bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of an enzyme-linked immunosorbent assay for occult dirofilariasis in a population of naturally exposed dogs
Authors: Scholtens Robert G. , Patton Sharon
Published: February 2025

Dogs seen at a veterinary teaching hospital were classified on the basis of their apparent exposure to filarial worms, and their sera were examined in an enzyme-linked immunosorbent assay test, using a Dirofilaria immitis-derived antigen. The geometric mean titers of 103 dogs varied from 30 (61 noninfected dogs) to 2,896 (in 8 dogs without microfilaremia, but with signs of occult dirofilariasis [respiratory insufficiency, radiographic evidence of pulmonary hypertension] and a history of possible exposure to the mosquito vectors of heartworms). The mean titer of 28 dogs with patent filarial infections was 122, slightly higher than the mean titer of 64 in 8 dogs with a history of previous heartworm infection. The titers of dogs with evidence suggestive of occult dirofilariasis were significantly higher (P = 0.05) than the mean titers of those without evidence of filarial infections, with patent filarial infections, or with a history of dirofilariasis.
Antigenic relationship between porcine and canine parvoviruses
Authors: Mengeling W. L. , Bunn T. O. , Paul P. S.
Published: February 2025

Porcine parvovirus and canine parvovirus were found to have a minor, reciprocal antigenic relationship. One or more common or similar antigens were demonstrated by serum-neutralization and hemagglutination-inhibition tests and immunofluorescence microscopy.
Effect of chlorpyrifos on Holstein steers and testosterone-treated Holstein bulls
Authors: Haas Paul J. , Buck William B. , Hixon James E. , Shanks Roger D. , Wagner William C. , Weston Patricia G. , Whitmore Howard L.
Published: February 2025

The effect of chlorpyrifos application was studied in a high-testosterone (testosterone-treated bulls) and a low-testosterone group (com oil-treated steers). Frequent sampling of blood before and after 2 chlorpyrifos applications was used to monitor plasma testosterone concentrations and blood cholinesterase activities.

Bulls had significantly higher testosterone concentrations (P < 0.01) than did the steers, before and after the 1st and 2nd chlorpyrifos applications. Bulls had higher cholinesterase activities (P < 0.01) than did steers before the 1st chlorpyrifos application. However, cholinesterase activity decreased more in bulls when compared with that in steers (P < 0.01) after the 1st and 2nd chlorpyrifos application. Abnormal clinical signs were not observed in the steers, but 2 of 4 bulls had severe clinical signs of organophosphorus insecticide toxicosis after the 2nd application. Seemingly, chlorpyrifos is more toxic for testosterone-treated bulls than for com oil-treated steers of similar age and weight.
Improved method for recovering ascarid and other helminth eggs from soil associated with epizootics and during survey studies
Authors: Kazacos Kevin R.
Published: February 2025

Two noncentrifugal and 5 centrifugal flotation methods for the recovery of infective Baylisascaris procyonis eggs from contaminated soil were evaluated after an epizootic of fatal cerebrospinal nematodiasis in bobwhites. All involved the use of inexpensive, readily available materials and routine procedures. In all but 1 of the methods, sizes of the soil samples were 30 g; in 1 centrifugal method, the sample size was 1 g. The centrifugal methods included various combinations of (i) anionic detergent (Tween) pretreatment of the soil, (ii) 3x washing of the sediment, (iii) NaNO3 or ZnSO4 flotation solution, and (iv) resuspension and reexamination of the sediment.

By the 30-g sample centrifugal methods, significantly more eggs (av 251 to 448) were recovered than by the noncentrifugal methods (av 7 and 12) or the 1-g sample method (av 44). In the most efficacious method, the combination of Tween pretreatment, washed sediment, NaNO3 flotation solution, and resuspension/reexamination of the sediment was used.

This method was tested against the 1-g sample method on soil from a naturally occurring infection of Toxocara cati visceral larva migrans in a child. On initial examination of 5 areas, 3 to 10 eggs were recovered by the 30-g sample method vs 0 eggs by the 1-g sample method. Using sandbox soil and 10 replicates each, recoveries by the 30-g sample method averaged 9.2 eggs/replicate (range 5 to 12) and those by the 1-g sample method, 0.1 eggs (range 0 to 1).
Genetic variation of bluetongue virus serotype 11 isolated from host (sheep) and vector (Culicoides variipennis) at the same site
Authors: Rao C. D. , Roy P.
Published: February 2025

Genetic relatedness of 2 strains of bluetongue virus (btv) serotype 11 that were isolated from the same geographic site—one from host (sheep) and the other from the vector Culicoides variipennis during an enzootic of bluetongue at Bruneau, Idaho, in August 1973—was determined by comparing the oligonucleotide fingerprint analyses of the individual double-stranded RNA segments of the genomes. It was observed that the 2 strains of btv-11 exhibit considerable differences in their genotypes, the percentage of diversity being different for each of the corresponding RNA species of the 2 strains of btv-11. These results indicate that more than one genotype of btv can circulate in juxtaposition in a given geographic site. The observed genotypic diversity might be due to the accumulation of point mutations on specific RNA species or antecedent reassortment of RNA segments between different btv in nature or both.
Sensitivity of equine herpesviruses 1 and 3 in vitro to a new nucleoside analogue, 9-[[2-hydroxy-1-(hydroxymethyl) ethoxy] methyl] guanine
Authors: Smith Kendall O. , Galloway Karen S. , Hodges Sherie L. , Ogilvie Kelvin K. , Radatus Bruno K. , Kalter Seymour S. , Heberling Richard L.
Published: February 2025

The following members of the Herpetoviridae family were tested to determine their sensitivities to the new antiviral drug, BIOLF-62: equine herpesvirus types 1 and 3, human herpesvirus types 1 and 2, swine herpesvirus, bovine herpesvirus type 4, feline herpesvirus, canine herpesvirus, and herpes simiae virus. Equine herpesviruses 1 and 3, human herpesviruses 1 and 2, and herpes simiae virus were all sensitive to BIOLF-62 at concentrations of less than 0.55 μg/ml. Equine herpesvirus types 1 and 3 were particularly sensitive, viral median effective dose (ed50) concentrations of the drug being only 0.033 and 0.16 μg/ml, respectively. Such high antiviral potency and low cell toxicity indicate that BIOLF-62 might be useful in the treatment of infected animals.
Pseudorabies virus, porcine parvovirus, and porcine enterovirus interactions with the zona pellucida of the porcine embryo
Authors: Bolin S. R. , Turek J. J. , Runnels L. J. , Gustafson D. P.
Published: February 2025

Porcine embryos (n = 93) were incubated on cell monolayers that had been previously inoculated with pseudorabies virus, porcine parvovirus (ppv), or each of 2 porcine enteroviruses. After 2, 24, or 48 hours of incubation, the embryos were fixed in glutaraldehyde and examined by electron microscopic procedures. It was found that pseudorabies virus adsorbed to the zona pellucida (zp) and entered sperm tracks in the zp. The ppv and both enteroviruses entered pores in the zp and were associated with sperm that were at or near the outer surface of the zp. In addition, ppv was seen enmeshed in cellular debris on the outer surface of the zp. Evidence of a productive viral infection of the blastomeres of the embryos was not found.
Accuracy of isoflurane delivery by halothane-specific vaporizers
Authors: Steffey E. P. , Woliner M. J. , Howland D.
Published: February 2025

The precision of isoflurane delivery from 4 vaporizers designed and calibrated for halothane was studied. Isoflurane concentration in oxygen (O2) was determined for various vaporizer dial settings (0 to maximum) and O2 flow rates (0.375 to 15 L/min). The effects on vaporizer output of time (settings constant for up to 15 minutes), ambient temperature (15, 22, 30 C), and conditions simulating intermittent positive-pressure ventilation were also studied. The performance of the 4 halothane-specific vaporizers with isoflurane was qualitatively similar and was within the range expected as normal accuracy for halothane delivery in these same vaporizers. At room temperature, isoflurane concentrations were generally greater than dialed percentages with low carrier gas flows and were less than dialed percentages at higher gas flows for most vaporizers.

The relationship of halothane output relative to isoflurane measured during similar conditions fits arithmetic coordinates well. Compared with concentrations of halothane, slightly higher concentrations of isoflurane were delivered from 3 halothane vaporizers studied (av 14%, 15%, and 8%). Temporal changes in delivered isoflurane concentration at room temperature were relatively small at low dial and carrier gas-flow rate settings. However, as gas-flow rate and vaporizer dial settings increased, vaporizer output decreased with time. Alterations in accuracy of isoflurane delivery by 1 vaporizer with temperature changes were most pronounced at the higher gas-flow rates, higher vaporizer dial settings, and lowest temperature. There was little effect of simulated positive-pressure breathing on vaporizer output at peak inspired circuit pressures < 12 mm of Hg. Use of halothane-specific vaporizers to deliver isoflurane has advantages and disadvantages which must be evaluated individually. The delivery of isoflurane by halothane-specific vaporizers is not recommended by anesthetic and vaporizer manufacturers.
Use of prostaglandin F2α in the treatment of unobserved estrus in lactating dairy cattle
Authors: Elmarimi A. A. , Gibson C. D. , Morrow D. , Marteniuk J. , Gerloff B. , Melancon J.
Published: February 2025

A field trial was conducted to evaluate the use of prostaglandin F2α (pgf2α) (lutalyse)a in lactating dairy cattle with unobserved estrus in the presence of a functional corpus luteum (cl) and clinically normal reproductive tract.

Seventy-three Holstein and 9 Jersey cows, weighing between 340.0 and 772.7 kg, were allotted to treatment and control groups. All treated cows were inseminated within 80 hours after treatment as assigned by this trial. Control cows were inseminated at the first observed estrus. Of the treated cows, 50% showed estrus within 80 hours after treatment.

In this trial, 96% of the treated cows and 92% of the control cows were determined to have at least 1 functional cl on the day of treatment. For the treatment group and the control group, mean serum progesterone concentrations were 4.1 ng and 3.5 ng (P < 0.2, by Student's t test), respectively, on day of treatment and were 0.4 ng and 5.0 ng (P < 0.005, by Student' t test) on day 5 after treatment. Pregnancy rates were 57% for treated and 47% for control cows (P = 0.5, by X2). Days from treatment to first-observed estrus, treatment to first service, and treatment to conception were significantly reduced in the treatment group compared with these criteria for the control group (P < 0.05, 0.005, and 0.01 respectively). It was concluded that induction of luteolysis with pgf2α in lactating dairy cattle with unobserved estrus and a palpable functional cl will be an effective addition to reproductive health programs.
Efficacy of fenbendazole against tapeworms in calves
Authors: Ciordia H. , Stuedemann J. A. , McCampbell H. C.
Published: February 2025

Forty-five commercial-grade Angus calves naturally infected with tapeworms (Moniezia sp) were used in 2 controlled experiments to evaluate the cestocidal efficacy of 3 dosage levels of fenbendazole, methyl-5-(phenylthio) -2-benzimidazolecarbamate. In the 1st trial, 15 calves were divided into 3 groups of 5 each. One group served as nonmedicated controls. Other groups were drenched with fenbendazole at dosage rates of 10 and 15 mg/kg of body weight. Thirty calves used in the 2nd experiment were divided into 3 equal groups. One group served as nonmedicated controls and the other 2 groups were drenched at dosage rates of 7.5 and 10 mg/kg. Calves were necropsied 13 days after treatment. Doses of 10 and 15 mg/kg were 100% efficacious in reducing the number of tapeworm scolices, and a dose of 7.5 mg/kg was 91.7% effective. Signs of toxicosis were not observed in medicated cattle from time of treatment to necropsy.
Observation of Rickettsia ruminantium in leukocytic cell cultures from heartwater-infected goats, sheep, and cattle
Authors: Sahu S. P. , Dardiri A. H. , Wool S. H.
Published: February 2025

Inclusion bodies of Rickettsia ruminantium, the causative agent of, heartwater, were demonstrated in leukocytic cell culture made from blood collected from Rickettsia-infected goats, sheep, and cattle. These were identified, using Giemsa and direct fluorescent antibody stains and transmission electron microscopy.
Enzyme-linked immunosorbent assay for the detection of antileptospiral antibodies in swine sera
Authors: Waltman W. Douglas , Dawe Donald L.
Published: February 2025

A genus-specific enzyme-linked immunosorbent assay (elisa) was applied to the detection of antileptospiral antibodies in swine sera. Results of the elisa directly correlated with the results of the microscopic agglutination test. The elisa had a sensitivity of 100%, specificity of 86.4%, and predictive accuracy of 91.3%. Because the elisa is a simple and extremely accurate test, it lends itself as a diagnostic screening test for large numbers of samples.
Phototoxic effect of Thamnosma texana (Dutchman's breeches) in sheep
Authors: Oertli E. H. , Rowe L. D. , Lovering S. L. , Ivie G. W. , Bailey E. M.
Published: February 2025

Oral exposure of sheep to the airdried, aerial portions of Thamnosma texana (Dutchman's breeches) resulted in severe photosensitization. Sheep fed the plant at 9 or 12 g/kg of body weight/day and held in direct sunlight exhibited signs of phototoxicosis within 24 to 48 hours. The clinical signs manifested were increased body temperature; photophobia; edema of the muzzle, ears, and vulva; keratoconjunctivitis with edema of the cornea; and exudative dermatitis of the skin of the ears, muzzle, and vulva. Lesser dosages of the plant produced similar effects after several days, except that corneal edema and opacity were not seen. Histopathologic studies indicated no hepatic lesions, consistent with primary photosensitization. The photosensitizing effects of T texana can be attributed to the presence of photosensitizing linear furocoumarins (psoralens) in the plant.
Inheritance of congenital cataracts and microphthalmia in the Miniature Schnauzer
Authors: Gelatt Kirk N. , Samuelson Don A. , Bauer John E. , Das Noveen D. , Wolf E. Daniel , Barrie Kathleen P. , Andresen Thomas L.
Published: February 2025

Congenital cataracts and microphthalmia in the Miniature Schnauzer were inherited as an autosomal recessive trait. Eighteen matings of affected × affected Miniature Schnauzers resulted in 87 offspring with congenital cataracts and microphthalmia (49 males/38 females). Two matings of congenital cataractous and microphthalmic Miniature Schnauzers (2 females) × a normal Miniature Schnauzer (1 male) yielded 11 clinically normal Miniature Schnauzers (7 males/4 females). Eighteen matings of congenital cataractous and microphthalmic Miniature Schnauzers (6 males) × carrier Miniature Schnauzers (9 females) produced 81 offspring; 39 exhibited congenital cataracts and microphthalmia (20 males/19 females) and 42 had clinically normal eyes (17 males/25 females).
Graft-vs-host response in Alcaligenes faecalis-infected turkey poults
Authors: McCorkle F. M. , Simmons D. G. , Luginbuhl G. H.
Published: February 2025

The ontogeny of graft-vs-host immune response for turkeys was studied. Splenic lymphocytes from young turkeys were capable of a response. The graft-vs-host response from Alcaligenes faecalis-infected turkeys was enhanced over noninfected turkeys.
Frequency and immunologic cross-reactivity of encapsulated Staphylococcus aureus in bovine milk in New York
Authors: Opdebeeck J. P. , Norcross N. L.
Published: February 2025

A total of 213 milk samples, which were positive by bacteriologic cultural examination for Staphylococcus aureus, were obtained from lactating cows on 55 farms throughout the dairying areas of New York. The S aureus isolates were evaluated for encapsulation directly from milk by the serum-soft agar technique. Results indicated that 93% of S aureus field isolates showed evidence of encapsulation on direct evaluation from milk. Suppression of capsule formation in vitro was seen in 72.7% of isolates when grown in the presence of 1% of anticapsular sera. One of the 3 anticapsular sera used exhibited a significantly higher level of cross-reactivity with the field isolates than did the 2 other sera. Increasing the concentrations of the antisera to 2% and 4% in the serum-soft agar had no effect on the expression of capsule in those isolates which had shown no evidence of capsule suppression with the specific antisera at the 1% level. Limited subculture of randomly selected encapsulated isolates on artificial media resulted in a decrease in the percentage of encapsulation from 100 to 33.3.
Canine cobalt cardiomyopathy: A model for the study of heart failure
Authors: Unverferth Donald V. , Croskery Richard W. , Leier Carl V. , Altschuld Ruth , Pipers Frank S. , Thomas James , Magorien Raymond D. , Hamlin Robert L.
Published: February 2025

The purpose in this study was to describe the canine cobalt cardiomyopathy model and the accompanying myocardial histologic features, metabolism, and central and regional hemodynamic properties. Six dogs were treated with cobalt sulfate (given iv) at a dose of 5 mg/kg/day to a cumulative dose of 150 ± 20 mg/kg; another 6 dogs were controls. Evaluation included study of echocardiograms and systolic-time intervals, and uses of cardiac catheterization to record dp/dt max and chamber pressures and of radiolabeled microspheres to determine cardiac output and regional flow distribution. Transmural biopsies of the left ventricle were analyzed for catecholamine concentration, adenine nucleotides, and percentage of fibrosis.

Compared with the control group, the cobalt-treated group developed tachycardia, increased ratio of preejection period to left ventricular ejection time, decreased dp/dt max, depressed angiographic ejection fraction, and decreased systemic pressures. There were no significant changes of cardiac index or left ventricular end diastolic pressure. Although total systemic resistance was less in the cobalt-treated dogs, there was redistribution of blood flow from midbrain, cerebral cortex, renal cortex, esophagus, and stomach to the pancreas and myocardium. Epicardial blood flow increased more than did endocardial flow, so that the ratio of endocardial-to-epicardial blood flows (1.40 ± 0.12 in the control group) was 1.14 ± 0.10 (P < 0.05) in the cobalt-treated dogs. The ratio of endocardial-to-epicardial adenosine triphosphate concentration was 1.24 ± 0.13 in the control group and depressed to 0.74 ± 0.16 (P < 0.05) in the treated dogs. The ratio of fibrosis in the endocardium and that in the epicardium was constant in the 2 groups. In addition, myocardial stores of norepinephrine were depleted in the cobalt-treated dogs, whereas urinary catecholamine concentrations were 3 times greater than those in the controls.
Blood pressure response to phenylephrine infusion in halothane-anesthetized dogs given acetylpromazine maleate
Authors: Ludders J. W. , Reitan J. A. , Martucci R. , Fung D. L. , Steffey E. P.
Published: February 2025

To quantitate acetylpromazine-induced α-adrenergic receptor blockade, phenylephrine was infused into dogs. The amount of phenylephrine necessary to increase the mean arterial blood pressure (map) 50% above base line, with or without the prior administration of acetylpromazine, served to quantify the degree of acetylpromazine-induced α-adrenergic receptor blockade.

Seven dogs were anesthetized with thiopental, maintained on halothane in oxygen, and mechanically ventilated. All infusions were made through a catheter in the cephalic vein. Continuous recordings were made of map and a lead II ecg.

After induction of anesthesia, instrumentation, and stabilization of heart rate, map, and ventilation, 6 group I dogs were infused with phenylephrine until a 50% increase in map was recorded (phenylephrine control). On subsequent research days, each dog was anesthetized, instrumented as described, and given (iv) 1 of 3 dosages of acetylpromazine in the following order—0.05, 0.125, and 0.25 mg/kg. The dose of phenylephrine necessary to increase map 50% in the presence of acetylpromazine was recorded.

Five group II dogs were studied as in group I, but each dog was given (im) atropine (0.04 mg/kg) before anesthetization. Two dosages of acetylpromazine were studied in the following order—0.05 and 0.25 mg/kg.

Group I dogs, when compared with their phenylephrine controls, were given significantly more phenylephrine to raise map 50% at each dose of acetylpromazine studied. The same trend was observed in group II dogs, but at smaller doses of phenylephrine, probably as a result of the positive chronotropic effect of atropine on the heart.
Congenital hypothyroidism in a dog due to an iodide organification defect
Authors: Chastain C. B. , McNeel S. V. , Graham C. L. , Pezzanite S. C.
Published: February 2025

A 10-month-old dwarfed male pup born of large-breed parents with normal stature had congenital goiter. Hypothyroidism due to failure to form organic iodine was diagnosed based on low serum thyroxine and triiodothyronine assays, radiographic findings in the epiphyses, and an abnormal perchlorate discharge test. Replacement of thyroid hormone resulted in more than 450% increase in body weight and a 600% increase in shoulder height over an 8-month period of treatment. A relapse in mental and physical condition occurred when hormone replacement therapy was later withdrawn. Postmortem findings are described.
Pulmonary thromboembolism during therapy of dirofilariasis with thiacetarsamide; Modification with aspirin or prednisolone
Authors: Keith James C. , Rawlings Clarence A. , Schaub Robert G.
Published: February 2025

The effects that 4 weeks of treatment of dirofilariainfected dogs with either aspirin or prednisolone had on the pulmonary thromboembolism which occurs after they are given thiacetarsamide were determined, using light and electron microscopies. Pulmonary lesions in control dogs at 4 weeks after thiacetarsamide was given were compared with lesions in dogs which were treated with either aspirin (22 mg/kg daily) or prednisolone (1 mg/kg daily) during the 4-week period after adulticide was given. Pulmonary vascular and perivascular lesions were most severe in the prednisolone-treated dogs and least severe in the aspirin-treated dogs. The aspirin-treated dogs had greater resolution of pulmonary arterial proliferative disease, and prednisolone-treated dogs had the lesser resolution.
Comparison of the microtitration agglutination test and the enzyme-linked immunosorbent assay for the detection of herds affected with swine dysentery
Authors: Egan Isabel Turney , Harris D L. , Joens L. A.
Published: February 2025

A method was designed to evaluate and compare the microtitration agglutination test (mat) and the enzyme-linked immunosorbent assay (elisa) to detect antibodies in swine sera to Treponema hyodysenteriae and thereby establish a method for determining the prevalence of swine dysentery (SD) in herds. According to sampling criteria based on the hypergeometric distribution, sera were collected from 3 age groups of swine from farms having a history of SD on the premises (SD+) recently or being free of the disease (SD-). The highest degree of test sensitivity was obtained when sera from market age swine were evaluated with the elisa. Of 14 SD+ herds from which sera were obtained from market-age swine, 13 were positive with the elisa (93%); none of the 8 SD-herds was positive.

The detection rates of individual swine in the SD+ herds for the 2 tests by age group were as follows: mat—adult swine 1.4%, market-age swine 6%, and weaned pigs 0.8%; elisa—adult swine 16%, market swine 31%, and weaned pigs 0.5%.
Flubendazole: Dose range and efficacy studies against common internal parasites of swine
Authors: Bradley R. E. , Guerrero Jorge , Becker H. N. , Michael B. F. , Newcomb Kathleen
Published: February 2025

The anthelmintic spectrum of activity and efficacy of flubendazole, using pigs naturally infected with helminth parasites, were determined in 4 experiments, using 157 pigs. Flubendazole (1.5 mg/kg of body weight) mixed in feed or top-dressed on feed for 5 consecutive days was highly effective as an anthelmintic. This dosage level indicated 100% efficacy against mature Ascaris suum, Oesophagostomum dentatum, Trichuris suis, and Metastrongylus apri. There was 88% efficacy against Strongyloides ransomi and 85% efficacy against Stephanurus dentatus and immature Ascaris suum. There was some activity against Globocephalus sp and Macracanthorhynchus hirudinaceus, but insufficient numbers of these parasites were present to make an accurate assessment.
Oxytetracycline concentrations in healthy and diseased calves
Authors: Ames Trevor R. , Larson Vaughn L. , Stowe Clarence M.
Published: February 2025

Pneumonia was induced in a group of calves that were then treated with oxytetracycline (otc). When the plasma pharmacokinetics and tissue concentrations of this group were compared with those of healthy controls, obvious differences were observed. The volume of distribution and the half-life of otc were increased in the group with pneumonia. Tissue concentrations of otc (1.48 ± 0.29 μg/ml) were greater in the lungs of calves with pneumonia than that in the lungs (1.09 ± 0.09 μg/ml) of healthy controls. For the dose of otc used, the correlation between serum concentration and tissue concentrations at 24 hours was poor. Seemingly, current concepts of antibiotic dosages and dosage intervals may be inadequate because they are based on blood and tissue values of healthy animals.
Anthelmintic efficacy of ivermectin against gastrointestinal nematodes in calves
Authors: Benz G. W. , Ernst J. V. , Crawley R. R.
Published: February 2025

Anthelmintic activities of ivermectin against induced gastrointestinal nematode infections of Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia oncophora, C punctata, and Oesophagostomum radiatum were evaluated in 6-month-old calves. In experiment 1, 10 group 1 calves were used as nonmedicated controls and other calves were given ivermectin (200 μg/kg of body weight, subcutaneously) when the nematodes were in the early 4th-larval stage (group 2, n = 10) or adult stage (group 3, n = 10). Group 1 control calves had a geometric mean of 20,037 nematodes at necropsy 7 or 8 days after treatment of the group 3 calves. In groups 2 and 3 calves, overall reductions of nematodes exceeded 99%. Overall reductions for each species and total reductions were highly significantly different (P < 0.01) from that in control calves. One group 2 calf died with severe esophagitis 9 days after treatment, apparently caused by the death of migrating Hypoderma larvae.

In experiment 2, group 4 calves (n = 8) were used as nonmedicated controls and other calves were given ivermectin (200 μg/kg orally) as a drench (group 5, n = 8) or as a paste (group 6, n = 8) when the nematodes were in the adult stage. Group 4 control calves had a geometric mean of 24,050 nematodes at necropsy 7 or 8 days after treatments. In group 5 and 6 calves, overall reductions of nematodes exceeded 99%. The overall reductions, as well as the reductions for each species, were highly significantly different (P < 0.01) from that in the control calves given either formulation. Significant differences were not found between formulations.
Long-term study of thyroid function in healthy Beagle dogs, using 125I
Authors: Wilson Ove , Stone J. M. , Monty D. E.
Published: February 2025

Maximum thyroid 125I uptake and thyroid 125I release rates were studied in 11 adult Beagles which were maintained in a controlled environment and fed a diet containing 240 to 480 mg of iodine, depending on the food intake of the individual dog. Maximum thyroid 125I uptake occurred 48 to 72 hours after the administration of the isotope, and ranged from 8.6 to 22.3% of the administered dose, with an average of 14.2 ± 4.9%. Thyroid 125I release was measured for up to 198 days. The uptake and release-rate curves were adequately described by a general 3 exponential model equation. The initial uptake phase was followed by a 2 exponential release-rate curve, containing rapid and slow exponential components. The B½ of the rapid release-rate exponential ranged from 8.6 to 13.8 days, with an average of 9.8 ± 2.5 days, while the slow release-rate exponential ranged from 33.7 to 52.1 days, with an average of 36.6 ± 6.3 days. The average B½ for 100 days, between days 3 and 103 after administration of the isotope, ranged from 15.5 to 23.8 days, with an average of 18.1 ± 2.6 days. Total plasma 125I (TP125I), protein-bound 125I (PB125I) and plasma 125iodide (P125I-) were measured for 50 to 70 days. The PB125I levels reached maximum in 48 to 72 hours and ranged from 0.27 to 1.27% of the administered dose/L plasma, with an average of 0.60 ± 0.32%. The B½ of PB125I ranged from 6 to 18 days, with an average of 10.7 days.

The study demonstrated the nonlinear form of the thyroid radioiodine release-rate curve in the dog, and the marked individual variation within littermate and nonlittermate dogs. Individual inconsistency in the maximum thyroid uptake was demonstrated by measurements repeated 8 to 12 months later, while the approximate time to maximum uptake and the form of the thyroid 125I release-rate curve was reproducible in each dog. The sensitivity and responsiveness of the thyroid 125I release rate and PB125I, TP 125I, and P125I- disappearance rate curves to changes in thyroid function were demonstrated with thyroid-stimulating hormone injection, indicating the usefulness of this method for demonstrating changes in thyroid activity such as may be related to environmental temperature, stress, pregnancy, and drugs.
Evaluation of various serotests to detect antibodies in ponies and horses infected with contagious equine metritis bacteria
Authors: Sahu S. P. , Rommel F. A. , Fales W. H. , Hamdy F. M. , Swerczek T. W. , Youngquist R. S. , Bryans J. T.
Published: February 2025

Rapid plate agglutination (rpa), antiglobulin, enzyme-linked immunosorbent assay (elisa), passive hemagglutination (pha), complement-fixation (cf), and agargel diffusion (agd) tests were used to detect antibodies in pony mares and Thoroughbred mares and stallions infected with contagious equine metritis (cem).

Antibody responses to cem bacterial antigens were different in Thoroughbred mares than in pony mares. In pony mares, the induction of antibodies to cem bacteria was directly related to the number of organisms inoculated. Antibodies to cem bacteria were detected by the rpa, cf, pha, elisa, and antiglobulin tests in mares inoculated with at least 1 × 108 colony-forming units. Results of the cf test on pony mares’ sera were inconsistent. Pony mares exposed to ≤ 1 × 106 colony-forming units developed antibodies by 30 days after inoculation, as demonstrated by elisa and pha test.

Antibodies to cem bacteria in sera of Thoroughbred mares were detected by the elisa, rpa, cf, and pha tests. The cf test was unreliable during the chronic stage of infection in Thoroughbred mares due to the anticomplementary activity and low cf titer. A large percentage of acute and chronic cem infections in Thoroughbred mares was detected when the rpa test was used in conjunction with the elisa and pha test. Antibodies to cem bacteria were detected in approximately 2.2% (9 of 414) of a noninfected equine population surveyed using the elisa, rpa, and pha tests.
Hemolytic complement titers and complement C3 levels in endotoxin-induced mastitis
Authors: Mueller R. , Carroll E. J. , Panico L.
Published: February 2025

Escherichia coli lipopolysaccharide B was instilled through the lactiferous duct of cows to induce acute mastitis. Hemolytic complement (C) activity and C3 concentrations were determined in blood serum and in rennin-precipitated whey before, and at certain times after, mastitis was induced.

Hemolytic complement activity was detected in the whey only during the first 36 hours after endotoxin was instilled, whereas activity was not seen before and 48 or more hours after the endotoxin was given. The maximum titer as measured with the guinea pig rbc/bovine natural antibody system was 1:64. The C3 concentrations in normal whey (before installation of endotoxin), measured by radial immunodiffusion, were between 1% and 4% of the base-line blood serum values (pool from healthy cows). The whey concentration of C3 increased (to 5% to 18%) during the first 8 hours of mastitis. However, at 72 hours, the whey values were back to preinstillation concentrations in all quarters.
Clinical, clinicopathologic, and pathologic alterations of monensin toxicosis in swine
Authors: Van Vleet John F. , Amstutz Harold E. , Weirich Walter E. , Rebar Alan H. , Ferrans Victor J.
Published: February 2025

Toxicosis was produced in 10 weanling pigs given monensin (40 mg/kg, orally) to allow making a characterization of the sequential clinical, clinicopathologic, and pathologic alterations on postdosing days 1, 2, 4, 8, and 16. Clinical signs of monensin toxicosis were apparent on day 1 (lethargy, anorexia, diarrhea, and muscle weakness) and had completely regressed by day 6. Electrocardiographic abnormalities were present in 7 of the 10 pigs on day 1, but were infrequently observed thereafter. Serum aspartate aminotransferase and creatine kinase activities were greatly increased on day 1 and moderately increased on days 2 and 4, and were within the base-line limits on days 8 and 16.

Elevation of aspartate aminotransferase and creatine kinase activities coincided with the development of acute myocardial and skeletal muscle necroses. Selective atrial myocardial necrosis appeared in 5 of the 10 pigs. Affected atria were pale, and microscopically, there were necrosis with contraction bands on day 1, macrophagic invasion and lysis on days 2 and 4, and resolving lesions of myocyte loss with persistent myocardial stroma on day 16. Skeletal muscle damage was present in 9 of the 10 pigs as pale areas (more obvious on cut section). Of the muscles examined (n = 7), the frequency and severity of damage were high in diaphragm, vastus lateralis, semitendinosus, triceps, and intercostal; moderate in longissimus lumborum; and low in tongue. Damage appeared to be greatest in muscles that contained a high proportion of type I fibers. In the damaged muscles, there were hyaline necrosis on day 1, macrophagic infiltration on days 2 and 4, and regeneration of necrotic fibers on day 4 and thereafter. With the regeneration, there was a rapid and complete restoration of skeletal muscle structure and function.
Hydralazine pharmacodynamics in the dog
Authors: Kittleson Mark D. , Hamlin Robert L.
Published: February 2025

The pharmacodynamics of hydralazine, an arteriolar dilator, were studied in dogs with induced heart failure. The dogs were studied 5 days after heart failure was induced by injecting microspheres into the left circumflex coronary artery. All dogs had a stroke volume index < 25 ml/beat/m2 of body surface and a left ventricular filling pressure ≥ 16 mm of Hg. Approximately 1 mg of hydralazine/kg of body weight was administered orally each hour until the total systemic resistance index decreased below 1,700 dynes·s·cm-5·m2. The drug effect was monitored hemodynamically until it dissipated.

Hydralazine increased the cardiac index from 3.06 ± 0.47 (± sd) to 6.81 ± 0.87 L/min/m2 (P < 0.01), stroke volume index from 20.9 ± 1.6 to 36.8 ± 9.3 ml/beat/m2 (P < 0.01), and heart rate from 146.2 ± 17.2 to 187.8 ± 42.8 beats/min (P < 0.05). It decreased mean arterial pressure from 111.5 ± 20.4 to 83.8 ± 4.7 mm of Hg (P < 0.05) and total systemic resistance index from 2,903 ± 149 to 992 ± 83 dynes·s·cm-5·m2 (P < 0.001). It did not affect left ventricular filling pressure or contractility. Peak drug effect occurred at 3 to 5 hours after drug administration and duration of effect was 11 to 13 hours. Recurrence of ventricular dysrhythmias occurred in 2 dogs and 1 dog died during a recurrence.

Hydralazine improved cardiac performance in the dog with left ventricular failure.
In vitro action of combinations of antimicrobial agents and EDTA-tromethamine on Pseudomonas aeruginosa
Authors: Wooley R. E. , Jones M. S. , Gilbert J. P. , Shotts E. B.
Published: February 2025

Combinations of EDTA-tromethamine and 7 antimicrobial agents (chloramphenicol, nalidixic acid, oxytetracycline, penicillin, polymyxin-B, streptomycin, and triple sulfa) were tested for synergistic activities against Pseudomonas aeruginosa. Three in vitro tests were used, including minimal inhibitory concentrations of the drugs, a 2-dimensional Microtiter checkerboard technique, and bacterial inhibition studies. A synergistic inhibitory action was observed with combinations of EDTA-tromethamine plus penicillin and EDTA-tromethamine plus oxytetracycline. When chloramphenicol, streptomycin, nalidixic acid, polymyxin-B, or triple sulfa was mixed with EDTA-tromethamine, synergistic action did not occur.
Motor nerve conduction velocity in normal chickens
Authors: Kornegay Joe N. , Gorgacz Edward J. , Parker Marcia A. , Schierman Louis W.
Published: February 2025

Muscle potentials evoked by proximal and distal tibial nerve stimulation were evaluated and used to calculate motor nerve conduction velocity in 65 chickens. Two potentials analogous to the M and F waves recorded in persons consistently were evoked. The mean tibial motor nerve conduction velocity ± sd of the birds was 32.3 ± 4.0 m/s. This value varied significantly (P < 0.05) with both age and cloacal temperature.
Hemoglobin enhancement of experimental infection of mice with Pasteurella haemolytica
Authors: Chengappa M. M. , Carter G. R. , Chang T. S.
Published: February 2025

A 2% hemoglobin preparation injected into mice along with Pasteurella haemolytica culture was found to be as good an enhancer of virulence as a 7% swine gastric mucin preparation. The hemoglobin preparation was easier to prepare and was less toxic than mucin for mice when injected intraperitoneally.
Procaine in the urine of racing Greyhounds: Possible sources
Authors: Sundlof Stephen F. , Duer Wayne C. , Hill Dennis W. , Gancarz Terry , Dorvil Marie G. , Rosen Penni
Published: February 2025

Greyhounds (n = 25) were given procaine in the form of procaine HCl or procaine penicillin G or were fed meat prepared from a heifer given procaine penicillin G on 3 consecutive days before slaughter. Dogs given procaine HCl or procaine penicillin G were given daily doses equivalent to 9 mg of procaine/kg. Urine samples were collected from the dogs twice daily before dosing, during the dosing period, and for 4 days after final dose administration.

All dogs excreted detectable concentrations of procaine in the urine, regardless of the dose form or route of administration. Blood plasma samples were prepared from 10 Greyhounds to determine procaine esterase activity. Hydrolysis of procaine by plasma esterases did not occur. Low plasma procaine esterase activity, coupled with rapid oral absorption of procaine, resulted in high urinary concentrations of the parent drug in dogs given procaine HCl or procaine penicillin G (9 mg/kg). Even in the dogs given relatively small doses (0.85 mg/kg) of procaine in the form of meat residues, urinary procaine concentrations were found.

The results of these studies indicate that procaine is rapidly absorbed following oral administration and that meat from livestock given procaine penicillin before slaughter may serve as a source of urinary procaine in Greyhounds consuming the meat.
Use of monoclonal antibodies directed against Eimeria tenella sporozoites to determine stage specificity and in vitro effect on parasite penetration and development
Authors: Danforth Harry D.
Published: February 2025

Three different hybridoma-produced monoclonal antibodies (Ab) were used to study their reactivities with in vitro developmental stages of Eimeria tenella and their effects on sporozoite penetration and intracellular development. One Ab (designated B10) was stage-specific, whereas the other 2 Ab (designated C3 and E5) reacted with various intracellular developmental stages of the coccidia. The E5 Ab interacted with the cytoplasm of cultured cells that were infected with sporozoites at 24 hours after inoculation. All 3 Ab inhibited penetration to various degrees—the one designated B10 having the greatest inhibitory effect. These 3 Ab also inhibited development of the parasite in cell culture, provided that Ab was continuously present in the cell culture medium. Removal of Ab from the medium allowed coccidial development to continue at about the same rate as in controls. A longer pretreatment time of the sporozoites with the Ab before cell inoculation increased the inhibitory effect with respect to both the penetration and the development of the parasite.
Cyclic nucleotides in hamster retina
Authors: Buyukmihci Ned , Elliott Hugh F. , Giri Shri N.
Published: February 2025

The concentrations of cyclic 3′:5′-adenosine monophosphate (cyclic amp) and cyclic 3′:5′-guanosine monophosphate (cyclic gmp) were determined in white light- and dim red light-adapted golden Syrian hamster retinas. Retinas from animals in dim red light had cyclic amp concentrations of 9.29 ± 2.94 pmol/mg of protein and cyclic gmp concentrations of 110.62 ± 32.98 pmol/mg of protein. After white light adaptation, retinal cyclic amp and cyclic gmp concentrations were reduced to 74% and 45% of the previous values, respectively. In another experiment with white light-adapted animals, the sex or method of immobilization of the animals (cervical dislocation vs sodium pentobarbital) had no significant effect on cyclic nucleotide values.
Acetylcholinesterase activity in pregnant and nonpregnant ewes
Authors: Pope Andrew M. , Heavner James E.
Published: February 2025

Twenty-six ewes were bred in mid-May, and whole blood acetylcholinesterase (ache) activity was measured at 3,6,9,15, and 26 weeks after breeding. The ache activity declined to its lowest value 9 weeks after breeding (mid-July) for all ewes, regardless of pregnancy status, and then increased to greater than baseline values by 21 weeks after breeding (early October). Seemingly, a relationship exists between ambient temperature and fluctuations in ache activity.
Anthelmintic activity of ivermectin in pigs naturally infected with Ascaris and Trichuris
Authors: van Veen T. W. Schillhorn , Gibson C. D.
Published: February 2025

The anthelmintic efficacy of ivermectin administered by subcutaneous (sc) injection or orally via the drinking water was investigated in feeder pigs naturally infected with Ascaris suum and Trichuris suis. Group 1 pigs (n = 5) were given drinking water as a placebo, group 2 pigs (n = 5) were given ivermectin by sc injection (300 μg/kg of body weight), and group 3 pigs (n = 5) were given ivermectin in water also at a dosage rate of 300 μg/kg of body weight.

At necropsy 11 days later, the mean worm counts in group 1 pigs were 4 for Ascaris and 50.2 for Trichuris. All adult and juvenile ascarids were removed from the intestine in groups 2 and 3 pigs. Compared with the number of Trichuris in group 1 pigs, the number of Trichuris was reduced by 91.2% and 78.1%, respectively, for the orally and sc treated pigs.
Gentamicin pharmacokinetics in horses given small doses of Escherichia coli endotoxin
Authors: Wilson Robert C. , Moore James N. , Eakle Nora
Published: February 2025

The pharmacokinetics of gentamicin (3 mg/kg of body weight) were evaluated in 6 healthy horses and in 6 horses after they were given Escherichia coli endotoxin (0.113 μg/kg). In the horses given endotoxin, there were a maximum temperature increase of 1.97 ± 0.44° (C) and a fever index (between the 2 groups) of 8.754 units. Other mild signs of endotoxemia also occurred.

Statistically significant changes were not observed in the rate constants for distribution (α) or elimination (β) or in body clearance (ClB) of gentamicin in the 2 groups of horses. In the horses given endotoxin, significant (P < 0.05) increases were found in the serum concentration data (A, B, and Cso), and significant decreases were found in the apparent volume of distribution [Vd(area)] and in the volume of the central compartment (Vc). The alterations in gentamicin kinetics in the horses given endotoxin are believed to result from the decrease in Vc. This indicates that the extracellular fluid volume available for gentamicin distribution may be reduced by endotoxin.
Further tests of activity of levamisole on Ostertagia ostertagi in dairy calves with notes on overwinter survival of gastrointestinal helminths on pasture
Authors: Lyons E. T. , Drudge J. H. , Tolliver S. C. , Hemken R. W. , Button F. S.
Published: February 2025

Two controlled tests were conducted in 1981 and 1982 in dairy calves on the University of Kentucky research farm to determine activity of the bolus formulation of levamisole given at the dose rate of 8 mg/kg against naturally occurring infections of Ostertagia ostertagi. Removal efficacies of mature O ostertagi were 98% in the 1981 test (3 treated and 3 nontreated calves) and 94% in the 1982 test (7 treated and 8 nontreated calves). Against immature Ostertagia spp, removal efficacies were 100% and 65% for the 1st and 2nd tests, respectively. The calves were grazed on the same pasture as dairy calves in previous controlled tests in 1979 and 1980 where activity of levamisole against mature O ostertagi (data recently published) was much less than in the present tests. It does not appear that the poor performance in the early tests can be attributed to the drug resistance phenomenon.

Data on overwinter survival (119 days) of free-living stages of gastrointestinal parasites on pasture were derived from the nontreated calves in the 1982 controlled test. The calves, raised helminth-free, were placed on the pasture on Apr 5,1982. Helminths recovered at necropsy of the calves, besides O ostertagi, included Trichostrongylus axei, Nematodirus helvetianus, Nematodirus spp, Cooperia oncophora, Trichuris spp, and Moniezia spp. The lungworm, Dictyocaulus viviparus, previously found in cattle on the farm, was not found in these calves.
Reservoir of St. Louis encephalitis virus in Ohio bats
Authors: Herbold John R. , Heuschele Werner P. , Berry Richard L. , Parsons Margaret A.
Published: February 2025

Inoculation of the big brown bat (Eptesicus fuscus) with a small dose of a St. Louis encephalitis (sle) virus strain isolated in Ohio indicated that the big brown bat was susceptible to infection. The virus was maintained in the bats through hibernation (70 days), and the bats developed a viremia within 4 days of arousal from hibernation (105 days after inoculation). A field survey of 390 big brown bats and little brown bats (Myotis lucifugus) conducted in 5 regions of Ohio during 1979 to 1981 revealed a sle virus-neutralizing antibody prevalence of 9%. Cohabitation of natural caves and abandoned mineshafts in Ohio by Culex pipiens mosquitoes, big brown bats, and little brown bats was also documented. Demonstration of a 9% prevalence rate of neutralizing antibody to sle virus in big brown bats and little brown bats in Ohio during a nonepizootic period indicated that the bat may be involved in the maintenance of sle virus in enzootic foci and could have a role in dissemination of sle virus to epizootic foci.