Acute small intestinal obstruction associated with Parascaris equorum infection in young horses: 25 cases (1985–2004)

AIMS: To retrospectively evaluate the medical and surgical records of horses with acute small intestinal obstructions associated with Parascaris equorum infection; to describe the gastrointestinal lesions; and to determine the outcome of cases with such lesions.

METHODS: Records of 25 horses with acute small intestinal obstruction associated with P. equorum between 1985 and 2004 were reviewed to determine signalment, history, physical examination, surgical or post-mortem findings, and outcome.

RESULTS: All horses except one were less than 12 months old. Standardbreds were over-represented in the population studied. Sixteen horses (72%) had been administered anthelmintics, including pyrantel (n=8), ivermectin (n=7), and trichlorphon (n=1), within 24 h prior to the onset of colic. Of the 25 cases reviewed, 16 had simple obstructive ascarid impactions (SOAIs), and nine had complicated obstructive ascarid impaction (COAI) including volvulus (n=6) or intussusception (n=3), both concurrent with ascarid impaction of the small intestine. Short-term survival (discharge from hospital) occurred in 79% of horses treated for SOAI, and was 64% for all horses. Long-term survival (>1 year) occurred in 33% of horses with SOAI, and the overall long-term survival was 27% for all horses. Formation of adhesions was the most frequent finding associated with death for horses that did not survive long-term.

CONCLUSIONS AND CLINICAL RELEVANCE: The incidence of anthelmintic treatment within 24 h of the onset of colic in this study population (72%) was higher than that previously reported. Resistance of P. equorum to ivermectin recently reported in Ontario may be associated with increased ascarid burdens, predisposing horses to ascarid impaction. The long-term survival of these horses was better than that reported previously.     

Bighorn sheep pneumonia: Sorting out the cause of a polymicrobial disease

Pneumonia of bighorn sheep (Ovis canadensis) is a dramatic disease of high morbidity and mortality first described more than 80 years ago. The etiology of the disease has been debated since its initial discovery, and at various times lungworms, Mannheimia haemolytica and other Pasteurellaceae, and Mycoplasma ovipneumoniae have been proposed as primary causal agents. A multi-factorial “respiratory disease complex” has also been proposed as confirmation of causation has eluded investigators. In this paper we review the evidence for each of the candidate primary agents with regard to causal criteria including strength of association, temporality, plausibility, experimental evidence, and analogy. While we find some degree of biological plausibility for all agents and strong experimental evidence for M. haemolytica, we demonstrate that of the alternatives considered, M. ovipneumoniae is the best supported by all criteria and is therefore the most parsimonious explanation for the disease. The strong but somewhat controversial experimental evidence implicating disease transmission from domestic sheep is consistent with this finding. Based on epidemiologic and microbiologic data, we propose that healthy bighorn sheep populations are naïve to M. ovipneumoniae, and that its introduction to susceptible bighorn sheep populations results in epizootic polymicrobial bacterial pneumonia often followed by chronic infection in recovered adults. If this hypothesized model is correct, efforts to control this disease by development or application of vectored vaccines to Pasteurellaceae are unlikely to provide significant benefits, whereas efforts to ensure segregation of healthy bighorn sheep populations from M. ovipneumoniae-infected reservoir hosts are crucial to prevention of new disease epizootics. It may also be possible to develop M. ovipneumoniae vaccines or other management strategies that could reduce the impact of this devastating disease in bighorn sheep.     

Möglichkeiten der gezielten Bekämpfung von Pyrethroid-resistenten Rapsglanzkäferpopulationen – Ergebnisse von Ringversuchen mehrerer Bundesländer

From 2006 to 2008, tests for regulating pyrethroid-resistant pollen beetle populations using new insecticidal agents were conducted in the states of Brandenburg, Saxony, Saxony-Anhalt and Thuringia. Reason for this test series were high yield losses in winter rape in some states in 2006. These losses were the result of unilateral licensing procedures focussing on class??II pyrethroids. Organophosphates, like chlorpyrifos-ethyl and chlorpyrifos-methyl, as well as class??I pyrethroids like etofenprox and bifenthrin were examined during the tests concerning their efficiency towards Meligethes aeneus. As a comparative agent, neonicotinoid based on thiacloprid was used. Mixtures of class??II pyrethroids with piperonylbutoxid were not admitted by the producers in 2008 despite good insecticidal effects due to economic reasons. Therefore, in 2008, insecticides with different mode of action agents were tested for pollen beetle control. Investigations at five different locations showed that pymetrozin (Plenum 50 WG) and indoxacarb (STEWARD) were identical in their efficiency as thiacloprid (Biscaya) against pyrethroid-resistant pollen beetle. Metaflumizone (Alverde), a semicarbazone, is not eligible for controlling M.??aeneus populations in both investigated formulations. In order to avoid further selection of neonicotinoid-resistent pollen beetle populations, the admittance of other insecticidal agents in the coming years is necessary. For that purpose, organophosphates and insecticides based indoxacarb and pymetrozin would be good alternatives.     

杆菌肽锌和弗吉尼亚霉素对猪生产性能的影响

<正>在生长育肥猪日粮中,杆菌肽锌—Albac(益力素,雅来大药厂)的允许使用剂量为10～50g/t,能够提高猪日增质量和饲料转化率,并且无需休药期。弗吉尼亚霉素—Stafac(美国辉宝有限公司)     

Validation of a national disease recording system for dairy cattle against veterinary practice records

In Sweden, morbidity in dairy cattle is monitored through a national disease recording system. This system gives valuable information for research as well as advisory work and genetic evaluation. Our main objective was to evaluate the completeness in the disease recording system.Farm copies of veterinary records (n = 851) from 112 herds, from March 2003 to April 2004, were compared with the information registered in the recording system. The evaluation of completeness was performed at two stages: (i) in the raw data transferred from the Swedish Board of Agriculture (SBA) to the Swedish Dairy Association (for records, cases and diagnostic events) and (ii) in the dairy disease database (DDD) at the Swedish Dairy Association (for diagnostic events). The evaluation was stratified by record type: manual and computerized records from state-employed veterinarians and private veterinarians, respectively.The completeness was high both for records (95–100%) and cases (90–99%) except manual records from private veterinarians (76% for records and 74% for cases). The overall completeness for diagnostic events was 75% in the DDD, with significant differences between record types. For all record types other than manual records from private veterinarians, the majority of diagnostic events lost disappeared after registration in the raw data from the SBA. The reasons for loss found suggest that there is potential for improvement.A multilevel logistic regression analysis showed that the completeness of diagnostic events in the DDD depended on region, diagnosis and veterinary employment. The random effect of veterinarian accounted for 35% of the modeled variation.Future studies are needed to assess how the differential misclassification affect estimates based on the data, and how to account for it.     

Testing mechanisms underlying the Hedley sequential phosphorus extraction of soils

The Hedley fractionation has become the preeminent measure for estimating the bioavailability of phosphorus (P) in soils. However, mechanisms underlying P extractability have never been tested. We hypothesize that P sequentially extracted by individual steps can either be referred to a specific mineral source (Hypothesis 1) or to its binding strength to minerals (Hypothesis 2). We prepared mineral‐P associations in the laboratory using various secondary mineral phases and P forms (orthophosphate, phytic acid, ribonucleic acid), which were then subject to the Hedley sequential extraction scheme (anion exchange resin in form, 0.5 M NaHCO₃, 0.1 M NaOH, 1 M HCl, and concentrated HCl at 80°C). Extracts were analyzed for P as well as for the main mineral‐borne elements by inductively coupled plasma–optical emission spectroscopy (ICP–OES). In order to test if the observed mineral dissolution patterns match those of natural soils, we applied the Hedley fractionation to forest soils comprising various P stocks and measured in addition to extracted P also iron, aluminum, and calcium by ICP – OES. Phosphorus extractability from mineral‐P associations differed between P forms and mineral phases. Adsorbed P always contributed to several or all extracts, Hypothesis 1 was thus not tenable. Aluminum hydroxide, allophane, ferrihydrite, and goethite completely dissolved during Hedley fractionation from the third extraction step onwards. Successive mineral dissolution also occurred for the soil samples. Thus, extracted P represents partly desorbed P from various soil constituents and partly P co‐released upon dissolution of various minerals. Consequently, also Hypothesis 2 could not be confirmed, i.e., the sequential extraction is not suitable to assess different binding strengths between P forms and minerals. We conclude that the method hardly provides information for studies aiming at the mechanistic understanding of P bioavailability in soil.     

Infestation of a cattle herd with the ear mite Raillieta auris (Acarina, Mesostigmata)

An infestation with Raillietia auris in a 4 years old cow is reported. For a period of 3 weeks the animal showed an increasing unrest, extreme efforts while trying to feed, and continuous shaking of the head which slanted to the left. After slaughter numerous specimens of the ear-mite R. auris were found in the basic part of the left auditory canal, located in the vicinity of a purulent paste-like plug. Histological examinations of the brain revealed a severe non-purulent meningoencephalitis with necroses of the vascular walls, focal malacia and gliosis. An etiological correlation of these lesions with the mite-infestation, however, is considered to be most unlikely. To the best of our knowledge the occurrence of R. auris in Switzerland was up to now unknown.