Hemodynamic alterations in dogs with shock induced by intravenous injection of heartworm extract

To elucidate one way of the shock mechanisms, the hemodynamic alterations were examined in 7 dogs with heartworm (HW) extract-induced shock. The first alteration observed after injection of HW extract was a decrease in right ventricular end-diastolic pressure (RVEDP). After that, left ventricular (LV) end-diastolic pressure, LV systolic pressure, and LV dp/dt fell significantly, followed by a decrease in the cardiac output of all dogs to below the detectable level (1.00 l/min). Since RVEDP depends on blood flow into the right ventricle, the decrease in RVEDP means a reduction in venous return. Therefore, this study showed that the first trigger of a decrease in blood pressure in HW extract-induced shock is the reduction in venous return.     

Galanin-like immunoreactive neural elements in domestic ruminant pancreas

The distribution and ontogeny of the galanin-like immunoreactive (Gal-IR) neural structures in the pancreas of cattle, sheep and goat were investigated immunohistochemically. The present study confirmed the previous findings on the immunolocalization of galanin both in the neural elements and endocrine cells of cattle, and reported for the first time its exclusive localization in the neural elements of sheep and goat. The frequency of Gal-IR nerve fibers and nerve cell bodies was high in cattle and low in sheep and goat. Their first detection was at the first fetal trimester in cattle and third trimester in sheep and goat. In cattle, a marked increase in the frequency of Gal-IR nerve fibers was observed from the third trimester to early neonatal stage followed by a decrease after three months postnatal. In contrast to the non-preferential distribution pattem in sheep, the Gal-IR nerve fibers in cattle and goat pancreas were predominantly associated with the acini, excretory ducts and blood vessels, but rarely detected in the pancreatic islets. The Gal-IR nerve cell bodies were observed as isolated bodies in the intra- and interlobular connective tissues and as a group within the intrapancreatic ganglia. At the vicinity of the nerve cell bodies, Gal-IR nerve fibers were observed. The present findings may suggest that: (1) galanin regulates pancreatic function as neurotransmitter/neuromodulator in ruminants; (2) galanin plays a more important role in large than in small ruminants; and (3) particularly in cattle, it exerts its most dramatic effect during perinatal development.     

Identification of the tetracycline resistance gene, tet(M), in Erysipelothrix rhusiopathiae

This is the first report to demonstrate the presence of tet(M) in naturally occurring isolates of tetracycline-resistant Erysipelothrix rbusiopathiae, which causes swine erysipelas. The tet(M) gene was isolated from E. rhusiopathiae strain KY5-42. The nucleotide and the deduced amino acid sequence were 99% identical to the tet(M) gene from Enterococcus faecalis. The gene was necessary and sufficient for the expression of tetracycline resistance in Escherichia coli. The presence of the tet(M) gene in the 114 tetracycline-resistant E. rhusiopathiae isolates from diseased pigs was detected by the polymerase chain reaction assay. The specific amplified DNA fragment was obtained from all 114 tetracycline-resistant strains. It was suggested that the tet(M) gene was widely present in the field isolates of E. rhusiopathiae resistant to tetracycline.     

Avian haemosporidian parasites infection in wild birds inhabiting Minami-daito Island of the Northwest Pacific, Japan

Haemosporidian parasites infection among wild birds inhabiting Minami-daito Island was studied. Blood films from 183 birds representing 4 species of 4 families were examined microscopically. Avian haemosporidian parasites were detected in 3 species with an overall prevalence of 59.6%. None of the 30 Daito scops owls (Otus scops interpositus) examined were infected. Either Haemoproteus sp. or Plasmodium sp. infection was found in 14 of 31 (45.2%) Borodino islands white-eyes (Zosterops japonicus daitoensis). Plasmodium spp. were found in 94 of 102 (92.2%) bull-headed shrikes (Lanius bucephalus) and 1 of 20 (5%) tree sparrows (Passer montanus).     

Estimation of heritability for superficial digital flexor tendon injury by Gibbs sampling in the Thoroughbred racehorse

The superficial digital flexor tendon (SDFT) injury causes considerable wastage of racing Thoroughbreds. In this study, the heritability of SDFT injury of the forelimbs was estimated in the Thoroughbred racehorses based on the Bayesian analysis with Gibbs sampling using threshold animal models. New horse patients of SDFT injury at the age of 2–5 years accommodated in the training centers in 2005 were used for the analyses. Based on clinical data of 8198 horses, heritability of SDFT was estimated to be the order of 0.17 (posterior mode) to 0.19 ± 0.05 (posterior mean ± posterior SD).     

Mortality, death interval, survivals, and herd factors for death in gilts and sows in commercial breeding herds

The objectives of this study were to measure death intervals and survival, to determine mortality rate and mortality risks, and to investigate the association of herd factors with mortality risk in individual female pigs. This study was conducted by obtaining female data with lifetime records of 65,621 females born between 1999 and 2002, and herd data with mean measurements of 5 yr from 2000 to 2004 in 105 herds. Annualized mortality rate was calculated as the number of dead females divided by the sum of life days in all gilts and sows, multiplied by 365 d. Mortality risk was calculated as the number of dead females divided by the number of surviving females at farrowing in each parity. Death interval in gilts was defined as the number of days from birth to death, and that in sows was the number of days from the last farrowing to death. A Cox proportional hazards model was used to obtain the survival probability by parity. Logistic regression analyses were used to investigate the association of herd factors with mortality risk in individual females in each parity. Of the 65,621 females, the mortality risk was 9.9%, and the annualized mortality rate was 3.9%. Of the 6,501 dead females, death intervals in gilts and sows were 294.7 and 55.0 d, respectively. In gilts, survival probability rapidly decreased at 33 and 50 wk of age, around the first mating and the first parturition. In contrast, survival probability in sows decreased at wk 1 after farrowing, and rapidly decreased at wk 20 and 21 after farrowing in all parity groups that were around a subsequent peripartum period. The percentages of death on wk 0, 1, and 2 after the last farrowing in all the dead sows were 6.5, 23.5, and 10.1%, respectively. Approximately 10% of deaths also occurred from wk 20 to 21 after the last farrowing. Death interval in parity > or =5 was the shortest among all parity groups (49.2 d; P < 0.05). Mortality risks in parities 0 and 1 were 1.44 and 1.83%, respectively. As parity increased from 2 to > or =5, mortality risk increased from 1.63 to 5.90%. Herd factors (greater herd mortality, less herd productivity, and smaller herd size) were associated with greater mortality risk in individual females in parity 0 to > or =5, parity 4 and > or =5, and parity 1 to 4, respectively (P < 0.05). In conclusion, females in peripartum periods, gilts, and high-parity sows are at a greater risk of dying. Increased care should be implemented for prefarrowing females and early-lactating sows.     

Isolation and characterisation of Rhodococcus equi from submaxillary lymph nodes of wild boars (Sus scrofa)

Rhodococcus equi has been isolated from the submaxillary lymph nodes of domesticated pigs, but little is known about the presence of R. equi in wild boars. The aim of the study was the evaluation of the incidence of R. equi in wild boars and the characterisation of them. Of 482 submaxillary lymph nodes of wild boars shot in 39 settlements throughout Hungary, R. equi was isolated from 60 specimens, and plasmid types of 82 isolates were examined. The isolates were tested for the presence of 15-17-kDa (VapA) and 20-kDa virulence-associated protein antigen (VapB) genes by polymerase chain reaction (PCR). Plasmid DNAs were isolated and analysed by digestion with restriction endonucleases to estimate size and compare their polymorphisms. None of the 82 isolates contained vapA gene but 21 isolates (25.6%) were positive for vapB gene showing 827bp product of the expected size in the PCR amplification. Sixty-one strains (74.4%) did not contain plasmid. The 21 isolates of intermediate virulence contained virulence plasmids that were identified as types 1 (1 isolate), 5 (16 isolates), 21 (1 isolate), and three new distinct plasmid variants (1-1-1 isolate), respectively. On the basis of restriction digestion patterns of plasmid DNAs, we tentatively designated the new variants as types 25-27, respectively. The prevalence of R. equi strains of intermediate virulence among the isolates originated from the submaxillary lymph nodes of wild boars (25.6%) is very similar to those of domestic pigs (26.8%) in Hungary, and plasmid type 5 is the predominating one in both groups. This is the first report of isolation of VapB-positive R. equi from wild boars in the world.     

Quantitative assessment of the effects of outside temperature on farrowing rate in gilts and sows by using a multivariate logistic regression model

It is well known that pigs are sensitive to heat stress, but few studies have assessed the critical temperature that affects farrowing rate. Therefore, the objective of the present study was to assess the effects of outside temperature on farrowing rate by using a multivariate logistic regression model. Data were obtained from 25 commercial farms, including 26,128 service records for gilts and 120,655 service records for sows. Two variables, maximum temperature (MAX) and temperature humidity index (THI), were used as an indicator for climate conditions. In gilts, an interaction between climate conditions and service number was associated with farrowing rate (p < .05). In the first service, farrowing rate decreased as climate conditions increased, whereas no relationship was found in the second service or later. In sows, farrowing rate at first service decreased as MAX increased from 22°C or THI increased from 66 (p < .05), but no apparent reduction under heat conditions was found in the second service or later. Additionally, effect of heat stress on farrowing rate in parities 1–2 was higher than those in parities 3–5 and ≥6 (p < .05). These results can be applied to field conditions as a standard for the critical temperature for farrowing rate.