bluuebunny/crossref_metadata_2025 huggingface dataset:
Propionate loading test for liver function during experimental liver necrosis in sheep
Authors: Gröhn Y. , Bruss M. L. , Lindberg L.-A.
Published: February 2025

The first objective of this work was to study the conversion of propionate to glucose by liver of the sheep during experimentally induced liver necrosis. An additional objective was to determine the most appropriate sampling time after a propionate load has been given to use glucose concentration as an aid in the diagnosis of disturbed liver function. Sodium propionate (3 mmol/kg) was injected iv into 6 healthy sheep before and after they were given carbon tetrachloride (20% CCl4 in mineral oil; 0.25 ml of CCl4/kg, orally). To differentiate the effects of liver necrosis from the effects of decrease in food intake after CCl4 administration, 5 sheep which were fasted for 2 days, but not given CCl4, were studied.

Microscopically, liver necrosis was observed, as well as an increase of fatty infiltration in nonnecrotic liver tissue. After sheep were given CCl4, the plasma liver-specific enzyme activities (namely, those of iditol dehydrogenase and γ-glutamyl-transferase) were elevated. Microscopic and enzymatic changes were not observed in fasted animals. Serum sulfobromophthalein (bsp) half-life (t½) was markedly increased in the sheep given CCl4 treatment (t½ = 22.8 ± 11 minutes) when compared with the t½ before treatment (t½ = 2.5 ± 0.2 minutes). The bsp t½ did not differ between fed and fasted sheep. The t½ of the iv propionate load increased significantly, from 6.9 ± 0.4 minutes in the control sheep to 12.8 ± 2 minutes in the CCl4-treated sheep, whereas an insignificant increase was seen after fasting (6.8 ± 1 minutes to 8.3 ± 1 minutes). Changes in plasma glucose concentrations subsequent to propionate loading differed significantly before and after CCI4 treatment. Two days' fasting did not have a significant effect on change in glucose concentration after propionate loading when compared with the response before fasting.

Glucose concentration after propionate loading served as a good indicator of liver function. Changes in glucose concentration of < 2 mM at 7 minutes after propionate loading indicated disturbance of liver function in sheep.
Effects of atropine, acepromazine, meperidine, and xylazine on gastroesophageal sphincter pressure in the dog
Authors: Strombeck Donald R. , Harrold Doris
Published: February 2025

Gastroesophageal sphincter (ges) pressure was 47.9 ± 1.2 mm of Hg in nontreated dogs. Treatment with atropine, acepromazine, and xylazine reduced ges pressure to 13.2 ± 2.03, 18.6 ± 2.14, and 11.7 ± 1.19 mm of Hg, respectively. Treatment with meperidine resulted in phasic contractions with minimum and maximum pressures of 27.9 ± 4.55 and 98.9 ± 9.16 mm of Hg, respectively. Drugs used in anesthetic procedures can reduce ges pressure in dogs.
Diagnosis of Fasciola hepatica infection in beef calves by plasma enzyme analysis
Authors: Wyckoff J. H. , Bradley R. E.
Published: February 2025

Plasma analysis for albumin, total bilirubin, and total protein values and aspartate aminotransferase (ast), arginase, and γ-glutamyl transpeptidase (ggt) activities was H used for the early and quantitative diagnosis of experimental Fasciola hepatica infections in beef calves. Calves were infected on 3 occasions with 1,000 (n = 5), 100 (n = 5), or 10 (n = 4) metacercariae for a total infective dose of 3,000, 300, or 30, respectively. Albendazole (l5 mg/kg of body weight) was administered to 7 infected calves on postinfection (initial) week (piw) 13. All calves were euthanatized and necropsied on piw 16 for the determination of fluke infections.

Plasma constituents were determined weekly. Significant (P < 0.05) increases in ast activity occurred as early as piw 4 and ggt activity at piw 9, as compared with that in noninfected controls. Fluke burden-related differences were observed in ggt activity from piw 9 onward. Increases in ast activity reflected parenchymal liver damage, whereas increases in ggt reflected hepatobiliary damage; therefore, differentiation could be made between the migratory and ductal phases of the infection. There was no correlation between arginase activity and fluke infection.

As compared with fecal examination results, plasma enzyme analysis gave an earlier and semiquantitative indication of F hepatica infection in experimentally infected calves. Although increases in these plasma constituents were not definitely diagnostic of fascioliasis, useful information on the size of the fluke burden and progress of the disease process could be obtained by these methods. Plasma enzyme analyses of ast and ggt were not indicative of chemotherapeutic success or failure when calves with mature F hepatica (14 weeks old) infections were treated.
Development of an indirect fluorescent antibody test, using microfluorometry as a diagnostic test for bovine anaplasmosis
Authors: Goff W. L. , Johnson W. C. , Kuttler K. L.
Published: February 2025

The indirect fluorescent antibody test for the diagnosis of Anaplasma marginale infection in cattle was modified for use with microfluorometry. The test was standardized by use of a fluorometer that measures intensity of fluorescence. Standardization included A marginale-infected blood smears on microscope slides as antigen, serum from an inoculated calf as a positive control containing specific antibody, and an affinity-purified fluorescein-conjugated anti-bovine immunoglobulin as 2nd antibody.

The modified test and microfluorometry allowed for titration of sera from A marginale (Florida isolate)- inoculated cattle with a degree of accuracy exceeding visual determinations. In addition, the fluorometric test was more sensitive than the complement fixation or card agglutination tests in identifying cattle that had previous Anaplasma infections.
Failure of superoxide dismutase to alter equine arachidonic acid-induced platelet aggregation, in vitro or ex vivo
Authors: Clemmons R. M. , Lee M. R. Dorsey , Bliss E. L. , Asbury A. C. , Cook D. , Brown V.
Published: February 2025

Superoxide dismutase (sod), a free radical scavenger with anti-inflammatory activity, was administered im to horses. Ex vivo platelet aggregation in response to arachidonic acid was monitored to determine whether exogenous sod altered equine platelet prostaglandin metabolism. Preparations of platelet-rich plasma obtained before sod administration were incubated with different concentrations of sod and were aggregated with arachidonic acid. Superoxide dismutase did not exert a demonstrable effect, either ex vivo or in vitro. Aspirin abolished arachidonic acid-induced platelet aggregation in vitro. This indicates that sod (in the resting state) does not exert an effect on platelet-derived free radicals that could alter the arachidonic acid pathway of equine platelets, that equine platelets do not release free radicals, or that equine platelets are insensitive to the products formed from free radicals by sod.
Pathologic changes caused by transplacental infection with an adenovirus-like agent in pigs
Authors: Narita Minoru , Imada Tadao , Fukusho Akio
Published: February 2025

Five hysterectomy-derived colostrum-deprived pigs housed in individual cages with positive ventilation developed severe skin cyanosis and edema of the subcutaneous tissues in the submandibular, thoracic, and abdominal regions. The 5 pigs were killed 7 to 10 days after birth. Eosinophilic intranuclear inclusion bodies were found in endothelial cells of capillary and small blood vessels throughout the body. Ultrastructurally, nuclei of these affected endothelial cells contained small crystalline arrays of virus particles, which were considered to belong to the adenovirus-like group from their size and structure. The present results indicated that the porcine adenovirus-like agent might also have the ability to produce transplacental infection.
Sensory action potentials in the ulnar and radial nerves of dogs; Effect of stimulation site and voltage
Authors: van Nes Jan J.
Published: February 2025

The influence of stimulation site and voltage on amplitude, wave form, conduction time, and velocity of sensory action potentials in the ulnar and radial nerves was evaluated in 25 healthy dogs. A 5-fold increase in stimulation voltage above threshold caused a 300% increase in the amplitude of evoked sensory nerve potentials. An additional 2-fold increase in stimulation voltage (to 10 times threshold) resulted in an additional 40% increase in amplitude. An absolute saturation voltage was not found. Latency velocity was increased by increasing stimulation voltage, but conduction velocity was not affected. Multicomponent nerve action potentials were frequently found at the proximal recording sites. The number of components was not affected by stimulation voltage. Proximal displacement of the stimulation site resulted in an increase in amplitude of the nerve action potentials, increased latency velocity, and fewer components; conduction velocity was not affected.

As a consequence of these findings, preference was given to simultaneous recording at 2 sites along the nerve, stimulation at the more proximal stimulation site distal to the carpus, and stimulation voltages between 5 and 10 times the threshold.

The occurrence of multicomponent wave forms, the absence of an absolute saturation voltage, and the lowering of the number of components by proximal displacement of the site of stimulation may all be related to the relatively small number of sensory nerve fibers that can be activated at the stimulation site.
Synovial membrane changes after experimental transection of the cranial cruciate ligament in dogs
Authors: Lipowitz Alan J. , Wong Pauline L. , Stevens Jerry B.
Published: February 2025

Degenerative joint disease and inflammation of the synovial membrane were produced in the left stifle of 16 dogs by severing the cranial cruciate ligament. Arthrotomy only was performed on the right stifle. Synovial membrane from these joints was histologically examined at 1, 2, 8, and 13 weeks after surgical operation. Similar tissue was obtained from 4 healthy dogs for comparison. Inflammatory changes in the synovium of the left stifle progressed with time and were prominent at 8 weeks postoperatively, subsynovial fibrosis was greatest at 13 weeks. Inflammation of the synovial membrane and subsynovial tissue was characterized by synovial cell hypertrophy and hyperplasia, plasma cell and lymphocyte infiltration, and increased vascularization of the subsynovial region.
Pharmacokinetics of gentamicin at steady-state in ponies; Serum, urine, and endometrial concentrations
Authors: Haddad Nadim S. , Pedersoli W. M. , Ravis W. R. , Fazeli M. H. , Carson R. L.
Published: February 2025

Gentamicin (gt) was administered im to 6 healthy mature mare ponies at a dosage of 5 mg/kg of body weight every 8 hours for 7 consecutive days (total, 21 doses). Two venous blood samples were collected before (trough) and at 1 hour (peak) after the 5th, 10th, 14th, and 19th doses. An endometrial biopsy was done of each mare on days 4 and 7. On the 7th day, just before the 21st administration of gt, base-line blood samples were collected, and 22 blood samples were collected over a period of 48 hours after gt was given. The mares were catheterized on the 7th day, and urine was collected for 24 hours. Serum, urine, and endometrial gt concentrations were determined by a radioimmunoassay technique (sensitivity of 0.3 μg/ml of serum).

Serum gt concentration data obtained from the terminal phase were best fitted by a 1-compartment open model with a biological half-life of 2.13 ± 0.43 hours. Total body clearance and renal clearance were 1.69 ± 0.41 and 1.40 ± 0.26 ml/min/kg, respectively. Mean endometrial concentrations on day 4 and day 7 were 5.02 ± 3.3 and 12.75 ± 1.6 μg/g. To achieve mean serum gt concentrations (μg/ml) at steady state of 6.47 ± 1.51, a maximum steady-state concentration of 12.74 ± 1.60, and a minimum steady-state concentration of 1.43 ± 0.57, a dosage of 5 mg/kg every 8 hours is recommended. Serum urea nitrogen, serum creatinine, and the fractional clearance of sodium sulfanilate were determined before and after gt treatment. Renal function remained within the base-line range during 7 days of gt administration.
Production and preliminary characterization of monoclonal antibodies to Actinobacillus sp isolated from epididymitis lesions in a ram
Authors: Healey Mark C. , Kleinschuster Stephen J. , Gharpure Hemant M. , Johnston Alice V.
Published: February 2025

A panel of 55 monoclonal antibodies to an Actinobacillus sp isolate (As8C strain) cultured from the epididymides of an infected ram was produced. Cell lines producing 5 of these antibodies were cloned and expanded by hybridoma tumor production in Balb/c mice. An isotype profile revealed that 1 cloned antibody belonged to the immunoglobulin (Ig) M class and the 4 remaining antibodies belonged to the IgG class. Within the IgG class, 1 clone produced IgG1, 1 clone produced IgG2a, and 2 clones produced IgG2b.

Ascites fluid antibody titers from the cloned hybridomas ranged from 6,400 to 51,200, as determined by enzyme-linked immunosorbent assay. Specificity of the antibodies to target As8C antigens could be demonstrated by enzyme-linked immunosorbent assay inhibition. Ascites fluid from 2 clones contained antibodies that agglutinated As8C. Two additional clones produced antibodies capable of only partial agglutination, whereas 1 clone produced antibody that did not agglutinate As8C.

The indirect fluorescent antibody test revealed that target antigens for at least 4 of the 5 monoclonal antibodies were most likely located on the bacterial cell surface. Antigens were extracted from As8C, using 5 surface active chemicals. An attempt to immunoprecipitate these antigens in agarose by reacting individual extracts with each of the antibodies was unsuccessful.
Transient leakage across the blood-cerebrospinal fluid barrier after intrathecal metrizamide administration to dogs
Authors: Johnson Gayle C. , Fuciu Denise M. , Fenner William R. , Krakowka Steven
Published: February 2025

Cerebrospinal fluid samples from 9 dogs given 84 mg of metrizamide/kg of body weight intrathecally were collected at intervals from 3 hours to 30 days after treatment and were compared with csf samples collected before metrizamide treatment (base line) and with samples taken at similar intervals from 2 nontreated control dogs. Increased csf albumin (mean 19.2 mg/dl) and immunoglobulin (Ig) G (mean 5.91 mg/dl) concentrations occurred 1 day after myelography, compared with base-line concentrations (6.15 and 1.24 mg/dl, respectively) and with concentrations from controls. Immunoglobulin M and IgA concentrations also were increased in some of these samples. However, immediately after myelography (3 hours after treatment) csf albumin and IgG concentrations were comparable with those of controls, and these values returned to base line within 5 days of myelography and remained so for 30 days.

A high correlation between albumin and IgG concentrations of individual csf samples indicated the likelihood that leakage across the blood-csf barrier was the origin of the increased values. A transient increase in csf leukocytes, consisting of mononuclear cells and neutrophils, was also noticed 1 day after treatment but not at other times and not in controls. Nonsuppurative, predominately histiocytic meningitis of decreasing intensity was noticed in dogs euthanatized at 1 or 5 days, but not in dogs euthanatized at 10, 20, or 30 days after treatment. The meningeal cells stained intensely with periodic acid-Schiff stain and intracellular contrast medium was ultrastructurally apparent in phagolysosomes. Control dogs killed after 30 days did not have these changes. The intrathecal administration of metrizamide resulted in transient leakage of serum components into csf and an accompanying transient meningitis.
Comparison of crystalloid and sanguineous cardioplegic solutions in the dog
Authors: Spackman Claire J. A. , Caywood Dennis D. , Gannon Paul G. , Irmiter Richard A. , Louis Charles F.
Published: February 2025

Myocardial protection provided by 2 types of cold cardioplegic solution and by cold saline solution was compared experimentally in dogs on cardiopulmonary bypass. Techniques and solutions used simulated clinical conditions. Serial biopsies of myocardium were assayed for adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. Maintenance and recovery of each phosphate was calculated as a percentage of the prebypass value for each type of solution; these values were used to compare the myocardial protection afforded by the 3 solutions. A difference in these values was not observed between the 2 types of cardioplegic solution; both values were greater than for the control solution, which may indicate improved myocardial protection with cardioplegic arrest.
Serum concentrations of gentamicin in cats
Authors: Jacobson Elliott R. , Groff Joseph M. , Gronwall Ronald R. , Moreland Alvin F. , Chung Menger
Published: February 2025

Twenty-one adult cats, allotted into 2 groups, were given gentamicin sulfate at dosages of either 5.0 mg/kg of body weight or 2.5 mg/kg as a single im injection. During a 24-hour period, serum concentrations of gentamicin were measured serially, using a fluorescence immunoassay. The mean peak serum concentration of gentamicin in cats given 5.0 mg/kg was 23.1 μg/ml at postinjection hour (pih) 0.5; thereafter, the mean serum concentration steadily decreased to 2.0 μg/ml at pih 24. The mean peak serum concentration for cats administered 2.5 mg/kg was 9.1 μg/ml at pih 0.5; thereafter, the mean serum concentration steadily decreased to 1.3 μg/ml at pih 12. Serum therapeutic concentrations, without exceeding toxic concentrations, were attained at the 2.5 mg/kg dosage.
Borrelia theileri: Isolation from ticks (Boophilus microplus) and tick-borne transmission between splenectomized calves
Authors: Smith Ronald D. , Miranpuri Gurwattan S. , Adams John H. , Ahrens Elmer H.
Published: February 2025

The bovine spirochete, Borrelia theileri, was detected in Giemsastained blood smears from a splenectomized calf 17 days after exposure to a laboratory colony of the tropical cattle tick, Boophilus microplus. Spirochetes were detected in the hemolymph and ovary of all engorged female ticks examined, indicating a high infection rate in this tick colony. Spirochetes were detected in a 2nd splenectomized calf 15 days after exposure to the larval offspring of ticks from the 1st calf. The only observable effect of infection in the 2 calves was a maximum rectal temperature increase to 40.2 C, which coincided with the first detectable parasitemia. The tick colony did not have any adverse effects, despite extensive multiplication of spirochetes in their tissues.
Effect of wound location and the use of topical collagen gel on exuberant granulation tissue formation and wound healing in the horse and pony
Authors: Bertone Alicia L. , Sullins Kenneth E. , Stashak Ted S. , Norrdin Robert W.
Published: February 2025

Preformed collagen gel was topically applied to cutaneous wounds of the equine dorsal fetlock (thoracic limb) and metatarsal regions to evaluate the effect on exuberant granulation tissue production and wound healing.

In 6 horses and 3 ponies (< 140 cm high at the withers and < 365 kg), 36 standardized cutaneous limb wounds were surgically induced (4 wounds/animal); 18 wounds were treated topically with collagen gel, and 18 wounds were not treated (controls). Collagen gel was initially applied to the wound at 0, 2, or 7 days after wound formation (groups 1, 2, and 3, respectively). Four measurements were regularly made: amount of wound contraction and the size of the granulation bed, epithelial covering, and total wound. Sequential skin and wound biopsies were evaluated histologically to assess wound healing. Using a computer, data were analyzed for differences in the 4 measurements between treated and control wounds, between fetlock wounds and metatarsal wounds, and among groups 1, 2, and 3. Analyses were performed on days 15 and 45 of wound healing and on the final day of healing.

A significant difference (P > 0.05) in the production of exuberant granulation tissue, rate of epithelialization, or degree of wound contraction was not detected between the collagen-treated and control wounds. Total healing time and final scar size were similar. Wound healing patterns were significantly different (P < 0.05) in the fetlock wounds and metatarsal wounds. All wounds enlarged up to day 15 with fetlock wounds enlarging significantly more than did the metatarsal wounds. Fetlock wounds had a faster rate of contraction than did the metatarsal wounds at day 45; but, due to their smaller size, metatarsal wounds healed significantly faster than did fetlock wounds. The resulting scar size of fetlock and metatarsal wounds was similar. Metatarsal wounds required more resection of exuberant granulation tissue than did fetlock wounds.

Propensity to develop exuberant granulation tissue and the rate of healing were directly correlated to body size of the horse. Larger horses required more frequent resection of the granulating wound bed and healed more slowly, despite the relatively smaller wound size as compared with their larger limb size. Ponies (< 140 cm high at the withers and < 365 kg of body weight) healed faster than horses; wounds of the ponies also healed without exuberant granulation tissue formation. Therefore, ponies are not adequate models of wound healing for horses.
Anatomic predisposition to perianal fistulae formation in the German Shepherd Dog
Authors: Budsberg S. C. , Spurgeon T. L. , Liggitt H. D.
Published: February 2025

Gross and microanatomic features which may predispose the German Shepherd Dog to perianal fistulae formation were studied in 2 groups of clinically healthy dogs: a predisposed group (German Shepherd Dogs) and a control group comprising breeds not ordinarily affected by perianal fistulae. The dimensions of the anal crypts (depth, base width, and length), measured and compared statistically between samples, identified no significant variation between groups (P > 0.05). Major tissue components of the anal canal were measured microscopically and were similarly evaluated: epithelial height in each zone, thickness of the lamina propria in each zone, thickness of the internal and external anal sphincter muscles, and density of the circumanal, sebaceous, and apocrine sweat glands. The only significant finding was an increase in density of apocrine sweat glands in the zona cutanea in the predisposed dog group. In a semiquantitative analysis of the inflammatory responses frequently seen in the anal glands, more mature fibroplasia was seen in the German Shepherd Dogs, indicating that inflammation was more longstanding in this group.
Reversal of thiopental-induced anesthesia by 4-aminopyridine, yohimbine, and doxapram in dogs pretreated with xylazine or acepromazine
Authors: Hatch Roger C. , Wilson Robert C. , Jernigan Antoinette D. , Clark J. Derrell , Brown John
Published: February 2025

Groups of atropinized dogs (6 dogs/group) were sedated, using xylazine HCl (2.2 mg/kg of body weight, im) or acepromazine maleate (0.25 mg/kg, im), and were anesthetized to loss of pedal reflexes, using thiopental, iv. The dogs were given 1 of the following test antagonists, iv: saline solution (2 ml; control group), 4-aminopyridine (4-ap; 0.5 mg/kg), yohimbine (0.4 mg/kg), doxapram (5.0 mg/ kg), or dual combinations of the latter 3 substances in the same doses as used for each agent.

In xylazine-treated dogs, the mean dosage of thiopental required to induce anesthesia was 4.8 mg/kg. Control mean arousal time (mat) and walk time (mwt) were 37.1 minutes and 53.8 minutes, respectively. These values were decreased to < 2 minutes and < 3 minutes, respectively, by yohimbine, 4-af + yohimbine, and doxapram + yohimbine. With doxapram and with 4-ap + doxapram, mat was < 2 minutes and mwt was < 8 minutes.

In acepromazine-treated dogs, the mean dosage of thiopental required for anesthesia was 15.0 mg/kg. Control mat and mwt were 20.7 minutes and 36.5 minutes, respectively. These values were decreased to 8.1 minutes and 18.1 minutes, respectively, by doxapram, and to 3.5 minutes and 19.9 minutes, respectively, by doxapram + yohimbine. Doxapram, 4-ap + doxapram, and doxapram + yohimbine caused periodic extensor rigidity before and during arousal. This rigidity was accompanied by opisthotonos in 2 dogs of the doxapram + yohimbine group and may have been mild tonic seizures.

On arousal, respiratory rates were most rapid in xylazine-treated dogs given yohimbine, 4-ap + doxapram, or doxapram + yohimbine, and in acepromazine-treated dogs given doxapram, 4-ap + doxapram, or doxapram + yohimbine. Heart rates were most rapid in xylazine-treated dogs given yohimbine or doxapram + yohimbine, and in acepromazine-treated dogs given yohimbine, doxapram, 4-ap + yohimbine, or doxapram + yohimbine. Cardiac irregularities were not detected by auscultation or palpation of the dogs during the study. None of the dogs relapsed after arousal or walking.

In dogs, yohimbine may be used to shorten duration of xylazine-thiopental anesthesia. Doxapram may be used to shorten duration of acepromazine-thiopental anesthesia. Dual combinations of 4-ap, yohimbine, and doxapram have no advantages for shortening duration of xylazine- or acepromazine-thiopental anesthesia in dogs.
Resistance plasmids of Pasteurella multocida isolated from turkeys
Authors: Hirsh Dwight C. , Martin Lori D. , Rhoades Keith R.
Published: February 2025

From 1940 through 1978, fifty-eight strains of Pasteurella multocida (serotype 3) were isolated from turkeys throughout the United States and were examined for R-plasmids. Forty-one of the isolates contained plasmid DNA, of which 7 isolates were found to encode resistance to tetracycline, streptomycin, and sulfonamides, or to streptomycin and sulfonamides. The R-plasmids were 2 to 10 megadaltons, nonconjugal, and contained a moles percent guanine plus cytosine ratio in the range of 57 to 61. The R-plasmids did not belong to any of the 19 incompatibility groups evaluated, including Inc Q. Digestion with restriction endonuclease indicated that 2 of the plasmids from P multocida isolated in 1960 and 1962 were identical, whereas 4 of the 5 plasmids obtained from P multocida isolated after 1966 were identical, with the 5th plasmic closely related to the other 4. The results indicated that R-plasmids were not widely dispersed among P multocida (serotype 3) isolated from turkeys in the United States. The nontransmissible nature of these plasmids was probably the major reason for their lack of dissemination.
Vaccination of swine with thymidine kinase-deficient mutants of Pseudorabies virus
Authors: McGregor S. , Easterday B. C. , Kaplan A. S. , Ben-Porat T.
Published: February 2025

A mutant of Pseudorabies virus (prv) deficient in thymidine kinase (tk−) activity was isolated and characterized. The mutant grew well in cell culture and did not revert to the thymidine kinase-positive pheno-type. The prv-tk− was not virulent when inoculated intranasally into 3-to 4-week-old pigs and could not be reactivated from the ganglia of these pigs by explantation and cocultiva-tion with susceptible cells several weeks after virus inoculation. Pigs that had been exposed to prv-tk− were immune to challenge exposure with a virulent strain of prv. Furthermore, the challenge virus was not recovered from the ganglia of most of these pigs, indicating that colonization of the ganglia by a super-infecting virulent prv strain was considerably reduced by vaccination.
Changes in digital venous pressures of horses moving at the walk and trot
Authors: Ratzlaff Marc H. , Shindell Roger M. , DeBowes Richard M.
Published: February 2025

Blood pressures from the catheterized lateral digital vein of the fore-limbs of 6 clinically normal horses were measured at rest, at the walk, and at the trot. Digital venous pressures were compared with the phases of the stride and weight-bearing forces, using electrogoniometry and a force platform.

Rapid increases in digital venous pressures to maximal values were observed immediately before maximal forces during the support period of the stride. At the trot, increases in peak vertical forces were paralleled by increases in peak digital venous pressures. Seemingly, the hydrodynamics of the digital circulatory system help to dissipate the initial impact of hoof strike at the walk and the trot.
Stimulation and killing of bovine mononuclear leukocytes by bacterial lipopolysaccharide (endotoxin)
Authors: Banks Keith L. , Michaels Frank H.
Published: February 2025

Bovine adherent mononuclear leukocytes were incubated with bacterial lipopolysaccharides (lps) in vitro, and these cells produced a factor that increased the blastogenic reaction of mouse thymocytes to concanavalin A. This factor most resembles interleukin 1. The lps were also cytotoxic for bovine adherent mononuclear leukocytes in a dose- and time-dependent manner. Cytotoxicosis was determined by the release of cytoplasmic lactic dehydrogenase. This cytotoxicosis was blocked by treating the cells with corticosteroids. Variation in the reaction to lps occurred in cells collected from the same cow on different days and from cells collected from different cows.
Arachidonic acid metabolites in milk of cows during acute coliform mastitis
Authors: Anderson K. L. , Kindahl H. , Petroni A. , Smith A. R. , Gustafsson B. K.
Published: February 2025

Concentrations of prostaglandin F2α (pgf2α) and thromboxane B2 (txb2) were evaluated in the milk of cows with naturally occurring (n = 3) and experimentally induced (n = 5) acute coliform mastitis. These arachidonic acid metabolites were measured by radioimmunoassay in unextracted milk. Experimental infections were induced by inoculating 600 to 1,200 colony-forming units of Escherichia coli into 1 mammary quarter per experimental cow. In the experimental cows, milk was collected before inoculation and at 12, 24, 36, 48, 60, and 72 hours after inoculation. Somatic cell concentrations, bovine serum albumin, and concentrations of pgf2a and txb2 were determined in milk collected at each sampling.

Mild-to-moderate increases in milk pgf2α and txb2 concentrations were observed in cows with naturally occurring mastitis; the increases corresponded to the clinical severity and course of mastitis. In the experimental cows, increases in milk pgf2α and txb2 concentrations were observed, but the increases were not significant, using a statistical model that included factors of treatment, cows, hours after inoculation, cows-by-treatment and hours-by-treatment interactions, and random error (residual).

Results of the present study indicated a large biological variability in milk arachidonic acid metabolite concentrations in cows with acute coliform mastitis, and that arachidonic acid metabolites may be important in the pathophysiologic process of acute coliform mastitis.
Mechanism of renal excretion of creatinine by the pony
Authors: Finco Delmar R. , Groves Carlotta
Published: February 2025

Free-flow and stop-flow procedures conducted on 2 female and 2 testosterone-treated castrated male ponies indicated that [14C]inulin and exogenous creatinine clearance values were the same. These results indicated that creatinine was neither reabsorbed nor secreted by the renal tubules and that exogenous creatinine clearance was an accurate method for determining glomerular filtration rate. As in other species which have been studied, endogenous creatinine clearance probably underestimated glomerular filtration rate because of the presence of noncreatin-ine chromogens in plasma.
Effects of intraoperative irradiation on gastric and urinary bladder incisions in the dog
Authors: Craig James A. , Sigler Robert , Walker Michael
Published: February 2025

Fourteen adult dogs of mixed breeding were given intraoperative irradiation (25 Gy) after surgical incisions were made into the greater curvature of the stomach and the ventral surface of the urinary bladder. Sequential biopsy samples were obtained 10 days to 180 days after surgical operation. All irradiated stomachs developed gastritis and persistent ulceration of the irradiated field. Microscopic changes induced by irradiation of both the bladder and stomach progressed from severe submucosal edema to severe submucosal fibrosis. A parallel progression of fibrinoid degeneration of the small blood vessels was seen in both organs. Severe gastric ulceration persisted up to 180 days after irradiation, although a degree of mucous neck cell and gastric gland regeneration did occur.

Pathologic changes were less severe in the bladder than in the stomach. The bladder had greater resiliency and capability for healing and, in contrast to the stomach, showed a capability to reepithelialize the radiation-induced ulcers.

Conclusions of this study are as follows: (a) the canine urinary bladder tolerated intraoperative radiation therapy after tissue resection better than did the canine stomach, (b) the combination of surgical operation and irradiation resulted in a more prolonged and complicated healing pattern than did either procedure alone, and (c) the introduction of a surgical procedure upon irradiated tissue within an undetermined time span relative to irradiation resulted in a similar pattern of disturbed healing.
Fate of sodium pentobarbital in rendered products
Authors: O'Connor John J. , Stowe Clarence M. , Robinson Robert R.
Published: February 2025

The fate of pentobarbital through rendering was evaluated by following a group of euthanatized animals through a commercial rendering facility. Samples of material were collected at various points in the rendering process, and assays for pentobarbital were conducted by an ultraviolet spectrophotometric method. The results indicated that the pentobarbital, or a closely related analogue, survived rendering without undergoing degradation. The pentobarbital was distributed approximately equally between the meat and bone meal and tallow fractions. If pentobarbital-euthanatized animals are processed along with other raw materials throughout a day's production, the likelihood of significant residues being present in rendered products is minimal.
High-yield preparation of purified Anaplasma marginale from infected bovine red blood cells
Authors: McCorkle-Shirley S. , Hart L. T. , Larson A. D. , Todd W. J. , Myhand J. Donovan
Published: February 2025

Purification of Anaplasma marginale from infected bovine rbc was achieved through enzyme treatment and density-gradient centrifugation. A relative yield of 41.6% was obtained by dividing the number of organisms in the final purified preparation by the number of A marginale-infected rbc. Purified parasites were verified as A marginale by light microscopy, electron microscopy, and immunologic tests. The purified parasites reacted positively with calf and rabbit anti-A marginale sera in interfacial and slide agglutination tests. Anti-bovine rbc serum did not agglutinate purified A marginale, indicating absence of any contaminating rbc stroma. Anaplasma marginale was antigenic, but did not cause infection when the preparation was inoculated into a susceptible calf. The density of A marginale was determined to be 1.19 g/ml and cell diameters ranged from 0.25 to 0.63 µm. This method provided procedures for obtaining A marginale free of bovine rbc antigens for accurate biochemical assays and vaccine production.
Enzyme histochemical features of equine gluteus muscle fibers
Authors: van den Hoven R. , Meijer A. E. F. H. , Wensing Th. , Breukink H. J.
Published: February 2025

Gluteal muscle specimens were taken from 4 horses. From 1 of the 4 gluteal muscles, serial sections were prepared. Individual muscle fibers were identified and studied, using photomicrographs of sections stained by different enzyme histochemical methods. In specimens in which cytoplasmic soluble enzymes were studied, use was made of the semi-permeable membrane technique to hamper enzyme diffusion into reaction fluids. Enzymes involved in glycogenolysis, glycolysis, the tricarboxylic acid cycle, synthesis of reduced nicotinamide adenine dinucleotide phosphate, the pentose phosphate cycle, the α-glycerolphosphate shuttle, the respiratory chain, catabolism, and muscular contraction were studied. Some key enzymes of different metabolic pathways were also included.

Each of 3 fiber types identified had distinct features. Type I fibers were characterized by a relatively strong aerobic capacity, compared with type IIA fibers, which were more glycolytic and had strong aerobic and moderate-to-strong anaerobic capacity. Type IIB fibers were characterized by a relatively low aerobic and a relatively high anaerobic capacity, and were glycolytic. Activities of phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and α-naphtylesterase (nonspecific esterase) were so markedly different in the 3 fiber types that fiber typing was possible, aided by the demonstration of the activities of these enzymes. In type IIB fibers, the pentose phosphate cycle was more important than in the other fiber types. Except for the unexplained high α-naphtylesterase activity in type IIB fibers, catabolic enzymes were not active in healthy equine muscle fibers.
Relationship of serum concentrations of several enzymes to the porcine stress syndrome
Authors: Borgman Robert F. , Handlin Dale L. , Skelley George C.
Published: February 2025

Serum enzyme concentrations were determined in 319 Hampshire pigs (approx 2 months of age). Significant positive correlations were found when creatine kinase (ck) concentrations were compared with lactate dehydrogenase and malate dehydrogenase values, but not when compared with aspartate aminotransferase or alanine aminotransferase values. In an additional study, a litter from a sow with high serum ck concentrations was observed at 2, 3, 4, and 5 months of age for serum ck concentrations. The ck concentration increased as the pigs aged, and soft exudative pork was found upon slaughter of the pigs at 5 months of age. It is believed that ck, lactate dehydrogenase, and malate dehydrogenase determinations in weanling pigs would have value for reducing the frequency of the porcine stress syndrome and soft exudative pork in breeding stock. If only a portion of the genetic carriers was removed, the effect would be considerable within a few generations.
Attempted reactivation of contagious ecthyma in Dall sheep
Authors: Zarnke Randall L. , Dieterich Robert A.
Published: February 2025

Dexamethasone was administered to 2 Dall ewes that had clinically recovered from contagious ecthyma in an attempt to reactivate contagious ecthyma in the sheep. Clinical signs of disease were not detected within 24 days after corticosteroid injection, and virus was not detected in tissues collected at necropsy.
Effects of canine distemper virus on natural killer cell activity in dogs
Authors: Ringler Susan S. , Krakowka Steven
Published: February 2025

An in vitro 51Cr-release assay was developed to detect the cytotoxicity of natural killer cells (nk) of canine peripheral blood mononuclear leukocytes to canine distemper virus (cdv) target cell membrane-bound antigens. Leukocytes from 23 young (≥ 1 week of age), cdv-naive gnotobiotic dogs could discriminate between noninfected control and cdv-infected Vero target cells. However, the amount of preinfection nk activity did not positively correlate with the ultimate outcome of the disease process when these same dogs were given virulent R252-cdv. Evaluation of preinfection and postinfection cdv-specific nk activity indicated that infection-associated increases in cytolysis of cdv-infected or noninfected Vero targets did not occur. In vitro infection of peripheral blood leukocytes with cdv did not change the kinetics or magnitude of nk-mediated cytolysis of homologous virus-infected or other NK-susceptible target cells.
Clinical pharmacokinetics of amikacin in dogs
Authors: Baggot J. Desmond , Ling Gerald V. , Chatfield Ronald C.
Published: February 2025

After iv, im, and subcutaneous injection of single dosages of amikacin (5, 10, and 20 mg/kg of body weight) in each of 4 dogs, the elimination kinetics of amikacin were determined. The pattern of urinary excretion and cumulative amount excreted unchanged in 24 hours were also determined. Amikacin had a short half-life (approx 1 hour) that was independent of the dosage. Intravenous injection of 10 mg/kg gave apparent volume of distribution of 226 ± 37 ml/kg and body clearance of 2.64 ± 0.24 ml/min·kg (mean ± sd, n = 4). Within 6 hours, > 90% of the antibiotic was excreted in the urine, regardless of the route of administration. For isolates of common bacterial species from the canine urinary tract, minimum inhibitory concentrations of amikacin, gentamicin, tobramycin, and kanamycin were determined in vitro. Cumulative percentages were approximately the same for urinary isolates of Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and coagulase-positive staphylococci that were susceptible (minimum inhibitory concentrations ≤ 32 fig/ml) to increasing concentrations of amikacin, gentamicin, and tobramycin, in vitro. Klebsiella pneumoniae was significantly more susceptible to amikacin than were the other bacteria evaluated. Widest variations in susceptibility to aminoglycosides were found with urinary isolates of streptococcal species. For dogs with normal renal function, an amikacin dosage of 10 mg/kg (im or subcutaneously) is recommended every 8 hours for treatment of systemic infections, and every 12 hours for treatment of urinary tract infections caused by susceptible bacteria.
Epinephrine-induced ventricular arrhythmias in dogs anesthetized with halothane: Potentiation by thiamylal and thiopental
Authors: Bednarski Richard M. , Majors Lynda J. , Atlee John L.
Published: February 2025

Epinephrine-induced ventricular arrhythmias were studied in 8 dogs anesthetized at weekly intervals with halothane (1.09% end-tidal concentration) preceded by thiamylal or thiopental (20 mg/kg of body weight). Lead II, bundle of His and high right atrial electrograms, and femoral artery and airway pressures were recorded. Epinephrine was infused in logarithmically spaced increasing rates (initial rate = 0.25 μg/kg/min) for a maximum of 2.5 minutes. The maximal (≥ 4 ventricular premature depolarizations within 15 s of each other) and minimal (all other ventricular or junctional rhythms) arrhythmogenic doses were calculated (infusion rate − time to arrhythmia). The mean (± sd) minimal arrhythmogenic dosages for the thiamylal-halothane, thiopental-halothane, and halothane-only groups were 1.84 ± 0.66,1.83 ± 0.64, and 3.69 ± 1.32 μg/kg, respectively; the mean (± sd) maximal arrhythmogenic dosages were 2.32 ± 0.77, 3.37 ± 1.30, and 8.86 ± 4.40 μg/kg, respectively, with no change after 4 hours of anesthesia. During infusion of the maximal arrhythmogenic dosages, the mean infusion of the maximal arrhythmogenic dosages, the mean percentage increase in serum K+ for thiamylal-halothane, thiopental-halothane, and halothane-only groups was 33 ± 14%, 31 ± 13%, and 38 ± 18%, respectively.
Ketamine in dogs
Authors: Haskins Steve C. , Farver Tom B. , Patz John D.
Published: February 2025

The cardiopulmonary consequences of ketamine (10 mg/kg, iv) were evaluated in 18 dogs. Heart rate, cardiac output, systemic blood pressure, left ventricular work, oxygen transport, oxygen consumption, carbon dioxide production, and core temperature increased. Breathing rate, minute ventilation, and arterial partial pressure of oxygen transiently decreased. Arterial partial pressure of carbon dioxide, alveolar-arterial oxygen gradient, and venous admixture transiently increased.

The duration of action of ketamine for surgical anesthesia was short. Muscle tone and salivation were excessive, and spontaneous muscular activity was prominent.
Efficacy of fenbendazole and cambendazole against Muellerius capillaris in dairy goats
Authors: Bliss E. L. , Greiner E. C.
Published: February 2025

Two anthelmintics, fenbendazole and cambendazole, were used in an attempt to eliminate Muellerius capillaris infections in a group of 44 goats. During the course of this study (508 days), M capillaris larvae were found in at least one fecal specimen from each of 22 of the 44 goats. All 44 goats were dewormed with fenbendazole (30 mg/kg of body weight) at the onset of this study (day 18). Two additional dewormings with fenbendazole at 4- to 8-week intervals were restricted to the goats that continued to shed M capillaris larvae. On the basis of routine fecal examinations, fenbendazole eliminated M capillaris larvae from the feces of 8 (36%) of these 22 goats.

On day 253, cambendazole (60 mg/kg) was given orally to 17 of these 22 goats (2 of the 22 had died and 3 were not available for treatment); 13 of these goats were still shedding M capillaris larvae. Cambendazole eliminated M capillaris larvae from the feces of 10 (77%) of these 13 goats chronically infected with M capillaris.
Binding characteristics of swine erythrocyte insulin receptors
Authors: Dieberg G. , Bryan G. S. , Sartin J. L. , Williams J. C. , Prince T. J. , Kemppainen R. J.
Published: February 2025

Crossbred gilts (controls; n = 7) had 8.8 ± 1.1% (mean ± sem) maximum binding of [125I]insulin to insulin receptors on erythrocytes. The number of insulin-binding sites per cell was 137 ± 19, with a binding affinity ranging from 7.4 × 107M−1 to 11.2 × 107M−1 and mean of 8.8 × 107M−1. Pregnant sows (n = 5) had a significant increase (P < 0.01) in maximum binding due to an increase in number of receptor sites per cell. Lactating sows fed a high-fiber diet (n = 3) and a low-fiber diet (n = 4) did not develop a significant difference in maximum binding of insulin. Sows fed the low-fiber diet had a significantly higher number of binding sites and a significantly lower binding affinity than did sows fed a high-fiber diet. Receptor-binding affinity was lower in the low-fiber diet group than in cycling gilts, whereas data from sows fed the high-fiber diet did not differ from data for cycling gilts.

Data from this study indicated that insulin receptors of swine erythrocytes have binding characteristics similar to those in other species. Pregnancy and diet will alter insulin receptor binding in swine.
Hormonal response to thyrotropin-releasing hormone in healthy horses and in horses with pituitary adenoma
Authors: Beech Jill , Garcia Marolo
Published: February 2025

Cortisol, triiodothyronine (T3), thyroxine (T4), insulin, and glucose responses to thyrotropin-releasing hormone (trh) were evaluated in 12 healthy, mature horses and in 7 horses and 4 ponies with clinical signs of pituitary adenoma (pa). Within 1 hour after trh administration, the increase in T3 and T4 was similar in healthy horses and animals with pa. Plasma cortisol in the group with pa increased (P < 0.05) within 0.25 hours after trh administration, and remained increased for 1.5 hours. In the control group, a significant increase in plasma cortisol concentrations did not develop after trh administration. Plasma glucose and insulin concentrations were higher in animals with pa than in the healthy horses throughout the experiment (6 hours).