bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of Pasteurella haemolytica in transported calves
Authors: Frank G. H. , Smith P. C.
Published: February 2025

In 2 different years, calves from individual farms were sampled by nasal swab for Pasteurella haemolytica at the farm, at an auction barn, and at a feedyard after they had been transported 1,600 km. Serum antibody titers were determined and P haemolytica isolates were serotyped. The frequencies of P haemolytica isolations were low at the farm, greater at the auction barn, and markedly high at the feedyard. Serotype 2 was the predominant isolate at the farm, and serotype 1 was the predominant isolate at the feedyard and from the pneumonic lungs of the calves that died of acute respiratory tract disease. There was a significant farm-to-farm variation in the percentages of calves that developed respiratory tract disease.
Ivermectin for the control of swine scabies: Relative values of prefarrowing treatment of sows and weaning treatment of pigs
Authors: Courtney C. H. , Ingalls W. L. , Stitzlein S. L.
Published: February 2025

Ivermectin given in a single subcutaneous dose (300 μg/kg of body weight) was tested for activity against swine scabies (Sarcoptes scabiei). Efficacy was determined by recoveries of mites from ear scrapings and by observations of clinical signs. Treatment of infected sows 8 to 37 days before farrowing eliminated scabies from the sows and prevented its transmission to their offspring. Pigs farrowed by ivermectin-treated sows remained non-infected throughout the study regardless of whether they were treated with ivermectin at weaning. Placebo-treated sows remained infected and transmitted scabies to their offspring.

Ivermectin treatment of pigs at weaning eliminated the infection, whereas placebo treatment did not. The placebo-treated pigs remained infected while in the nursery, but ivermectin treatment eliminated the infection when they were moved to the growing and finishing floor at 12 weeks of age.

It appears that an effective control program for swine scabies using ivermectin could be based on a single treatment of the sows before farrowing. Any infection (epizootic) appearing in growing pigs could be controlled by a single treatment of all in-contact pigs.
Preliminary isolation of a myodegenerative toxic principle from Cassia occidentalis
Authors: Hebert C. D. , Flory W. , Seger C. , Blanchard R. E.
Published: February 2025

Aqueous and organic extractions of ground seeds of Cassia occidentalis were obtained. Chickens were dosed with extracted material to assess the toxicity of the extracts. Organic extracts with methanol, ethanol, chloroform, ethyl acetate, and benzene were ineffective in removing the toxin from the seeds. Aqueous extractions, using 25 mM sodium bicarbonate or 250 mM sodium citrate, removed the toxin from the seeds, but left the toxin bound to particulate matter in the extract. Addition of Triton X-100 to the aqueous buffers effectively solubilized the toxin from the particulate matter.

Signs of intoxication in the chickens were loss of weight, weakness, diarrhea, hypothermia, occasionally ataxia, and recumbency; then death. Gross lesions included paleness of skeletal and cardiac muscles and congestion of the liver. Microscopic lesions in muscle tissue were vacuolation, proliferation of sarcolemmal nuclei, and separation of myofibrils. Electron microscopic examination revealed disruption of mitochondrial cristae and swelling and rupture of mitochondria.
Sensory nerve conduction velocities in forelimb of ponies
Authors: Blythe L. L. , Kitchell R. L. , Holliday T. A. , Johnson R. D.
Published: February 2025

Normal nerve conduction velocity values in 10 ponies were determined for sensory nerve fibers in the median and ulnar nerves. A percutaneous signal-averaging technique was developed and used. Medial and lateral palmar digital nerves on the abaxial surface of the proximal sesamoid bones were used as the sites for percutaneous stimulation, whereas recording sites included the medial and lateral palmar nerves just distal to the carpus and the median and ulnar nerves in the middle of the radius. Sensory nerve conduction velocities can be evaluated simply and clinically in the limbs of horses, using percutaneous signal-averaging techniques.
Role of predominant rumen bacteria in the cause of polioencephalomalacia (cerebrocortical necrosis) in cattle
Authors: Haven Thomas R. , Caldwell Daniel R. , Jensen Rue
Published: February 2025

Rumen contents of 2 heifers with acute polioencephalomalacia (cerebrocortical necrosis) were compared with rumen contents from a healthy steer fed a fibrous diet. Also examined were (i) the quantitative nature of the predominant rumen microflora, (ii) the distribution of morphologic types of bacteria in the rumen contents, (iii) the extent that morphologic groups produced or degraded thiamine, and (iv) the cumulative effects of metabolic activities of the predominant rumen bacteria concerning the net production or degradation of thiamine. The differences in the frequency of occurrence of particular bacterial morphologic groups, the extent of growth, and the amount of thiamine metabolism in relationship to growth were also evaluated. The cumulative thiamine metabolism of the predominant bacteria associated with the rumen of polioencephalomalacia-affected heifers led to substantial net thiamine destruction, whereas metabolism associated with the rumen of a normal steer led to thiamine production. Polioencephalomalacia may occur as a consequence of alteration of the metabolic activities of the predominant resident ruminal bacteria associated with diseased cattle.
Marek’s disease virus-induced transient paralysis: Clinical and electrophysiologic findings in susceptible and resistant lines of chickens
Authors: Kornegay Joe N. , Gorgacz Edward J. , Parker Marcia A. , Brown John , Schierman Louis W.
Published: February 2025

Results of neurologic examination, eeg, and motor nerve conduction velocity quantitation were analyzed in a line of chickens susceptible to Marek’s disease virus-induced transient paralysis and compared with findings in a resistant line. Both lines were evaluated on the day before virus inoculation (day 1; base line) and on days 12 and 19. The susceptible birds frequently became depressed and paretic on day 11 or 12 and then recovered, and the resistant line rarely was affected clinically. The eeg of clinically affected birds from the susceptible line correlated well with the clinical course of the disease. Electroencephalographic abnormalities were absent in these birds at base line, evident at 12 days, and had remitted when they were reevaluated on day 19. The pattern in these clinically affected birds was predominantly low voltage-fast activity with frequent spikes. In contrast, the eeg recorded in resistant birds remained essentially the same throughout the study. Mean motor nerve conduction velocity values for the 2 lines of birds did not differ significantly when compared either between or within groups. These findings indicate that Marek’s disease virus-induced transient paralysis may be an inflammatory encephalopathy.
Ultrastructure of the equine hoof wall secondary epidermal lamellae
Authors: Leach D. H. , Oliphant L. W.
Published: February 2025

The ultrastructure of cells of the secondary epidermal lamellae from the hoof wall of 8 adult horses was described. Stages of progressive keratinization were not observed in this cell population. The morphologic features of cells of the secondary epidermal lamellae indicated that these lamellae were composed of nonmobile populations of cells and that primary epidermal lamellae moved past the secondary lamellae by breaking of the desmosomes connecting these 2 cell populations. Seemingly, debris present in the intercellular space between primary and secondary lamellae was a by-product of this remodeling.
Comparison of manually performed Microtiter plate and semiautomated (cuvette) indirect enzyme-linked immunosorbent assays for the serodiagnosis of mycoplasmal pneumonia of swine
Authors: Freeman M. J. , Sands-Freeman Linda , Armstrong C. H.
Published: February 2025

SUMMARY AND CONCLUSIONS

Standardized enzyme-linked immunosorbent assays for the serodiagnosis of mycoplasmal pneumonia of swine were developed, using the traditional Microtiter plate method and a method based on semiautomated processor-analyzer instrumentation. The results of the 2 procedures were not significantly different when the titers of positive and negative anti-Mycoplasma hyopneumoniae standard reference sera were determined in triplicate in 3 separate experiments. Although both methods yielded reproducible results, the instrument-assisted enzyme-linked immunosorbent assay would be preferable if large numbers of samples are to be tested.
Effects of bovine parainfluenza-3 virus on phagocytosis and phagosome-lysosome fusion of cultured bovine alveolar macrophages
Authors: Hesse Richard A. , Toth Thomas E.
Published: February 2025

Bovine parainfluenza-3 virus (PI-3V) replicated in cultured bovine alveolar macrophages (bam) in vitro. Cytopathic changes included spindle cell and giant cell formation, diffuse cell lysis, and cellular detachment progressing to total destruction of the monolayer. Direct immunofluorescent microscopy revealed viral antigen in > 90% of bam on postinoculation day (pid) 3. Virus titers in culture supernatants increased by a factor of 1.6 × 106 tcid50 by pid 6.

Candida glabrata was phagocytized by a similar proportion of glass-adherent PI-3V-infected and sham-inoculated control bam. However, when the number of glass-adherent cells available for assay was taken into account (normalization), the percentage of phagocytic PI-3V-infected bam was significantly lower than that of the control cells at pid 5 and 7 (P < 0.01).

Phagosome-lysosome fusion assays had a marked reduction of fusion activity in PI-3V-infected bam as compared with that of control bam. Proportions of infected cells that showed fusion were approximately 50% of that of the control cells at pid 4 and 6 (P < 0.05). Normalization of these values reduced the fusion rate of PI-3V-infected bam to 34% of that of control bam (P < 0.01).
Efficacy of gonadotropin-releasing hormone administered at the time of artificial insemination of heifers and postpartum and repeat breeder dairy cows
Authors: Lee C. N. , Maurice E. , Ax R. L. , Pennington J. A. , Hoffman W. F. , Brown M. D.
Published: February 2025

The efficacy of gonadotropin releasing hormone (GnRH) on the fertility of dairy heifers and postpartum cows was studied. In one study, 300 cows were assigned randomly to 1 treatment from a 2 × 2 design, and 2 ml of 0.15M saline solution or 100 µg of GnRH was given im on postpartum day (ppd) 14 and at the time of 1st postpartum breeding. In a 2nd study, repeat breeder cows (n = 346) were given saline solution or GnRH at the time of the 3rd breeding. In a 3rd study, heifers (n = 185) were given saline solution or GnRH at 1st breeding.

Animals were observed for repeat estrus, and pregnancy diagnoses were made by rectal palpation 45 to 60 days after breeding. Conception rates were 15% to 18% higher for cows given GnRH, whether at ppd 14 or at the first postpartum breeding. When GnRH was given at the first breeding, conception rates were significantly higher (P < 0.05). Conception rates for repeat breeder cows given GnRH were 25% higher than those in controls (P < 0.005). Conception rates for heifers did not differ between treatments.
Isolation of specific peptides from Mycobacterium paratuberculosis protoplasm and their use in an enzyme-linked immunosorbent assay for the detection of paratuberculosis (Johne's disease) in cattle
Authors: Abbas Babiker , Riemann Hans P. , Lonnerdal Bo
Published: February 2025

An antigen was isolated from the protoplasm of Mycobacterium paratuberculosis by a combination of gel filtration, ion exchange, and affinity chromatography. The purified antigen constituted 7.8% of the total protein in the protoplasm. The specificity and sensitivity of the enzyme-linked immunosorbent assay (elisa) for paratuberculosis, using the purified antigen, were evaluated with sera from 104 cattle which were examined (surveyed) for M paratuberculosis infection by fecal cultural technique. The elisa was positive in 50 of 60 infected animals. Five of 44 noninfected animals were also test-positive. When a crude protoplasmic extract was used as antigen in the elisa, sera from 37 infected and from 18 noninfected animals were test-positive.

Cross-reactions were encountered in both complement-fixation test and the elisa between crude or partially purified M paratuberculosis antigens and antisera to Nocardia asteroides, M avium, M phlei, and M fortuitum. The purified antigen gave no complement-fixation reaction with any of these antisera. In the elisa, cross-reaction was not found when purified antigen was used and the sera were screened at 1:40 dilution.
Physiologic and behavioral evaluation of CO euthanasia of adult dogs
Authors: Chalifoux André , Dallaire André
Published: February 2025

Pure CO was used to euthanatize 18 dogs. During the procedure, physiologic parameters: eeg, ecg, arterial blood pressure, heart rate, respiratory rate, and Cortisol values were monitored. Behavioral manifestations were also noted.

The eeg modifications indicated a cortical voltage increase followed by rapid cerebral death. Higher heart and respiratory rates during eeg modifications indicated stress, and arterial blood pressure decreased significantly (P = < 0.05) at the same time. Serum Cortisol values were already high before the euthanasia process.

Based on these observations, a precise time could not be set for unconsciousness. A gray zone, during which vocalization and agitation occurred for approximately 20 to 25 s, was 3 to 8 s in 10 dogs. These behavioral manifestations could still occur in the conscious phase.
Genotypic, phenotypic, and biological characteristics of Moraxella bovis
Authors: Schurig G. G. , Lightfoot D. R. , Troutt H. F. , Finkler Beth I.
Published: February 2025

Several isolates of Moraxella bovis obtained from cattle with infectious bovine keratoconjunctivitis killed monocytes and macrophages in vitro and carried 3 to 5 plasmids. Cloned and noncloned M bovis isolates readily induced the disease, killed the phagocytes in vitro, and carried 3 plasmids. Moraxella bovis isolates of low in vivo virulence carried 5 plasmids and did not kill phagocytes to the extent that isolates with 3 plasmids did. The possible implications of these findings in the pathogenesis of infectious bovine keratoconjunctivitis are discussed. Also, a classification of M bovis colonies into rough or smooth varieties according to their staining characteristics with crystal violet is suggested.
Role of blood cells in degradation of progesterone in bovine blood
Authors: Vahdat F. , Seguin B. E. , Whitmore H. L. , Johnston S. D.
Published: February 2025

The nature of progesterone decline in samples of bovine blood as affected by whole blood incubation time and temperature was investigated in 3 experiments. In 2 experiments, progesterone concentrations were determined in plasma, in hemolyzed (by freezing and thawing) blood, and in washed blood cells and blood cell washes before and after 8 hours of incubation at 22 C to study the effect of rbc on detected progesterone. In the third experiment, the effect of alteration in rbc metabolism on progesterone degradation by these cells was studied by using potassium oxalate-sodium fluoride as anticoagulant.

Results of these experiments indicated that (a) progesterone was significantly reduced because of whole blood incubation time and temperature, (b) lost progesterone was not detectable on or in blood cells indicating chemical degradation of progesterone, (c) intact blood cells were needed to obtain the decrease in the progesterone, (d) a small amount of circulating blood progesterone was associated with blood cells, and (e) degradation of bovine blood progesterone by blood cells was dependent on the glycolytic process. Potassium oxalate-sodium fluoride anticoagulant and refrigeration provided the best progesterone results when blood samples were not processed immediately after collection.
Progesterone receptors in feline mammary adenocarcinomas
Authors: Johnston Shirley D. , Hayden David W. , Kiang David T. , Handschin Bill , Johnson Kenneth H.
Published: February 2025

Estradiol and progesterone receptors were measured in tumor cytosols from 3 intact and 4 neutered female cats with spontaneously occurring mammary adenocarcinomas. Serum from 2 of the intact cats which had been in estrus 4 and 4 to 6 weeks before tumor excision contained progesterone concentrations of 16.2 and 2.2 ng/ml, respectively; serum progesterone in the other cats was < 2 ng/ml. Estradiol receptors were not detected in any cytosols. Progesterone receptors were detected in all of the cytosols, in concentrations ranging from 4.0 to 11.7 (X = 7.2) fmol/mg of protein.

Scatchard plot analysis of tumor cytosol from an 8th cat with mammary adenocarcinoma revealed presence of high affinity progesterone binding with a dissociation constant (Kd) of 3.47 nM. Tumor receptor content could not be correlated with stage of the estrous cycle nor with whether the cat was intact or neutered.
Selenium concentrations in feeds and effects of treating pregnant Holstein cows with selenium and vitamin Ε on blood selenium values and reproductive performance
Authors: Kappel L. C. , Ingraham R. H. , Morgan Ε. B. , Dixon J. M. , Zeringue Laura , Wilson Deborah , Babcock D. K.
Published: February 2025

Holstein cows (n = 104) and heifers (n = 35) were used to determine the effects of treatment with selenium (Se) and vitamin Ε on whole blood Se values and fertility. At 21 ± 3 days before parturition, 55 cows and 19 heifers were injected with 680 IU of vitamin Ε and 50 mg of Se as sodium selenite. Treatment had no effect on days to first estrus, days to first service, days to conception, services per conception, or number of uterine infusions required. Blood samples were obtained from 33 nontreated cows and heifers and 32 treated animals at 21 and 14 days (± 3) before calving and at 7 and 14 days (± 3) after calving. Mean whole blood Se level at -21 days (day 0 was day of parturition) and before Se-vitamin Ε treatment was 0.109 μg/ml. At days -14, 7, and 14, blood Se was significantly higher in the treated than the non-treated animals. Blood Se was lower on all sampling days in cows calving in July through November than in cows calving in December through April. Heifers in their 1st lactation had lower blood Se concentrations than did cows in their 2nd or later lactation.

In feeds sampled at 2-week intervals, mean concentrations of Se in Bahia grass, mixed ryegrass and oats, corn silage, and sorghum silage were < 0.1 μg/g on a dry matter basis. Bermuda grass, alfalfa hay, and concentrates contained > 0.1 μg of Se/g. Large variation existed in Se concentrations of individual feedstuffs.
Immunofluorescent demonstration of Campylobacter hyointestinalis and Campylobacter sputorum subsp mucosalis in swine intestines with lesions of proliferative enteritis
Authors: Chang Kecken , Kurtz Harold J. , Ward Gilbert E. , Gebhart Connie J.
Published: February 2025

An indirect fluorescent antibody technique was developed to identify Campylobacter spp in lesions of swine proliferative enteritis (spe). Rabbit antisera to C hyointestinalis and C sputorum subsp mucosalis were produced. Bacterial smears stained by fluorescent antibody test with homologous antisera differentiated C hyointestinalis from subsp mucosalis.

Ileal frozen sections from 29 pigs with histologic lesions of spe had specific fluorescent staining of C hyointestinalis in all 29 and subsp mucosalis in 24. Bacterial structures of C hyointestinalis were seen in large numbers and were broadly distributed in intestinal luminal exudate, mucosal necrotic tissues, surface epithelium, lamina propria, and proliferative cryptal epithelium. Numerous C hyointestinalis organisms were always present in the apical cytoplasm of proliferative cryptal epithelium.

Fluorescent subsp mucosalis bacteria were seen less frequently and were distributed focally in the mucosa. Numerous subsp mucosalis organisms were more common in cellular debris and in necrotic tissues of surface mucosa, and less common in the epithelial cells of proliferative crypts. Ileal sections from 13 pigs without spe had no fluorescent staining of C hyointestinalis and subsp mucosalis.
Influence of phentolamine and propranolol on the length of tonus and clonus in pentylenetetrazol-induced seizures in dogs
Authors: Cunningham James G. , Stephenson Robert B.
Published: February 2025

The goal of this study was to test the hypothesis that phentolamine and propranolol premedication would affect tonus differently than clonus in pentylenetetrazol (ptz)-induced tonic-clonic seizures in dogs. Tonic-clonic seizures were induced with iv infusion of ptz, given as an initial 300-mg bolus and then 100-mg boluses every 10 s until a seizure began. Premedication with phentolamine (2 mg/kg of body weight) significantly shortened clonus (P < 0.05), whereas propranolol (1 mg/kg) significantly lengthened clonus (P < 0.05). Neither phentolamine nor propranolol significantly altered the length of tonus or the dose of ptz required to induce seizures (P > 0.05). This indicates that tonus and clonus may have different neural mechanisms and that adrenergic receptors may be involved in the neural mechanisms of clonus.
Application of the enzyme-linked immunosorbent assay to detect canine erythrocyte antibodies
Authors: Campbell Karen L. , George Jeanne Wright
Published: February 2025

A double-antibody enzyme-linked immunosorbent assay (elisa) was developed to detect antibodies bound to canine rbc. The method used a horseradish peroxidase conjugate, o-dianisidine, as a water-soluble chromogen and osmotically lysed rbc on which antibody was detected. The elisa method was compared with the traditional antiglobulin (Coombs’) test on positive controls, using sheep rbc sensitized with dilutions of canine anti-sheep rbc serum and on rbc from canine patients tested for auto-antibodies to rbc. The elisa method appeared to be more sensitive than the Coombs’ test and gave an estimate of the amount of antibody present without the need for serial antiserum dilutions to determine the antibody titer.
Impedance monitoring of equine intestinal motility
Authors: Lamar C. H. , Masty J. , Adams S. B. , Tacker W. A.
Published: February 2025

Myoelectrical and myomechanical activities of the distal portion of the jejunum and pelvic flexure were studied in 7 ponies, using permanently implanted monopolar and bipolar stainless steel electrodes. Dental acrylic embedded recording electrodes were surgically sutured to the serosal surface of the distal portion of the jejunum and pelvic flexure. Myoelectrically, regular spike bursts and irregular spike bursts were observed in the jejunum. Short spike bursts and long spike bursts were recorded and associated with spike potentials, using impedance recording techniques.

Electrical and mechanical data could be monitored simultaneously from the same recording electrode, using separate channels on a physiograph. This method proved effective to monitor periodically myomechanical activity at the same time that myoelectrical activity was being evaluated. The recording system required fewer recording devices to be attached to the intestinal tract, was an inexpensive method of obtaining myomechanical recordings, and did not alter markedly the myoelectrical activity when mechanical activity was being monitored.
Comparison of early splenic changes associated with replication of viruses in murine monocytic macrophages
Authors: Kenyon Alan J.
Published: February 2025

An effect of replication of certain viruses in murine monocytic macrophages was manifested by depletion of cells through degenerative and necrotizing changes in thymus-dependent areas of lymphoid structures. In mice infected with murine hepatitis virus (mhv-3) or lactate dehydrogenase virus, these changes were transient in mice killed on postinoculation day (pid) 2.

To study these morphologic changes due to viral replication, adult Swiss specific-pathogen-free homozygous nude mice (nu/nu) and their heterozygous haired littermates (nu/+) were inoculated with 105 ld50 of mhv-3, euthanatized, and necropsied on pid 1, 2, 4, 6, 8, and 10 along with noninoculated controls. The nu/+ and nu/nu mice killed on pid 2 had lymphocytic karyorrhexis and depletion of cells in the thymus-dependent area. In the heterozygote, these characteristic lesions were transient; whereas in the homozygote, lesions persisted and were present in survivors euthanatized and necropsied on pid 16. Although the intensity of lesions due to mhv-3 varied between nu/+ and nu/nu mice, virus titers determined on liver homogenates were similar for the homozygote and heterozygote during acute disease.

Nude and nonnude mice given lactate dehydrogenase virus and killed on pid 2 had a transient depletion of lymphocytes; whereas mice given lymphocytic choriomeningitis virus and killed on pid 4 had a similar lesion. Lesions neither occurred when mice were treated with silica before inoculation, indicating that functional monocytic macrophages were required, nor occurred when another virus, herpes simplex virus type 1, was given.
Antagonism of xylazine and ketamine anesthesia by 4-aminopyridine and yohimbine in geldings
Authors: Kitzman Joseph V. , Wilson Robert C. , Hatch Roger C. , Booth Nicholas H.
Published: February 2025

Thirty-six fasted, mixed horse breed geldings (6 groups of 6 animals each) were anesthetized with xylazine and ketamine, and when maximally sedated, were given 1 of the following antagonists: saline solution, 4-aminopyridine (4-ap), small-dose yohimbine, large-dose yohimbine, 4-ap plus low-dose yohimbine, or 4-ap plus high-dose yohimbine. Measured data included mean standing time (mst), heart rate, respiratory rate, rectal temperature, and mean total recovery time (mtrt). Emergence phenomena were also observed and recorded as smooth, fairly smooth, fairly rough, or rough.

Groups given 4-ap alone, small-dose yohimbine alone, or large-dose yohimbine alone produced a significant (P < 0.05) decrease in mst (9.9 ± 1.6 minutes, 11.3 ± 1.7 minutes, and 10.6 ± 2.3 minutes, respectively) compared with that in the saline control group (24.3 ± 9.2 minutes). The mtrt were not significantly P > 0.05) different (47.2 ± 10 minutes, 90.4 ± 15.1 minutes, and 83.2 ± 23 minutes, respectively) from control values (66.2 ± 13.4 minutes). When the antagonists were combined, 4-ap plus small-dose yohimbine and 4-ap plus large-dose yohimbine produced significant (P < 0.05) decreases (10.3 ± 2 minutes and 8.3 ± 2.6 minutes, respectively) in mst compared with that of saline controls. The mtrt was significantly longer in the combined antagonist group (4-ap + samall-dose yohimbine—131.8 ± 28.9 minutes; 4-ap + large-dose yohimbine—131.3 ± 19.4 minutes) compared with that of control or any antagonist alone. Emergence phenomena were recorded as follows: saline control—smooth; 4-ap alone—fairly smooth; small-dose yohimbine alone—fairly rough; large-dose yohimbine alone—rough; 4-ap plus small-dose yohimbine—fairly rough; and 4-ap plus large-dose yohimbine—rough.

All antagonists and antagonist combinations tested significantiy reduced mst in geldings anesthetized with xylazine and ketamine, 4-Aminopyridine alone was judged the best antagonist overall because it provided rapid, safe, and permanent reversal of anesthesia with the fewest undesirable emergence phenomena. Either 4-ap alone or in combination with other anesthetic antagonists may prove useful in reversing xylazine/ketamine anesthesia in horses.
Maximum-distention retrograde urethrocystography in healthy male dogs: Occurrence and radiographic appearance of urethroprostatic reflux
Authors: Feeney Daniel A. , Johnston Gary R. , Osborne Carl A. , Tomlinson Michael J.
Published: February 2025

Urethroprostatic reflux was found during retrograde urethrocystography in 21 of 24 mature healthy Beagles. Minimal parenchymal-positive contrast “blushes” near the urethra were identified, but no massive accumulations of contrast medium within the prostate were found.

A particulate contrast medium, sterilized barium sulfate, was used in 12 of the dogs. After retrograde urethrocystography, the barium particles were found in the secretory (acinar) portion of the prostatic parenchyma, confirming that urethroprostatic reflux extended beyond the prostatic duct system that directly empties into the urethral lumen.
Confirmation of Pseudorabies virus infection, using virus recrudescence by dexamethasone treatment and in vitro lymphocyte stimulation
Authors: Thawley David G. , Solorzano Robert F. , Johnson Michael E.
Published: February 2025

A corticosteroid treatment regimen, together with peripheral blood lymphocyte transformation and virus isolation, were used as epizootiologic tools to study pigs seropositive to pseudorabies (pr) virus, but of unknown pr viral infection status. After treatment with 160 mg of dexamethasone daily for 5 days, pr virus was isolated from 2 of 3 adult littermate boars that carried antibodies to pr virus. These pigs also transferred infection to a specific-pathogen-free sentinel penmate.

After dexamethasone treatment, increased lymphocyte stimulation indices were detected in all pr virus seropositive pigs. Pseudorabies virus was not isolated from a seronegative littermate gilt of the seropositive boars. The gilt also remained pr virus seronegative and negative for lymphocyte transformation.

Before dexamethasone treatment, the 3 boars and 1 gilt were seronegative to the pr viral serum neutralization (sn) test at 11 weeks of age. At 13 weeks of age while still sn negative, these pigs were moved to a building and randomly penned with 76 other sn-negative pigs. At 18 weeks of age, all pigs in the building were pr virus seronegative, but at 25 weeks of age, the 3 boars were seropositive and the gilt was seronegative. There were no other pigs in the building that had antibodies to pr virus before the addition or after the removal of these pigs. Seemingly, the 3 boars were infected with pr virus before 13 weeks of age indicating that pr virus infection of swine may occur in the absence of detectable sn antibodies.
Support of an anephric dog for 54 days with ambulatory peritoneal dialysis and a newly designed peritoneal catheter
Authors: Thornhill J. A. , Hartman J. , Boon G. D. , Riviere J. E. , Jacobs D. , Ash S. R.
Published: February 2025

A bilaterally nephrectomized dog was successfully supported with peritoneal dialysis for 54 days, using a radically new design of access catheter and a human dialysis schedule designated as continuous ambulatory peritoneal dialysis. The dog remained active and alert with a stabilized blood urea nitrogen of 30 to 40 mg/dl and a serum creatinine concentration of 4 to 6.5 mg/dl. Problems encountered with the peritoneal dialysis included the propensity for developing peritonitis, anorexia, and a significant plasma protein loss in the dialysate fluid as result of leakage across the peritoneum. Protein loss coupled with anorexia produced a catabolic state, and the animal was euthanatized because of this, at postnephrectomy day 54.

The development of a new catheter design alleviated the drainage problems of the straight tube Tenckhoff catheter. Its use coupled with the continuous ambulatory peritoneal dialysis schedule and detailed management techniques allowed using the anephric dog as a model of uremia. In addition, peritoneal dialysis could be a viable treatment for animals presenting with acute reversible anuric or oliguric renal failure where conservative medical management with fluids and diuretics has failed to give clinical improvement.
Immunofluorescence studies of renal basement membranes in dogs with spontaneous diabetes
Authors: Jeraj K. , Basgen J. , Hardy R. M. , Osborne C. A. , Michael A. F.
Published: February 2025

Renal tissue from 12 dogs with spontaneous diabetes and 16 control dogs were studied by light, immunofluorescence, and electron microscopies. Significant linear staining for immunoglobulin G and albumin were observed in the glomerular and tubular basement membranes of dogs with spontaneous diabetes—similar to that observed in human diabetes. On immunohistochemical grounds, it would appear that the dog with spontaneous diabetes is an appropriate model of diabetes in persons.
Immediate postnatal inoculation of a microbial barrier to prevent neonatal diarrhea induced by Clostridium difficile in young conventional and gnotobiotic hares
Authors: Dubos Françoise , Martinet Lise , Dabard J. , Ducluzeau R.
Published: February 2025

The cecal content of a healthy young hare (a 10-fold dilution prepared in anaerobiosis) was transferred into gnotobiotic recipient mice. The fecal flora of recipient mice was inoculated into 49 conventional young hares (kept in a closed building) immediately after birth. All the inoculated hares survived until weaning whereas 35% of 48 non-treated conventional hares died of diarrhea. Clostridium difficile and C perfringens were present in all the diarrheal noninoculated hares, whereas these species were present only in 50% of healthy inoculated or noninoculated hares at low concentrations (< 106/g of feces). A microbial barrier effect against challenge-exposure strains of C difficile and C perfringens was evidenced in the intestinal tract of recipient gnotobiotic mice and young hares. Seemingly, the protective effect of the microbial inoculum was due to antagonisms exerted against C difficile and C perfringens in the intestinal tract of inoculated conventional hares.
Preliminary study of the ultrasonographic diagnosis of pregnancy and fetal development in the dog
Authors: Cartee Robert E. , Rowles Terri
Published: February 2025

A total of 18 dogs were examined by ultrasound during their gestation period. At gestational day 7, a uterus indicative of possible pregnancy was observed. At gestational day 10, the embryo was observed. Fetal and cardiac activities appeared at 28 days. Rapid increases of the crown-rump length and biparietal diameter occurred between the 5th and the 6th weeks of gestation and of the body diameter between the 4th and 5th weeks and again between the 6th and the 7th weeks of gestation.
Effects of cyclophosphamide on the immune response of pigs to Salmonella cholerae-suis var kunzendorf
Authors: Griffith Ronald W. , Kramer Theodore T. , McRill Connie
Published: February 2025

The effects of the immunosuppressive agent cyclophosphamide (cy) on the immune response of pigs given im challenge inoculations of a moderately virulent strain of Salmonella cholerae-suis var kunzendorf were examined. Five groups of Yorkshire-cross pigs (approx 6 kg) were given Salmonella, cy, or both at various times after the 1st of a series of doses of cy was given. The drug was administered subcutaneously in 3 doses, 2 days between doses, at a rate of 20 mg/kg of body weight. Cyclophosphamide was observed to produce significant numerical decrease of circulating leukocytes, especially the polymorphonuclear neutrophils. Circulating lymphocyte numbers were reduced to 40% to 60% of base-line values. Pigs (group 4) given 3 × 106 S cholerae-suis im at the time the initial cy dose was given were clinically ill during days 6 to 12; 2 of the 5 pigs died. In contrast, pigs (group 5) given 3 × 106 S cholerae-suis at the time of the 3rd dosing with cy did not become clinically ill until 10 days later. A significant increase in antibody titer to S cholerae-suis was delayed in this latter group beyond that of the groups of pigs (group 4) inoculated on the 1st dosing with cy and of pigs (group 6) not given cy. A significant and prolonged increase in mean rectal temperature was observed in those pigs challenge inoculated at the time of the initial cy dose. Pigs also were sensitized to Mycobacterium avium 2 weeks before cy administration. Delayed hypersensitivity reactions were depressed in pigs treated with cy at the time of testing.
African swine fever convalescent sows: Subsequent pregnancy and the effect of colostral antibody on challenge inoculation of their pigs
Authors: Schlafer Donald H. , McVicar John W. , Mebus Charles A.
Published: February 2025

The effect of African swine fever (asf) virus infection on reproductive performance of recovered sows and their pigs was investigated. Six sows were inoculated with a 1979 asf isolate from the Dominican Republic. One sow was bred on postinoculation day (pid) 58 and killed on pid 148. Four sows were bred between pid 368 and 419 and were allowed to farrow. One sow did not conceive. Samples collected during pregnancy, at farrowing, and during lactation were tested for virus by tissue culture and animal inoculations to determine whether asf virus recrudesced during these natural stresses. Virus was recovered only from tissues of the sow killed on pid 148. Virus was not detected in tissue samples from the 4 other sows or from any fetus or neonate.

Sow and neonatal pig sera, colostral whey, and milk whey were assayed for antibodies against asf viral antigens, using an enzyme-linked immunosorbent assay. Antibody values in sows' sera did not change appreciably during pregnancy, farrowing, or lactation.

One litter of pigs was raised with their sow. Weekly serum samples were tested for passively acquired antibodies. At 7 weeks of age, the litter was challenge inoculated with the same virus as that used initially to infect their dam. Viremia titers, duration of viremias, and clinical course were reduced. One young pig did not develop fever, viremia, clinical disease, or antibody response to virus challenge exposure. The altered course of infection was attributed to protective effect of passively acquired antibodies.
Effects of social stress on response to ketamine anesthesia in chickens
Authors: McGrath C. J. , Gross W. B. , Lee J. C.
Published: February 2025

Chickens were housed in low, high, and optimal social stress environments for 16 weeks before they were given ketamine iv. The sleep time was significantly (P < 0.01) longer in the groups exposed to the low (n = 14) and high (n = 30) social stress environments than in the group exposed to optimal-stress environment (n = 12) or controls (n = 12). Birds (n = 12) removed from optimal-stress environment and exposed to high-stress environment for 48 hours did not exhibit longer sleep time than the group in the optimal-stress environment. Long-term exposure to different social stress environments markedly altered ketamine-induced sleep time in chickens.
Morphology of colonies of Anaplasma marginale in nymphal Dermacentor andersoni
Authors: Kocan Katherine M. , Yellin Theodora N. , Ewing S. A. , Hair Jakie A. , Barron Selwyn J.
Published: February 2025

Colonies of Anaplasma marginale Theiler were studied in midgut epithelial cells of nymphal Dermacentor andersoni Stiles that had become infected by feeding on splenectomized calves with anaplasmosis. Colonies of A marginale were not observed in nymphal ticks killed during the 6-day feeding period, but were present in sections of midgut epithelial cells of ticks killed as early as 5 days after repletion. Colonies of A marginale also were present in ticks examined throughout development to the adult stage. Two distinct morphologic types of colonies were observed and categorized by light microscopy as nymphal types 1 and 2. Colonies that were morphologically indistinct with characteristics common in both types were termed transitional nymphal (TsN) colonies. Nymphal type 1 (Ny1) colonies were observed at 5 days after repletion and nymphal type 2 (Ny2) colonies were first observed at 20 days after feeding.

Representatives of each colony type were selected by light microscopy and were sectioned for electron microscopy. The Ny1 contained small particles and large, round reticulated forms, some of which appeared to be dividing by binary fission. The Ny2 also contained reticulated organisms, but they were rod-like in shape, and there was no morphologic evidence of binary fission. Organisms within Ny2 appeared to be surrounded by 2 double-layered membranes. Electron-dense forms, commonly observed in adult ticks, were not seen in colonies (Ny1, Ny2, or TsN) from nymphal ticks.
In vitro action of combinations of antimicrobial agents with EDTA-tromethamine on Proteus vulgaris of a canine origin
Authors: Wooley R. E. , Jones M. S. , Gilbert J. P. , Shotts E. B.
Published: February 2025

Combinations of EDTA-tromethamine and 7 antimicrobial agents (chloramphenicol, nalidixic acid, oxytetracycline, penicillin, polymyxin-B, streptomycin, or a combination of sulfamethazine, sulfapyridine, and sulfathiazole) were tested for synergistic activities against Proteus vulgaris of canine origin. Three in vitro tests were used, including minimal inhibitory concentrations of the drugs, a 2-dimensional microtiter checkerboard technique, and bacterial inhibition studies. A synergistic inhibitory action was observed with combinations of EDTA-tromethamine plus penicillin, oxytetracycline, nalidixic acid, chloramphenicol, polymyxin-B, or sulfamethazine-sulfapyridine-sulfathiazole by at least one test system. A synergistic effect was not recorded with combinations of EDTA-tromethamine and streptomycin. Poor correlation between data from the 3 test systems was noticed, despite the fact that each monitors bacteriostatic end points.
Quantitative aspects of the transmission of African swine fever
Authors: McVicar John W.
Published: February 2025

The contagiousness of pigs during different stages of infection with African swine fever virus was assessed by measuring the amount of virus excreted and the amounts of virus in the blood and other tissues, as well as determining the infectious dose of the virus by various routes. The virus was present in substantial amounts in secretions and excretions of acutely infected pigs for only 7 to 10 days after the onset of fever and was present in the greatest amount in the feces. Virus persisted in the blood of some recovered and clinically normal pigs for 8 weeks and in the lymphoid tissues for at least 12 weeks. The intranasal/oral id50, and the iv/im id50 of a moderately virulent isolate of African swine fever virus were determined to be 18,500 and 0.13, 50% headsorbing units, respectively. A highly virulent isolate required approximately 10-fold more virus to cause infection by the intranasal/oral route.
Enzyme-linked immunosorbent assay for detection of equine infectious anemia antibody to purified P26 viral protein
Authors: Shen D. T. , Gorham J. R. , McGuire T. C.
Published: February 2025

An indirect enzyme-linked immunosorbent assay (elisa) was developed for the detection of equine infectious anemia (eia) antibody in horse sera. Purified P26 viral protein was the antigen; alkaline phosphatase linked to rabbit anti-horse immunoglobulin G was the conjugate. The elisa detected eia antibodies in horse sera as early as 11 to 14 days after experimental inoculations. There was full agreement between the results of elisa and the agar-gel immunodiffusion tests on eia proficiency test sera. The elisa readily detected eia antibody in horse sera that had weak positive reactions on agar-gel immunodiffusion.
Effect of ophthalmic prednisolone acetate on the canine adrenal gland and hepatic function
Authors: Roberts Steven M. , Lavach J. D. , Macy Dennis W. , Severin Glenn A.
Published: February 2025

Iatrogenic hypothalamic-hypophysis-adrenal axis suppression occurred in 5 small dogs as a result of ophthalmic instillation of 1% prednisolone acetate. An ophthalmic suspension was applied 4 times a day to each eye, such that 4 mg/day was delivered for 2 weeks followed by 2.67 mg/day for 2 weeks. After treatment week 2, serum Cortisol decreased from base-line mean values of 17.66 ng/ml (before ACTH) and 139.16 ng/ml (60 minutes after ACTH) to 3.22 ng/ml (before ACTH) and 13.58 ng/ml (60 minutes after ACTH). After treatment week 4, serum Cortisol values decreased to a mean of 1.76 ng/ml (before ACTH) and 4.82 ng/ml (60 minutes after ACTH). Before ACTH Cortisol values returned to base line 2 weeks after discontinuing treatment. Values after ACTH administration remained 26% lower than base line (P = 0.0132), although within a normal response range.

Hepatic carbohydrate metabolism was altered, allowing marked glycogen accumulation. Marked increases in the blood glucose values after glucagon stimulation testing occurred at 3, 5, 15, 30, and 60 minutes after glucagon administration. The greatest increase corresponded to the 30-minute sample with a mean glucose increase of 112.40mg/dl from base-line values (P = 0.0022) as a result of the ophthalmic corticosteroid applied.

Seemingly, topical ophthalmic corticosteroids have the potential for causing adrenocortical suppression and hepatic metabolic changes. The dosage level of treatment was low enough to avoid major hematologic changes. The exaggerated response to the glucagon tolerance test indicated that this test can be used in detecting hyperglucocorticism.
Comparison of a commercial enzyme-linked immunosorbent assay with electron microscopy, fluorescent antibody, and virus isolation for the detection of bovine and porcine rotavirus
Authors: Benfield David A. , Stotz Ivan J. , Nelson Eric A. , Groon Kathy S.
Published: February 2025

The purpose in this study was to compare the sensitivity of a commercial enzyme-linked immunosorbent assay (elisa) with electron microscopy (em), fluorescent antibody (fa), and virus isolation (vi) for the detection of bovine and porcine rotavirus (rv). Seventy-three bovine and 116 porcine accessions were evaluated by 1 or all 4 diagnostic tests, where suitable specimens were available. For the bovine samples, agreement was 33% between fa and em, 33% between fa and elisa, and 92% between em and elisa. For the porcine samples, agreement was 79% between em and fa, 72% between em and elisa, and 82% between elisa and fa. Virus was isolated from 68% and 41% of the bovine and porcine fecal samples, respectively. Commercial elisa was as sensitive as em, but was more sensitive than fa or vi for the detection of rv in bovine feces. Electron microscopy was more sensitive than fa, elisa, or vi for detection of rv in porcine feces. The elisa was an advantageous alternative to the conventional methods of em, fa, and vi for the diagnosis of rv in calf feces, but not for porcine feces.
Radioimmunoassay of conjugated bile acids in canine and feline sera
Authors: Bunch S. E. , Center S. A. , Baldwin B. H. , Reimers T. J. , Balazs T. , Tennant B. C.
Published: February 2025

A solid-phase radioimmunoassay for the measurement of total conjugated bile acids was validated for use in dogs and cats. The method used an 125I-labeled iodoglycocholate tracer and polypropylene assay tubes coated with rabbit antiserum against the major conjugated bile acids. Standard solutions of sodium taurocholate provided with the kit and serial dilutions of canine and feline sera containing low, medium, and high endogenous bile acid concentrations inhibited binding of the [125I]iodoglycocholate tracer to the antibody in a parallel manner; this inhibition indicated specificity of the assay for bile acids in the serum of dogs and cats. Increased serum bile acid concentrations in animals with liver disease confirmed the biologic specificity of the assay in dogs and cats. Accuracy was shown by quantitative recovery of purified sodium taurocholate from canine and feline sera, Intra-assay precision was 7.2% to 17.3% for dogs and 8.5% to 18.5% for cats. Interassay precision was 4.8% to 17.2% for dogs and 3.5% to 11.2% for cats. The sensitivity of the assay in dogs and cats was 0.4 μmol/L. Solid-phase radioimmunoassay is a valid method for the direct measurement of total conjugated bile acids in the dog and cat, and is of value in the diagnosis of hepatobiliary disease in these species.
Chlamydia psittaci experimental abortion in goats
Authors: Rodolakis Annie , Boullet C. , Souriau A.
Published: February 2025

To study abortive cblamydiosis in goats, 11 pregnant goats were inoculated intradermally at the 3rd month of pregnancy with 2 × 107 or 2 × 106 plaque-forming units of a strain of Chlamydia psittaci isolated from naturally occurring abortions in goats. The 11 inoculated does aborted 24 to 56 days after they were inoculated and shed Chlamydia. This shedding began at least 9 days before abortion (1 goat) and persisted 12 days after abortion (1 goat). Retained placenta or metritis were observed in 4 of the goats.