Allometric scaling of M-mode cardiac measurements in normal adult dogs

Indices for M-mode measurements in dogs usually have been based on the assumption that a linear relationship exists between these measurements and body weight (BW) or body surface area (BSA). The relationships between the geometry of 3-dimensional objects do not support this assumption. The purposes of this study were to retrospectively examine M-mode data from a large number of dogs of varying sizes and breeds that were examined by a large number of ultrasonographers, to use the allometric equation to determine the appropriate BW exponent required to predict these cardiac dimensions, and to determine normal mean values and prediction intervals for common M-mode variables. Linear regression analyses of data from 494 dogs (2.2-95 kg) revealed a good correlation between M-mode measurements and BW after logarithmic transformation of the data (r2 = .55-.88). Most variables were most closely related to an index of body length, BW(1/3), although the exponent that best predicted diastolic and systolic left ventricular wall thicknesses was closer to 0.25. No variable indexed well to BW or BSA. With these data, appropriate mean values and prediction intervals were calculated for normal dogs, allowing veterinarians to correctly and appropriately index M-mode values. The equations developed from this study appear to be applicable to adult dogs of most breeds.     

Control of coccidiosis in turkeys with diclazuril and monensin: effects upon performance and development of immunity to Eimeria species

The effects of diclazuril and monensin, when included in the feed of turkeys from 0 to 10 wk, upon performance and development of immunity to Eimeria species was investigated. Birds were initially inoculated with a low dose of oocysts of three species of Eimeria at 3, 5, 7, and 9 days of age in order to simulate a natural infection. Weight gain and feed intake from 0 to 6 wk of age was significantly greater in medicated birds compared with those that received no anticoccidial medication. Weight gain and feed intake from 6 to 10 wk was greater in birds that received diclazuril than in unmedicated birds. No differences in performance were evident after drug withdrawal from 10 to 16 wk. Immunity to Eimeria species developed by 10 wk in birds that received no anticoccidial medication but did not develop in those given diclazuril or monensin.     

Brain size, brain composition and intracranial fat bodies in a population of free-living crested ducks ('Hochbrutflugenten')

(1) Brain sizes and brain structure volumes of crested specimens from a population of 'Hochbrutflugenten' ducks (HBTcr), living under seminatural conditions, were compared with those of other duck breeds, among them the breed 'Landente' with the same morphological trait, the crest (LEcr). (2) Brains of both HBTcr and LEcr were larger than expected from an allometric comparison with uncrested breeds. (3) Fat bodies invading the skull were observed in both breeds. (4) In LEcr they could be voluminous; after subtraction of their volume from the brain volume, most brain structures measured were allometrically of the same size as in uncrested breeds. (5) In contrast, HBTcr had small fat bodies, and most of their brain structures were allometrically larger than those of the other breeds. (6) A small fat body in the skull does not appear to influence the survival of HBTcr under seminatural conditions.     

Determinants of weak femoral artery pulse in dogs with mitral valve prolapse

In three substudies encompassing 247 dogs from two breeds predisposed to myxomatous mitral valve disease (MMVD), femoral artery pulse strength was palpated and related to potential explanatory factors, including quantitative echocardiographic measures of MMVD, aortic and femoral artery diameter and wall thickness and blood pressure. In addition, in 109 Cavalier King Charles Spaniels (of which 61 were included in the three substudies mentioned above), the relation between femoral artery pulse strength and presence of thrombocytopenia was investigated. In 26% of the dogs, a pulse 相似文献   

Comparison of electroencephalogram activity and auditory evoked responses during isoflurane and halothane anaesthesia in the rat

Objectives To compare the second differential index (SDI) calculated from the auditory evoked potential (AEP) and electroencephalogram (EEG) parameters: median frequency (MF), spectral edge frequency (SEF) and burst suppression rate (BSR) determined at four equivalent minimum alveolar concentrations (MAC) of isoflurane or halothane. Animals Twelve male Wistar rats weighing 418 g (SD ± 18.4 g). Methods Auditory evoked potentials and EEG responses were recorded in animals implanted with electrodes at established anaesthetic concentrations. Depth of anaesthesia was assessed using the strength of the pedal withdrawal reflex (PWR), and data were analysed using repeated measures anova and paired t‐tests. Results The SEF tended to decrease with increasing depth of halothane anaesthesia (F = 4.198, p = 0.05), but not with isoflurane. The MF and SDI were significantly higher during halothane than with isoflurane (F = 5.82, p = 0.036 and F = 5.263, p = 0.045, respectively) at equivalent depths of anaesthesia, and EEG burst suppression occurred at deeper planes of isoflurane but not halothane anaesthesia. Conclusions The study demonstrated that EEG and AEP characteristics recorded at MAC equivalent concentrations were suppressed to a greater degree by isoflurane than by halothane. These findings have strong implications for research projects where EEG recordings are collected, and also cast more general doubts upon the value of such parameters for evaluating depth of isoflurane anaesthesia in rats.     

Obstruction of the cecocolic orifice by ileocecocolic intussusception following jejunocecostomy in a horse

A 4-year-old Thoroughbred stallion was referred for signs of mild to moderate colic, anorexia, and decreased water intake of 3 weeks' duration. Ultrasonographic examination revealed an intussusception, the most common of which would be a cecal inversion or ileocecal intussusception. Surgical exploration identified an ileocecocolic intussusception with extension of the intussusceptum into the right ventral colon; however, the cause of the intussusception could not be identified. The intussusception could not be surgically corrected, and the horse was euthanatized. A side-to-side jejunocecostomy that had been performed previously was identified at necropsy. The ileal stump had intussuscepted into the right ventral colon and become hypertrophied, causing partial obstruction of the cecocolic orifice and clinical signs of colic. In horses requiring an ileocecal or jejunocecal anastomosis, the ileal stump may be left to slough within the cecum as part of the treatment for an irreducible ileocecal intussusception or intentionally inverted into the cecum when the ileal stump is necrotic and cannot be exteriorized and resected. Efforts should be made to minimize the size of the ileal stump to reduce the liklihood of intussusception.     

Pathogenicity of two recombinant avian leukosis viruses

We have recently described the isolation and molecular characteristics of two recombinant avian leukosis subgroup J viruses (ALV J) with an avian leukosis virus subgroup A envelope (r5701A and r6803A). In the present study, we examined the role of the subgroup A envelope in the pathogenesis of these recombinant viruses. Chickens of line 151(5) x 7(1) were inoculated at 1 day of age with r5701A, r6803A, Rous-associated virus type 1 (RAV-1), or strain ADOL-Hcl of ALV-J. At 2, 4, 10, 18, and 32 wk postinoculation (PI), chickens were tested for avian leukosis virus (ALV)-induced viremia, shedding, and neutralizing antibodies. All except one chicken inoculated with the recombinant viruses (98%) developed neutralizing antibodies by 10 wk PI compared with only 16% and 46% of the ADOL-Hcl and RAV-1-inoculated birds, respectively. ALV-induced tumors and mortality in the two groups inoculated with recombinant viruses were different. The incidence of tumors in groups inoculated with r5701A or RAV-1 was 100% compared with only 9% in the groups inoculated with r6803A or ADOL-Hcl. The data suggest that differences in pathogenicity between the two recombinant viruses might be due to differences in the sequence of the 3' untranslated region (presence or absence of the E element), and, therefore, not only the envelope but also other elements of the viral genome play an important role in the pathogenesis of ALV.     

Bovine adenovirus serotype 7 infections in postweaning calves

OBJECTIVE: To detect bovine adenovirus serotype 7 (BAV-7) infections in calves by use of viral isolation and serologic testing. ANIMALS: 205 postweaning calves. PROCEDURE: 121 calves were assembled by an order buyer through auction markets in eastern Tennessee and transported to New Mexico where they were commingled with 84 healthy ranch-reared calves. Tests included viral isolation in cell culture from peripheral blood leukocytes (PBL) and detection of serum BAV-7 antibodies by use of microtitration viral neutralization. RESULTS: BAV-7 was isolated from PBL of 8 calves and seroconversion to BAV-7 was detected for 38 of 199 (19.1%) calves. Concurrent bovine viral diarrhea virus infections were detected in most calves from which BAV-7 was isolated. CONCLUSIONS AND CLINICAL RELEVANCE: Results of our study indicate that BAV-7 infections can be found in postweaning commingled calves and may develop more commonly in calves with concurrent infections with viruses such as bovine viral diarrhea virus (BVDV).     

Eradication of virulent footrot from sheep and goats in an endemic area of Nepal and an evaluation of specific vaccination

Programmes based on the identification and treatment of cases and the culling of animals refractory to treatment had failed to eradicate virulent footrot from two districts in the western region of Nepal. From 1993 to 1996 vaccination against two endemic virulent strains of Dichelobacter nodosus was tested for its potential to contribute to the eradication of footrot from the region. Only sheep and goats which had been free of signs of footrot at three inspections at monthly intervals before their annual migration to alpine pastures were eligible for inclusion. From November 1992, the treatment of cases identified during inspections included the injection of specific vaccine. Successfully treated cases migrated with their flocks but were excluded from the vaccine trial. Non-responding cases were culled. Forty combined flocks of sheep and goats (approximately 9500 animals) were used initially to compare three vaccination regimens. Eleven flocks (sheep and goats) were treated with two doses of specific vaccine (group A), nine (sheep and goats) were treated with commercial vaccine followed by specific vaccine (group B) and 10 (sheep and goats) were treated with two doses of commercial vaccine (group C) in March to April 1993 before the annual migration; 10 flocks (sheep and goats) remained unvaccinated (group D). Only sheep and goats free of signs of footrot were allowed to migrate. Nevertheless, virulent footrot recurred in many flocks three months later. However, its prevalence was significantly lower in group A than in the other three groups combined. Groups A, B and C then received the specific vaccine before their migrations in 1994 to 1996; group D remained unvaccinated. The annual programme of inspection and identification and treatment of cases continued for seven years, but the vaccinations ceased after four years. There was no recurrence of virulent footrot after November 1993. After the first season the virulent strains of D nodosus used in the specific vaccine could no longer be isolated, although antigenically distinct, benign strains of the organism persisted in cases of benign footrot.     

Development of a fast agglutination screening test (FAST) for the detection of anti-Leishmania antibodies in dogs

A fast agglutination screening test (FAST) for the detection of anti-Leishmania antibodies in serum samples from dogs with visceral leishmaniosis was developed. The test is based on the direct agglutination test (DAT), but combines a higher parasite concentration with a smaller test volume. In contrast to the DAT, the FAST makes use of only one serum dilution and the results can be read within 3 h as opposed to 18-20 h for the DAT. The FAST was evaluated using serum samples of confirmed cases of the disease and healthy controls collected in the most important endemic regions of canine visceral leishmaniosis, import cases of canine leishmaniosis in a non-endemic country, from non-endemic healthy controls and from dogs with other diseases. The performance of the FAST was compared with standard DAT. In the present study, the FAST had a sensitivity of 93.6% and a specificity of 89.0%. The DAT had a sensitivity of 88.6% and a specificity of 96.7%. Furthermore, using a large panel of serum samples of previously examined DAT positive or negative dogs it was shown that degree of agreement between the two tests was high (95.7%; kappa value = 0.91). The FAST offers the advantages of the DAT based on freeze-dried antigen with respect to stability of the antigen, sensitivity and specificity. Moreover, the FAST allows the rapid screening of a large number of samples, which makes the test very useful for epidemiological screening of large populations of dogs.