bluuebunny/crossref_metadata_2025 huggingface dataset:
Virulence factors and markers in Escherichia coli from calves with bacteremia
Authors: Mohamed Ou Said Ahmed , Contrepois Michel G. , Der Vartanian Maurice , Girardeau Jean P.
Published: February 2025

Relative pathogenicity of 151 Escherichia coli isolates from 36 calves with bacteremia after necropsy was studied by measurement of the ld50 after mice were inoculated ip with E coli isolates. Study of virulence factors and markers revealed that the pathogenicity of E coli was associated with the production of hydroxamate siderophores and with resistance to serum bactericidal effects. Production of colicins, including colicin V, and of surface antigen 31A was correlated with virulence. The close association between phenotypic expression of virulence factors and markers was consistent with a hypothesis of a localization of genes coding for virulence factors and markers on the same plasmid.
Efficacy of water vapor-saturated air in the treatment of exercise-induced pulmonary hemorrhage in Thoroughbred racehorses
Authors: Sweeney Corinne Raphel , Hall Jennifer , Fisher John R. S. , Leary Herbert J. , Soma Lawrence R. , Spencer Pamela A.
Published: February 2025

The efficacy of water vapor-saturated air as a treatment for horses with exercise-induced pulmonary hemorrhage (eiph) was studied. Horses selected for study (n = 14) had grade 1 or greater hemorrhage in the trachea after a minimum of 4 breezes between 0.8 and 1 km, as determined by endoscopy. Nine horses were treated with water vapor-saturated air; 5 horses were not treated.

When the mean and maximal eiph scores from the pre-treatment period were compared with the mean and maximal eiph scores from the treatment period in both treated and nontreated groups, there was no significant difference between groups. There was a suggestion of a linear relationship between exercise speed and the mean eiph score of the first 4 breezes in all 14 horses.
Detection of eastern equine encephalomyelitis virus antigen in equine brain tissue by enzyme-linked immunosorbent assay
Authors: Scott Thomas W. , Olson James G. , All Benjamin P. , Gibbs E. Paul J.
Published: February 2025

Sensitivity and specificity of an antigen-capture elisa vs virus isolation in cell culture were evaluated for the detection of eastern equine encephalomyelitis (eee) virus in the brain tissue of naturally infected equids. Brain specimens from 16 equids with neurologic disease were examined by elisa and by inoculation onto baby hamster kidney cell cultures. Of 10 brain samples from which virus was isolated in the cell culture bioassay, all were correctly identified as containing eee virus antigen by elisa. None of the remaining 6 specimens, without detectable infectious eee virus, contained detectable antigen. Sensitivity and specificity of the elisa were 100% with no false-positive or false-negative results. The antigen-capture elisa was a rapid, sensitive, specific, and simple alternative to a traditional bioassay for the detection of eee virus.
Serum concentrations of thyroxine and 3,5,3′-triiodothyronine in dogs before and after administration of freshly reconstituted or previously frozen thyrotropin-releasing hormone
Authors: Rosychuk R. A. W. , Freshman J. L. , Olson P. N. , Olson J. D. , Husted P. W. , Crowder-Sousa M. E.
Published: February 2025

Concentrations of serum thyroxine (T4) and 3,5,3′-tri-iodothyronine (T3) were determined after the administration of freshly reconstituted thyrotropin-releasing hormone (trh), reconstituted trh that had been previously frozen, or thyrotropin (tsh) to 10 mature dogs (6 Greyhounds and 4 mixed-breed dogs). Thyrotropin-releasing hormone (0.1 mg/kg) or tsh (5 U/dog) was administered iv; venous blood samples were collected before and 6 hours after administration of trh or tsh. Concentrations of the T4 and T3 were similar (P > 0.05) in serum after administration of freshly reconstituted or previously frozen trh, indicating that trh can be frozen at −20 C for at least 1 week without a loss in potency.

Concentrations of T4, but not T3, were higher after the administration of tsh than they were after the administration of trh (P < 0.01). Concentrations of T4 increased at least 3-fold in all 10 dogs given tsh, whereas a 3-fold increase occurred in 7 of 10 dogs given freshly reconstituted or previously frozen trh. Concentrations of T4 did not double in 1 dog given freshly reconstituted trh and in 1 dog given previously frozen trh. Concentrations of T3 doubled in 5 of 10, 2 of 10, and 5 of 10 dogs given tsh, freshly reconstituted trh, or previously frozen trh, respectively.

Results suggested that concentrations of serum T4 are higher 6 hours after the administration of tsh than after administration of trh, using dosage regimens of 5 U of tsh/dog or 0.1 mg of trh/kg. Additionally, results suggested that Greyhounds have lower concentrations of serum T4 than do mixed-breed dogs, but Greyhounds tend to have higher concentrations of serum T3.
Evaluation of Haemonchus contortus infections in sexually intact and ovariectomized ewes
Authors: Fleming Michael W. , Rhodes Richard C. , Gamble H. Ray
Published: February 2025

Three experiments were conducted to investigate experimentally the occurrence of periparturient nematode egg rise in ewes and the hormonal modulation of Haemonchus contortus infections. In the first experiment, fall-bred and winter-bred pregnant (n = 4 and 14, respectively) and nonpregnant (n = 5 and 29, respectively) ewes were treated with anthelmintic and were pastured together on fields that were contaminated with H contortus. Three weeks before lambing, all ewes were placed in concrete pens; fecal egg counts for the winter-bred group were obtained on alternate days. Pregnant and lactating ewes had significantly larger numbers (P < 0.01) of H contortus eggs than did the nonpregnant controls 1 week before and after lambing. Lactating, fall-bred ewes had significantly (P < 0.01) more adult worms in their abomasum through natural acquisition than the nonpregnant controls.

In the second experiment, fall-bred and winter-bred, helminth-free, pregnant (n = 4 and 8, respectively) and nonpregnant (n = 3 and 15, respectively) ewes were inoculated on 5 alternate days, beginning 70 days after breeding with 20,000 infective H contortus larvae. The ewes were maintained on concrete pens throughout pregnancy. Fecal egg counts were significantly (P < 0.05) greater in pregnant ewes, beginning 1 week before lambing until 1 week after lambing. Abomasums of lactating ewes from both lambing seasons yielded significantly (P < 0.01) more adult worms at necropsy than nonpregnant ewes.

In the third experiment, ewes were ovariectomized (n = 15) or sham-operated (n = 9); half of the control ewes were bred. Beginning on day 70 of pregnancy, all ewes were inoculated orally with 20,000 infective H contortus larvae on 5 alternative days. Abomasums were removed from all ewes after lambing, and adult worms were recovered. Pregnant ewes and half of the ovariectomized ewes had significantly (P < 0.05) more worms than did the sham-operated ewes.
Response to intradermal skin testing with four cat allergen preparations in healthy and allergic dogs
Authors: White Stephen D. , Ohman John L.
Published: February 2025

Intradermal skin testing with 4 cat allergens was performed on 40 dogs. The allergens used were a commercial preparation, cat allergen 1, cat pelt extract, and cat serum. Twenty dogs had inhalant allergies (canine atopy) and 20 dogs were healthy. The dogs in these 2 groups were further allotted to groups of dogs with or without exposure to cats. Cat pelt extract was the only allergen that caused a statistically significant (P < 0.025) difference in the number of positive reactions in healthy vs allergic dogs, with healthy dogs having the greater number of positive reactions. Seven (35%) of the 20 dogs with no known exposure to cats had positive reactions to at least one of the allergens. In dogs that had been exposed to cats, positive reactions developed in twice the number of dogs without clinical signs of canine atopy, compared with those with clinical signs of canine atopy. These data showed that dogs do become sensitized to cat allergen, but that this sensitization may not indicate known exposure to cats or clinical disease.
Experimentally induced bluetongue virus infection in white-tailed deer: Coagulation, clinical pathologic, and gross pathologic changes
Authors: Howerth E. W. , Greene C. E. , Prestwood A. K.
Published: February 2025

Ten yearling white-tailed deer (Odocoileus virginianus) were inoculated with bluetongue virus serotype 17. Two yearling white-tailed deer were inoculated with sonicated heparinized noninfected blood and served as controls.

Clinical signs of bluetongue virus infection included increased rectal temperature, erythema, facial edema, coronitis, and stomatitis. By postinoculation day (pid) 8, excessive bleeding and hematoma formation at venipuncture sites, dehydration, and diarrhea developed. At necropsy, the most consistent findings were oral lesions and widespread hemorrhage, which ranged from petechia to massive hematoma formation.

Bluetongue virus caused progressive prolongation of activated partial thromboplastin time and prothrombin time, and progressive reduction of Factors VIII and XII plasma activities beginning on pid 6. A progressive decrease in platelet numbers also developed on pid 6. Changes in platelet size were not detected. Mean thrombin time was shortened, but prolongation developed in 1 deer. Mean fibrinogen concentration and Factor V plasma activity initially increased and then decreased, but remained above preinoculation values. Factor V activity was low in a few deer. Results of screening tests for inhibitors of the intrinsic coagulation system were positive in 2 deer. High concentrations of fibrin(ogen) degradation products were first detected between pid 3 and 6.

Hematologic changes included leukopenia, lymphopenia, neutrophilia, and low total plasma protein concentration. Differences in pcv, hemoglobin concentration, or rbc counts were not detected between infected and control deer. Serum total bilirubin concentration increased by pid 6, primarily because of increased unconjugated bilirubin concentration. Mild to severe increases in serum aspartate transaminase activity were accompanied by more marked increases in creatine kinase activity. Indirect Coombs test results were negative in all deer. Examination of bone marrow revealed normal cellularity with progressive megakaryocyte hyperplasia.

These data document the development of disseminated intravascular coagulation in deer with bluetongue, and indicated that this process is an important factor in the development of hemorrhagic diathesis in white-tailed deer with bluetongue.
Tissue residues of diacetoxyscirpenol in pigs and calves after intravenous dosing
Authors: Coppock R. W. , Swanson S. P. , Gelberg H. B. , Buck W. B.
Published: February 2025

Pigs (n = 19) were given 0, 0.1, 0.5, or 1 mg of diacetoxyscirpenol (das)/kg of body weight, and heifers (n = 7) were given 0 or 0.5 mg of das/kg. Animals were anesthetized and exsanguinated 8 hours after administration of das, and liver, kidney, skeletal muscle, mesenteric lymph node, and spleen were analyzed for das. Diacetoxyscirpenol was not detected in tissues from animals not given das. All tissues from pigs and calves given das contained at least traces (≤ 10 ng/g of tissue) of das.
Comparison of the effect of T-2 toxin with that of dexamethasone or cyclophosphamide on resistance to Babesia microti infection in mice
Authors: Corrier Donald E. , Wagner Gerald G.
Published: February 2025

The effect of T-2 toxin on host resistance to acute and latent Babesia microti infections was evaluated in mice and was compared with the effects of the immunosuppressive drugs dexamethasone and cyclophosphamide. Mice with acute or latent B microti infection were treated with 2 mg of T-2 toxin/kg of body weight, 0.2 mg of dexamethasone/kg, or 30 mg of cyclophosphamide/kg daily for 5 days. Treatment with dexamethasone or cyclophosphamide caused significant (P < 0.05) increases in Babesia parasitemia during acute infection and significantly (P < 0.05) prolonged the duration of parasitemia during acute babesiosis. Treatment with T-2 toxin caused a transient significant (P < 0.05) increase in Babesia parasitemia on day 10 after acute infection and numerical, though statistically nonsignificant, increases in the maximal level and duration of parasitemia during acute babesiosis. Significant (P < 0.005) recrudescence of parasitemia was observed in the dexamethasone- and cyclophosphamide-treated mice with latent Babesia infection. Treatment with T-2 toxin did not cause recrudescence of parasitemia in mice with latent Babesia infection.
Radiographic assessment of liver volume in dogs
Authors: van Bree Henri , Jacobs Veerle , Vandekerckhove P.
Published: February 2025

In a group of 65 dogs, radiographic liver length, the length of the axis from the most cranial part of the diaphragm to the apex of the liver tip, was correlated significantly (P < 0.000001) with real liver volume. Within this group, radiographic liver length, compared with the length of the eleventh thoracic vertebra, was correlated with liver volume per kilogram of body weight.

In a group of 30 dogs, with histologically normal liver, this measurement was not affected by thoracic conformation. These findings suggest that radiographic liver length is a reliable measurement for estimating liver volume in dogs and that it is not influenced by thoracic conformation.

For 60 of the 65 dogs, a method of assessment of liver volume was formulated that required 2 measurements to be made on the lateral abdominal radiograph and 1 to be made on the dog itself.
Obstructive Jaundice Associated with Chronic Active Hepatitis in a Dog
Authors: Meyer Dennis J. , Iverson William O. , Terrell Timothy G.
Published: February 2025

A cholestatic syndrome was the primary manifestation of chronic active hepatitis in a dog. Enzyme determinations did not differentiate between extrahepatic and intrahepatic cholestasis as the cause of the conjugated hyperbilirubinemia, thus necessitating percutaneous liver biopsy. The dog was treated with prednisolone but developed gastrointestinal hemorrhage and terminal hepatic encephalopathy. Morphologic variations in liver biopsy specimens obtained simultaneously and in the specimen obtained at necropsy demonstrated that the disease activity varied by locales in the liver.
Bluetongue and Epizootic Hemorrhagic Disease Virus Isolations from Vertebrate and Invertebrate Hosts at a Common Geographic Site
Authors: Foster N. M. , Metcalf H. E. , Barber T. L. , Jones R. H. , Luedke A. J.
Published: February 2025

One serotype of bluetongue virus (btv) and two serotypes of epizootic hemorrhagic disease virus (ehdv) were isolated from vertebrate and invertebrate hosts on a farm in Colorado. The isolations were from blood samples collected a week apart from a dairy heifer with stomatitis and laminitis; ehdv serotypes 1 and 2 were isolated from the first blood sample, and btv serotype 13 and ehdv serotype 1 were isolated from the second. Antibodies to ehdv and btv were detected in the serum from this heifer. Both ehdv serotypes and btv serotype 13 were isolated from pools of female biting gnats (Culicoides variipennis) that had not had a recent blood meal. The btv insect isolate was biologically transmitted by female gnats from an infected donor sheep to a recipient host sheep. Culicoides variipennis was the predominant insect collected during three nights of light trap captures at the farm.
Filaroides hirthi in a Dog: Fatal Hyperinfection Suggestive of Autoinfection
Authors: August J. R. , Powers R. D. , Bailey W. S. , Diamond D. L.
Published: February 2025

Progressive dyspnea in a dog began 1 month after it had been hit by a car. Radiographs revealed diffuse interstitial and alveolar pneumonia. Large numbers of embryonated eggs were observed in bronchial washings; and many small nematodes, later identified as Filaroides hirthi, were found in the fine needle aspirates of pulmonary tissue. Numerous nematode larvae were demonstrated on fecal flotation. The severe hyperinfection strongly suggested autoinfection, probably associated with depressed immunologic competence due to chronic stress.
Polymyositis in Dogs
Authors: Kornegay Joe E. , Gorgacz Edward J. , Dawe Donald L. , Bowen John M. , White Nathaniel A. , DeBuysscher Eduard V.
Published: February 2025

Polymyositis was diagnosed in nine dogs. Factors utilized in making the diagnosis included (1) muscle pain or weakness, (2) high concentrations of serum muscle enzymes, (3) electromyographic abnormalities, and (4) histopathologic evidence of muscle necrosis and inflammation.

Clinical signs included muscle pain, weakness, stilted gait, and pyrexia. Serum muscle enzyme concentrations were high in only three dogs. There was no apparent correlation between enzyme concentrations and severity of clinical involvement or degree of muscle necrosis on biopsy. Electromyographic changes included polyphasic motor unit potentials, fibrillation potentials, and positive waves. Variable degrees of muscle regeneration, degeneration, and inflammation were seen.

Prednisone (2.2 mg/kg, OD, per os) was used effectively to treat four dogs. One dog improved initially but was euthanatized later when clinical signs became more pronounced. Three other dogs developed aspiration pneumonia secondary to megaesophagus and either died or were euthanatized.
Evaluation of the Demand Valve for Resuscitation of Horses
Authors: Riebold T. W. , Evans A. T. , Robinson N. E.
Published: February 2025

Arterial blood gas values, rate of pulmonary nitrogen washout, respiratory rate, arterial blood pressure, heart rate, and cardiac output were determined during ventilation of six anesthetized horses, with a demand valve. The horses were allowed to ventilate spontaneously, or intermittent positive pressure ventilation was utilized. When compared with spontaneous ventilation, intermittent positive pressure ventilation caused a significant increase in the rate of pulmonary nitrogen washout and a significant decrease of arterial carbon dioxide. It was concluded that intermittent positive pressure ventilation with a demand valve provides a simple method for resuscitation of horses.
Osteochondritis Dissecans of the Tarsocrural Joint in Three Canine Siblings
Authors: Olson Neil C. , Mostosky Ulreh V. , Flo Gretchen L. , Tvedten Harold W.
Published: February 2025

Osteochondritis dissecans of the tarsocrural joint was diagnosed in three canine siblings. The lesion, unilateral in one dog and bilateral in two dogs, was on the caudomedial aspect of the trochlea of the talus. Surgical treatment resulted in marked improvement of hindlimb gait.
Halogeton Poisoning in Range Cattle
Authors: Lincoln Stuart D. , Black Baxter
Published: February 2025

Acute Halogeton glomeratus poisoning occurred in 16 of 680 range cattle during and following a trail drive. Signs of toxicosis included posterior ataxia, recumbency, coma, and death. Histopathologically, abundant, refractile calcium oxalate crystals were seen in renal tubules. Inasmuch as the plant is generally unpalatable for cattle, poisoning in this case was enhanced by a preceding period of food deprivation.
Implications of Mycotoxins in Animal Disease
Authors: Pier A. C. , Richard J. L. , Cysewski S. J.
Published: February 2025

Mycotoxins are formed on animal feeds when conditions of moisture and temperature permit the growth of naturally occurring toxigenic fungi. In general, mycotoxins are low molecular weight, nonantigenic substances, many of which are relatively heat stable. Mycotoxins can cause acute disease episodes when animals consume critical quantities of them. Specific toxins affect specific organs or tissues such as the liver, kidney, oral and gastric mucosa, brain, or reproductive tract. In acute mycotoxicoses, the signs of disease often are marked and directly referable to the affected target organs. Most frequently, however, concentrations of mycotoxin in feeds are below those that cause acute disease. At lower concentrations, the effects of mycotoxins are more protean. They reduce the growth rate of young animals, and some interfere with native mechanisms of resistance and impair immunologic responsiveness, making the animals more susceptible to infection. These effects on immunity and resistance are difficult to recognize because the signs of disease are associated with the infection rather than with the mycotoxin that predisposed the animal to infection. Animals vary in their susceptibility to some mycotoxins, according to the species and age of animal; young growing animals are more susceptible to certain mycotoxins than are adults. The major effects, sources, and dose response relationships of mycotoxins important to the health of food-producing animals are presented in accompanying tables.
Expanding Food-Animal Veterinary Services Through Nutritional Consultation
Authors: Lesch Timothy E. , Troutt H. F. , Jones G. M.
Published: February 2025

Practitioners can increase their value to their clients as well as increase the gross veterinary product by developing supplemental expertise in nontraditional disciplines. This can be accomplished through continuing education and the utilization of technical support services such as the professional nutritionist. In addition, contemporary technology such as the electronic moisture tester and the pH meter can be implemented in the acquisition of nutritional diagnostic data. A comprehensive herd health program is precisely the delivery system into which such complimentary expertise can be integrated successfully.
Dairy Herd Reproductive Health Programs Compared with Traditional Practices
Authors: Heider Lawrence E. , Galton David M. , Barr Harry L.
Published: February 2025

Reproductive herd health programs have been advocated for many years, and rational approaches that are cost effective have been demonstrated. Dissemination of this information to dairymen can help create a demand for veterinary service. Similarly, the information can be utilized by veterinarians to encourage dairy clients to utilize profitable practices and programs. The study described demonstrated an improvement in biologic goals when a reproductive herd health program was incorporated into the management scheme. The program achieved economic success by reducing costs related to reproduction.
Capillaria plica Infection in Dogs
Authors: Senior D. F. , Solomon G. B. , Goldschmidt M. H. , Joyce T. , Bovee K. C.
Published: February 2025

The prevalence, pathologic effects, and treatment of Capillaria plica infection were investigated in two breeding kennels. The prevalence of C plica infection in mature dogs in two kennels (127 dogs) was 76% and 59%. Pups less than 8 months old did not pass C plica eggs in the urine. Age, breed, or sex predilection was not observed in mature dogs. In infected dogs, hematuria, dysuria, and pollakiuria developed without secondary bacterial cystitis. A direct life cycle could not be demonstrated experimentally.

Histologically, adult C plica were seen in the submucosa of the bladder and ureter, where they induced a mild inflammatory reaction and submucosal edema.
Epidemiologic Monitoring Following an Episode of Pseudorabies Involving Swine, Sheep, and Cattle
Authors: Thawley David G. , Wright James C. , Solorzano Robert F.
Published: February 2025

In April 1978, an episode of pseudorabies involved swine, sheep, and cattle on a farm in north-central Missouri. The herd of 48 farrowing sows was vaccinated, then separated from the sheep and cattle by double fencing. Within 4 days, death losses in sheep and cattle ceased, indicating that separation by double fencing is an effective means of controlling interspecies virus spread. Monitoring of pseudorabies in sows and their vaccinated offspring was done by serum neutralization testing and virus culturing of pharyngeal swabs for the following 12 months. Pseudorabies virus carriers were in the sow herd 6 months after the initial episode. The serologic response to vaccination of the offspring from immune sows was poor, but pigs segregated from their dams at weaning remained free of detectable infection. It was concluded that segregation at weaning may be useful when expensive breeding lines must be salvaged from an infected herd.
Avulsion Fractures of the Origin of the Suspensory Ligament in the Horse
Authors: Bramlage L. R. , Gabel A. A. , Hackett R. P.
Published: February 2025

Five horses with avulsion fractures of the proximal origin of the suspensory ligament were examined for lameness. The horses in the series each had lameness of acute onset; four were severely lame, and one moderately lame. The condition was difficult to diagnose because commonly used local anesthetic blocks did not result in improvement during the routine examination. Local infiltration of the area with local anesthetic returned the horses to soundness. After a period of rest, varying from a few weeks in the acute injury to 6 months in the chronic injuries, the horses were returned to racing without lameness.
Pharmacotherapeutics of the Newer Tetracyclines
Authors: Aronson Arthur L.
Published: February 2025

The newer tetracyclines are defined as those tetracyclines available in the United States but not approved for veterinary use. These include demeclocycline, methacycline, doxycycline, and minocycline. Of these, doxycycline and minocycline appear to offer advantages that would render them useful in certain situations in veterinary medicine. Their major advantage lies in their greater lipid solubility relative to other tetracyclines. This characteristic probably accounts for their enhanced antimicrobial effectiveness for some organisms, more efficient absorption after oral administration, and enhanced distribution in the body. The principal excretory organ for doxycycline is the intestine, where the drug diffuses through the intestinal mucosa into the intestinal tract. This unique characteristic makes this drug useful in cases of preexisting renal dysfunction and may render this drug superior to other tetracyclines in the treatment of intestinal infections. Doxycycline is used in other countries for respiratory tract and intestinal tract diseases of poultry. The usefulness of doxycycline and minocycline in food-producing animals may be limited because of persistent drug residues. Minocycline has, in large doses, been used with streptomycin in the elimination of the carrier state of canine brucellosis. The superiority of doxycycline and minocycline, relative to other tetracyclines, in their distribution to areas of the body such as the eye, brain, cerebrospinal fluid, and prostate gland suggests that trials of their efficacy in tetracycline-sensitive infections of these areas are indicated. Pharmacokinetic studies designed to determine optimal dosage schedules have not been made for domestic animals. These determinations are necessary to evaluate most effectively the usefulness of the newer tetracyclines in veterinary medicine.
Distribution of Antimicrobial Agents in Normal and Diseased Animals
Authors: Baggot J. Desmond
Published: February 2025

Antimicrobial agents are distributed throughout the body by the circulating blood and must reach the focus of infection to exert their action; the majority are excreted unchanged in the urine. Extensive (> 80%) binding to serum proteins (mainly albumin) reduces the fraction of drug which is free in the serum and which consequently is available to enter other tissues. It may either hinder or facilitate elimination, depending on the mechanism of the process. Lipid solubility is the principal physicochemical property of an antimicrobial agent which influences the pattern and extent of distribution, as well as the rate of elimination. Abnormal pH reaction of extracellular fluid can, by changing degree of ionization, alter drug distribution. When comparing the apparent volume of distribution of a drug between normal and diseased animals, the apparent steady-state distribution volume (Vd(ss)) is the only meaningful term as it is independent of elimination processes. This term may be considered in conjunction with the apparent volume of the central compartment (Vc) and the individual rate constants (k12, k21, kel) of the pharmacokinetic model.

When renal function is impaired, elimination of drugs which are excreted mainly by the kidneys is decreased. This necessitates an appropriate adjustment of the dosage regimen. Reduced serum protein binding (mostly organic acids), resulting from hypoalbuminemia (nephrotic syndrome) or the uremic state (chronic renal failure), will increase the free, unbound fraction of drug that is available for extravascular distribution. Based on limited evidence, it appears that fever increases the steady-state distribution volume of antimicrobial agents without changing the apparent volume of the central compartment and the total body plasma clearance. The increased distribution volume associated with the febrile response might be attributed to an enhanced capacity to penetrate cellular barriers. It may be tentatively concluded that the response to therapy, which depends on an effective concentration of drug being achieved and maintained at the focus of infection, should be favorably influenced by the febrile state.
Drug Selection and Use in Mastitis: Systemic vs Local Therapy
Authors: Ziv G.
Published: February 2025

The optimal properties of antibacterial drugs, (administered parenterally or intracisternally during clinical mastitis) required for achieving and maintaining effective drug concentrations at the site of infection are reviewed. The in vitro sensitivity of the udder pathogen, expressed as the minimal inhibitory concentration (mic) of the drug, and the physicochemical properties of the antibiotic are major determinants in the duration of effective drug concentrations in the udder.

Injectable oxytetracycline and chloramphenicol possess limited im bioavailability properties, and therefore, should be administered iv. Effective passage of drug from blood into the udder is best achieved with the macrolide antibiotics, but the antibacterial spectra of these drugs are limited to gram-positive pathogens.

For intramammary treatment, drugs that are distributed throughout the udder and are quickly absorbed into the general blood circulation should be preferred. A second priority should be given to those drugs possessing more limited distribution characteristics. Some of the most active drugs in vitro are poorly and unevenly distributed in the udder and are absorbed only to a limited extent.
Availability and Usage of New Antibacterial Drugs in Europe
Authors: Ziv G.
Published: February 2025

The present-day availability and usage of established and new antibacterial drugs approved for clinical and therapeutic purposes in food-producing animals and poultry in the United States and Europe were compared. Presently, 42 such drugs are approved in Europe, 13 of which were approved since Dec 31, 1974. In the United States, 17 such drugs are currently approved, only four were approved since Dec 31, 1974. Most drug products approved in Europe contain two or more antibacterial agents, whereas most of the products approved in the United States are single drug entities.

Drugs approved in Europe but not in the United States include sulfonamide and trimethoprim combinations, nafcillin, oxacillin, metampicillin, cephoxazole, cephalonium, cephacetrile, cephalexin, gentamicin, rifamycin SV, nifuroquine, tiamulin, chloramphenicol, colistin, and polymyxin B. Pharmacologic and clinical features of several of these drugs are briefly described.
Safety Assessment of Drug Residues
Authors: Jackson Benjamin A.
Published: February 2025

The safety assessment of drug residues is part of the process for defining the conditions for the safe use of drugs in food-producing animals. The information needed to assess the safety of drug residues is provided by chemical and toxicity tests. Toxicity tests are conducted to identify the type of effect produced and to determine the exposure concentrations that would be expected not to produce the effect. These tests include acute, subacute, and chronic toxicity tests, as well as reproduction studies and other special tests. The results are used to find an acceptable daily intake for drug residues that can be used to set a tolerance.
Statistical Considerations in Clinical Field Evaluation of Drugs
Authors: Powers J. D. , Powers T. E.
Published: February 2025

Statistical problems associated with clinical field evaluation of drugs are many. The Food and Drug Administration requires that the safety and efficacy of a drug must be shown in adequate and well-controlled clinical investigations. From a statistical point of view, safety and efficacy must be precisely defined, and a quantitative method must be developed to measure these properties. It is proposed that efficacy be defined in both the therapeutic and pharmacologic aspects. Further, to measure therapeutic efficacy, it is suggested that an appropriate health index be used. This index would provide information regarding degree of improvement and also the time course of improvement. To measure or evaluate pharmacologic efficacy, it is suggested that kinetic studies be done to compare half-lives, volumes of distribution, and any other relevant kinetic parameter(s).
Toxicity and Drug Interactions of Levamisole
Authors: Hsu Walter H.
Published: February 2025

Clinical signs and lesions of levamisole toxicosis include: nausea, vomiting, increased salivation, frequent urination and defecation, colic, dizziness, headache, muscle tremors, ataxia, anxiety, hyperesthesia with irritability, clonic convulsions, depression, rapid respiration, dyspnea, prostration, collapse, hemorrhages in the subepicardium and thalamus, enteritis, hepatic degeneration and necrosis, and splenic congestion. Most of these signs and lesions are similar to those observed in nicotine poisoning. Levamisole causes vasopressor and panting effects which are blocked by ganglionic blocking agents hexamethonium and mecamylamine but are not blocked by atropine. The vasopressor effect of levamisole is blocked by α-adrenergic antagonists phentolamine and dibenamine; however, the respiratory effect of levamisole is not affected by these α-adrenergic antagonists. Repeated iv injections of levamisole cause a tachyphylactic response. With levamisole-induced tachyphylaxis, the effects of other ganglionic stimulants dimethylpiperazinium and nicotine are also abolished. Levamisole causes an electroencephalographic arousal which is antagonized by atropine sulfate and mecamylamine. There is also a structural similarity of levamisole to nicotine. These studies suggest that levamisole is a nicotine-like compound. Possible treatment of levamisole poisoning is discussed. Drug interactions of levamisole with organophosphates and anthelmintics, eg, pyrantel, methyridine, and diethylcarbamazine, are also discussed.
Chemotherapeutic Management of Transmissible Venereal Tumors in 30 Dogs
Authors: Brown Nancy O. , Calvert Clay , MacEwen E. Gregory
Published: February 2025

Thirty dogs with transmissible venereal tumors were examined either at The Donaldson-Atwood Cancer Clinic of The Animal Medical Center or at The University of Georgia Veterinary Medical Teaching Hospital. After biopsy, all dogs were treated with a combination chemotherapy regimen consisting of vincristine, cyclophosphamide, and methotrexate. Results of therapy were evaluated after a mean interval of 533 days; 28 had complete regression of tumor, 1 had a partial response, and 1 had a minimal response.
Rocky Mountain Spotted Fever in Dogs
Authors: Lissman Barry A. , Benach Jorge L.
Published: February 2025

Infection with rickettsiae of the spotted fever group was clinically and serologically diagnosed in four dogs from two households on Long Island. In two dogs, clinical signs included high fever (to 40.5 C), abdominal pain, lethargy, depression, anorexia, and nystagmus. One of these dogs had conjunctivitis and petechial hemorrhages in the oral mucous membranes. The third dog initially had high fever, evidence of abdominal pain, anorexia, and depression. The fourth dog appeared clinically normal. Clinical signs disappeared following treatment with tetracycline given orally.
Gapeworm Infection of Domestic Cats in Puerto Rico
Authors: Cuadrado Ricardo , Maldonado-Moll José F. , Segarra Joaquín
Published: February 2025

In a survey of 40 adult cats in Puerto Rico, 13 (33%) were found to be infected with the gapeworm Syngamus (Mammomonogamus) ierei. Direct fecal smear and necropsy were the methods used to detect the infection. Fourteen adult worm pairs were collected in one cat; the average was four. Histologically, evidence of chronic inflammation was observed in the nasopharynx of infected cats.

The parasite occurs widely in the Caribbean region. It was concluded that the similarity of the gapeworm egg with those of hookworms and the recondite location of the adult gapeworm probably explain the lack of reports on the infection.
Electrocardiographic and Echocardiographic Findings in Four Cases of Bovine Endocarditis
Authors: Lacuata Alfredo Q. , Yamada Haruo , Nakamura Yokichi , Hirose Tsuneo
Published: February 2025

Surface limb lead electrocardiograms were recorded in four cases of endocarditis in dairy cows in which the clinical diagnosis was suggested by echocardiography, then later confirmed at necropsy. The electrocardiographic findings common to all cases were sinus tachycardia, right axis deviation (between −178 and −137 degrees); and a QRS complex of a QS variety, with an average amplitude of −0.7 mV and a mean duration of 0.06 second in lead II. These findings were not diagnostic of endocarditis.
Identification and Epidemiologic Significance of Nematodes in a Dairy Barn
Authors: Herd R. P. , Riedel R. M. , Heider L. E.
Published: February 2025

In a study on nematodes recovered from dairy barn mangers, stalls, calf pens, and exercise yards at The Ohio State University, over 99% of the nematodes were nonparasitic species of the family Rhabditidae. The only parasitic species recovered was Strongyloides sp, a rhabditoid nematode of minor clinical importance to adult cattle. These findings were in disagreement with widely publicized claims that adult dairy cattle in confinement are continuously exposed to trichostrongylids and that all cows should be routinely treated with anthelmintics.
Evaluation for Immune System Failures in Horses and Ponies
Authors: Perryman Lance E. , McGuire Travis C.
Published: February 2025

Between January 1973 and September 1979, 2,092 horses and ponies were evaluated for immunologic disorders. A total of 418 abnormalities were detected in 416 (20%) of the animals tested. Disorders encountered were failure or partial failure of colostral immunoglobulin transfer from mare to foal (228 cases), combined immunodeficiency (159 cases), selective immunoglobulin M deficiency (19 cases), agammaglobulinemia (3 cases), transient hypogammaglobulinemia (2 cases), and lymphosarcoma (7 cases).

Four conclusions were drawn from the study. (1) Immunologic abnormalities occur commonly in horses and ponies. (2) Failure and partial failure of passive transfer were the most common disorders, involving 19.7% of surveyed foals at risk. (3) Combined immunodeficiency remains a disease limited to Arabian horses. (4) Considering the high frequency of immunologic disorders in horses and the availability of diagnostic tests for the disorders, older animals with recurrent infections as well as all newborn foals should be evaluated for immune disorders.
Subepiglottic Cyst in Three Foals
Authors: Stick John A. , Boles Charles
Published: February 2025

Three foals with chronic cough, bilateral nasal discharge, and pneumonia were found to have a subepiglottic cyst as the inciting cause. Consistent findings were dysphagia and aspiration pneumonia, in addition to the abnormal respiratory noise usually found in the adult horse with a subepiglottic cyst. Histologic examination of the cysts suggested their origin was traumatic rather than embryonic.
Canine Tuberculosis
Authors: Liu Si-kwang , Weitzman Irene , Johnson Gerald G.
Published: February 2025

In a survey of 15,272 canine necropsies, natural infection with Mycobacterium tuberculosis was found to have been diagnosed in eight dogs (0.05%). Clinical findings were anorexia, loss of body weight, lethargy, vomiting, and leukocytosis; radiography revealed pleural and pericardial effusion, ascites, and hepatomegaly. Granulomatous lesions with acid-fast bacilli were consistently found. Mycobacterium tuberculosis was isolated from lesions in the lungs, liver, or lymph nodes of five dogs. All eight dogs had a history of contact with human patients with tuberculosis.
Evaluation of a Canine Adenovirus Type 2 Strain as a Replacement for Infectious Canine Hepatitis Vaccine
Authors: Bass E. P. , Gill M. A. , Beckenhauer W. H.
Published: February 2025

A modified live strain of canine adenovirus type 2 (CAV-2) was developed and evaluated as a replacement for infectious canine hepatitis (canine adenovirus type 1; CAV-1) vaccines. In a genetic stability test, the vaccine strain remained nonpathogenic through five back passages in dogs and when given by the intranasal route. Following necropsy of 16 vaccinated dogs, gross and microscopic lesions characteristic of CAV-2 infection were not observed. Results of virus isolation tests for various tissues from the same dogs were negative except for low viral infectivity titers for tonsillar tissue from two dogs and bronchial lymph nodes from one dog. Ninety seronegative dogs remained clinically normal following iv inoculation with the CAV-2 vaccine strain. Of 37 control dogs inoculated with a CAV-1 vaccine strain, 8 (21.6%) developed postvaccination ocular lesions. In an immunogenicity test, 20 vaccinated dogs remained clinically normal following CAV-1 challenge that killed all five susceptible control dogs. A second group of 20 vaccinates remained clinically normal following CAV-2 challenge that clinically affected all five susceptible control dogs. Postchallenge necropsy findings and results of virus isolation tests for tissues from the 40 vaccinates were negative. The vaccine strain (in various combinations with canine distemper and canine parainfluenza vaccine and Leptospira bacterin) was evaluated for safety in 19,323 dogs vaccinated by private practitioners. A total of 170 reactions, most of them minor and transient, were reported. Ocular lesions attributable to vaccination were not reported.
Diskospondylitis in Dogs
Authors: Kornegay Joe N. , Barber Don L.
Published: February 2025

During a 3-year period, diskospondylitis was diagnosed in 32 dogs. The condition affected primarily large dogs, with males outnumbering females by approximately 2:1. Diagnosis was made principally by evaluation of radiographs, wherein various degrees of vertebral lysis, sclerosis, and spondylosis were seen.

Evaluation of titers for Brucella canis and bacterial cultures of blood, urine, and bone were used to identify the causative organism(s). Six of 24 dogs were seropositive for B canis, 21 of 26 dogs were blood culture-positive, 10 of 23 dogs were urine culture-positive, and 9 of 11 dogs were bone culture-positive. Staphylococcus aureus was the most common organism identified by cultures of blood, urine, and bone.

Antibiotic therapy alone and in combination with vertebral curettage was used to treat dogs with minimal neurologic dysfunction. Dogs with severe neurologic deficits were treated with curettage, hemilaminectomy, vertebral immobilization, and antibiotics.

Follow-up information was available for 29 dogs. Twenty dogs were clinically normal after treatment. Five dogs were euthanatized because of the severity of neurologic dysfunction; three of these dogs were not treated, and two deteriorated despite treatment. Three dogs died while hospitalized, and one dog died after discharge.
Repair of Digital Flexor Tendon Lacerations in the Horse, Using Carbon Fiber Implants
Authors: Valdez H. , Clark R. G. , Hanselka D. V.
Published: February 2025

Flexible medical grade carbon fiber was surgically implanted in tenectomized or lacerated superficial and deep digital flexor tendons of 13 horses (7 clinical cases and 6 experimental), ranging in age from 15 months to 10 years and weighing 300 to 500 kg. The 6 experimental horses were euthanatized at 30-, 45-, 60-, and 90-day intervals for gross and histologic evaluation of the results. Three of the experimental horses served as their own controls. Of the 7 clinically affected horses, 3 were euthanatized because they developed laminitis or the wound failed to heal. The remaining 4 horses in that group were discharged; 3 returned to their previous activities, and 1 was unavailable for follow-up. Carbon fiber produced a structure of approximately the same size and function as a normal tendon. Histologically, the fibroblasts and collagen fibers organized and aligned themselves in the early stages of healing. The implants appeared grossly and histologically to produce a cosmetically acceptable, strong, and functional tendon.
Myocarditis Induced by Parvoviral Infection in Weanling Pups in the United States
Authors: Mulvey James J. , Bech-Nielsen Steen , Haskins Mark E. , Jezyk Peter F. , Taylor H. Wayne , Eugster A. Konrad
Published: February 2025

In a nationwide survey from January 1978 through September 1979, acute parvovirus-induced myocarditis was identified in 76 of 147 (52%) pups in 19 litters. The affected pups were from 12 states. Birth of all pups registered with the American Kennel Club during this period increased during the spring months, peaking in May, which was correlated in 4 to 8 weeks with the greatest number of cases in the study. Serologic data available for 4 dams, for 6 of their surviving pups, and for 3 contact pups indicated that all had been exposed to parvovirus. In 2 kennels, cases of acute myocarditis were preceded within 2 months by cases of severe gastroenteritis in older litters on the same premises.
Miracidia Hatching Technique for Diagnosis of Canine Schistosomiasis
Authors: Goff W. L. , Ronald N. C.
Published: February 2025

A method of processing feces with subsequent hatching of Heterobilharzia americana eggs was found to be preferable to saline sedimentation for the diagnosis of canine schistosomiasis. The feces were filtered and washed in 3 changes of 0.85% NaCl solution. The remaining sediment was flooded with distilled water to promote the hatching of viable eggs. Miracidia were subsequently observed, which confirmed infection in naturally infected raccoons and experimentally infected dogs.
A Pasteurella sp Associated with Respiratory Disease in Captive Desert Tortoises
Authors: Snipes K. P. , Biberstein E. L. , Fowler Μ. E.
Published: February 2025

Bacteria isolated from captive healthy desert tortoises were compared with bacteria from captive tortoises with respiratory illness and with bacteria from free-ranging tortoises from the Mojave Desert. Major differences were not observed among these groups when bacteria from the mouth, nares, trachea, lungs, and cloaca were compared.

Frequently encountered organisms in all 3 groups included: coagulase-negative, catalase-positive, gram-positive cocci; Corynebacterium sp; members of Enterobacteriaceae, including Proteus spp; and a bacterium apparently belonging to the genus Pasteurella. The Pasteurella sp was consistently found to be associated with respiratory lesions in captive tortoises with signs of respiratory disease but was also found to be part of the gastrointestinal and nasal flora of healthy tortoises. It was hypothesized that respiratory disease in captive desert tortoises involves a commensal bacterium with the potential to be an opportunistic pathogen when the tortoise is stressed by a captive environment.
Contagious Streptococcal Lymphadenitis in Cats
Authors: Swindle Μ. Μ. , Narayan O. , Luzarraga Μ. , Bobbie D. L.
Published: February 2025

A Lancefield group G β-hemolytic streptococcus was isolated from a group of laboratory cats with acute lymphadenitis of the head and neck and systemic signs of sepsis. The infection appeared to be transmitted by the oral route and was experimentally reproduced in cats after the isolant was inoculated by oral and subcutaneous routes.