bluuebunny/crossref_metadata_2025 huggingface dataset:
Canine and feline aural hematoma: Clinical, experimental, and clinicopathologic observations
Authors: Kuwahara Jiro
Published: February 2025

The pathogenesis of canine and feline aural hematoma (ah) was investigated. Clinical observations, selected experimental procedures, and clinicopathologic examinations were done on 40 dogs and 20 cats affected with ah. Eighteen healthy dogs and 14 healthy cats were used as the controls. The results of this investigation provide a valid basis for questioning the conventionally held view that ah is caused by trauma and for postulating that the actual cause is immune mediated.
Neutrophil depletion of calves with hydroxyurea: Methods and clinical and pathologic effects
Authors: Slocombe R. F. , Malark J. , Ingersoll R. , Derksen F. J. , Robinson N. E.
Published: February 2025

Twenty-six Holstein calves were treated with hydroxyurea in order to induce neutropenia. Calves were given a daily dosage of hydroxyurea (70 mg/kg of body weight) for 4 consecutive days, and clinical signs, blood leukograms, hemograms, and platelet counts were monitored daily until the calves became neutropenic. Once a neutropenic state was induced, the calves were anesthetized and pulmonary function tests were performed. Subsequently, calves were euthanatized and complete necropsies were performed. Hydroxyurea treatment induced profound neutropenia in all calves by 8 days after initiating treatment, with mild decreases in circulating numbers of lymphocytes. Treatment did not cause clinical or pulmonary functional abnormalities. Severe pathologic changes were restricted to the bone marrow and consisted of partial to complete destruction of myeloid elements, with less severe effects on erythrocytic precursors and megakaryocytes. Hydroxyurea was useful for the induction of neutropenic states in calves and did not induce major toxic effects on other cells when given at 70 mg/kg.
Identification of Mycobacterium bovis, using miniaturized thin-layer chromatography and morphologic characteristics
Authors: Jarnagin J. L. , Colgrove G. S.
Published: February 2025

Lipid analysis was performed on 204 isolates of mycobacteria, using miniaturized thin-layer chromatography (mtlc). A previously described lipid component was found in 92 (96.8%) of 95 isolates of Mycobacterium bovis and in 2 (1.8%) of 109 isolates of other mycobacteria. Using mtlc, an isolate could be identified as M bovis 3 to 4 weeks earlier than by use of conventional biochemical techniques. Examination of isolates for colonial and cellular morphologic characteristics was a useful adjunct in the identification of M bovis by use of mtlc.
Efficacy of ivermectin in a topical formulation against induced gastrointestinal and pulmonary nematode infections, and naturally acquired grubs and lice in cattle
Authors: Alva-Valdes R. , Wallace D. H. , Holste J. E. , Egerton J. R. , Cox J. L. , Wooden J. W. , Barrick R. A.
Published: February 2025

Efficacy of ivermectin in a topical formulation was evaluated in cattle against adult gastrointestinal and pulmonary nematode infections (experiment 1, n = 24 ), the 2nd- and 3rd-stage larvae of Hypoderma spp (experiment 2, n = 12), and the biting louse Damalinia bovis (experiment 3, n = 12). Nematode infections were induced and grubs and lice were naturally acquired. Treatments consisted of a single dose of ivermectin in a topical formulation of 200, 500, or 1,000 μg/kg of body weight in experiment 1 or 500 μg/kg in experiments 2 and 3.

At 1,000 μg/kg, ivermectin was 100% effective against Ostertagia ostertagi, Trichostrongylus colubriformis, Oesophagostomum radiatum, Nematodirus helvetianus, Haemonchus placei, and Dictyocaulus viviparus and was >99% effective against Cooperia oncophora, C punctata, and T axei. At 500 μg/kg, the efficacy was 100% against C oncophora, C punctata, O ostertagi, T axei, Oes radiatum, N helvetianus, Haem placei, and Dict viviparus and > 99% against T colubriformis. At 200 μg/kg, the efficacy was 100% against Oes radiatum, Haem placei, and Dict viviparus, > 99% for O ostertagi, 96% for C oncophora, 86% for C punctata, 90% for T axei, 85% for T colubriformis, and 71% for N helvetianus. At 500 μg/kg, ivermectin was highly effective against the grubs Hypoderma bovis and H lineatum and eliminated the louse Damalinia bovis.
Inoculation of pigs against Trichinella spiralis, using larval excretory-secretory antigens
Authors: Gamble H. R. , Murrell K. D. , Marti H. P.
Published: February 2025

Pigs were inoculated with Trichinella spiralis excretory-secretory products derived from short-term in vitro maintenance of infective muscle larvae. Intraperitoneal administration of excretory-secretory products in Freund’s complete adjuvant or aluminum hydroxide induced moderate, but variable, degrees of immunity to challenge exposure in a nondose-dependent manner; im administration of products in Freund’s incomplete adjuvant was less successful. Inoculated pigs harbored fewer adult worms, and the fecundity of female worms (numbers of newborn larvae shed in vitro) recovered after challenge exposure was significantly lower (α = 0.05) than the fecundity of females recovered from control pigs. The degree of resistance in inoculated pigs was directly related to serotiter against excretory-secretory antigens, as determined in an enzyme-linked immunosorbent assay.
Endotoxin-induced bovine mastitis: Immunoglobulins, phagocytosis, and effect of flunixin meglumine
Authors: Anderson K. L. , Smith A. R. , Shanks R. D. , Whitmore H. L. , Davis L. E. , Gustafsson B. K.
Published: February 2025

Milk whey immunoglobulins (Ig) and phagocytosis of staphylococci by milk polymorphonuclear neutrophilic leukocytes (pmn) were measured in 12 cows (allotted to 6 pairs) during acute bovine mastitis induced by intramammary inoculation of endotoxin. Six of these cows (or 1 in each pair) were treated with flunixin meglumine and were compared with the others (given only saline solution).

The endotoxin inoculation comprised 10 μg of Escherichia coli O26:B6 lipopolysaccharide injected into one of the rear quarters (mammae). Flunixin meglumine was administered parenterally at a dosage of 1.1 mg/kg every 8 hours (total of 7 doses) beginning at 2 hours after endotoxin was injected. Milk samples were obtained, and whey samples were prepared from each quarter of each cow 3 times before inoculation and at 2, 4, 8, 12, 24, 48, 72, 96, 120, 144, 168, and 336 hours after endotoxin was inoculated.

Significant increases (P < 0.05) in milk whey IgG1, IgG2, IgM, and IgA concentrations were observed in whey samples from endotoxin-inoculated quarters. Greatest relative increase was seen for IgG2. Increased whey Ig concentrations were not observed in quarters which were not inoculated with endotoxin. Concentrations of whey IgG1 and IgM in endotoxin-inoculated quarters were significantly (P < 0.05) decreased in flunixin meglumine-treated cows, compared with those in saline solution-treated cows.

Significant increases in phagocytosis of staphylococci by milk pmn were observed in whey samples from endotoxin-inoculated quarters. Significant differences in pmn phagocytosis were not found in whey samples from cows given flunixin meglumine when compared with whey samples from cows given saline solution.
Pulmonary function in dogs with mitral valve regurgitation
Authors: Miller Joan Ellen , Eyster George , DeYoung Bonnie , Milar Bobbi , Robinson N. Edward
Published: February 2025

Mitral valve regurgitation was created in 2 groups of dogs. Groups were selected on absence (group 1) or presence (group 2) of clinical signs of congestive left ventricular failure. Group-2 dogs, in which mean left atrial pressures were > 30 mm of Hg, had increases in heart rate, pulmonary arterial mean pressure, left atrial diameter, and left ventricular diastolic diameter. These changes were associated with decreased arterial O2 tension, decreased static and dynamic compliance, reduced lung volumes, and increased pulmonary resistance. Group-1 dogs, in which mean left atrial pressure was < 30 mm of Hg, had moderate changes in hemodynamics, but no changes in pulmonary function, except during exercise when arterial O2 tension decreased.
Endotoxin-induced changes in plasma concentrations of thromboxane and prostacyclin in neonatal calves given antiserum to a mutant Escherichia coli (J-5)
Authors: Morris Debra Deem , Bottoms Gerald D. , Whitlock R. H. , Johnson Martha A.
Published: February 2025

Plasma concentrations of the stable hydrolysis products of thromboxane (Tx) A2, TxB2, and prostacyclin (6-keto-prostaglandin F1α; pgf1α) were evaluated in 22 neonatal calves given endotoxin (0.5 μg/kg) by slow iv infusion over a 5-hour period. The effect of pretreatment with bovine antiserum to a mutant of Escherichia coli O111:B4 (J-5) on plasma concentrations of these eicosanoids was determined.

Plasma concentrations of TxB2 and 6-keto-pgf1α were increased in response to endotoxin infusion. The mean plasma concentrations of TxB2 peaked 1 hour after endotoxin infusion began and was significantly increased from base line through 8 hours. Mean plasma 6-keto-pgf1α concentration increased more slowly and was increased from base line only at 2 hours after endotoxin infusion began. Administration of bovine J-5 antiserum had no significant effect on endotoxin-induced thromboxane and prostacyclin production.
Restriction endonuclease patterns of bovine herpesvirus type 1 isolated from bovine mammary glands
Authors: Kennedy T. P. , Evermann J. F. , Cheevers W. P.
Published: February 2025

Restriction endonuclease analysis was used, in conjunction with viral neutralization and growth-curve experiments, to compare a bovine herpesvirus type 1 (bhv-1) isolate, originally obtained from bovine mammary gland lesions, with a standard bhv-1 strain, infectious bovine rhinotracheitis virus. Although differences were not detected by viral neutralization or growth-curve experiments, restriction fragment patterns generated by Bam HI, Eco RI, Hind III, and Hpa I, revealed definite differences between the isolate and the prototype strain. Additionally, Eco RI, Hind III, and Hpa I patterns revealed that the mammary gland isolate had DNA-fragment patterns characteristic of infectious pustular vulvovaginitis strain of bhv-1, type 2b. Seemingly, type-2b isolates, similar to types 1 and 2a, may be capable of causing divergent types of infection of variable severity in cattle.
Surface oximetry of healthy and ischemic equine intestine
Authors: Snyder Jack R. , Pascoe John R. , Holland Melissa , Kurpershoek Cornelis J.
Published: February 2025

Measurements of jejunal, ileal, and large colon (pelvic flexure) surface O2 tension (Pso2) were made in halothane-anesthetized horses with a nonheated miniature oxygen polarographic electrode. Assisted ventilation with 100% O2 was used to maintain Paco2 tension at 50 ± 8 mm of Hg while mean arterial blood pressure was maintained ≥70 mm of Hg. Mean ± sd Pso2 for the intestinal segments were: jejunum (horses 1 to 4), 71 ± 20 mm of Hg; ileum (horses 1 to 4), 61 ± 8 mm of Hg; and pelvic flexure of the large colon (horses 1 to 10), 55 ± 13 mm of Hg. The response of the sensor to intestinal ischemia was studied in the large colon of an additional 12 halothane-anesthetized horses, using 4 types of vascular occlusion: venous (4 horses); arterial and venous (4 horses); venous and intramural vascular obstruction (2 horses); and arterial, venous, and intramural obstruction (2 horses). Venous and arterial occlusions were maintained for 30, 60, 90, and 120 minutes, whereas intramural obstruction combined with either type of vascular obstruction was studied for 60 to 120 minutes. After vascular occlusion, Pso2 decreased to 8 ± 7 mm of Hg for venous obstruction, 4 ± 3 mm of Hg for arterial and venous obstruction, 6 ± 0 mm of Hg for intramural and venous obstruction, and 3 ± 0 mm of Hg after intramural and arterial and venous obstruction. Thirty minutes after release of the clamps, the Pso2 increased to ≥ 50% of the preoccluded large colon value. Vascular obstruction produced variable gross changes in the appearance of the large colon, including altered serosal color, swelling of the intestinal wall, and leakage of serum from the serosal surface. Seemingly, surface oximetry could be used to detect intestinal ischemia and may be useful for determining intestinal viability.
Instrumental neutron-activation analysis of canine urinary calculi for some selected elements
Authors: Zinn Kurt R. , Glascock Michael D. , Schmidt Donald A.
Published: February 2025

Thirty canine urinary calculi, most of which had been qualitatively classified as struvite calculi, were analyzed by instrumental neutron activation analysis at the University of Missouri Research Reactor. Measurements of sodium, magnesium, aluminum, silicon, phosphorus, chloride, potassium, and calcium were possible, using a dual irradiation procedure. Magnesium was used to calculate the percentage of struvite mineral, Mg(NH4) (PO4)-6H2O, in the calculi by making use of the stoichiometric relationship of the element magnesium to the mineral. For those calculi containing greater than 80% struvite, the mean elemental concentrations were found to be 0.12% Na, 9.35% Mg, 0.0033% Al, 12.1% P, 0.02% Cl, 0.85% K, and 2.05% Ca.

A new method for determination of silicon in urinary calculi also was discussed. Two calculi were found to contain 45.0% and 37.3% silicon, and 1 mixed calculus was composed of 1.4% silicon.
Endotoxemia in neonatal calves given antiserum to a mutant Escherichia coli (J-5)
Authors: Morris Debra Deem , Cullor James S. , Whitlock Robert H. , Wickstrom Mark , Corbeil Lynette B.
Published: February 2025

Endotoxemia was characterized in neonatal calves given a small amount of colostrum and smooth Escherichia coli endotoxin by small-dosage (0.5 μg/kg of body weight), slow (5-hour) iv infusion to mimic natural conditions. Responses were compared among 22 calves freely allotted to groups treated with saline solution (group I), preimmunization plasma (pp, group II), or antiserum to the rough mutant of E coli O111:B4 (J-5, group III) before endotoxin was infused. Bovine J-5 antiserum was produced by immunization of 4 cattle with J-5 boiled cell bacterin. The antiserum titers of immunoglobulin (Ig) M, IgG1, and IgG2 to the J-5 boiled cells, as determined by enzyme-linked immunosorbent assay, were 240, 7,680, and 960, respectively. The pp had enzyme-linked immunosorbent assay titers to J-5 of 240, 480, and 60 of IgM, IgG1, and IgG2, respectively.

Endotoxemia in the 3 groups was characterized by significant (P < 0.05) time-related changes in rectal temperature, heart rate, respiratory rate, capillary refill time, oral mucous membranes, nose moistness, scleral injection, attitude, pcv, total plasma protein concentration, wbc count and differential, plasma glucose, and lactate concentrations. The only significant treatment effects on clinical or laboratory values were higher mean total plasma protein concentrations in groups II and III 10 to 30 hours after endotoxin infusion was started than that in group I and increasing mean most-severe attitude abnormality score in groups I, III, and II (P < 0.05).

The administration of bovine J-5 antiserum to neonatal calves resulted in significantly higher serum IgG1 and IgG2 titers to J-5 boiled cells (P < 0.05), and cross-reactive IgG2 to the challenge endotoxin (P < 0.01) than did treatment with pp or saline solution; however, this antiserum did not mitigate the effects of sublethal endotoxemia. There was a significant negative correlation between IgG2 to J-5 at base line and the mean attitude abnormality score at 4.5 hours after infusion was started (P < 0.05).
Adherence of Bordetella avium to turkey tracheal mucosa: Effects of culture conditions
Authors: Arp Lawrence H.
Published: February 2025

Adherence of Bordetella avium to the tracheal mucosa of turkeys was evaluated, using bacteria grown under different culture conditions. Several solid and liquid media were used at incubation times of 12, 24, 36, or 48 hours with incubation temperatures of 18, 26.5, or 35 C. Adherence of B avium was greatest when the bacteria were grown on solid media at 35 C. Use of Bordet-Gengou or brain-heart infusion agar was associated with significantly greater (P < 0.05) adherence compared with adherence of bacteria grown on other media. Adherence was greatest, using cultures in the stationary phase of growth; however, with some media, adherence diminished when incubation was extended beyond 36 hours. Adherence of B avium was reduced but not completely prevented when cultures were incubated at 18 C.
Gnotobiotic calves: Derivation, maintenance, Thiry-Vella loop preparation, and ethylene oxide gas sterilization
Authors: Newman Louis E. , Whitehair C. K. , Mullaney Thomas P.
Published: February 2025

Twenty-four pregnant Holstein cows were used to develop techniques and procedures to obtain calves by hysterotomy and to maintain them in a closed gnotobiotic environment (sterile plastic-film isolators) for as long as 10 days for infectious disease research. Thiry-Vella loop preparation for obtaining intestinal loop secretions was done in a surgical isolator and was successful in 12 of 14 gnotobiotic calves. Ethylene oxide gas was effective in sterilizing heat-labile and moisture-sensitive instruments and equipment.
Evaluation of the repair process of cartilage defects of the equine third carpal bone with and without subchondral bone perforation
Authors: Vachon Anne , Bramlage Lawrence R. , Gabel Albert A. , Weisbrode S.
Published: February 2025

To determine the effect of subchondral bone drilling (forage) on the cartilage repair process after injury has occurred, a cartilage defect (1 cm in diameter) was created on the radial facet of the proximal surface of each third carpal bone in 6 adult horses. In one of the third carpal bones (right or left thoracic limb) of each horse, a 1-cm cartilage defect was created, and 5 holes (1 mm in diameter and 10 mm deep) were drilled through the subchondral bone into the cancellous bone. In the other thoracic limb, an identical defect was created, but not drilled. Analyses of cell numbers and types in the synovia and the mucin precipitate quality were done before, at 1 week after, and 3 weeks after surgical manipulation was done and showed no significant difference between the joint environment of drilled carpi and those of nondrilled carpi.

At 21 weeks after surgical manipulation was done, each joint was examined radiographically, macroscopically, and microscopically to compare the condition of the joints and the state of repair of the cartilage in each defect.

The amount of surface of the defect covered by the dense fibrous and fibrocartilagenous repair tissue and the thickness of the repair tissue were significantly greater (P < 0.05 and P < 0.01, respectively) in the drilled carpal bones. In addition, the attachment of the repair tissue to underlying chondro-osseous tissue was better in the drilled carpal bones. Fibrocartilage was resurfacing the drilled defects, whereas only fibrous tissue was present in the nondrilled defects. Drilling through the subchondral plate into the cancellous bone did not promote osteoarthritis, as determined in comparative examinations of drilled and nondrilled joints. It was concluded that drilling through the subchondral bone plate into the cancellous bone improves the healing of cartilage defects of the third carpal bones in horses and has no identifiable adverse effects on the joint.
Systematic identification of endobronchial anatomy during bronchoscopy in the dog
Authors: Amis Terence C. , McKiernan Brendan C.
Published: February 2025

The endobronchial anatomy of 10 inflated, air-dried, canine lungs and 8 healthy anesthetized, sternally recumbent, mixed-breed dogs was evaluated, using a flexible fiberoptic bronchoscope. On the basis of the order of branching of lobar and segmental bronchi observed in these lungs, a nomenclature system was devised to systematically identify individual lobar, segmental, and subsegmental bronchi during bronchoscopy in the dog.
Pedigree analysis of Abyssinian cats with familial amyloidosis
Authors: DiBartola Stephen P. , Hill Ronald L. , Fechheimer Nathan S. , Powers Jean D.
Published: February 2025

Pedigrees of 62 Abyssinian cats with familial amyloidosis were compared with those of 100 Abyssinian cats registered with the Cat Fanciers Association. The inbreeding coefficients of the 2 samples of cats were not significantly different. Analysis of the pedigrees with respect to specific ancestors, however, showed that certain cats were significantly more common in the pedigrees of affected cats than in those of cats in the randomly selected sample. These data support a genetic basis for this disease, but do not allow determination of the mode of inheritance.
Blood lead concentrations in rabbits
Authors: Gerken Diane F. , Swartout Margaret S.
Published: February 2025

Blood lead concentrations in 68 healthy rabbits from laboratory (n = 15), meat production (n = 45), and home environments (n = 8) were determined. The median blood lead concentration of this heterogeneous population was 8 μg/dl (range = 2 to 27 μg/dl).
Effect of sulfadimethoxine-ormetoprim in the treatment of calves with induced Pasteurella pneumonia
Authors: Ames T. R. , Casagranda C. L. , Werdin R. E. , Hanson L. J.
Published: February 2025

The efficacy of sulfadimethoxine (sdm)-ormetoprim (omp) was evaluated in calves with induced Pasteurella pneumonia. A dose-titration study comparing 3 doses of sdm-omp was performed to determine the optimal dose. Treatments included: group 1—nontreated controls; group 2—33 mg of sdm-omp/kg of body weight, orally on day 1 and 17 mg/kg on days 2 to 5; group 3—66 mg of sdm-omp/kg, orally on day 1 and 33 mg/kg on days 2 to 5; group 4—99 mg of sdm-omp/kg, orally on day 1 and 50 mg/kg on days 2 to 5; and group 5—11 mg of oxytetracycline/kg, iv daily for 4 days. Group-2 calves responded to treatment as well as did group-5 calves. Group-4 calves responded the same as did group-3 calves. However, group-2 calves did not respond as well as did groups 3, 4, and 5 calves.
Anthelmintic effect of levamisole hydrochloride or ivermectin on tissue toxocariasis of mice
Authors: Carrillo Martha , Barriga Omar O.
Published: February 2025

Paranatal transmission of Toxocara canis infection could be prevented in pups if an effective drug were administered to pregnant bitches. This drug also could eliminate the larvae in dogs that have been experimentally infected repeatedly to produce protective immunity. For these reasons, we assayed the effect of 2 doses of levamisole hydrochloride or ivermectin on T canis larvae.

Mice (5 groups) were infected with 1,000 infective T canis larvae and then treated with 2 different dosages of levamisole hydrochloride (6 mg/kg or 12 mg/kg, given subcutaneously), 2 different dosages of ivermectin (0.2 mg/kg or 0.4 mg/kg, given im) or 0.15M NaCl (given subcutaneously) once a day from days 15 to 28 of infection. On day 33 of infection, the parasites in liver, lungs, brain, and carcass were obtained and compared between groups. The smaller dosage of levamisole hydrochloride (6 mg/kg) significantly decreased only carcass parasitism to 17% of that in the controls, but did not affect significantly the total parasite load. The larger dosage of levamisole hydrochloride (12 mg/kg) decreased the infection in all organs, but particularly in carcass and brain; total parasitism was only 36% of that in the controls. The smaller dosage of ivermectin (0.2 mg/kg) significantly increased the number of larvae in the lungs to 550% of that in the controls, but it did not significantly affect the total parasite load. The larger dosage of ivermectin (0.4 mg/kg) significantly decreased only brain parasitism, but liver and total parasitism were decreased to 40% and 57%, respectively, compared with that in the controls. These drugs were ineffective in eradicating the parasite in the tissues, but levamisole hydrochloride at a dosage of 12 mg/kg may be useful in symptomatic infections.
Smooth muscle inhibition by an extract of Sesbania drummondii
Authors: Venugopalan C. S. , O'Malley N. A. , Marceau-Day M. L. , Flory W.
Published: February 2025

The acute effects of an extract of Sesbania drummondii were assessed in vitro on the smooth muscle contractility of intestine and lung parenchyma in the chicken and aortic arch in the rat. Dose-response contraction curves for histamine, carbachol, and norepinephrine were obtained in the ileal, parenchymal, and aortic strips, respectively. After washing was completed, the strips returned to baseline tensions and then were incubated for 10 minutes with an ethyl acetate extraction fraction of S drummondii (molecular weight < 500). Dose-response curves to the same agonists were repeated at the end of the incubation period.

Contractile responsiveness of chicken ileum was little affected by acute incubation of the tissue with the extract. Comparison with the great inhibition of in vitro ileal contractility seen previously in chickens with chronic toxicosis indicated that intestinal inhibition was not due to acute effects of sesbania, but required time for a toxic metabolite to be formed or for damage to occur from affected vasculature. Contractile responsiveness of chicken lung parenchyma to histamine (10−5M and 10−4M) was significantly decreased, as was rat aortic responsiveness to norepinephrine (10−7M to 10−4M). Responses in parenchyma were not as greatly inhibited as those in tissue from animals with chronic toxicosis. Greatest inhibition of contractility was seen in the vascular strips, indicating that vascular inhibition has a role in pathologic changes. To test the vasculature inhibition effect in vivo, anesthetized, catheterized rats were given 100-μ.l aliquots of dilutions of the extract, iv. Dose-response decreases in mean arterial pressure were observed, which lasted 9 to 10 minutes in some rats. The results of the present study indicate that acute effects of the toxic principle of Sdrummondii on vascular smooth muscle may precede the observed effects of chronic toxicity on lung and intestinal tissues.
Single- and repeat-dose pharmacokinetic studies of chloramphenicol in horses: Values and limitations of pharmacokinetic studies in predicting dosage regimens
Authors: Varma K. J. , Powers T. E. , Powers J. D.
Published: February 2025

A single-dose pharmacokinetic study of chloramphenicol in propylene glycol was done in 6 horses after 22 mg/ kg was administered iv. Serum drug concentrations obtained at various predetermined intervals were determined by an electroncapture gas-chromatographic technique. The time-concentration data were described by a 2-compartment open model, and various pharmacokinetic variables were estimated. The median elimination rate constant was estimated to be -0.0185 minute-1 ( -0.0225 to -0.0148 minute-1), and the median half-life was 37.36 minutes (30.74 to 46.90 minutes). The median apparent volume of distribution and total body clearance were 1.46 L/kg (1.13 to 1.60 L/kg) and 25.56 ml/kg/min (23.66 to 32.21 ml/kg/min), respectively.

On the basis of these data, single- and repeat-dose kinetic studies were done in another group of 6 animals. The drug was administered at a dosage of 22 mg/kg every 4 hours for 3 days. Blood samples were obtained for pharmacokinetic studies after the first and the last doses were given.

The half-life, volume of distribution, and total body clearance did not change significantly (Wilcoxon signed rank test) after 3 days of therapy with chloramphenicol. The iv dose schedule for treating bacterial infections with organisms of different sensitivities has been determined from the estimates of the pharmacokinetic variables. The limitations of calculating the dose schedules for chloramphenicol on the basis of pharmacokinetic variables in horses are discussed.
Evaluation of γ-glutamyl transpeptidase-to-creatinine ratio from spot samples of urine supernatant, as an indicator of urinary enzyme excretion in dogs
Authors: Gossett K. A. , Turnwald G. H. , Kearney M. T. , Greco D. S. , Cleghorn B.
Published: February 2025

γ-Glutamyl transpeptidase activity was measured accurately in canine urine supernatant without gel filtration and was relatively stable at 4 C for at least 4 days after collection. The urinary γ-glutamyl transpeptidase-to-creatinine ratio in spot samples was simple and quick to measure and was correlated with the 24-hour enzyme excretion. However, the usefulness of this ratio may be limited by within-day variation, and a questionable theoretical basis for its validity.
Experimentally induced ovine border disease: Extensive hypomyelination with minimal viral antigen in neonatal spinal cord
Authors: Anderson Charles A. , Sawyer Mary , Higgins Robert J. , East Nancy , Osburn Bennie I.
Published: February 2025

Border disease (bd) was experimentally induced in 9 lambs by inoculation of their dams with the BD-31 strain of border disease virus (bdv) at 50 days of gestation. These ewes developed serum-neutralizing antibody titers to bdv. The diagnosis of bd in their lambs was confirmed by hairy birthcoats, intrauterine growth retardation, tremors, and hypomyelination. Three clinically healthy age-matched control lambs, whose dams had been given an inoculum containing only bdv-free cell culture supernatant, were studied in parallel. There were significant differences in birth weights and in the lengths of the right tibiae and radii between the affected and the control lambs. There was a gradient in severity of clinical neurologic signs among the affected lambs, which directly correlated with the severity of hypomyelination in their spinal cords. However, the difference in severity of the neurologic deficits did not correlate with differences either in the pre-colostral serum-neutralizing antibody titers to bdv in these lambs or in the number of bdv antigen-containing cells in their spinal cords. Only approximately 0.01% to 0.3% of spinal cord cells, both in gray matter and white matter, were bdv antigen positive in the affected lambs. These results indicate that extensive infection of CNS cells with their subsequent destruction or functional alteration may not be a critical part of the pathogenesis of the hypomyelination in bd.
Effects of Bordetella avium infection on the pulmonary clearance of Escherichia coli in turkeys
Authors: Van Alstine W. G. , Arp L. H.
Published: February 2025

Thirty-six 1-day-old turkeys were inoculated intranasally with Bordetella avium (ba) strain 838. Noninoculated hatchmates (n = 36) were housed separately. At 2 and 4 weeks of age, 15 inoculated (ba+) and 15 noninoculated (ba-) turkeys were exposed to an aerosol of virulent Escherichia coli. The remaining six ba+ turkeys and six ba-turkeys were used as controls (ie, not exposed to E coli). Turkeys were necropsied on postaerosolization days 0 (immediately after aerosolization), 1, 3, 5, and 7. Lung and tracheal specimens were collected from each turkey for bacterial quantitation and histologic examination. A 1-ml blood sample was collected for detection of bacteremia. Numbers of E coli in lung specimens from 2- and 4-week-old turkeys were not significantly different between ba+ and ba- groups (pooled data over time); however, numbers of E coli isolated from tracheal specimens were significantly greater in ba+ turkeys than those in ba- turkeys. Although the incidence of pulmonary abcesses and E coli bacteremia was greater in 2-week-old turkeys than in 4-week-old turkeys, the incidence was not different between ba+ and ba- turkeys. At both ages, air sacculitis developed more often and was more severe in ba+ turkeys than in ba- turkeys. Hyperplastic bronchus-associated lymphoid tissue was found more often in ba+ turkeys than in ba- turkeys and appeared to be the first site of heterophil infiltration after E coli aerosolization.
Frequency and significance of feline leukemia virus infection in necropsied cats
Authors: Reinacher Manfred , Theilen Gordon
Published: February 2025

Feline leukemia virus (FeLV) infection was diagnosed immunohistologically on paraffin-embedded tissues obtained from 1,095 necropsied cats. Significant association of FeLV infection was demonstrated by χ2 and Fisher's tests with various conditions and diseases (ie, anemia, tumors of the leukemia/lymphoma complex, feline infectious peritonitis, bacterial infections, emaciation, FeLV-associated enteritis, lymphatic hyperplasia, and hemorrhage). Unexpected findings associated with FeLV infection were icterus, several types of hepatitis, and liver degeneration. A negative association with FeLV infection was found for most parasitic and viral infections, including feline panleukopenia. Neither positive nor negative associations were established for FeLV infection and most forms of nephritis, including severe glomerulonephritis. Feline leukemia virus-infected cats were significantly (Kruskal-Wallis test) older than were FeLV-negative cats with the same nonneoplastic FeLV-associated diseases.
Oxytocin precipitation of prostaglandin-induced farrowing in swine: Determination of the optimal dose of oxytocin and optimal interval between prostaglandin F2α and oxytocin
Authors: Dial G. D. , Almond G. W. , Hilley H. D. , Repasky R. R. , Hagan J.
Published: February 2025

The influence of dose of oxytocin and the interval between prostaglandin (pg) F2α and oxytocin administration on the synchrony of farrowing, the prevalence of intrapartum complications, and the number of pigs dying perinatally was investigated. In study 1, sows were given 10 mg of pgf2α im on day 112, 113, or 114 of gestation or were not treated. Twenty hours after pgf2α administration, sows were given 0, 5,10,20, or 30 USP U of oxytocin im. Sows treated with pgf2α or pgf2α plus oxytocin had a shorter interval to farrowing than sows not treated or treated with oxytocin alone. Treatment with pgf2α plus 30 U of oxytocin induced the most rapid onset and the greatest synchrony of farrowing, with the mean onset occurring 2.1 ± 0.4 hours after oxytocin vs > 8 hours for all other treatments. Sows treated with 5 or 10 U of oxytocin had a delayed onset and a less synchronous farrowing, compared with sows treated with 0 or 20 U. Day of pgf2α treatment influenced (P < 0.05) the interval from oxytocin to onset of farrowing. As day during gestation decreased, there was a corresponding decrease in the interval between oxytocin administration and farrowing. Number of interventions to remove retained pigs was not influenced (P > 0.05) by day of pgf2α administration. All sows treated with pgf2α followed by oxytocin had a higher rate of manual interventions, compared with that in sows given pgf2α but not oxytocin. The rate of intervention increased from ≤ 0.10 interventions/sow in sows not treated with pgf2α or oxytocin to 1.9 interventions/sow for sows given pgf2α plus 30 U of oxytocin.

In study 2, sows were given 20 U of oxytocin 16, 20, or 24 hours after pgf2α administration. Time of treatment with oxytocin had no influence on the interval to farrowing. Treatment with oxytocin at 16 hours resulted in the highest prevalence of interventions. Seemingly, doses of oxytocin after pgf2α treatment, which induced the highest synchrony and the most rapid onset of farrowing, also had the highest requirement for manual intervention. The optimal time to administer oxytocin after pgf2α appeared to be 24 hours.
Comparative analgesia of xylazine, xylazine/morphine, xylazine/butorphanol, and xylazine/nalbuphine in the horse, using dental dolorimetry
Authors: Brunson David B. , Majors Lynda J.
Published: February 2025

Xylazine, morphine, butorphanol, and nalbuphine were evaluated in 5 adult male horses, using dental dolorimetry. Comparisons were made at 30, 60, and 100 minutes after iv drug administration. Peak analgesia and the time to develop peak analgesia also were compared. Xylazine induced a marked increase in the tooth pulp pain threshold measurements as did the xylazine/narcotic combinations. Statistical differences were not detectable between these treatments. Xylazine and xylazine/butorphanol were better analgesics than was butorphanol alone at 30 and 60 minutes. Xylazine resulted in peak analgesia faster than did butorphanol or the combination of xylazine/butorphanol. Additive analgesic effects were not detected with the combined treatments.
An antegrade surgical uterine flush technique for ova collection in the ewe
Authors: Smith C. L. , Murphy C. A.
Published: February 2025

A surgical uterine flush technique was evaluated for percentage of ova/corpora lutea (cl) collected and development of reproductive adhesions in 79 superovulated ewes. The median collection rate for ova/cl was 70%, and 47 of 79 ewes had ≥ 67% ova/cl. At 50 to 80 days after uterine flushing, celiotomies were performed on 50 of the 79 ewes to evaluate the reproductive tract for adhesions. Adhesions of the reproductive tract were not found. Thirty ewes were given prostaglandin F2α, were mated, and became pregnant. The ova collection rates were comparable with rates reported in ewes in which oviductal flush methods were used; however, adhesions did not develop and reproductive function was maintained after surgery.
Effect of vehicular volume on the early pulmonary injury and inflammatory response in rats inoculated intratracheally with silica
Authors: Lopez Alfonso , Yong Shirley , Sharma Arvind , Prior Michael
Published: February 2025

The effect of vehicular saline solution volume on early lesions induced in rats by intratracheal administration of silica was evaluated. Seventy-two male Long-Evans rats were randomly assigned 6 each to 12 factorial groups (3 × 2 × 2): 3 doses of silica (0, 2.5, and 5 mg), 2 volumes of vehicle (saline solution; 0.1 and 0.5 ml), and 2 postinoculation times (1 and 3 days). Lactate dehydrogenase and alkaline phosphatase activities in the bronchoalveolar lavage fluid supernatant and cell viability of bronchoalveolar cells were used as indicators of cell injury. The number of pulmonary alveolar macrophages and polymorphonuclear leukocytes were used as indicators of inflammatory response.

Dose of silica and postinoculation time had a significant (P < 0.05) effect on the biochemical and cellular composition of lavage fluid. The volume of vehicle in which silica was suspended significantly (P < 0.05) enhanced the pulmonary injury and inflammatory response. However, dose-volume interaction was only significant (P < 0.05) in 1 of 6 parameters, indicating that the effect was additive, but not synergistic, in nature. Seemingly, vehicle volume had an enhanced effect on the injury and the inflammatory response induced by intratracheal inoculation of silica.
Peripheral metabolism of thyroid hormones and iodide in healthy and hyperthyroid cats
Authors: Broome Michael R. , Hays Marguerite T. , Turrel Jane M.
Published: February 2025

The metabolic clearance rate, volume of distribution, and fractional clearance rate of thyroxine (T4), triiodothyronine (T3), and iodide were calculated for 6 healthy and 7 hyperthyroid cats, using single-compartmental and noncompartmental methods of analysis. The mean T4 volume of distribution of the hyperthyroid cats was 32.0% less than that of the healthy cats; it was the only variable that was significantly different (P < 0.05) between these 2 groups of cats. The mean fractional clearance rate of T4 in the hyperthyroid cats was 53.2% greater than that in the healthy cats, but this difference was not significant. Hyperthyroid cats had no significant differences in T3 or iodide kinetic variables when compared with those in healthy cats. Single-compartmental analysis significantly overestimated T4 kinetic variables of healthy cats and T4, T3, and iodide kinetic variables of hyperthyroid cats when compared with the noncompartmental method of analysis.
Bovine postparturient hemoglobinemia: Hypophosphatemia and metabolic disorder in red blood cells
Authors: Ogawa Eri , Kobayashi Kosaku , Yoshiura Nobuyuki , Mukai Jun
Published: February 2025

Mechanism of hemolysis in postparturient hemoglobinemia was studied in 7 cows. Cows 1 to 5 had a history of hemoglobinemia at a previous calving, but hemoglobinemia did not occur during the present parturition. Cow 6, a daughter of cow 4, and cow 7 from another farm, developed postparturient hemoglobinemia and had hemoglobinuria on days 20 and 21 and 10 to 17 after calving, respectively. During the time cows 6 and 7 had hemoglobinuria, both cows had a marked decrease in serum inorganic phosphorus, rbc adenosine 5'-triphosphate (atp), and reduced glutathione, and a significant (P < 0.01) increase in methemoglobin concentration. In cow 6, these changes were observed before the onset of hemoglobinuria, indicating metabolic disorder of rbc. After phosphate administration iv, serum inorganic phosphorus was corrected, and rbc atp was increased above base-line value. During the time cows 6 and 7 had hemoglobinuria, pcv, hemoglobin concentration, and rbc count decreased progressively and reached nadir values, 40% to 50% of baseline values, on day 22 in cow 6 and on day 19 in cow 7. Cows 6 and 7 were anemic, even after serum inorganic phosphorus and rbc atp values returned to acceptable values. Glycolytic disorder and depletion of atp, resulting from phosphorus deficiency, appeared to be a primary and essential step leading to hemolysis in postparturient hemoglobinemia in cows 6 and 7.
Intravenous administration of lenperone and glycopyrrolate followed by continuous infusion of sufentanil in dogs: Cardiovascular effects
Authors: Benson G. J. , Thurmon J. C. , Tranquilli W. J. , Corbin J. E.
Published: February 2025

Cardiopulmonary effects of iv administration of lenperone (0.44 mg/kg) and glycopyrrolate (0.011 mg/kg) were determined in 6 healthy adult (2 to 5 years) Pointers during controlled ventilation with oxygen. Sufentanil was then administered as a loading dose (5 μg/kg, iv) and continually infused (0.1 μg/kg/min) for 120 minutes. Lenperone-glycopyrrolate did not significantly affect heart rate, but induced a significant decrease in systemic vascular resistance, rate-pressure product, and mean arterial pressure, and significantly increased cardiac index. Administration of sufentanil did not significantly affect mean arterial pressure. Heart rate and rate-pressure product were significnatly decreased during sufentanil infusion. Systemic vascular resistance gradually increased during the 2-hour sufentanil infusion and was not significantly different from base-line values at end of study. Cardiac index was not significantly different from baseline values during sufentanil infusion, except at 90 and 120 minutes, when it was significantly less. As administered in the present study, lenperone, glycopyrrolate, and sufentanil are safe and efficacious in adult dogs.
Blue-green algae (Microcystis aeruginosa) hepatotoxicosis in dairy cows
Authors: Galey F. D. , Beasley V. R. , Carmichael W. W. , Kleppe G. , Hooser S. B. , Haschek W. M.
Published: February 2025

Twenty cows from a dairy herd consisting of 60 healthy, lactating Holsteins developed clinical signs of anorexia, mental derangement, dehydration, recumbency, and ruminal atony after ingesting water containing blue-green algae. Of the 20 cows, 9 died. The algal bloom, which developed in a stagnant pond during hot, dry weather, was identified as the cyanobacterium Microcystis aeruginosa, a potentially hepatotoxic algae. One week after the onset of toxicosis, affected cows seemed healthy, although liver-associated enzyme activities (alkaline phosphatase, γ-glutamyl transferase, aspartate transaminase, and lactate dehydrogenase) were increased.

Intraruminal administration of the intact wet bloom to a healthy 125-kg Angus heifer was followed by hepatic necrosis and death. The liver was large, friable, and gun-metal blue, with microscopically evident hepatocyte dissociation, degeneration, and necrosis. The ingesta of the heifer contained typical clumps of cells that were identified as M aeruginosa. The intraperitoneal administration of lyophilized cell material from that bloom to 18 mice caused marked hepatic enlargement. The intraperitoneal median lethal dose of the dried bloom was estimated to be 10 mg/kg of body weight. A cyclic peptide toxin purified from the algae seems to be similar structurally to toxins from other characterized hepatotoxic blooms of M aeruginosa.
Effects of acute pancreatitis on circulating lipids in dogs
Authors: Whitney Marlyn S. , Boon G. Daniel , Rebar Alan H. , Ford Richard B.
Published: February 2025

Effects of acute pancreatitis on circulating lipids in dogs were evaluated by comparing the serum cholesterol and triglyceride concentrations and plasma lipoprotein electrophoretic patterns of 4 dogs with experimentally induced pancreatitis (eip), 2 (healthy) sham-operated control (soc) dogs, and 4 dogs with naturally acquired pancreatitis (nap) with the concentrations and patterns of 23 healthy, nonoperated control (hnc) dogs. Blood samples were collected once from hnc dogs, 1 to 3 times during the course of the disease in dogs with nap, and prior to and at 6, 12, 24, 48, 72, and 96 hours after induction of pancreatitis in dogs with eip or after the sham operation in the soc dogs. The dogs with eip did not have turbid serum and did not develop hypercholesterolemia or hypertriglyceridemia. Three of the dogs with nap had turbid serum and hypertriglyceridemia, and 3 had hypercholesterolemia. The electrophoretic tracings of hnc dogs had predominant α-1 peaks and small β peaks; 2 of the hnc dogs also had small α-2 peaks. The tracings of dogs with eip were similar to those of hnc dogs until 48 to 72 hours after induction of pancreatitis, when dogs with eip developed increased β lipoproteins, decreased α-1 lipoproteins, and movement of lipoproteins into the α-2 zone. The tracings of soc dogs were similar to those of hnc dogs at all times. Compared with hnc dogs, dogs with nap all had increased β lipoproteins, and 2 had decreased a-2 lipoproteins. Two dogs with nap had additional lipoprotein alterations, unlike any seen in dogs with
Relationship of cheek tooth abrasion to fluoride-induced permanent incisor lesions in livestock
Authors: Shupe James L. , Christofferson Paul V. , Olson Arland E. , Allred Earl S. , Hurst Rex L.
Published: February 2025

Teeth from cattle, sheep, and horses that ingested various fluoride intakes and teeth from field studies of these species plus deer, elk, and bison were examined for abnormalities. Approximately 99,000 animals in 322 herds were examined for fluorosis. From field studies, 988 cattle of various ages and with different degrees of dental fluorosis were slaughtered and necropsied. The severity of fluoride-induced mottling, hypoplasia, and abnormal abrasion of paired permanent incisor teeth was correlated with abrasion of premolar and molar (cheek) teeth that form and mineralize at approximately the same age. Severe irregular wear of cheek teeth impaired mastication and resulted in poor utilization of feed and unthriftiness. Excessive amounts of fluoride during tooth formation and mineralization induce characteristic dental changes. Offspring from the fluoride-affected animals did not have discernible fluoride-induced lesions in the deciduous teeth.