bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical and Pathologic Features of Chronic Adriamycin Toxicosis in Rabbits
Authors: Van Vleet John F. , Ferrans Victor J.
Published: February 2025

Chronic adriamycin (adr) intoxication was produced in 50 weanling rabbits by weekly injections of adr (2.4 mg/kg of body weight) for up to 17 weeks. All adr-treated rabbits developed prominent alopecia, edema, moderate anemia, and severe emaciation, The frequency and severity of cardiomyopathy were not strongly dose-related, but renal lesions were. The frequency and severity of cardiomyopathic lesions were highest in left ventricular free wall and ventricular septum, intermediate in atria, and lowest in right ventricular free wall. Cardiac lesions increased in frequency and severity basally in left ventricular free wall, ventricular septum, and atria, but not in right ventricular free wall. Nephropathy lesions were selective for inner cortex and constitute a common and important side effect of chronic adr intoxication in rabbits. Other lesions observed at necropsy were hepatic necrosis, skeletal muscle degeneration, osteodystrophy-associated fractures, peripancreatic fat necrosis, and testicular degeneration and atrophy.
Treatment of Klebsiella pneumoniae Respiratory Tract Infection of Squirrel Monkeys with Aerosol Administration of Kanamycin
Authors: Berendt Richard F. , Magruder Robert D. , Frola Frank R.
Published: February 2025

The therapeutic efficacy of im-administered kanamycin was compared with the efficacy of aerosol-administered kanamycin in Klebsiella pneumoniae-infected squirrel monkeys. Differences in mortality or morbidity were not seen with equivalent dosages of antibiotic ranging from 15 to 6.9 mg/kg of body weight/day. Seemingly, the im route of kanamycin administration was as effective as the aerosol route for therapy.
Haversian Bone-Remodeling Measurements in Young Beagles
Authors: Jorch U. Μ. , Anderson C.
Published: February 2025

Haversian bone remodeling was measured in Beagles (8.9 to 9.9 months of age) from a colony of laboratory-raised animals. The data were compared with data in published age-related curves. There was no marked dissimilarity between the measurements of haversian bone-remodeling values in Beagles from different sources.
Environmental and Genetic Effects on Hematologic Characteristics of Beef Cows
Authors: Fisher D. D. , Wilson L. L. , Scholz R. W.
Published: February 2025

The objective of this study was to determine the effects of certain environmental and genetic factors on selected hematologic characteristics of beef cows under wintering and grazing conditions in the Northeast. Packed cell volume pcv, hemoglobin concentration (Hb), rbc count, and wbc count were determined in serial blood samples collected periodically during 1976 from 24 young and mature, gestating and lactating, Angus and Angus-Charolais cows. The pcv, Hb, and rbc were significantly correlated (P < 0.001, n = 257; rpcv · Hb = 0.89, rpcv · rbc = 0.74, rHb · rbc = 0.72). Lactating cows grazing mixed swards containing 24% legume had higher (P < 0.001) pcv and Hb than did cows grazing all-grass swards fertilized with 168 kg of nitrogen/ha. The rbc was higher (P < 0.01) in cows grazing all-grass swards, whereas no differences in wbc were observed between groups. Angus cows had lower pcv (P < 0.001) and rbc (P < 0.005) than did Angus-Charolais cows. Individual cows of identical physiologic maturity-breed-diet groups differed (P < 0.05) in pcv, Hb, rbc, and wbc, indicating that there are repeatable differences in these traits among individual cows. Significant effects of season and physiologic state (pregnancy vs lactation) were observed for pcv, Hb, rbc, and wbc (P < 0.01).
Antibody Response of Pigs to Inactivated Monovalent and Bivalent Vaccines for Porcine Parvovirus and Pseudorabies Virus
Authors: Mengeling W. L. , Gutekunst D. E. , Pirtle E. C.
Published: February 2025

Groups of pigs vaccinated with an inactivated bivalent vaccine containing porcine parvovirus (ppv) and pseudorabies virus (prv) developed geometric mean titers (gmt) of humoral antibody for each of the viruses as high or slightly higher than those of other groups of pigs that were vaccinated with inactivated monovalent vaccines containing one or the other of the same viruses. An increase in gmt after challenge exposure of vaccinated pigs to live virus indicated that vaccination did not prevent virus replication. However, an indication that replication was less extensive in vaccinated pigs was provided by the following. Although neither vaccinated nor nonvaccinated (control) pigs had clinical signs after exposure to live ppv, the effect of vaccination was evident by the fact that gmt were higher in nonvaccinated pigs after exposure than they were in vaccinated pigs. Conversely, all pigs exposed to live prv had clinical signs, but these signs varied between mild-to-moderate and transient for vaccinated pigs to severe and fatal for nonvaccinated pigs.
Studies on In Vitro Lymphocyte Stimulation Assay in Cattle Naturally Infected with Brucella abortus and in Cattle Vaccinated with Strain 19
Authors: Kaneene J. Μ. B. , Anderson R. K. , Nicoletti P. , Brown R. , Christenberry C. C. , Swann A. I. , Johnson D. W.
Published: February 2025

Cell-mediated immune responses of cattle in infected herds vaccinated with Brucella abortus, strain 19, and of nonexposed controls were studied by an in vitro lymphocyte stimulation test (lst). Brucella abortus soluble antigen was used as a specific stimulator of lymphocytes. Lymphocyte suspensions were prepared from peripheral blood of cattle by the Ficoll-diatrizoate technique. Cultures were labeled with [3H]thymidine and were assayed for [3H]thymidine incorporation into DNA by liquid scintillation spectrometry. Seroagglutination tests and cultures from Brucella were conducted simultaneously with lst. Brucella abortus soluble antigen induced significantly higher (P ≤ 0.005) lymphocyte stimulation responses in lymphocytes from cattle infected with B abortus than in lymphocytes from cattle vaccinated with strain 19 or from nonexposed controls. There was a significant P = agreement in results of lst and seroagglutination tests in infected cattle. Among seropositive-vaccinated cattle and controls, the lst was negative.
Clinical Pharmacokinetics of Phenytoin in the Dog: A Reevaluation
Authors: Frey H. H. , Löscher W.
Published: February 2025

The pharmacokinetics of phenytoin, as well as drug plasma concentrations, during continued treatment were studied in the dog. After iv injection of 10 mg/kg, the average elimination half-life was 4.4 hours, which is in good agreement with previous studies. Bioavailability from tablet formulation was rather poor (av 36% compared with that obtained with iv) and showed great variation between dogs. Even with the dosage regimen of 20 mg of drug/kg given tid orally, therapeutic plasma concentrations could only be maintained for the first 2 or 3 days of treatment; these subsequently decreased to ineffective concentrations during the 1st week of treatment. This effect was accompanied by considerable reductions in half-life, indicating that phenytoin is a strong inducer of microsomal drug metabolism in the dog. Phenytoin must be considered as poorly suited for the treatment of canine epilepsy.
Immunizing Properties of Westphal Lipopolysaccharide from an Avian Strain of Pasteurella multocida
Authors: Rebers Paul A. , Phillips Marshall , Rimler Richard , Boykins Robert A. , Rhoades Keith R.
Published: February 2025

A purified lipopolysaccharide (lps) antigen from an encapsulated strain of Pasteurella multocida was obtained by a modification of the Westphal extraction procedure in which most of the capsular polysaccharides were separated from the lps by partitioning between water and phenol. The lps-enriched fraction was then digested with deoxyribonuclease and ribonuclease, pelleted by ultracentrifugation, and fractionated by equilibrium buoyant density gradient centrifugation in cesium chloride. These procedures removed most of the protein and extraneous polysaccharide components.

The capability of the original extract to induce protection in chickens, mice, and rabbits was determined; evidence of protection was obtained only in chickens. Chicken antiserum obtained by inoculation of the original extract or of the purified lps gave a single line in gel diffusion with homologous lps and with Heddleston's heat-stable antigen of the homologue type; a reaction was not obtained with any of the 15 other serotype antigens. The antiserum obtained by use of the original extract had the same qualitative reactions as did that obtained by use of the purified lps, but the antiserum obtained with the purified lps had stronger serologic reactions and was more effective in the passive protection test. Up to 86% of the chickens given 0.3 ml of the latter antiserum were protected against a challenge exposure which killed 100% of the controls. Pasteurella multocida lps is an important serologic marker in Heddleston's typing system, and antibodies induced against the lps contribute to the protection of chickens.
Effect of Cyclophosphamide Treatment on Clinical and Serologic Response of Rats to Infection with Leptospira interrogans serovar icterohaemorrhagiae
Authors: Thiermann A. B.
Published: February 2025

Young albino rats were immunosuppressed with cyclophosphamide and exposed to virulent and low-virulence Leptospira interrogans serovar icterohaemorrhagiae 820K. In rats exposed to virulent and low virulence leptospires, microscopic agglutinating antibody responses occurred later, and longer leptospiremic phase and more massive tissue invasion by the organisms were observed in immunosuppressed rats than in immunocompetent controls. Clinical and pathologic signs of illness were more severe in the immunosuppressed animals than in immunocompetent controls. When exposed to low-virulence leptospires, immunosuppressed rats became infected and developed signs of illness and 2 of 16 died. Immunocompetent rats rapidly developed a humoral response and did not develop any signs of illness, and with 1 exception, organisms were not recovered from any tissues.
Viral Contamination of Bovine Fetal Lung Cultures and Bovine Fetal Serum
Authors: Rossi C. R. , Bridgman C. R. , Kiesel G. K.
Published: February 2025

Commercial bovine fetal serum (bfs) and bovine fetal lung (bfl) cells were tested for viruses. The only virus detected in any sample was noncytopathogenic bovine viral diarrhea virus (bvdv). Of 37 bfl cultures initiated, 34 were negative for bvdv, 1 was positive, and 2 were suspicious in that the source of bvdv contamination was not certain. Of 9 lots of irradiated sera tested, 1 (10%) was positive for bvdv; of 21 lots of nonirradiated sera tested, 13 (62%) were positive for bvdv. As judged by intensity of fluorescence in infected cultures, some cell strains were much more susceptible to bvdv than other strains. Heat inactivation of serum at 56 C for 30 minutes was found to be an unreliable method of eliminating bvdv from sera.
Esophageal and Intrapleural Pressures in the Healthy Conscious Pony
Authors: Derksen F. J. , Robinson N. E.
Published: February 2025

Pleural and esophageal pressures were compared in 6 standing sedated ponies. Pleural pressure was measured with blunt needles attached to transducers and inserted in the 10th intercostal space level with and 10 and 20 cm above the point of the shoulder. Two balloons (a condom and an esophageal balloon) attached to transducers measured esophageal pressure in the cranial, middle, and caudal portions of the thoracic part of the esophagus. Tidal volume was measured by integrating a flow signal derived from a pneumotachograph attached to an endotracheal tube inserted through a tracheostomy. Frequency responses of all measuring systems were matched. The change in pleural pressure during respiration was greatest in the middle and ventral portions of the thorax, less in the dorsal portion of the thorax and in the middle and caudal portions of the thoracic part of the esophagus, and least in the cranial portion of the thoracic part of the esophagus. The type of esophageal balloon had no effect on the measured pressure change. Regional variations in esophageal or pleural pressure during breathing caused variations in the calculated dynamic compliance. Pleural pressure gradients of 0.33 cm of water/cm of descent and 0.484 cm of water/cm of descent were recorded in the dorsal and ventral halves of the thorax, respectively, and may result in regional variations in lung inflation similar to those observed in persons.
Influence of Plasma A Esterase on Anthelmintic Action of Haloxon in Sheep
Authors: Baker Norman F. , Fisk Robert A.
Published: February 2025

Controlled trials were conducted to evaluate the anthelmintic action of haloxon in 2 phenotypes of lambs, 1 having an A esterase in plasma which rapidly hydrolyzes di-(2-chloroethyl)aryl phosphates and the other without this enzyme. A total of 116 lambs, 57 with and 59 without the plasma A esterase, 6 to 9 months old, harboring naturally acquired nematode infections were used in 3 trials. Haloxon was administered orally at 20, 25, and 35 mg/kg of body weight. Nematodes against which haloxon was evaluated in the abomasum were Ostertagia circumcincta and Trichostrongylus axei and in the small intestine were T vitrinas, T colubriformis, Nematodirus spathiger, and N filicollis. The anthelmintic efficiency of haloxon did not differ in the 2 phenotypes of sheep.
Evaluation of an Induced Pasteurella multocida Swine Pneumonia Model
Authors: Bentley O. Eugene , Farrington Daniel O.
Published: February 2025

A reproducible swine pneumonia model was developed, utilizing Pasteurella multocida (strain MSU 7) and a rapid endotracheal inoculating technique. The model provided a means of testing various factors, such as therapeutic agents that may influence the course of pulmonary pasteurellosis. In a series of experiments, 81 infected nonmedicated pigs had a morbidity of 96% and a mortality of 22%. Pasteurella multocida was isolated from 62% of the lungs at necropsy; 86% of the lungs had gross lesions characteristic for strain MSU 7 pneumonic pasteurellosis when the pigs were necropsied 7 days after inoculation.
Sedimentation Coefficient of African Swine Fever Virus
Authors: Trautman R. , Pan I. C. , Hess W. R.
Published: February 2025

SUMMARY AND CONCLUSIONS

The sedimentation coefficient of the infective unit of African swine fever in tissue culture harvest fluids was measured in a preparative ultracentrifuge. The boundary locator method used also permitted making an estimate of heterogeneity. The sedimentation coefficient ranged from 3,000 to 8,000 Svedberg units, representing many classes of infective particles.

Electron microscopy on culture fluids from infected cells showed many kinds of virus-containing units.

Sucrose-CsCl gradient centrifugation was used to concentrate and to purify (partly) African swine fever virus for analytical ultracentrifugation. The optical patterns of the physical particles revealed a range of coefficients from 1,800 to 3,200 Svedberg units in tris-buffered saline solution at 20 C and buoyant densities from 1.19 to 1.24 g/ml in CsCl. The disparity of these values from those obtained by preparative ultracentrifugation indicates a change in the virus structure or a selection of viral populations on purification (or both).
Attempts to Reactivate Bovid Herpesvirus-2 in Experimentally Infected Calves
Authors: Castrucci G. , Frigeri F. , Cilli V. , Tesei B. , Arush A. M. , Pedini B. , Ranucci S. , Rampichini L.
Published: February 2025

A study was carried out to determine whether bovid herpesvirus-2 (bhv-2) is able to induce a recurrent infection in experimentally infected calves.

Twelve calves infected with the virus were treated with dexamethasone (dms) beginning 69 days after the infection, ie, several weeks after the animals had recovered from the disease and were negative for bhv-2.

The stress induced by dms treatment failed to reactivate the clinical condition or to induce shedding of bhv-2. However, treatment with dms reactivated a latent infectious bovine rhinotracheitis (ibr) virus infection in all calves previously inoculated with bhv-2, and also in 2 noninoculated controls. The reactivation of ibr virus occurred without any clinical evidence of the disease, but the virus was isolated from nasal and pharyngeal swabbings and from the organs. A proliferative ganglionitis of the trigeminal ganglion was also observed.

Because of the interference by ibr virus, this study did not resolve the question as to whether bhv-2 can induce a recurrent infection.
In Vivo and in Vitro Measurement of Tendon Strain in the Horse
Authors: Lochner Frank K. , Milne Dennis W. , Mills Earl J. , Groom Jack J.
Published: February 2025

Strain gauges were applied to the superficial flexor tendon, deep flexor tendon, and suspensory ligament of sound adult horses. Maximum tendon strain occurred during full weight bearing while walking, when the forelimb was perpendicular to the ground surface. There was decrease in tendon strain with increase in hoof angle for the deep digital flexor, but no change in tendon strain for the superficial digital flexor and suspensory ligament with changing hoof angle. At physiologic rates of strain, tendons were able to withstand large loads without yielding. Load strain curves developed in vitro indicated that during walking, the deep digital flexor was calculated to load to 416.8 kg; the superficial flexor tendon to 362.9 kg; and the suspensory ligament to 172.4 kg. This study shows that in the horse, strain in flexor tendons during walking was in excess of 5%, indicating strains within the visco-elastic range.
Incompatibility of R Plasmids Derived from Salmonella and Escherichia coli Strains Isolated Simultaneously from a Bovine Fecal Sample
Authors: Ishiguro Naotaka , Sato Gihei , Ichijo Shigeru , Konishi Tatsuo
Published: February 2025

Seven strains of Salmonella typhimurium were isolated from 2 fecal samples of calves, and the strains were resistant to ampicillin, chloramphenicol, kanamycin, nalidixic acid, streptomycin, sulfadimethoxine, and tetracycline. Also, 11 Escherichia coli strains were obtained from 1 of the 2 samples, and these strains possessed the identical drug resistance patterns as did the salmonellae.

The thermosensitive R plasmids conferring sextuple drug resistance and mercury resistance from Salmonella strains were Fi− (no fertility inhibition) and belonged to incompatibility group H1, whereas conjugative 6 R plasmids isolated from 11 E coli strains were Fi+ (fertility inhibition) and belonged to incompatibility group FII. Thermosensitive R plasmids conferring sextuple drug (ampicillin, chloramphenicol, kanamycin, streptomycin, sulfadimethoxine, and tetracycline) have not been reported in Japan. Genetic relationship of R plasmids derived from the multiresistant strains of Salmonella and E coli was discussed on the basis of incompatibility properties of R plasmids.
Glucose-Stimulated Fluid Absorption in the Pig Small Intestine During the Early Stage of Swine Dysentery
Authors: Argenzio R. A.
Published: February 2025

Kinetics of glucose-stimulated water absorption and small bowel absorptive function in normal pigs and pigs affected with swine dysentery were examined with a steadystate perfusion technique. Glucose-dependent stimulation of solute and water absorption was shown in normal pigs with a transport constant of 46.9 mM and a maximum change in volume transport capacity of 78.3 ml/h/50 cm of jejunum. The entire small intestine of normal pigs absorbed 10 ml/min of an isotonic fluid when the luminal glucose concentaatinn was 80 mM, whereas the intestine secreted 3 ml/min when glucose was replaced by mannitol. These absorptive and secretory rates in infected pigs were identical to those in control pigs. Electrolyte and acid-base values in arterial blood were unchanged after the rapid administration of 500 ml of a glucose-electrolyte solution into the proximal portion of the small bowel, and the plasma glucose response in control and infected pigs was identical. Seemingly, small bowel absorptive function is normal in pigs with swine dysentery and provides a rational approach to oral, glucose-electrolyte therapy for restoring the extracellular fluid losses that occur with this disease.
Evaluation of a Modified Live-Virus Vaccine for the Prevention of Porcine Parvovirus-Induced Reproductive Disease in Swine
Authors: Paul P. S. , Mengeling W. L.
Published: February 2025

Each of 5 gilts was vaccinated im with modified live-virus (mlv) vaccine for porcins parvovirus (ppv), and 5 gilts were used as nonvaccinated controls. Vaccinated gilts developed hemagglutination-inhibiting (hi) antibodies to ppv (titer of 320 to 1,280) by 2 weeks after vaccination. All gilts were bred, and at about 40 days of gestation their immunity was challenged by intranasal and oral administration of a virulent strain of ppv. Gilts were killed at about 84 days of gestation and their Utters were examined. Litters from vaccinated gilts comprised 59 live and 2 dead fetuses. Neither the virus nor antibodies to the virus were detected in any of the fetuses. In contrast, litters from nonvaccinated gilts comprised 25 live and 29 dead fetuses, and ppv was isolated from all dead and 9 live fetuses. Viral antigen was detected by direct immunofluorescence in the lungs of all ppv-infected fetuses, and 7 of the live infected fetuses had hi antibodies.

Modified live virus did not cause transplacental fetal infection in 3 seronegative gilts inoculated at about 40 days of gestation. All 3 gilts had antibodies to ppv (80 to 640) when killed at about 84 days of gestation, and neither hi antibodies nor ppv were detected in any of the 20 live and 1 dead fetuses from these gilts. Modified live virus replicated in the tissues of fetuses of 2 gilts inoculated in utero. Seven of 8 fetuses inoculated with mlv died and were infected.

These results demonstrated the efficacy of mlv vaccine for the prevention of ppv-induced reproductive disease in swine. Although mlv did not cross the placental barrier in pregnant animals, its pathogenicity for porcine fetuses after direct in utero inoculation indicates that its use should be limited to nonpregnant animals.
Response of Muscle Spindle Primary Endings to Static Stretch in Acute and Chronic Spinal Cats
Authors: Bailey Cleta Sue , Lieberman James S. , Kitchell Ralph L.
Published: February 2025

To evaluate fusimotor activity, the response of muscle spindle primary endings to static stretch was recorded from group Ia fibers in 8 control cats and in 31 cats at 3, 6, 14, 30, and 60 days after lumbar spinal cord transection. The spindle responses and clinical status of each group were compared with those of the control group. At 3 days after transection, the cats were hypotonic and mildly hyperreflexic. Spindle responses were significantly depressed. By day 6, the cats were mildly hypertonic and significant spindle recovery had occurred, although the responses were still significantly depressed from control levels. Spindle responses, hypertonia, and hyperreflexia continued to increase to day 30. At this time, spindle responses remained significantly depressed, although the cats were markedly hypertonic and hyperreflexic. A significant change in spindle activity or clinical status did not occur from 30 to 60 days after transection.
Antiparasitic Activity of Ivermectin in Critical Tests in Equids
Authors: Lyons E. T. , Drudge J. H. , Tolliver S. C.
Published: February 2025

Ten critical tests, using 9 horses and 1 pony, were conducted to evaluate antiparasitic activity of a solution of ivermectin [22, 23-dihydroavermecin B1 (MK-933)] administered in single doses via stomach tube at dosage rates of 50 (3 tests), 100 (3 tests), or 200 (4 tests) μg/kg of body weight.

Removal of 91% to 100% was recorded at all 3 dosage levels (No. of infected animals in parentheses) for 2nd instar (7) and 3rd instar (10) Gaserophilus nasalis, immature (5) and mature (5) Oxyuris equi, Strongylus vulgaris (9), S edentatus (8), and small strongyles (10; only 83% removal in 1 animal at 100 μg/kg). Small strongyles in 2 animals were from benzimdazole-resistant sources and removal was 96% (200 μg/kg) and 100% (100 μ/kg). All mature Parascaris equorum parasites in 2 animals (50 μg/kg) and S equinus in 2 animals (100 μg/kg and 200 μg/kg) were removed.

Removal of G intestinalis 2nd instar (9) was 79% to 100%, 97% to 99%, and 100%, and of 3rd instar (10) was 67% to 88%, 86% to 100%, and > 99% to 100% at dosage rates of 50, 100, or 200 μg/kg, respectively. Probable activity against 4th-stage Habronema spp, 5th-stage Habronema muscae, or both (all 3 dosage levels) and 5th-stage Draschia megastoma (100 μg/kg) was indicated. There was no activity found against tapeworms (Anoplocephala magna and A perfoliata). Transient loosening of feces was obtserved for 1 animal 200 (μg/kg) after treatment but whether it was drug related was unknown.
Endomyocardial Biopsy in the Dog
Authors: Burk Ronald L. , Tilley Lawrence P. , Henderson B. Marshall , James V. C.
Published: February 2025

A technique for transvenous endomyocardial biopsy of the right ventricular septum was modified from an existing procedure described in man and was applied in the dog. More than 120 procedures were performed in 36 dogs. One dog died, but lesions noticed at necropsy were not sufficient to establish the specific cause of death. Other fatalities or major complications were not encountered.
Efficacy of Ivermectin Against Dirofilaria immitis Larvae in Dogs 31, 60, and 90 Days After Infection
Authors: Blair Lyndia Slayton , Campbell William C.
Published: February 2025

Ivermectin, given as a single oral dose of 0.05 mg/kg, prevented the maturation of Dirofilaria immitis in dogs if given at 31 or 60 days after infection. When treatment was delayed 90 days after infection, maturation of worms occurred in 3 of 5 dogs.
Transmission of Anaplasma marginale Theiler by Dermacentor andersoni Stiles and Dermacentor variabilis (Say)
Authors: Kocan Katherine M. , Hair Jakie A. , Ewing S. A. , Stratton Louie G.
Published: February 2025

Cattle were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source for laboratory-reared Dermacentor andersoni Stiles and D variabilis (Say) nymphs. Following a molt and subsequent feeding of adult ticks on susceptible cows, transstadial transmission of A marginale occurred from cattle with parasitemias ranging from undetectable (in a carrier cow) to a peak of 27% (in an acutely ill cow). Homogenates of gut tissue from unfed, incubated, and feeding adult ticks that were infected as nymphs were all infective; however, the prepatent period varied according to treatment of ticks after they had molted to the adult stage. Prepatent periods of infections in calves resulting from injection of homogenated tissue from unfed adult ticks was 29 and 34 days longer than the prepatent periods that developed in calves exposed to homogenated tissue from ticks that were feeding or incubated at 37 C for 3 days. Transovarial transmission did not occur when F1 larvae, hatched from eggs produced by female ticks known to be infective, fed on susceptible cattle.
Carriage of Campylobacter jejuni in Healthy and Diarrheic Animals
Authors: Prescott J. F. , Bruin-Mosch C. W.
Published: February 2025

Feces from normal and diarrheic animals were cultured for Campylobacter jejuni. A clear difference could not be detected in carriage between normal and diarrheic cattle, horses, pigs, and dogs. Too few diarrheic goats, sheep, and rabbits were sampled for conclusions to be made. Carrriage rates (%) detected in normal animals were as follows: ducks 88.3, chickens 23.8, sheep 13.6, rabbits 11.3, goats 2.7, cattle 2.5, and dogs 0.5. The organism was not isolated from horses and mink. Carriage rates varied within a species between animals from different sources.
Lasalocid for Improved Weight Gains and Control of Coccidia in Lambs
Authors: Foreyt William J. , Parish Steven M. , Foreyt K. M.
Published: February 2025

Lasalocid at 25 mg/kg of feed was highly effective in reducing numbers of oocysts in feces of naturally infected ewes and lambs. Treated ewes were fed lasalocid-medicated feed before and after parturition, and the 17 lambs from these ewes also were fed medicated feed until market weight. Lambs fed medicated feed gained 5.26 kg more (P < 0.05) than did the 17 nontreated lambs from nontreated ewes. Naturally infected lambs maintained in semiconfinement acquired coccidia infections between 23 and 64 (mean of 38) days after birth. A coccidiostat given before and during the time coccidia-naive lambs were first exposed to coccidia was necessary to achieve the greatest production response to treatment.

When naturally infected feeder lambs (30.9 kg) maintained in semiconfinement were fed lasalocid-medicated feed at 25 mg/kg of feed or unmedicated feed for 91 days, no significant difference (P > 0.05) in rate or efficiency of gain was detected, even though lasalocid was highly effective against coccidia.
Enzyme-Linked Immunosorbent Assay for Detection of Bluetongue Virus Antibodies
Authors: Hübschle O. J. B. , Lorenz R. J. , Matheka H. D.
Published: February 2025

The immune response to bluetongue virus in sheep and cattle was studied by applying a newly developed indirect enzyme-linked immunosorbent assay (elisa). Purified virus obtained by sucrose gradient centrifugation was used at a concentration of 0.01 optical density units to coat individual wells (200 μl) of a microtitration plate. Dilution of antigen was performed in 0.05 M carbonate buffer, pH 9.6, and adsorption lasted for at least 16 hours at 4 C. Coated plates retained their activity for 10 weeks when stored at 4 C. Sera recovered from experimentally infected sheep and cattle were tested together with known negative sera. A good correlation between results was obtained with the modified complement-fixation test and the elisa; however, the elisa proved to be more sensitive. The group specificity of the elisa was proven by testing various type-specific sheep and cattle immune sera. The elisa has potential for the detection of group-specific antibodies to bluetongue virus infection.
Somatosensory-Evoked Potential in Clinically Normal Dogs
Authors: Kornegay Joe N. , Marshall Arvle E. , Purinton P. Thomas , Oliver John E.
Published: February 2025

Repetitive electrical peripheral nerve stimulation produces a multiphasic cerebrocortical potential termed the somatosensory-evoked potential (sep). Scalp sep recordings were made from 12 clinically normal dogs tranquilized with acepromazine. Three individual potentials were recognized in most sep recordings and were identified as n1, p1, and n2.

Additional positive potentials consistently followed n2, but their latencies and amplitudes varied considerably, so these waveforms were not numbered. They were termed late-positive potentials. Mean peak latencies ± sd of the 3 potentials were determined to be 13.5 ± 1.5 ms (n1, 19.6 ± 2.7 ms (p1), and 43.3 ± 10.4 ms (n2). The 1st negative deflection (n1 occurred between 11.0 and 16.0 ms after the stimulus and was consistently followed by a positive deflection (p1) which occurred at a latency ranging from 15.5 to 24.0 ms. The 2nd negative deflection (n2) occurred between 32.0 and 54.0 ms after the stimulus and was followed by a solitary prominent positive deflection or multiple positive potentials. Late-positive potential peak latencies ranged from 47.5 to 231.5 ms.
Fatty Acid Composition of Equine Plasma
Authors: Luther D. Gene , Cox Hollis Utah , Dimopoullos G. T.
Published: February 2025

Fatty acid composition of plasma lipids of normal horses was determined. Four fatty acids (C16:0, C18:0, C18:1, and C18:2) comprised 86.73% of the total, with C18:2 comprising 44.04% of the total. Eight other fatty acids were found in small amounts. Unsaturated fatty acids constituted 66% of the total. Marked variation was demonstrated in fatty acid occurrence and distribution in the sterol ester, triglyceride, phospholipid, and free fatty acid fractions.
Effects of Bovine Viral Diarrhea Virus Infection on Bovine Polymorphonuclear Leukocyte Function
Authors: Roth J. A. , Kaeberle M. L. , Griffith R. W.
Published: February 2025

Four procedures were used to evaluate the function of polymorphonuclear leukocytes (pmn) isolated from the blood of cattle experimentally infected with bovine viral diarrhea (bvd) virus: (1) uptake of an emulsion of paraffin oil and Escherichia coli lipopolysaccharide, (2) nitroblue tetrazolium reduction, (3) chemiluminescence, and (4) iodination, or the conversion of iodide to a trichloroacetic acid-precipitable form. A marked impairment of iodination was consistently observed after infection with either a cytopathogenic or a noncytopathogenic strain of bvd virus. A corresponding decrease in paraffin oil uptake, nitroblue tetrazolium reduction, and chemiluminescence was not observed. Serum from bvd virus-infected animals did not depress iodination by normal control pmn in vitro. The iodination procedure evaluates the activity of the myeloperoxidase, hydrogen peroxide, halide system. This system has potent bactericidal, fungicidal, and virucidal effects. The data indicate that oxidative metabolism by pmn from bvd virus-infected cattle is normal, but that the myeloperoxidase, hydrogen peroxide, halide antibacterial system is impaired. This could be explained by an inhibition of degranulation in pmn from infected cattle. The observed defect in iodination by pmn after bvd virus infection was compounded by a decrease in the number of circulating pmn. The impairment of pmn function may partially explain the increased susceptibility of cattle to secondary bacterial infection during infection with bvd virus.
Estrogen Excretory Patterns in the Indian Rhinoceros (Rhinoceros unicornis), Determined by Simplified Urinary Analysis
Authors: Kassam A. A. H. , Lasley B. L.
Published: February 2025

Daily urine samples obtained at random from 3 mature Indian rhinoceroses (Rhinoceros unicornis) were evaluated for immunologic estrogen concentration and were indexed by creatinine (Cr) concentration. Chromatographic separation and enzyme hydrolysis of the estrogenic components indicated that the major urinary estrogen in this species is immunoreactive estrone (> 95%). Cyclic variations of immunoreactive estrogens (basal values of 0.1 to 0.3 μg/mg of Cr; peak values of 5.8 to 12.5 μg/mg of Cr) were observed at an interval of 43 ± 2 days (4 cycles) which appear to reflect the apparent ovarian cycles. The method presented offers a practical approach for the monitoring of ovarian events in large, nontractable species.
Scanning Electron Microscopy of Experimentally Induced Pyelonephritis in the Rat
Authors: Appleton Judith A. , Munnell John F. , De Buysscher Eduard V.
Published: February 2025

Scanning electron microscopy was used to observe epithelial and inflammatory changes in kidneys of rats during Corynebacterium renale-induced experimental ascending pyelonephritis. Bacteria were not observed adhering to pelvic epithelium, although there was evidence of cell sloughing. Bacteria were observed in the interstitium of the renal medulla. Bacteria, when present in the tubular lumen, were associated with discontinuities in cell membranes. Phagocytic cells appeared in the interstitium and phagocytosis was evident in the renal medulla.
Feline (Cat) Hemolytic Complement Optimal Testing Conditions
Authors: Barta Ota , Oyekan Priscilla P.
Published: February 2025

Optimal conditions for assaying feline (cat) hemolytic complement (C) were determined. Effects of the following factors on C titers were tested: pH, ionic strength; calcium, magnesium, and ethylenediamine tetraacetate concentrations; time and temperature of incubation. Guinea pig erythrocytes sensitized with feline antibody were the most sensitive target cells for feline C. A buffer of pH 7.3, with an ionic strength of 0.06 and containing 0.3 mM CaCl2 and 1 mM MgCl2, was optimal for feline C assay. A concentration of 4 mM ethylenediamine tetraacetate in calcium- and magnesium-free buffer inhibited the C reactivity to 1/53rd of the original titer. Sera from clinically healthy cats contained 70 to 150 CH50 (50% hemolytic) U/ml when tested, using 1 × 108 sensitized guinea pig erythrocytes/ml.
Possible Factors Influencing Immunoglobulin A Concentration in Swine Colostrum
Authors: Inoue Takeshi
Published: February 2025

The immunoglobulin (Ig) A concentration in swine colostrum was determined by the single radial immunodiffusion method, using 157 samples collected from the same number of farm-raised sows in the Yamaguchi Prefecture of Japan during 1976 and 1977. The mean IgA value was 12.26 ± 3.30 mg/ml, and the maximum and minimum values were 28.14 mg/ml and 5.63 mg/ml, respectively.

To determine factors influencing the IgA concentration in swine colostrum, the following items were analyzed in the present study: season, district, breed, number of parturitions, udder section from which samples were collected, kind of feed, vaccinations of swine (erysipelas live-organism vaccine, hog cholera live-virus vaccine, Japanese encephalitis live-virus vaccine, and transmissible gastroenteritis live-virus vaccine), type of farming, and number of sows raised on a farm. Relationships between the IgA concentration in swine colostrum and each of these 12 items were analyzed.

Of the 12 items, breed and number of parturitions were the most influential on the IgA concentration in colostra of farm-raised sows. Season, district, and vaccination with transmissible gastroenteritis live-virus vaccine were moderately influential. Udder section, kind of feed, vaccinations of swine (erysipelas live-organism vaccine, hog cholera live-virus vaccine, and Japanese encephalitis live-virus vaccine), type of farming, and number of farm-raised sows were slightly influential. The multiple correlation coefficient obtained was 0.5887 (P > 0.05).
Combination of Filtration and Histochemical Stain for Detection and Differentiation of Dirofilaria immitis and Dipetalonema reconditum in the Dog
Authors: Acevedo R. A. , Theis J. H. , Kraus J. F. , Longhurst W. M.
Published: February 2025

A comparison was made of measurements of lengths of Dirofilaria immitis and Dipetalonema reconditum microfilariae processed according to the Knott technique and the Nuclepore filtration method. The filtered microfilariae showed a marked shortening, due to the fixation in methanol, but a significant difference between lengths of the microfilariae of the 2 species remained.

The naphtol AS-TR phosphate method of localizing acid phosphatase was used on filters, confirming the originally described patterns for both microfilariae. This combination of filter and histochemical stain is considered the best available method for the detection and identification of microfilariae.
Comparison of Antibiograms Determined by Disk Diffusion and Microdilution Methods for Selected Gram-Negative Bacilli
Authors: Cox Hollis Utah , Luther D. Gene , Newman Susan S. , Roy Alma F.
Published: February 2025

Antimicrobial susceptibility studies were compared by the quantitative broth microdilution (md) and the standard disk agar diffusion (ad) methods. Isolates (379) of gram-negative bacilli obtained from clinical specimens from a wide variety of animals were evaluated. Results demonstrated that the md method provided reliable quantitative estimation of bacterial susceptibility that correlated significantly with the widely used ad procedure. The md method provided information which was more clinically relevant than that offered by the ad method for determining therapy of bacterial infections of animals.
Developmental Changes in the Composition of Beagle Dog Milk
Authors: Lönnerdal B. , Keen Carl L. , Hurley Lucille S. , Fisher Gerald L.
Published: February 2025

The concentrations of iron, copper, zinc, manganese, calcium, magnesium, protein, carbohydrate, and fat were analyzed in dog milk during the first 45 days of lactation. The concentration of iron decreased significantly from 13 μg/ml on day 0 to 6 μg/ml. Zinc concentration decreased only slightly from 9.6 μg/ml to 8.7 μg/ml. Calcium concentration increased significantly during early lactation, from 1,366 μg/ml to 1,757 μg/ml on day 10, but changed little thereafter. Protein concentration increased throughout lactation, from 4.3% early in lactation to 6.3% late in lactation. Fat concentration increased from 2.4% to 4.5% in early lactation, and then decreased to 2.7% in late lactation. The concentrations of copper, manganese, magnesium, and carbohydrate did not show strong developmental patterns; average values were 1.8 μg/ml, 0.14 μg/ml, 59 μg/ml, and 4.5%, respectively, throughout lactation. These data indicated that the nutrient intake of the pup changed markedly during the early neonatal period and that these changes should be taken into account in evaluating studies of suckling dogs.
Transplacental Transmission of Rabies Virus from a Naturally Infected Skunk
Authors: Howard D. R.
Published: February 2025

A female skunk (Mephitis mephitis) was submitted to the Veterinary Diagnostic Laboratory for routine rabies diagnosis. Rabies infection was confirmed by fluorescent rabies antibody examination on brain tissue. Additional tissues, including uterus, ovaries, and 6 embryos, were collected to study rabies pathogenesis. The fluorescent rabies antibody examination showed rabies virus antigen in 1 embryo, the uterus, and ovaries.
Pharmacokinetics and Behavioral Effects of Methylphenidate in Thoroughbred Horses
Authors: Shults Theodore , Kownacki A. A. , Woods W. E. , Valentine R. , Dougherty John , Tobin Thomas
Published: February 2025

In horses given (rapid iv) methylphenidate (Ritalin, α-phenyl-2-piperidinacetic acid methyl ester; 0.70 mg/kg), plasma concentrations of the drug decreased rapidly at first, with an apparent α half-life of about 19 minutes, and then more slowly, with an apparent β half-life of about 2.4 hours. These data were well fitted by a 2-compartment open model. In blood, about 40% of the methylphenidate present was in the plasma fraction, and of this, about 80% was plasma-protein bound. If given by subcutaneous or im injection, plasma concentrations of methylphenidate peaked in about 1 hour and were no longer detectable (cleared) from plasma by 6 hours. Urinary clearance time, however, was longer, and between 12 and 24 hours should be allowed for a dose of methylphenidate to “clear” from urine. Using a variable-interval responding apparatus, methylphenidate was shown to stimulate the responding rate of horses up to 6 times above base line, making it the most potent central stimulant tested in this responding apparatus to date. Peak central stimulation at 30 minutes after iv dosing was seen in horses given 0.4 to 1.0 mg of methylphenidate/kg.
Equine Cervical Esophagostomy: Complications Associated with Duration and Location of Feeding Tubes
Authors: Stick John A. , Derksen Frederik J. , Scott Edward A.
Published: February 2025

Cervical esophagostomy for tube feeding was evaluated in 11 ponies. Minor complications responded to supportive therapy in 8 ponies. Two died of complications, and 1 pony had a permanent fistula because of persistent infection.

There was a positive correlation between the duration of tube feeding and the event of closure of the esophageal stoma after the tube was removed. There was no difference in the frequency of complications related to duration of tube feeding.

When the distal end of the feeding tube was located in the thoracic portion of the esophagus, instead of in the stomach, tubes were more readily dislodged. Reinsertion of some tubes was difficult or impossible to do and resulted in false passage of the tube into the mediastinal space, dissecting infections into the thorax, or both. Reflux of food around the tube occurred in ponies with the distal end of the feeding tube located in the stomach, but this was not associated with other complications.
Effects of Cream on Bactericidal and Metabolic Functions of Bovine Polymorphonuclear Neutrophils
Authors: Eshelman J. E. , Eberhart R. J. , Scholz R. W.
Published: February 2025

The effects of cream on the bactericidal capacity and on selected metabolic characteristics of bovine blood polymorphonuclear leukocytes (pmn) were examined in vitro. These properties were also compared in blood pmn and pmn isolated from milk.

Addition of 4% cream to the incubation medium reduced killing of Staphylococcus aureus by blood pmn. The pmn from milk were as bactericidal as blood pmn when incubated in a synthetic medium without cream.

Cream reduced the phagocytosis-induced increment in O2 uptake in blood pmn. Compared to blood pmn in the absence of cream, pmn isolated from milk had reduced O2 uptake during phagocytosis. In all pmn preparations [14C]CO2 production from [1-14C]glucose and [6-14C]glucose was increased during phagocytosis. Rates of [14C]CO2 conversion from [1-C14]glucose were not significantly different among blood pmn, blood pmn plus cream, and milk pmn. Cream reduced [14C]CO2 conversion from [6-14C]glucose by blood pmn; milk pmn converted even less [6-14C]glucose to [14C]CO2 than did blood pmn in the presence of cream.

Cream added to blood pmn preparations in the absence of other phagocytizable particles increased O2 uptake, increased (nonsignificantly) [14C]CO2 conversion from [1-14C]glucose, and reduced conversion from [6-14C]glucose.

These studies confirm that cream reduces the bactericidal capacity of bovine pmn and reveal cream-induced alterations in selected metabolic pathways during phagocytosis. They show also that cream itself, in the absence of bacteria, alters pmn metabolism.
Effect of an Intramammary Polyethylene Device on the Concentration of Leukocytes and Immunoglobulins in Milk and on the Leukocyte Response to Escherichia coli Endotoxin and Challenge Exposure with Staphylococcus aureus
Authors: Paape M. J. , Schultze W. D. , Guidry A. J. , Kortum W. M. , Weinland B. T.
Published: February 2025

A sterilized polyethylene intramammary device (imd) was inserted through the papillary duct (teat canal) into a front mammary quarter and a rear mammary quarter of 7 cows. The device was 2 mm in diameter and 115 mm long; it was in the form of a loop of 25 mm diameter in situ. Insertion of the imd caused rapid increases in the concentration of milk somatic cells which stabilized at concentrations 50% higher than the milk somatic cell values for the control quarters. Fractions of milk were collected during machine milking to determine the concentrations of milk somatic cells, immunoglobulins (Ig), and bovine serum albumin (bsa). Milk somatic cell counts in the 1st, 2nd, and 20th 10-ml milk fractions and in the primary, stripping, and residual milk fractions for imd-fitted quarters averaged 1.090, 0.429, 0.485, 0.512, 1.781, and 1.763 × 106 cells/ml. The counts for control quarters averaged 0.280, 0.203, 0.211, 0.300, 0.481, and 0.800 × 106 cells/ml, respectively. Counts for imd-fitted quarters were significantly greater than for control quarters for all fractions except the primary milk fraction. The concentrations of Ig and bsa for imd-fitted quarters tended to be higher for all milk fractions when compared with the values for control quarters, but were significant only for IgG2 and bsa in the residual fractions.

There was no difference between imd-fitted and control quarters in milk yield, percentage of butterfat, percentage of protein, or solids-not-fat.

Injection of 0.01 μg of endotoxin into all quarters resulted in a greatly intensified leukocytic response for imd-fitted quarters compared with the control quarters. Milk somatic cell counts for imd-fitted quarters increased from 0.8 × 106 cells/ml before injection to 4.3 × 106 at 10 hours after injection, whereas the counts for control quarters increased from 0.4 × 106 cells/ml to 1.8 cells/ml of milk.

Experimental challenge exposure of all quarters of 5 cows with 23.8 to 115.0 colony-forming units of Staphylococcus aureus strain 305 resulted in infection in 9 of 10 control quarters and in 5 of 10 imd-fitted quarters. With few exceptions, infection occurred when the concentration of somatic cells in the gland was 7 × 105 or less/ml of milk at the time of bacterial challenge exposure and failed to occur when the somatic cell concentration was 8.8 × 105 or greater/ml.