Webb  Kristen R. Friedrichs 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2013,42(1):3-3

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The Effect of Bovine Growth Hormone on Growth,Carcass Composition and Meat Quality of Dairy Heifers     

Mogens Vestergaard  Kristen Sejrsen  John Foldager  Signe Klastrup  Dale E. Bauman 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):165-172

Abstract

Our objective was to examine the effects of bovine growth hormone (bGH) on growth, carcass composition and meat quality of dairy heifers. Nine monozygotic twin pairs of Friesian or Red Danish cattle were used, and pair-fed à diet consisting of grass silage, barley and soybean meal. Within each pair, one animal was given daily subcutaneous injections of 20 IU of pituitary-derived bGH (15–20 mg), while the other animal was injected with saline (excipient). Treatments started at 179±2 kg body weight and lasted for 15.6 weeks. At slaughter, carcass composition and meat quality were analyzed. bGH treatment increased gain by 8% (948 vs. 877 g/d; P <0.03). The amount of saleable meat in carcass and lean content of four main carcass cuts were on average increased by 2% (P <0.05). Concomitantly, carcass fat trim was reduced by 12% (P <0.001), fat trim of individual cuts by 4–21% (P <0.05), and kidney fat by 13% (P <0.01). Except for a 20% reduction of intramuscular fat content (P <0.001), meat quality assessed by objective as well as subjective methods was unaffected by bGH treatment. In summary, bGH treatment of dairy heifers around puberty stimulated growth and reduced carcass fattening including intramuscular fat, while eating quality of the meat was unaffected.  相似文献   

The use of oral transmucosal detomidine hydrochloride gel to facilitate handling in dogs     

Marie J. Hopfensperger  Kristen M. Messenger  Mark G. Papich  Barbara L. Sherman 《Journal of Veterinary Behavior: Clinical Applications and Research》2013,8(3):114-123

Safe and humane handling in the veterinary clinic can be challenging when dealing with fearful or anxious dogs. Historically, alpha-2 adrenergic agonists have been used via parenteral routes to facilitate handling of difficult canine subjects. Detomidine hydrochloride is an alpha-2 agonist sedative commercially available in an oral transmucosal (OTM) formulation (Dormosedan Gel; Pfizer Animal Health, Madison, NJ) approved for sedation and restraint in horses. The usefulness of this detomidine formulation has not been previously reported in dogs. This study evaluated the behavioral and physiological effects of OTM detomidine gel administration in dogs to assess its efficacy and safety for facilitation of handling canine subjects. Six healthy institution-owned adult dogs were administered detomidine gel at a dose of 0.35 mg/m² via OTM route. Behavioral and physiological assessments were performed pretreatment and repeated every 15–30 minutes for 5 hours after administration. Behavioral assessments included global sedation (GS), composite sedation (CS), global anxiolysis (GA), and ease of handling (EH) scores. Physiological assessments included heart rate and rhythm, respiratory rate, mucous membrane color, indirect blood pressure, rectal temperature, oxygen saturation, and capillary refill time. Posttreatment GS, CS, GA, and EH scores were improved for all 6 subjects as compared with pretreatment. For 4 of 6 dogs, maximal GS scores occurred at 45 minutes posttreatment, and duration of maximal GS scores was 30 minutes. Five of 6 dogs achieved adequate GS scores. EH scores were significantly higher during time points of adequate GS scores as compared with time points when adequate GS scores were not achieved. The physiological measures revealed transient bradycardia in 5 of 6 dogs and intermittent second-degree atrioventricular block in 1 dog. No other significant adverse events were noted, and all dogs recovered uneventfully. OTM detomidine gel was safely administered to 6 dogs at a dose of 0.35 mg/m² and resulted in measurable sedation, anxiolysis, and improved EH in all subjects. Although further evaluation is warranted for use in client-owned dogs, OTM detomidine gel offers a novel sedative and anxiolytic option to facilitate handling of canine subjects.  相似文献   

Clinical aspects of natural infection with Blastomyces dermatitidis in cats: 8 cases (1991-2005)     

Gilor C  Graves TK  Barger AM  O'Dell-Anderson K 《Journal of the American Veterinary Medical Association》2006,229(1):96-99

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Limited native plant regeneration in novel, exotic-dominated forests on Hawai’i   总被引：1，自引：0，他引：1  

Joseph Mascaro  Kristen K. Becklund  R. Flint Hughes  Stefan A. Schnitzer 《Forest Ecology and Management》2008,256(4):593-606

Ecological invasions are a major driver of global environmental change. When invasions are frequent and prolonged, exotic species can become dominant and ultimately create novel ecosystem types. These ecosystems are now widespread globally. Recent evidence from Puerto Rico suggests that exotic-dominated forests can provide suitable regeneration sites for native species and promote native species abundance, but this pattern has been little explored elsewhere. We surveyed 46 sites in Hawai’i to determine whether native species occurred in the understories of exotic-dominated forests. Native trees smaller than 10 cm in diameter were absent in 28 of the 46 sites and rare in the others. Natives were never the dominant understory species; in fact, they accounted for less than 10% of understory basal area at all but six sites, and less than 4% on average. Sites with native species in the understory tended to be on young lava substrate lacking human disturbance, and were mostly located close to intact, native-dominated forest stands. Even where we found some native species, however, most were survivors of past exotic encroachment into native forest, rather than products of active recolonization by native species. In contrast with successional trajectories in Puerto Rico, Hawaii's exotic-dominated forests can emerge, via invasion, without human disturbance and native Hawaiian plants are largely unable to colonize them once they appear. We suggest that a wide diversity of growth strategies among the exotic species on Hawai’i may limit the opportunities for native plants to colonize exotic-dominated forests.  相似文献   

Redwood/tanoak stand development and response to tanoak mortality caused by Phytophthora ramorum     

Kristen M. Waring  Kevin L. O’Hara 《Forest Ecology and Management》2008

Coast redwood (Sequoia sempervirens) and tanoak (Lithocarpus densiflorus) form mixed-evergreen forests along the northern California coast. In the mid-1990s, an introduced pathogen (Phytophthora ramorum) began causing extensive mortality of tanoak in these forests. This research reconstructed stand development patterns occurring in stands with and without the pathogen, measured stand responses to tanoak mortality, and developed projections of future stand development and structure in the presence of P. ramorum. Redwood forms an upper canopy layer while tanoak forms a multicohort lower canopy, resulting in distinct vertical stratification patterns. Individual redwood tree response patterns to tanoak mortality included crown expansion, increased basal sprouting, and increased basal area growth. Future stand structures will likely have greater proportions of redwood relative to tanoak.  相似文献   

Reference intervals: an essential,expanding, and occasionally equivocal standard     

Kristen R. Friedrichs 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2010,39(2):131-132

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Full recovery after cardiac arrest secondary to accidental iatrogenic venous air embolism in a cat     

Nicole Pacifico DVM  Kristen M. Weishaar DVM  Lindsay B. Boozer DVM  Reid K. Nakamura DVM  DACVECC 《Journal of Veterinary Emergency and Critical Care》2010,20(2):264-267

Objective – To describe the successful management of cardiac arrest following accidental venous air embolism (VAE) in a cat. Case Summary – A 3‐year‐old spayed female domestic shorthair cat, weighing 4 kg, was presented for continuation of its chemotherapy protocol. The cat was inadvertently administered approximately 5.5 mL of air IV during initiation of fluid therapy. Immediate cardiac arrest resulted and CPR successfully achieved return of spontaneous circulation. The cat was discharged 5 days later and is reportedly clinically normal 7 months post‐discharge. New or Unique Information Provided – VAE has been rarely reported in the veterinary literature. This is the first report of a cat surviving cardiac arrest secondary to VAE.  相似文献