bluuebunny/crossref_metadata_2025 huggingface dataset:
Cross protection in mice and swine immunized with live erysipelas vaccine to challenge exposure with strains of Erysipelothrix rhusiopathiae of various serotypes
Authors: Takahashi Toshio , Takagi Masami , Sawada Takuo , Seto Kenji
Published: February 2025

Mice and swine immunized subcutaneously with live vaccine prepared from acriflavine-fast attenuated Erysipelothrix rhusiopathiae, strain Koganei (serotype 2), were challenge exposed to virulent strains of E rhusiopathiae of various serotypes.

Vaccinated mice did not die after challenge exposure to serotypes 1a, 1b, 2, 3, 5, 6, 7, 8, 9, 11, 12, 15, 16, 18, 19, 21, or N, but 20% to 30% mortality occurred in vaccinated mice challenge exposed to serotypes 10, 14, 20, or 22. Nonvaccinated control mice died after challenge exposure to all serotypes tested.

Vaccinated swine challenge exposed to strain 14B (serotype 9) or strain 2179 (serotype 10) developed localized urticarial lesions at the site of intradermal exposure. Vaccinated swine challenge exposed to serotypes 1a, 1b, 2, 5, 8, 11, 12, 18, 19, or 21 did not have clinical signs of acute erysipelas. Nonvaccinated control swine developed acute generalized erysipelas or localized lesions at the site of intradermal exposure.
Distribution of immunoglobulin-bearing cells in the gut-associated lymphoid tissues of the turkey: Effect of antibiotics
Authors: Cook Jeanne , Naqi S. A. , Sahin Nigar , Wagner G.
Published: February 2025

Distribution of immunoglobulin (Ig)-bearing cells in the gut-associated lymphoid tissues of antibiotic treated and untreated control turkeys (Meleagris gallopavo) was compared. Antibiotic treatment was similar to a regimen used in commercial turkey production, which included preincubation dipping of fertile eggs in gentamicin solution, injection of turkeys with gentamicin at hatching, and inclusion of chlortetracycline in the diet. Tissues were examined from turkeys at 3, 7, 14, and 21 days of age with a direct immunofluorescence procedure.

Cell distribution in control turkeys was as follows: In the bursa of Fabricius, IgA-carrying cells predominated at 3 days of age, but at later intervals, the 3 classes of Ig-bearing cells were in equal numbers. In the cecal tonsils, IgM- and IgA-bearing cells were in larger numbers at 3 days of age, whereas, the IgG-bearing cells were sparsely distributed. By 7 days of age, IgM cells became more numerous in the cecal tonsils and remained numerous until 21 days of age.

At 3 days of age, IgA cells predominated in the small intestines and IgM cells predominated in the large intestine. At 7 and 14 days of age, IgM cells were more numerous in the small and large intestines, but by 21 days of age, IgA cell population equaled that of IgM. The IgG cells were generally sparse in the intestines.

Antibiotic treatment often resulted in lower numbers of Ig-positive cells, especially those bearing IgM and IgA. Normal development of the bursa of Fabricius was also retarded in this group.
Partial purification of extracellular toxic material of fish Vibrio
Authors: Moustafa Mohamed , Kodama Hiroshi , Ishiguro Shinryo , Mikami Takeshi , Izawa Hisao
Published: February 2025

Hemolytic activity of 3 pathogenic strains, of fish Vibrio commonly associated with vibriosis (V anguillarum NCMB6 and NCMB571 strains, and Vibrio sp N7802 strain) was examined, using chicken and mammalian erythrocytes. Vibrio strains NCMB6 and NCMB571 and their culture filtrates had hemolytic activity against 8 kinds of erythrocytes tested, whereas Vibrio strain N7802 produced only a little amount of hemolysin. Strain NCMB571 culture filtrate and its material partially purified by column chromatography were lethal in mice. From 2 peaks of protein, hemolysin was recovered from the 1st peak, which coincided with toxicity in mice. Heat-inactivation of culture filtrate indicated that hemolytic materials may be thermolabile proteins, but that toxic material may be comparatively thermostable.
Early clinicopathologic findings in dogs ingesting ethylene glycol
Authors: Grauer G. F. , Thrall M. A. , Henre B. A. , Grauer R. M. , Hamar D. W.
Published: February 2025

Fifteen dogs were given 9.5 ml of ethylene glycol/kg of body weight, orally. Physical examination and clinical laboratory findings were evaluated at 1 and 3 hours after ingestion. Three of these dogs were also evaluated at 6, 9, 12, 24, 48, and 72 hours after ingestion. At 1 and 3 hours, the dogs were depressed, ataxic and polydipsic with increased urine output and serum osmolality. Plasma bicarbonate and urine osmolality were decreased Theosmolal and anion gaps were increased at 1 and 3 hours, respectively. Calcium oxalate crystalluria was first observed at hours. Diminished renal excretory function was not evident until 48 hours. Depression, ataxia, metabolic acidosis, polydipsia, and polyuria in the presence of serum hyperosmolality were early (1 and 3 hour) findings that indicated ethylene glycol intoxication in dogs.
Antimicrobial susceptibility patterns of canine Staphylococcus intermedius isolates from veterinary clinical specimens
Authors: Phillips Walter E. , Williams Billy J.
Published: February 2025

Sixty-six Staphylococcus intermedius isolates from canine clinical specimens were tested for susceptibility to various antimicrobial agents by the Bauer-Kirby disk diffusion method and a commercial microdilution system. All isolates were susceptible to cephalothin, cloxacillin, gentamicin, methicillin, and vancomycin. Resistance to ampicillin, penicillin G, and tetracycline was frequent. There was an overall 87% agreement of results from the disk diffusion and microdilution methods for 10 antimicrobial agents. There was ≥ 94% agreement between the 2 methods for 7 antimicrobics; discrepancies were minor.
Isolation and characterization of nutritionally variant streptococci from animal sources
Authors: Chengappa M. M. , Bailie W. E. , Stowe E. C.
Published: February 2025

Ten nutritionally variant streptococci were recovered from clinical specimenssubmittedtotheKansas State University Veterinary Clinical Bacteriology laboratory over a 4-year period. Isolates were recognized visually on primary blood agar plates by their satellite growth around a previously overlaid Staphylococcus aureus culture. All isolates grew within 24 hours in Todd-Hewitt and heart infusion broths supplemented with 5% bovine fetal serum and 5% S aureus filtrate. They also grew anaerobically in supplemented broths within 48 hours. However, isolates did not grow aerobically or anaerobically in the absence of supplements up to a 7-day postinoculation period. As determined by the standard Kirby-Bauer technique, the isolates were highly susceptible to antimicrobial agents commonly recommended in veterinary medicine. The isolates did not react with the corresponding Lancefield group-specific antisera, as tested by the capillary precipitin test.
Comparison of the genomes of pseudorabies (Aujeszky's disease) virus strains by restriction endonuclease analysis
Authors: Pritchett R. F. , Bush C. E. , Chang T. J. , Wang J. T. , Zee Y. C.
Published: February 2025

The DNA of pseudorabies virus (prv) strains from the United States and Taiwan and attenuated vaccine strains from Romania were compared by restriction endonuclease analysis. Electrophoretically separated prv DNA fragments of KpnI and BamHI digests demonstrated cleavage pattern variations which clearly distinguished the 3 Taiwan isolates from all other strains, as well as from each other. One type of variation involved the loss or gain of restriction endonuclease cleavage sites. Examples of this type of variation were clearly observed in fragment patterns of the Taiwan isolates. Another type of variation that occurred at higher frequency for fragments mapping in the repeat and repeat-unique joint regions of the prv genome involved sequence additions or deletions from existing fragments. This second type of variation occurred in most of the strains analyzed.
Antagonism of xylazine sedation in steers by doxapram and 4-aminopyridine
Authors: Zahner Joanne M. , Hatch Roger C. , Wilson Robert C. , Booth Nicholas H. , Kitzman Joseph V. , Brown John
Published: February 2025

SUMMARY AND CONCLUSIONS

Five groups of 6 fasted crossbred steers were injected im with standard dosages of xylazine hydrochloride (0.3 to 0.5 mg/kg). At maximal sedation, the steers were injected iv with the antagonists doxapram (1.0 mg/kg), doxapram + yohimbine (0.125 mg of yohimbine/kg), doxapram + 4-aminopyridine (4-ap; 0.3 mg of 4-ap/kg), or 4-ap + yohimbine. One group was given 1.0 ml of saline solution iv instead of antagonists.

Doxapram, doxapram + yohimbine, doxapram + 4-ap, and 4-ap + yohimbine decreased mean standing time (time from antagonist injection until animal could stand unaided) to 17.0, 4.3, 3.3, and 4.5 minutes, respectively— significantly (P < 0.05) down from a control value of 49.8 minutes.

Mean total recovery time (time from xylazine injection until animal resumed eating) was decreased to 78 minutes by doxapram and 81.6 minutes by doxapram + 4-ap—significantly (P < 0.05) down from the control value of 142.9 minutes.

Respiratory character was improved (depth of respiration was increased) only by doxapram + 4-ap. Relapses to recumbency and marked sedation were not seen in steers given doxapram + 4-ap or the saline solution. One steer given doxapram, 2 given doxapram + yohimbine, and 1 given 4-ap + yohimbine relapsed to recumbency and sedation. Recovery was relatively smooth in steers given doxapram + 4-ap or 4-ap + yohimbine. Animals given doxapram or doxapram + yohimbine had difficult recoveries.

In steers (n = 6) given an overdose of xylazine (1 mg/ kg), the combination of doxapram + 4-ap produced a mean standing time of 7.0 minutes and a mean total recovery time of 225.7 minutes, Recovery of the xylazine-overdosed group was relatively smooth, respiratory character was improved by the antagonists, and relapses did not occur.

The combination of doxapram + 4-ap was judged overall to be the most effective antagonist of xylazine sedation in cattle. Other antagonists (doxapram, yohimbine, 4-ap, doxapram + yohimbine, or 4-ap + yohimbine) could also be used for rapid reversal of xylazine sedation in cattle if difficult recoveries and/or relapses to recumbency and sedation are of little concern.
Reversal of pentobarbital anesthesia with 4-aminopyridine and yohimbine in cats pretreated with acepromazine and xylazine
Authors: Hatch Roger C. , Kitzman Joseph V. , Clark J. Derrell , Zahner Joanne M. , Booth Nicholas H.
Published: February 2025

In 2 separate experiments, groups of atropinized cats (6 cats/group) were given acepromazine (0.25 mg/kg of body weight) or xylazine (2.2 mg/kg) im and anesthetized with pentobarbital. The mean dose of pentobarbital was decreased approximately 36% by acepromazine, and approximately 80% by xylazine, compared with published doses. Anesthetized cats were given iv saline solution (control groups) or were given the antagonists 4-aminopyridine (4-ap; 0.5 mg/kg), yohimbine (0.4 mg/kg), or 4-ap + yohimbine (0.5 mg/kg and 0.4 mg/kg, respectively).

In acepromazine-treated cats, 4-ap + yohimbine was the most effective antagonist; arousal and walking occurred in an average of 10.4 minutes and 91.7 minutes, respectively, Yohimbine enhanced the antagonistic effects of 4-ap, In xylazine-treated cats, yohimbine was an effective antagonist; arousal and walking occurred in an average of 2.8 minutes and 12.8 minutes, respectively. Yohimbine did not enhance the antagonistic effects of 4-ap.

Mean respiratory rates were decreased by acepromazine, but were increased by xylazine. Thus, respiratory rate depression by pentobarbital was not as marked with xylazine as it was with acepromazine. Changes in mean heart rate were not remarkable with either sedative, and cardiac irregularities were not palpated or auscultated.

In healthy cats, the duration of pentobarbital anesthesia can be controlled by 4-ap + yohimbine (acepromazine-pretreated cats) or by yohimbine alone (xylazine-pretreated cats).
Furosemide: Effects on the hemostatic mechanism of resting and exercised Standardbred horses
Authors: Kociba G. J. , Bayly W. M. , Milne D. W. , Wigton D. H. , Gabel A. A. , Muir W. W.
Published: February 2025

Two groups of 6 Standardbred horses each were used to study hemostatic functions at rest and after exercise with furosemide or a placebo. One group which was trained was given maximum exercise on the racetrack, and the other, a less-fit group, was given submaximum exercise on the treadmill. There was no difference in furosemide compared to placebo trial results in either group in coagulation screening tests, platelet concentration, or retention of platelets in a glass bead column. Increased fibrinogen concentration and enhanced platelet retention were associated with maximum exercise. Aggregation of platelets by adenosine diphosphate and bovine collagen was not different in furosemide and the placebo submaximal exercise trials.
Activity of closantel in the prevention of Gasterophilus and Strongylus vulgaris larval infections in equine foals and yearlings
Authors: Guerrero Jorge , Newcomb Kathleen , Seibert Barbara P. , Michael Bruce F.
Published: February 2025

Two controlled tests were conducted in equine foals and yearlings to determine the optimal oral dosage and the duration of activity of closantel for the prevention of Gasterophilus spp larval infections. Additional data were collected on the activity of closantel against Strongylus vulgaris larval infections. In experiment 1, 12 foals and 12 yearlings were equally allocated to 4 experimental groups, and were given oral treatments with closantel at dosages of 0 (nontreated controls), 2, 5, or 8 mg/kg of body weight every 2 months during bot season. The foals and yearlings were allowed to graze on open pasture throughout the experiment to provide a natural source for bot and helminth infections. All animals were euthanatized and necropsied 6 weeks after the final treatment. Closantel was highly effective (98.6% to 100%) at all doses in preventing Gasterophilus spp larval infections in the foals, but only the 8 mg/kg dose had significant (P < 0.05) activity (99.7%) in the yearlings. This dose also significantly reduced the numbers of 4th-stage and immature adult S vulgaris (86.0%) in the mesenteric arteries as compared with nontreated controls.

In experiment 2, 9 foals and 9 yearlings received a single oral treatment of 8 mg of closantel/kg of body weight; 3 foals and 3 yearlings were kept as nontreated controls. Groups of 6 treated (3 foals, 3 yearlings) and 2 control (1 foal, 1 yearling) animals were euthanatized and necropsied 1, 2, and 3 months after treatment. Closantel remained effective for 2 months in preventing infections of G intestinalis larvae in these foals and yearlings. Clinical signs of toxicosis were not observed in the treated animals of either study.
Endotoxin-induced hematologic and blood chemical changes in ponies: Effects of flunixin meglumine, dexamethasone, and prednisolone
Authors: Ewert K. M. , Fessler J. F. , Templeton C. B. , Bottoms G. D. , Latshaw H. S. , Johnson M. A.
Published: February 2025

To evaluate the effect of certain drugs on hematologic changes, blood chemical values, and survival in endotoxin shock, anesthetized ponies were given (iv) endotoxin (Escherichia coli O55:B5) and then treated as follows: Group A ponies—given a saline infusion at 5 minutes and at 3 hours after they were given endotoxin; group B ponies—given flunixin meglumine at 5 minutes and at 3, 6, 9, and 24 hours after they were given endotoxin; group C ponies—treated with dexamethasone; and group D ponies—treated with prednisolone at 5 minutes and at 3, 9, and 24 hours after they were given endotoxin. Anesthesia was maintained for 4 hours, after which time the ponies were allowed to recover. Throughout the experiment, samples of blood were collected for blood gas, hematologic, and blood chemical values.

The endotoxin effects were seen in the 4 groups: lactic acidosis, prolonged coagulation times, leukopenia, hemoconcentration, and elevated blood chemical values. Although none of the treatments prevented the effects of endotoxin, changes were less severe and survival times were longer in ponies treated with flunixin meglumine.
Experimental babesiosis in coyotes and coydogs
Authors: Roher Daniel P. , Anderson John F. , Nielsen Svend W.
Published: February 2025

One splenectomized and 6 intact coyotes (Canis latrans), and 2 coydogs were experimentally inoculated with a recent isolate of Babesia gibsoni. The disease was mild in intact animals, was fatal in the splenectomized coyote, and was characterized by a regenerative hemolytic anemia with the pcv decreasing to 16% in intact animals and to 6% in the splenectomized coyote. Peak parasitemia ranged from 3% to 21% of erythrocytes infected and was inversely correlated to pcv. Serum lactate dehydrogenase, bilirubin, and globulin concentrations were increased in all infected animals. Three weeks after inoculation, specific antibody titers increased to 1:65,536 and remained elevated in the chronically infected animals. The splenectomized coyote had progressive weakness until death, 24 days after inoculation. Intact animals had splenomegaly and anorexia at the height of infection. The splenectomized coyote had generalized edema, omental petechiae, renal and hepatic degeneration, membrano-proliferative glomerulonephritis and congestion, extramedullary hematopoiesis, lymphoid hyperplasia, and severe hemosiderosis in an accessory spleen. The only consistent change in the intact animals was splenomegaly.
Equine congenital defects
Authors: Crowe M. Ward , Swerczek T. W.
Published: February 2025

In a 13-year survey of equine congenital defects that resulted in death or required euthanasia in central Kentucky, necropsies were performed on 608 deformed fetuses or newborn foals. The following congenital anomalies were observed: contracted foal syndrome (33.2%), miscellaneous limb contraction (20%), multiple defects (5.3%), microphthalmia (4.6%), craniofacial malformations (4.3%), cleft palate (4.0%), heart defects (3.5%), umbilical defects (3.5%), and hydrocephalus (3.0%). Eleven less frequently occurring anomalies constituted the balance of the congenital defects in fetuses and newborn foals.
Common plasmid encoding resistance to ampicillin, chloramphenicol, gentamicin, and trimethoprimr-sulfadiazine in two serotypes of Salmonella isolated during an outbreak of equine salmonellosis
Authors: Ikeda Jack S. , Hirsh Dwight C.
Published: February 2025

An outbreak of equine salmonellosis occurred at the Veterinary Medical Teaching Hospital, University of California, Davis, between June 1981 and March 1982. Forty-four horses were infected with Salmonella saint-paul, a serotype rarely isolated from animals at the university before the outbreak. Unlike the isolates of S saint-paul obtained at the beginning of the outbreak, almost all strains isolated near the end were resistant to ampicillin, cephalothin, chloramphenicol, gentamicin, kanamycin, sulfadiazine, trimethoprim, and trimethoprim-sulfadiazine. A conjugal-resistance plasmid (R-plasmid) was responsible for resistance to these antimicrobics.

This R-plasmid was identical to an R-plasmid of S krefeld, a serotype that had been isolated repeatedly throughout the hospital before, during, and after the outbreak involving S saint-paul. This finding prompted the suggestion that in vivo transfer of the R-plasmid had occurred. Whether the donor organism was S krefeld is unknown.
Treatment of acute ocular Moraxella bovis infections in calves with a parenterally administered long-acting oxytetracycline formulation
Authors: Smith John A. , George Lisle W.
Published: February 2025

Acute ocular Moraxella bovis infections were induced in the uv-irradiated eyes of 10 calves. Eight calves developed corneal ulcers in at least 1 eye and were used for the treatment experiment. One randomly selected group of 4 calves with corneal ulcers and M bovis infections in 7 eyes was given a long-acting oxytetracycline formulation in 2 im dosages of 20 mg/kg of body weight each, 72 hours apart. The other 4 calves with corneal ulcers in 6 eyes and M bovis in all 8 eyes served as nontreated controls. Bilateral ocular cultures were obtained and clinical observations were made daily for 20 days after treatment. After administration of the long-acting drug, new ulcers did not develop in the treated calves, whereas 5 new ulcers developed in the control-group calves during this time. The average durations of increased lacrimation/ulcerated eye were 2 and 12 days after treatment in the treatment and control groups, respectively; the average durations of blepharospasm were 3 and 8 days, respectively. Moraxella bovis was not isolated from any of the eyes of the treatment-group calves for the first 6 days after the antibiotic was administered, but was isolated from 1 eye of 1 treated calf on posttreatment day 7 and daily thereafter, for a total of 14 positive cultures of 160 ocular cultures obtained from the treatment-group calves after treatment. The bacterium was isolated from all eyes and from 144 of 160 cultures from the control-group calves during this time.
Intracellular locations of dermonecrotic toxins in Pasteurella multocida and in Bordetella bronchiseptica
Authors: Nakai Toyotsugu , Sawata Akira , Kume Katsumi
Published: February 2025

Location of dermonecrotic toxin (dnt) in the cells of Pasteurella multocida or Bordetella bronchiseptica was investigated. After cell lysis by various procedures, various fractions prepared from bacterial cells grown in liquid culture media were assayed for dermonecrotic activity by skin testing of guinea pigs. During the death phase of the growth tested for the 2 bacterial species, little cell-free dnt was detected in the culture supernatants. Throughout the log and stationary phases of the growth, dnt activity was cell associated, but was not seen in the culture supernatants, which indicated that dnt was not secreted by actively growing P multocida or B bronchiseptica cells. Little dnt was released by subjecting whole cells to osmotic shock, a common procedure that releases proteins from the periplasmic space of many gram-negative bacteria. After sonication and centrifugation of whole cells, a substantial amount of dnt was released; results were similar when spheroplasts were used instead of whole cells. Treatment of whole cells with trypsin did not decrease the dnt activity, but trypsin treatment of sonicated cells resulted in a significant decrease in the dnt activity (P < 0.01). The results indicated an intracellular location of the dnt of P multocida or B bronchiseptica. The dnt of P multocida or of B bronchiseptica is probably located in the cytoplasmic space.
Cardiopulmonary effects of prostacyclin infusion in anesthetized horses
Authors: Trim C. M. , Moore J. N. , Hardee M. M. , Hardee G. E. , Graham D. A. M.
Published: February 2025

Prostacyclin was infused iv into 6 horses anesthetized with halothane. Three dosage rates (10, 30, and 100 ng/kg of body weight/min) were evaluated in each horse. Facial and pulmonary artery pressures, heart rate, cardiac output, blood temperature, and arterial and mixed venous pH, PCO2, and PO2 were measured. Arterial blood was collected for determination of glucose, lactate, and pcv. Mixed venous blood was sampled for assay of 6-keto-prostaglandin F1α and catecholamines.

Infusion of prostacyclin at 10 ng/kg/min had no effect on the variables measured, whereas the 30 ng/kg/min dosage decreased diastolic and mean arterial pressure at 15 and 30 minutes and PaO2 at 15 minutes (P < 0.05). Prostacyclin infusion at 100 ng/kg/min significantly decreased arterial pressure, total vascular resistance, and total pulmonary resistance. Heart rate increased slightly, and cardiac output increased by 44%. Arterial PO2 decreased from 311 mm of Hg to 137 and 135 mm of Hg at 15 and 30 minutes, respectively. Blood glucose was increased.

Prostacyclin infusions of 30 and 100 ng/kg/min increased blood concentrations of 6-keto-prostaglandin F1α alpha by factors of 5 and 40, respectively. Significant changes in catecholamine concentrations did not occur.
Effects of fentanyl citrate and droperidol on electroencephalographic findings in dogs
Authors: Katherman Anne E. , Knecht Charles D. , Redding Richard W.
Published: February 2025

Electroencephalograms were recorded from 10 dogs before, immediately after, and every 10 minutes (for 60 minutes) after iv injection of 0.005 ml of a fentanyl citrate and droperidol combination/kg of body weight. Narcosis was adequate for recording. At 30 to 40 minutes after injection, tail wagging was the only adverse reaction (eeg artifact) observed. The only changes in eeg activity observed were a slight increase in amplitude of the dominant activity and an increase in spindle-like activity. Daily repetition for 5 days did not alter the eeg pattern or the behavior of the dogs.
Continuous-flow hollow-fiber dialysis system for preparation of bovine carrier erythrocytes
Authors: DeLoach John R.
Published: February 2025

Small and large molecules were encapsulated in bovine rbc by a dialysis process. Encapsulation efficiencies were approximate 30%, yielding normal earner cells. The new process of encapsulation used hollow fibers and was a continuous-flow system. Preparation of carrier rbc by hollow-fiber dialysis was compatible with blood banking principles. The continuous-flow system was easily assembled from commercially available hollow-fiber units.
Transmission of the white-tailed deer cutaneous fibroma
Authors: Sundberg John P. , Chiodini Rodrick J. , Nielsen S. W.
Published: February 2025

Cutaneous fibromas were successfully transmitted to 7 white-tailed deer (Odocoileus virginianus) inoculated with crude fibroma extracts (2 deer) or with partially purified deer fibroma virus (5 deer). The fibromas were transmitted by intradermal and subcutaneous inoculation and by rubbing the virus preparation into tattoo sites. Inoculation by scarification was not successful. The induced tumors resembled those of naturally occurring fibromas. Tattoo inoculation sites underwent an initial acute inflammatory response followed by mesenchymal proliferation, perivascular lymphocytic infiltration, and finally regression. The deer developed antibody titers against deer fibroma virus as determined by hemagglutination inhibition, using mouse rbc. Viral antigens could not be detected by indirect immunofluorescence in any induced fibroma.
Evidence for the Pasteurella haemolytica cytotoxin as a product of actively growing bacteria
Authors: Shewen Patricia E. , Wilkie Bruce N.
Published: February 2025

The release of soluble cytotoxin from Pasteurella haemolytica type 1 cultured at 37 C in RPMI 1640 medium containing 7% bovine fetal serum was evaluated, using bovine alveolar macrophages in a microplate 51Cr-release assay. Heat-labile leukotoxic activity was detected in culture supernatant during the lag and logarithmic-growth phases, but not in stationary-phase culture; toxic activity could not be demonstrated in sonicates of logarithmic (1 hour) or stationary (18 hour) phase organisms. This pattern of toxin release, typical of a bacterial exotoxin or metabolic enzyme, is unique among bacterial leukotoxins, which are typically cell-associated and released after autolysis or sonication from outgrown cultures.
Comparative pharmacokinetics of febantel and its metabolites in sheep and cattle
Authors: Delatour Paul , Tiberghien Marie-Pascale , Garnier Franqois , Benoit Etienne
Published: February 2025

The pharmacokinetics of febantel and its main metabolites were studied in cattle and sheep. Seven ewes and 4 heifers were given febantel orally in a single dose of 7.5 mg/kg, 25 mg kg. or 45 mg kg of body weight. Plasma concentrations vs time of febantel and individual metabolites were determined by high-performance liquid chromatography analysis. Intestinal absorption of febantel was faster and biotransformations were more active in sheep than in 1 cattle.
Brain stem auditory-evoked response in the nonanesthetized horse and pony
Authors: Marshall A. Edward
Published: February 2025

The brain stem auditory-evoked response (baer) was measured in 10 horses and 7 ponies under conditions suitable for clinical diagnostic testing. Latencies of 5 vertex-positive peaks and interpeak latency and amplitude ratio of the 1st and 4th peaks were determined. Data from horses and ponies were analyzed separately and were compared. The stimulus was a click (n = 3,000) ranging from 10-to 90-dB hearing level (hl). Neither horses nor ponies responded with a baer at 10 dB nor did they give reliable responses at < 50 dB. The 2nd of the baer waves appeared in the record at lower stimulus intensities than did the 1st wave for the horse and pony. Horses and ponies had a decreasing latency for all waves, as a result of increasing stimulus intensity. Latencies were shorter for the ponies than for the horses at all stimulus intensities for the 1st, 2nd, 3rd, and 4th waves, but not the 5th wave. At 60-dB hl, the mean latencies for the 1st through 5th wave, respectively, for the horse were 1.73, 3.08, 3.93, 4.98, and 6.00 ms and for the pony 1.48, 2.73, 3.50, 4.56, and 6.58 ms. Interpeak latencies, 1st to 4th wave, averaged 3.22 ms (horse) and 3.11 ms (pony) for all stimulus intensities from 50- to 90-dB hl and had a tendency to decrease slightly as stimulus intensity increased. Amplitude ratios (4th wave/lst wave) were < 1 for all stimulus intensities in the horse. In the pony, the ratio was < 1 at ≥ 70-dB hl and > 1 at ≤ 60-dB hl.
Effect of transportation on cortisol concentrations and on the circadian rhythm of cortisol in gilts
Authors: Becker B. A. , Nienaber J. A. , DeShazer J. A. , Hahn G. L.
Published: February 2025

A study was conducted to determine whether the circadian rhythm of cortisol in gilts is disrupted or altered by transport. Sixteen ovariectomized gilts with indwelling jugular catheters were individually penned in an enclosed building (location 1). Blood samples were collected at 0700 and 1900 hours for 6 days. On day 7, gilts in groups of 4 were transported 5.6 km to environmentally controlled chambers (25 C) and were individually penned (location 2). On the day of transport, samples were collected at 0700 hours at location 1, immediately before and after transport in a trailer, after unloading at location 2, and at 1900 hours at location 2. For the first 6 days at location 2, blood samples were collected daily at 0700 and 1900 hours. For the 6 days at location 1, circadian rhythm was evidenced by higher cortisol concentrations in the am hours than in the pm hours. During transport, serum cortisol concentrations increased (P < 0.01). Highest concentrations developed at 0.5 hour after unloading; concentrations declined thereafter. During the first 6 days at location 2, circadian rhythm was evidenced by higher serum cortisol concentrations in the am hours than in the pm hours. Therefore, the transportation of gilts 5.6 km to new pens was a transient stress causing a temporary increase in serum cortisol concentrations, but did not cause a disruption in the endogenous rhythm of cortisol.
Blood flow in the renal portal circulation of the turkey: Effect of epinephrine
Authors: Palmare William P. , Ackerman N.
Published: February 2025

Control of blood flow in the renal portal circulation of turkeys given epinephrine was evaluated by determining the distribution of injected radiopaque contrast medium within the portal circulation. Radiopacity in the region of the renal parenchyma and/or the caudal renal portal vein was increased in each of the 6 birds after epinephrine (4.0 μg/kg of body weight) was injected into the wing vein. In 1 bird, the contrast medium also was distributed into the mesenteric vein. Thus, epinephrine not only induced flow of blood from the pelvic limb (leg) to the kidneys, but to the abdominal viscera as well. Regulation of the patency of the renal portal valve is thought to be one means by which renal portal blood flow is controlled. However, epinephrine had no consistent effect on the valve. Thus, epinephrine seemed to control renal portal blood flow and, perhaps, blood flow to other abdominal viscera at sites other than the renal portal valve.
Effect of collection time and exercise restriction on the prediction of urine protein excretion, using urine protein/creatinine ratio in dogs
Authors: McCaw Dudley L. , Knapp David W. , Hewett John E.
Published: February 2025

Nonproteinuric and proteinuric dogs were studied to determine whether the urine protein/creatinine ratio from a 24-hour urine sample could be used to predict urine protein excretion. Urine protein/creatinine ratios estimated from urine produced during daylight hours and from that produced during nighttime hours were compared to determine whether time of sample collection influenced the prediction of the urine protein excretion value. Urine protein/creatinine ratios in urine from male dogs were compared with those from female dogs to determine whether sex had an influence on the value. Hospitalized and nonhospitalized dogs were used to determine the effect of exercise restriction.

The urine protein/creatinine ratio varied significantly between healthy and proteinuric dogs (P = 0.0001). It was not influenced by collection period or sex. Animals not confined to hospital cages had a significantly lower urine protein/creatinine ratio than did hospitalized animals confined to a cage (P = 0.003).
M-Mode echocardiographic measurements in nonanesthetized healthy cats: Effects of body weight, heart rate, and other variables
Authors: Jacobs Gilbert , Knight David H.
Published: February 2025

Body weight, heart rate, and 19 M-mode echocardiographic variables were measured in 41 nonanesthetized healthy cats. Estimated limits were determined for the echocardiographic variables, and each variable was then correlated to body weight, heart rate, and the 18 other variables. A significant (P < 0.05) positive correlation to body weight was found with aortic diameter, left atrial dimension, septal and left ventricular systolic and left ventricular diastolic wall thicknesses, and left and right ventricular diastolic and right ventricular systolic internal dimensions. Significant inverse correlation (P < 0.05) to heart rate was found with body weight, left ventricular systolic and diastolic and right ventricular systolic internal dimensions, left atrial dimension, left atrial dimension to aortic ratio, mitral valve E point to ventricular septal separation, and left ventricular ejection time. Left ventricular shortening fraction in the short axis and velocity of circumferential fiber shortening were significantly correlated (P < 0.05) to heart rate. Significant correlation (P < 0.05) was also found between many echocardiographic variables.
Ultrastructural alterations of motor cortex synaptic junctions in Brown Swiss cattle with weaver syndrome
Authors: Aitchison C. Sue , Westfall Jane A. , Leipold Horst W. , Kelly Paul T.
Published: February 2025

An ultrastructural comparison was made between the motor cortex synapses of the brain of 4 adult Brown Swiss cattle with weaver syndrome and 2 healthy cattle (a Holstein steer and a Guernsey cow). Compared with the healthy cattle, the paramembranous densities at synaptic junctions of cattle with weaver syndrome had a decreased mean height of the presynaptic dense projections (P < 0.001), had significantly smaller peak-to-peak distances (P < 0.001), and had a significantly decreased mean thickness of the postsynaptic density (P < 0.0001). These synaptic changes in cattle with weaver syndrome may be associated with clinical manifestations of the syndrome, such as impairment of transmitter release, instability of postsynaptic receptor sites, lesion-induced synaptic turnover from injury elsewhere in the cns, or loss of a specific cell population of the motor cortex.
Enzyme-linked immunosorbent assay for the detection of bovine papillomavirus
Authors: El Shazly Mohamad O. , Sundberg John P. , McPherron Thomas , Smith Ronald D.
Published: February 2025

An enzyme-linked immunosorbent assay has been developed to detect and quantitate bovine papillomavirus in partially purified and in purified viral preparations, using rabbit antiserum against group-specific papillomavirus structural antigens and alkaline phosphatase-labeled affinity purified goat antibody to rabbit immunoglobulin G. Viral detection correlated well with negative-stain electron microscopy of the various preparations and peroxidase-antiperoxidase staining of paraffin sections of the original fibropapillomas. The technique is rapidly done and will detect minute amounts of viral protein (1 ng/ml).
Ruminal lactic acidosis: Relationship of forestomach motility to nondissociated volatile fatty acids levels
Authors: Crichlow E. C. , Chaplin R. K.
Published: February 2025

Ruminal lactic acidosis was produced in 9 overnight fasted rumen-fistulated sheep by placing ground wheat (40 g/kg of body weight) into the rumen, Ruminal stasis occurred within 8 hours of grain engorgement in 6 sheep (aarly stasis group) and between 10 and 12 hours in the remaining 3 sheep (late stasis group). The initial impairment to forestomach motility was a decrease in the mean frequency of reticulo-ruminal contractions which occurred within 4 hours of the intraruminal placement of wheat in the early stasis group and within 6 hours in the late stasis group. Since blood pH, carbon dioxide pressure, and serum bicarbonate were all normal, systemic acidosis was not a contributing factor to this decrease in contraction frequency. The concentrations of total nondissociated volatile fatty acids (vfa; acetic, propionic, and butyric acid) in ruminal fluid, however, were significantly increased, being 13.60 mM/L (mean, pH 4.92) in the early stasis group and 15.77 mM/L (pH 4.80) in the late stasis group. Free dl-lactic acid in ruminal fluids was 6.37 ± 6.1 mM/L, (mean ± sd) in the early stasis group and 9.72 ± 4.2 mM/L in the late stasis group.

A reduction in contraction amplitude was observed within 6 hours of grain engorgement in the early stasis group and within 8 hours in the late stasis group. At these times, the concentrations of nondissociated vfa were 10.19 mM/L (pH 4.46) in the early stasis group and 10.52 mM/L (pH 4.62) in the late stasis group. The ruminal values of free dl-lactic acid were 13.93 mM/L in the early stasis group and 16.14 mM/L in the late stasis group. At stasis, blood values were normal in the late stasis group, whereas in the early stasis group, uncompensated metabolic acidosis was evident (pH, 7.23 ± 0.07; serum bicarbonate, 16.5 ±3.8 mEq/L; and carbon dioxide pressure, 39.9 ± 2.6 mm of Hg), Nondissociated vfa in ruminal fluids had decreased to 4.33 ± 3.5 mM/L (pH 4.39) in the early stasis group and to 5.92 ± 3.7 mM/L (pH 4.52) in the late stasis group. Free dl-lactic acid, on the other hand, had increased to 15.14 mM/L in the early stasis group and to 29.01 mM/L in the late stasis group.
Gastric distention and gastrin in the dog
Authors: Leib Michael S. , Wingfield Wayne E. , Twedt David C. , Williams Anne R. , Bottoms Gerald D.
Published: February 2025

Gastric distention was induced in intact dogs by giving a wide range of volumes (11 to 111 ml/kg) of a liquid test meal resulting in a significant (P < 0.05) increase in plasma gastrin immunoreactivity at 10 and 25 minutes after distention. There was no significant decrease in gastrin immunoreactivity from 10 to 25 minutes of gastric distention. Pretreatment with atropine abolished the distention-induced gastrin release, indicating that distention-induced gastrin release in the intact dog was partially under cholinergic control. There was no relationship between the distending volume and magnitude of gastrin increase.
Autologous marrow transplantation as consolidation therapy for canine lymphoma: Efficacy and toxicity of various regimens of total body irradiation
Authors: Deeg H. Joachim , Appelbaum Frederick R. , Weiden Paul L. , Hackman Robert C. , Graham Theodore C. , Storb Rainer
Published: February 2025

Dogs with malignant lymphoma were given chemotherapy consisting of nitrogen mustard, vincristine sulfate, prednisone, l-asparaginase, and 6-mercaptopurine (mopa-6) for 14 days. Among 62 dogs that completed treatment with mopa-6, 47 (76%) had complete remission, and 13 (21%) had partial remission and 2 had no response to chemotherapy. Twenty-two of the 62 dogs were not returned by their owners for additional therapy and died 15 to 391 (median 21) days after mopa-6 from infections or recurrent disease. A median of 1 month after starting mopa-6 therapy, 40 dogs (35 in complete remission, 5 in partial remission) were given total body irradiation (tbi), followed by infusion of fresh autologous marrow. Twenty dogs were given 13.5 Gray (Gy) of tbi at 4 centi-Gray (cGyVmin. Among 16 evaluable dogs, 7 had recurrence of lymphoma at a median of 169 days. Two dogs died with veno-occlusive disease of the liver, 3 with pneumonia, 3 with hemorrhage, and 1 was killed. Twenty dogs were given 11.8 to 14.7 Gy of tbi at 2 cGy/min. Among 14 evaluable dogs, 9 had recurrence of lymphoma at a median of 117 days. The remaining 5 dogs were killed at 110 to 680 days; lymphoma was not present at necropsy. The results indicated that doses of tbi of 11.8 to 14.7 Gy did not reduce the recurrence of lymphoma, compared with results obtained in a previous study with 8.4 Gy of tbi. Furthermore, increased doses of tbi increased acute and delayed toxicities. Alternatively, recurrent disease may have been due to lymphoma cells contained in the infused remission marrow.
Ultrastructure of the testis of Pekin ducks fed methyl mercury chloride: Seminiferous epithelium
Authors: McNeil S. I. , Bhatnagar M. K.
Published: February 2025

Testicular cells of Pekin ducks (Anas platyrhynchos) fed with 0 (control), 0.5 (group 1), 5 (group 2), or 15 (group 3) mg of methyl mercury chloride (CH3HgCl)/kg of basal feed for 12 weeks were examined by electron microscope.

Sertoli's cells from ducks in group 2 had dilated smooth endoplasm reticulum, increased lysosomes, and large vacuoles, some with lipid droplets. Degenerative changes were more advanced in group 3 ducks. There were increases in lysosomes, myelinoid figures, vacuolations, cytoplasmic and nuclear debris, cristolyses of mitochondria, and distended Golgi's complexes, and a reduction in smooth endoplasm reticulum and microtubules when compared with those of the controls.

Spermatogonia were resistant to CH3HgCl exposure, except in 2 ducks from group 3 which had cells that showed electron-lucent cytoplasm, abnormal mitochondria, and membrane-bound vacuoles. In primary spermatocytes, degenerative changes were evident in ducks fed the larger dose levels. In nuclei, synaptonemal complexes showed unpaired elements. In cytoplasm, cellular debris and vacuoles predominated. There was an increase in synchronized meiosis and apparent incomplete cell division. In ducks from group 3, the cellular damage was more severe and was present throughout the germinal epithelium. Spermatids differentiation was affected variably in groups 2 and 3. Severity of damage increased with the increased dosage of mercury. Where there was spermiogenic activity, the electron-dense acrosome granules, manchette, and midpiece were rarely found. Since the seminiferous tubules from 2 ducks in group 3 had severe destruction of spermatocytes and spermatids, the spermiogenic activity was negligible.

Ingestion of CH3HgCl caused toxic injury to seminiferous tubules in groups 2 and 3 ducks. The degree of damage was related to the dietary amount of mercury.
Effects of dietary supplementation with ethoxyquin, magnesium oxide, methionine hydroxy analog, and B vitamins on tansy ragwort (Senecio jacobaea) toxicosis in beef cattle
Authors: Cheeke P. R. , Schmitz J. A. , Lassen E. D. , Pearson E. G.
Published: February 2025

Dried tansy ragwort containing pyrrolizidine alkaloids was fed as 2.5% of a complete (control) diet to Hereford steers, with and without (basal) a mixture of additives. The additives provided a dietary supplement equivalent to 0.1% ethoxyquin, 1% methionine hydroxy analog, 2% MgO, 2.7 mg of vitamin B6/kg of diet, 50 µg of vitamin B12/kg of diet, 0.45 g of folic acid/kg of diet, and 0.2 g of cobalt/kg of diet. The additives did not alter tansy ragwort toxicity substantially, as assessed by liver histologic changes, sulfobromophthalein clearance rate, and serum γ-glutamyl transpeptidase activity. After 281 days, 1 of 4 steers fed the basal diet was alive, whereas 3 of 4 steers in the basal plus additives group were alive, suggesting some protective activity. The chronic lethal dose of tansy ragwort in steers was 3.6% of initial body weight.
Bovine pneumonic pasteurellosis: Chemiluminescent response of bovine peripheral blood leukocytes to living and killed Pasteurella haemolytica, Pasteurella multocida, and Escherichia coli
Authors: Chang Yung-Fu , Renshaw Harland W. , Augustine John L.
Published: February 2025

A luminol-dependent chemiluminescence (ldcl) assay was used to evaluate the response of bovine polymorphonuclear leukocytes; (neutrophils [pmn]) to living and heat-kilied Escherichia coli, Pasteurella multocida (type A, serotype 3), and P haemolytica (biotype A, serotype 1), and to heat-killed P haemolytica and sterile culture supernatant from living P haemolytica. Control cultures containing pmn that had not been phagocytically stimulated with bacteria had a modest increase in ldcl during the initial 10 minutes of incubation, followed by a gradual decline throughout the 120-minute incubation period. Bovine pmn emitted ldcl more efficiently when the cells were exposed to living E coli or P multocida than when they were exposed to the same bacteria killed by heat. The mean ldcl values for reaction mixtures containing living E coli or P multocida peaked at 30 minutes of incubation and remained above values for mixtures containing the same heat-killed bacteria. Kinetics of the ldcl response of bovine pmn to heat-killed P haemolytica were similar (although reduced in amplitude) to that observed with killed E coli or P multocida. The ldcl response of bovine pmn to living P haemolytica was not like that for E coli or P multocida, and was characterized by the development of a peak response at 10 minutes followed by a precipitous decrease in responsiveness and a subsequent complete cessation of ldcl. Addition of sterile culture supernatant from living P haemolytica to test samples containing heat-killed P haemolytica induced a response similar to that obtained with the living microorganism. Collectively, the results indicated that metabolically active P haemolytica synthesized a heat-labile factor that was released into the culture supernatant and that was retained in a form associated with the cell. This factor, which may be the same as the P haemolytica cytotoxin described by others, had the ability to biologically incapacitate the oxygen-dependent activation of the hexose monophosphate shunt in pmn and thereby rendered inoperative an important antimicrobial system of the cell. The ldcl assay may be useful for further evaluations of this factor and for clarification of the factor's importance as a potential virulence factor of P haemolytica.
Frequency of persistent bovine viral diarrhea virus infection in selected cattle herds
Authors: Bolin S. R. , McClurkin A. W. , Coria M. F.
Published: February 2025

Sera and blood buffy coat samples were obtained from 3,157 cattle in 66 selected herds. Antibodies to bovine viral diarrhea (bvd) virus were detected in 89% of the serum samples by immunoprecipitation or virus-neutralization tests. Cytopathic or noncytopathic bvd viruses were isolated from blood buffy coat samples from 60 cattle in 6 herds. A second blood buffy coat sample was obtained from 54 of the 60 cattle 2 months after the initial sampling, and bvd virus was isolated again from each cow. The 54 cattle were considered persistently infected with bvd virus. The frequency of persistent infection was 1.7%.