bluuebunny/crossref_metadata_2025 huggingface dataset:
Histopathologic features of canine heartworm microfilarial infection after treatment with ivermectin
Authors: McManus Edward C. , Pulliam James D.
Published: February 2025

Tissues of dogs treated with ivermectin were examined microscopically to learn the fate of microfilariae of canine heartworm that disappear from the peripheral circulation within a few days of treatment. Medicated dogs were killed 18 hours, 3 days, and 6 days after treatment with 0.5 mg of ivermectin/kg of body weight subcutaneously. Ivermectin was dissolved in 60% propylene glycol and 40% glycerol formal.

In dogs killed at posttreatment hour 18, the peripheral microfilaremia had decreased by an average of 89%. At this time, a dense mass of rbc, wbc, and macrophages plus many microfilariae was found in pulmonary alveolar septae. Similar reactions were seen in liver, kidney, and spleen. Phagocytosis of microfilarial fragments was evident.

In dogs killed at posttreatment day 3, many microfilariae were fragmented and phagocytosis of the fragments was common. In dogs killed at posttreatment day 6, microgranulomas were common, particularly in such vascular organs as lungs, kidney, and liver. Microgranulomas containing microfilariae were also seen in spleen, skeletal and cardiac muscles, diaphragm, lymph nodes, gastrointestinal tract, and pancreas. Small glial nodules were seen in the cns. Denudation of the atrial epicardium was associated with fragments of microfilariae and granulomatous inflammatory cells.

Renal epithelial crescents were observed in treated and nontreated dogs. Plasma cells were conspicuous in treated and nontreated dogs, especially in some livers and kidneys.

Before treatment, all dogs were severely microfilaremic. At the end of the experiment, the peripheral microfilaremia was reduced by 98%. Of the 9 treated dogs, 1 was listless and had an increased body temperature for 2 days after treatment; other clinical signs of disease were not observed.
Contagious ecthyma virus-vaccination failures
Authors: Buddle Bryce M. , Dellers Robert W. , Schurig Gerhardt G.
Published: February 2025

Cross-protection experiments were undertaken to investigate reasons for contagious ecthyma (ce) virus-vaccination failures. Vaccination with sheep-passaged or with cell culture-passaged virus did not protect lambs against development of lesions after challenge inoculation with sheep-passaged virus. However, lesions which developed after challenge exposure with sheep-passaged ce virus healed significantly faster than did those induced by the initial vaccination with sheep-passaged virus (P < 0.001). A significant decrease in the healing time was not observed for lambs initially vaccinated with cell culture-passaged ce virus after challenge exposure with sheep-passaged virus (P > 0.05). Protection was evident when lambs were challenge inoculated with the less virulent cell culture-passaged virus and cross-protection between the ST and CSL isolates was detected.

This study indicated that complete protection even against homologous strain challenge was not achieved. Antigenic differences between vaccinal and field strains appeared an unlikely cause of vaccination failures. It also is evident that cell culture-propagated ce virus preparations are less effective for vaccination purposes than are those propagated in sheep.
Hemodynamics of progressive pneumopericardium in the dog
Authors: Reed John R. , Thomas William P.
Published: February 2025

The hemodynamics of progressive pneumopericardium were studied in 6 anesthetized healthy dogs (with intact thorax). Heart rate, cardiac output, and pericardial and intravascular pressures were recorded. Pressures were measured in the pericardial space by means of a percutaneously introduced, air-filled catheter, and in the right atrium, right ventricle, left atrium, left ventricle, pulmonary artery, and aorta by means of fluid-filled catheters. The gradual increase in mean pericardial pressure up to 11 ± 2 mm of Hg was associated with increases in heart rate and mean right atrial, mean left atrial, right ventricular end-diastolic, and left ventricular end-diastolic pressures and with decreases in cardiac output and stroke volume, with no change in left ventricular systolic and mean aortic pressures. Critical cardiac tamponade occurred at a pericardial pressure of 12.2 ± 2.8 mm of Hg, which was produced by 8.7 ± 1.9 cm3 air/kg of body weight. This was characterized by a sudden marked decrease in heart rate, cardiac output, stroke volume, left ventricular systolic pressure, and mean aortic pressure, and equilibration of mean right atrial, mean left atrial, right ventricular end-diastolic, left ventricular end-diastolic, and pulmonary artery diastolic pressures. These hemodynamic changes were similar to those of experimental pericardial effusion.
Effects of castration, with and without testosterone replacement, on leg bone integrity in the domestic fowl
Authors: Johnson A. L. , Rendano V. T.
Published: February 2025

Studies were conducted to assess the effects of castration on leg bone integrity of male White Leghorn chickens. Eighteen 5-week-old males were randomly allocated to 3 groups: group 1—intact controls, group 2—castrated, and group 3—castrated and subsequently treated with testosterone (T)-filled Silastic capsule implants. Body weight and plasma concentrations of luteinizing hormone, androgens, and total calcium were measured in each bird at intervals throughout the experiment. Subsequently, radiographs were performed upon the tibiotarsus-tarsometatarsus region of the left limb of birds from the 3 treatment groups at 7, 35, and 47 weeks of age and assigned a score of 1 to 3 (1 = normal; 3 = greatest pathologic change). Analysis of radiologic scores indicated that at 35 and 47 weeks, castrated birds (group 2) had a mean score significantly greater than that of control birds (group 1). The abnormality was typified by hyperossification with exostoses in the ossified tibial cartilage and lateral calcaneal ridge. In contrast, radiologic scores from individual T-implanted castrated birds (group 3) at 35 and 47 weeks were more variable, but the mean score was not statistically different from that of the control group.

We conclude that the depression of circulating concentrations of sex steroids, by castration, in young male chickens results in hypercalcification of the tibiotarsus-tarsometatarsus region of the limb. This effect appears to be mediated directly or indirectly by T or a metabolite of T.
Plasma copper concentration and packed cell volume and their relationships to fertility and milk production in Holstein cows
Authors: Kappel L. C. , Ingraham R. H. , Morgan E. B. , Babcock D. K.
Published: February 2025

Jugular blood samples were obtained from 55 summer-calving and 40 winter-calving Holstein cows fed diets which averaged 7.4 μg of Cu/g. Samples were collected within 3 days of 30, 11, and 4 days before calving and 4, 11, 18, 25, 39, 60, 88, 116, and 147 days after calving. Packed cell volume and plasma Cu concentrations were determined. Blood components were analyzed in relationship to season, milk production, lactation number, number of days to conception, number of postcalving uterine infusions, and time relative to calving. The environmental temperature-humidity index was used as a covariate in the analysis, so that seasonal effects represented feeding or production differences between seasons and were not due to the direct effects of climate.

Plasma Cu concentrations were within the usual laboratory limits (1.05 ± 0.20 μg/ml). These values were unrelated to pcv in the summer-calving cows, but were slightly related in the winter-calving cows (r = 0.11). Plasma Cu values increased around the time of calving, with the maximum level (1.13 μg/ml) occurring on postpartum day 11. Plasma Cu concentration was higher in cows that conceived within 80 days of calving than in cows which conceived at 120 days or more. Differences in plasma Cu among fertility groups were most evident during postpartum days 25 to 60. However, the relationship between plasma Cu concentrations and fertility was not consistent. Significant interactions existed for season × fertility groups and milk production groups × fertility groups. Plasma Cu concentration was significantly higher for the summer-calving cows and was inversely related to milk production level. The season × production group interaction also was significant for plasma Cu concentration.

The pcv decreased by 3.2% after cows had calved, with the lowest pcv occurring at postpartum day 39. The winter-calving cows had a significantly higher pcv than did the summer-calving group. Cows that conceived within 120 days of calving had a higher pcv than did cows which conceived later than 120 days after calving. These differences were significant at postpartum days 60, 88, 116, and 147 and were consistent over seasons and production groups. Cows given 2 or more uterine infusions before breeding had a lower pcv on 6 of the 9 postcalving sample collection days. First-lactation heifers had a significantly higher pcv. For the summer-calving cows, pcv was not related to milk production level. For the winter-calving cows, the high production group had the highest pcv from postpartum days 39 through 88 and then decreased to the lowest pcv at postpartum day 147.
Detection of canine antisperm antibodies by indirect immunofluorescence and gelatin agglutination
Authors: Rosenthal R. C. , Meyers Walter L. , Burke Thomas J.
Published: February 2025

Canine infertility has diverse and multiple causes. Immunologic infertility due to antisperm antibody is recognized and quantitated in other species, but this entity appears not to have been described in the dog. Before this time, there has been no practicable and reliable method to measure canine antisperm antibodies. This study was directed at inducing the production of such antibodies by immunizing dogswith sperm antigens and measuring the resulting antibodies, using the recognized techniques of indirect fluorescent antibody testing and sperm agglutination testing. Measurable antibody responses were observed.
Effects of dietary supplementation with butylated hydroxyanisole, cysteine, and vitamins B on tansy ragwort (Senecio jacobaea) toxicosis in ponies
Authors: Garrett B. J. , Holtan D. W. , Cheeke P. R. , Schmitz J. A. , Rogers Q. R.
Published: February 2025

Dried tansy ragwort, which contains pyrrolizidine alkaloids, was fed as 10% of a complete diet to ponies, with and without a mixture of additives. The additives provided a dietary supplement equivalent to 1% cysteine, 0.75% butylated hydroxyanisole, 200 μg of vitamin B12/kg of feed, and 5 mg of folic acid/kg of feed. The additives did not alter tansy ragwort toxicity, as assessed by survival time, liver changes, sulfobromophthalein (bsp) clearance rate, serum γ-glutamyl transpeptidase activity, and plasma amino acid patterns. In ponies fed tansy ragwort, bsp clearance rate was a sensitive indicator of liver damage, and decreased to about 20% of control values. γ-Glutamyl transpeptidase activities showed considerable variability, but generally were elevated in animals fed tansy ragwort. Liver iron and copper concentrations increased, and liver zinc concentrations decreased in tansy ragwort-fed ponies. Plasma amino acid patterns in tansy ragwort-fed ponies showed changes typical of those observed in liver disease.
Platelet concentration and platelet volume distribution in healthy cats
Authors: Weiser M. G. , Kociba G. J.
Published: February 2025

An electronic particle counter and size analysis system were used to determine platelet count, mean platelet volume (mpv), platelet volume heterogeneity (sd of platelet volumes), and platelet mass values in feline platelet-rich plasma (prp) prepared by brief centrifugation of blood. Electronic platelet counts correlated well with manual counts done by phase microscopy over a platelet count range of 5,000/μl to 840,000/μl (r = 0.93). Variability in manual and electronic counts was not significantly different. However, due to differential stratification of platelet concentration in prp, electronic counts on aspirated, mixed prp were significantly less variable (P < 0.01).

Reference values, determined on blood from 25 healthy adult cats, were platelet count: 296,000 to 850,000/μl; mpv: 11.0 to 18.1 fl; platelet volume heterogeneity: 5.8 to 10.6 fl, and platelet mass: 4.0 to 11.4 μl/ml of blood. There was a direct relationship between mpv and platelet volume heterogeneity and an inverse relationship between mpv and platelet count. Platelet concentration and size were not constant in different prp layers. Aliquots of prp near the top had a significantly lower platelet concentration (P < 0.001) and lower mpv (P < 0.001) than did aliquots from near the bottom of the prp layer. During the 4 hours after sample collection, there was a progressive decrease in platelet count and progressive increase in mpv, but the changes were not significant. When platelets were incubated in counting fluid, there was a slight increase in mpv by 1.5 hours. By 2.5 hours, there was a significant increase in mpv (P < 0.05).
Association of parainfluenza-3 virus with bovine macrophages and blood cells: An in vitro study
Authors: Stauber Erik H. , Weston Kathleen J.
Published: February 2025

Bovine blood cells and peritoneal and lung macrophages were exposed in vitro to parainfluenza-3 (pi-3) virus. Residual nonadsorbed pi-3 virus (expressed in percentage of input virus) in the supernate of the various cell fractions 1 hour after incubation at 37 C was as follows: lung macrophages, 11%; peritoneal macrophages, 59%; monocytes, 26%; rbc, 14%; lymphocytes, 28%; and polymorphonuclear cells (pmn), 63%. Lung macrophages, monocytes, lymphocytes, and pmn were monitored over a 72-hour period for hemadsorption of chicken rbc. Hemadsorption increased for lung macrophages and monocytes, whereas it decreased for lymphocytes and pmn. Infective virus could not be recovered from pmn, rbc, lymphocytes, or monocytes for more than 24 hours after pi-3 infection. Recovery of infective pi-3 virus from infected peritoneal and lung macrophages extended over 4 to 8 days, respectively.
Effects of isoflurane anesthesia on equine liver function
Authors: Engelking Larry R. , Dodman Nicholas H. , Hartman Gail , Valdez Henry
Published: February 2025

The acute 2-hour effects of isoflurane anesthesia on liver function and biliary excretion were examined in 2 ponies prepared surgically with chronic external biliary fistulas (T-tubes). Studies were conducted 2 to 8 months postoperatively with the enterohepatic circulation held intact between studies. Bile acid infusion iv (8.1 to 8.8 μmol/min) helped maintain bile flow and bile acid and bilirubin excretion during complete biliary diversion throughout each study. Following 3-hour control periods, anesthesia was induced and maintained at 1.3 to 1.5 minimal alveolar concentration plus O2 (spontaneous breathing) for 2 hours. Compared with the immediate 2-hour preanesthesia values, isoflurane caused significant increases in pcv (27%) and biliary bilirubin excretion (24%). However, no significant differences were detected in plasma or biliary bilirubin concentrations, biliary bile acid concentration or excretion, bile flow, or plasma aspartate aminotransferase concentrations between preanesthesia control and anesthesia periods.

The results indicate that although isoflurane anesthesia enhanced hepatic bilirubin excretion, its effects on hepatic bilirubin formation and/or clearance are modest, compared with effects of halothane anesthesia which have previously been shown to enhance equine bilirubin excretion by 138% and reduce bile acid excretion by 27%. Isoflurane anesthesia in ponies does not appear to affect hepatic bile acid transport or bile formation significantly.
Production of cutaneous analgesia by electroacupuncture in horses: Variations dependent on sex of subject and locus of stimulation
Authors: Bossut Daniel F. B. , Page Edwin H. , Stromberg Melvin W.
Published: February 2025

Cutaneous pain thresholds to pinprick, pinch, and heat stimuli were quantified during control and electroacupuncture trials in 23 horses. Pain thresholds for 8 areas of the body during control trials (no needles) were statistically compared with pain thresholds measured in the same areas of the same horse when given electroacupuncture treatment. Statistically significant increases of pain threshold were interpreted as induced analgesia and occurred mainly in 5 areas of the trunk, but not in the head or extremities. Analgesic efficacy varied between sexes and among 3 groups of points chosen from Chinese traditional veterinary literature. Analgesia was induced equally well in both castrated males and intact females by the electrostimulation of 5 needles inserted on the gluteal (rump) and lumbar (loins) regions. However, stimulation of 2 needles located only in the gluteal region caused a significant analgesia in females only. In contrast, stimulation of 2 needles located in the thoracic limb was analgesic in males, but infrequently so in females. Therefore, we observed differential analgesia due to an interaction between needle location and sex of subject.
Xenogeneic monoclonal antibodies to cell surface antigens of equine lymphocytes
Authors: Newman M. J. , Beegle K. H. , Antczak D. F.
Published: February 2025

Monoclonal antibodies to equine lymphocyte antigens were produced, using normal peripheral blood lymphocytes as the immunogen and standard hybridoma techniques. Antibody producing hybridomas were detected by a solid-phase enzyme-linked immunosorbent assay. Antibodies produced by 6 cloned hybrids were characterized further by microlymphocytotoxicity, indirect immunofluorescence, and agglutination assays on peripheral blood lymphocytes, platelets, and erythrocytes. Reaction patterns on leukocytes indicated that these antibodies may recognize at least 3 different cell-surface antigens: (1) an antigen present on most peripheral blood lymphocytes and on platelets, (2) an antigen present on most peripheral blood lymphocytes, but absent from platelets, and (3) an antigen expressed by a major subpopulation of lymphocytes and also present on platelets. This last antigen is polymorphic and is expressed on the lymphocytes of approximately 75% of horses. The distribution of this polymorphic antigen did not correlate with the antigen distribution of any of the defined antigens of the equine major histocompatibility system. None of the 6 monoclonal antibodies reacted with antigens expressed on erythrocytes. These results indicate that monoclonal antibodies may be useful for the identification and characterization of various leukocyte antigens in the horse.
Pharmacokinetics of tetracycline encapsulated in bovine carrier erythrocytes
Authors: DeLoach J. R. , Wagner G. G.
Published: February 2025

Tetracycline was encapsulated in erythrocytes with a dialysis technique. The effect of drug concentration (0.2 mg/ml of erythrocytes) on encapsulation of [14C]sucrose and [3H]tetracycline was reduction of the tetracycline encapsulation, but not [14C]sucrose. Carrier erythrocytes containing tetracycline reinjected in calves were studied for their pharmacokinetic constants. The drug half-life was 6.7 hours, with an overall elimination constant of 0.104 hour-1.
Efficacy of ivermectin in oral paste formulation against immature gastrointestinal and pulmonary nematodes in cattle
Authors: Alva-Valdes R. , Benz G. W. , Wallace D. H. , Egerton J. R. , Gross S. J. , Wooden J. W.
Published: February 2025

The anthelmintic efficacy of ivermectin in oral paste formulation was evaluated against the 4th-stage larvae of 8 gastrointestinal nematodes and the common lungworm in 14 experimentally inoculated calves. Two groups consisting of 7 calves each were formed by restricted randomization on body weight. The infective larvae were given orally to the animals on a staggered schedule so that the parasites were in the 4th larval stage when the animals were treated. One group was given vehicle paste, and the other group was treated with ivermectin in oral paste at the dose level of 200 μg/kg of body weight. The animals were killed 18 or 19 days after treatment. Ivermectin was 100% effective against Dictyocaulus viviparus, Oesophagostomum radiatum, Haemonchus placei, Ostertagia ostertagi, and Trichostrongylus axei and > 99% effective against Cooperia oncophora, C punctata, T colubriformis, and Nematodirus helvetianus.
Effects of sterilized micropulverized barium sulfate suspension and meglumine iothalamate solution on the genitourinary tract of healthy male dogs after retrograde urethrocystography
Authors: Feeney Daniel A. , Johnston Gary R. , Tomlinson Michael J. , Osborne Carl A.
Published: February 2025

A sufficient quantity of 30% w/v sterile barium sulfate suspension was infused into the caudal portions of urinary tracts of 12 young adult healthy male Beagles to induce vesicoureteral reflux. A control group of dogs was infused with a 7.5% solution of meglumine iothalamate. The dogs were radiographed at 1, 6, 13, and 29 days later. Three dogs from each group were euthanatized and necropsied (1 each) after radiography at each of these times. In some dogs, radiopacity in the prostate, urinary bladder, and renal pelvic diverticula due to barium persisted throughout the 30-day observation period. Opacity at or beyond 24 hours was not found in dogs infused with iothalamate.

Light microscopy revealed barium either free or within macrophages in the submucosa of the bladder, in glandular and stromal areas of the prostate, and in the kidney. Renal barium was limited to pelvic diverticula (3 dogs), in a medullary tubule (1 dog), and in cortical tubules (2 dogs). Significant lesions attributable to barium were not seen in kidneys of dogs in the barium group. Iothalamate induced focal to multifocal inflammatory responses in some prostates; barium was phagocytosed by macrophages. Focal transient inflammatory and ulcerative lesions induced by bladder distention were observed in the bladder and urethral mucosa in both groups.
Effects of single intravenous doses of dexamethasone on baseline plasma cortisol concentrations and responses to synthetic ACTH in healthy dogs
Authors: Kemppainen R. J. , Sartin J. L.
Published: February 2025

The duration of adrenocortical suppression resulting from a single iv dose of dexamethasone or dexamethasone sodium phosphate was determined in dogs. At 0800 hours, 5 groups of dogs (n = 4/group) were treated with 0.01 or 0.1 mg of either agent/kg of body weight or saline solution (controls). Plasma cortisol concentrations were significantly (P < 0.01) depressed in dogs given either dose of dexamethasone or dexamethasone sodium phosphate by posttreatment hour (pth) 2 and concentrations remained suppressed for at least 16 hours. However, by pth 24, plasma cortisol concentrations in all dogs, except those given 0.1 mg of dexamethasone/kg, returned to control values. Adrenocortical suppression was evident in dogs given 0.1 mg of dexamethasone/kg for up to 32 hours.

The effect of dexamethasone pretreatment on the adrenocortical response to ACTH was studied in the same dogs 2 weeks later. Two groups of dogs (n = 10/group) were tested with 1 μg of synthetic ACTH/kg given at 1000 hours or 1400 hours. One week later, half of the dogs in each group were given 0.01 mg of dexamethasone/kg at 0600 hours, whereas the remaining dogs were given 0.1 mg of dexamethasone/kg. The ACTH response test was then repeated so that the interval between dexamethasone treatment and ACTH injection was 4 hours (ACTH given at 1000 hours) or 8 hours (ACTH given at 1400 hours). Base-line plasma cortisol concentrations were reduced in all dogs given dexamethasone 4 or 8 hours previously. Although neither dose of dexamethasone altered the adrenocortical response to ACTH administered 4 hours after dexamethasone treatment, dogs given 0.1 mg of dexamethasone/kg 8 hours previously had a reduced responsiveness.
Immunoglobulin concentrations in serum and nasal secretions of calves at the onset of pneumonia
Authors: Corbeil L. B. , Watt B. , Corbeil R. R. , Betzen T. G. , Brownson R. K. , Morrill J. L.
Published: February 2025

Immunoglobulin (Ig) concentrations in serum and in nasal secretions were correlated with pneumonia and diarrhea during the first 12 weeks of life in 56 calves. The peak onset of pneumonia occurred between 2 and 4 weeks of age when the calves’ serum IgG1, IgG2, and IgA concentrations were lowest. As IgG2 concentrations increased, fewer calves developed pneumonia. Peak onset of pneumonia was also correlated with the lowest IgG and IgA concentrations in the calves’ nasal secretions.

Most calves developed pneumonia when serum concentrations of IgG1 were < 1.5 g/dl, IgG2 < 0.3 g/dl, IgA < 0.1 g/dl, and IgM < 0.2 g/dl and when the combined IgG and IgA values in nasal secretions were < 0.2 mg of Ig/mg of protein. In study A, diarrhea preceded pneumonia in 63% of 56 calves. In study B, 38% of 23 calves had diarrhea and/or hemorrhagic feces before pneumonia. Seemingly, there was a relationship between diarrhea and pneumonia. Furthermore, pneumonia occurred at or just after the time when IgG1, IgG2, and IgA concentrations in serum and the combined IgG and IgA concentrations in nasal secretions were lowest.
Diagnostic value of urinary dialkyl phosphate measurement in goats exposed to diazinon
Authors: Mount Michael E.
Published: February 2025

Recognition of exposure to diazinon, an organophosphate insecticide, was studied in goats. Urine and milk dialkyl phosphate concentrations (detp; O,O-diethyl phosphorothionate) and blood cholinesterase activity (ChE) and diazinon concentrations were measured. Groups (n = 3 each) given (orally) diazinon at doses of 0.5 mg/kg for 7 days (small dose) or 5 mg/kg for 7 days (large dose) were compared with goats acutely exposed to single doses of 150 mg/kg (n = 1) or 700 mg/kg (n = 1). Clinical signs of intoxication occurred only in the goat given the 700 mg/kg dose. Urinary detp concentrations were sensitive indicators of diazinon exposure and provided quantitative differences between small, large, and acute dosage exposures. Milk detp concentrations were not detected. Cholinesterase measurement was useful only in the acute exposure studies. Whole blood diazinon concentrations were detected only in goats given the large dose for 7 days and acutely exposed. Measurement of urinary detp was a sensitive aid for recognition of diazinon exposure.
Pharmacokinetics of ticarcillin in the horse after intravenous and intramuscular administration
Authors: Sweeney C. Raphel , Soma L. R. , Beech J. , Reef V. , Simmons R.
Published: February 2025

Serum and peritoneal fluid concentrations of ticarcillin were measured in 10 healthy adult horses from 0.5 to 8 hours after iv or im administration of 44 mg/kg of body weight. After iv injection, the serum concentration at 30 minutes was 104.3 ± 6.1 mg/L and the mean peak peritoneal fluid concentration (61.4 ± 29.0 mg/L) occurred 2 hours after injection. The peak serum (28.3 ± 5.5 mg/L) and the peak peritoneal fluid concentrations (19.2 ± 6.0 mg/L) occurred 2 hours after the im injection. Ticarcillin (≥ 2 mg/L) persisted in serum and peritoneal fluid for 6 hours after iv injection and 8 hours after im injection. The half-life of ticarcillin was 0.94 hour after iv injection and the bioavailability of ticarcillin administered im was 64.9%.
Use of fiberoptic bronchoscopy in experimental production of bovine respiratory tract disease
Authors: Potgieter L. N. D. , McCracken M. D. , Hopkins F. M. , Walker R. D. , Guy J. S.
Published: February 2025

Fourteen 6-month-old calves were infected with Pasteurella haemolytica or infectious bovine rhinotracheitis (ibr) virus. Four calves were inoculated sequentially with ibr virus followed by Ρ haemolytica at a 5-day interval. Calves were inoculated by allowing them to inhale an aerosol of the organism or by placing an inoculum in the right lung, using fiberoptic bronchoscopy. Clinical signs of infection were recorded, and the calves, if they survived, were killed and necropsied 3 days after inoculation with Ρ haemolytica (or 8 days after inoculation with ibr virus). The extent of pulmonary lesions was determined, and the lower respiratory tract (lungs and lower trachea) was examined for both organisms.

Inoculation of the calves by aerosolization with ibr virus alone resulted in mild respiratory tract disease. Mild-to-moderately severe respiratory tract disease developed as a result of sequential inoculations by aerosolization with ibr virus and P haemolytica. However, respiratory tract disease did not develop in calves exposed by aerosol to Ρ haemolytica alone. Large numbers of these organisms were recovered from the lower respiratory tract of the dually inoculated calves, only indicating delayed pulmonary clearance.

Mild clinical signs of disease but substantial, though localized, pneumonic lesions developed in calves inoculated with Ρ haemolytica by fiberoptic bronchoscopy. Calves inoculated with ibr virus by the latter procedure developed moderately severe respiratory tract disease involving 25% to 30% of the total lung volume. Lesions occurred mainly in the right lung, but the left lung also had marked lesions in these calves. A severe fibrinous bronchopneumonia and pleuritis involving > 50% of the volume of both lungs resulted when the calves were inoculated sequentially with ibr virus and Ρ haemolytica by the endobronchial route. Delayed pulmonary clearance of these organisms occurred in all calves after endobronchial inoculation. The value of using fiberoptic bronchoscopy for endobronchial inoculation in experimental production of bovine respiratory tract disease is discussed.
Counterimmunoelectrophoresis for the diagnosis of bovine mycoplasmosis
Authors: Bois J. M. , Roy R. S. , Guay P.
Published: February 2025

Counterimmunoelectrophoresis (cie) procedure has been established for mycoplasma identification from cultures, and the specificity and the sensitivity of this technique were evaluated. Preparations of milk samples and clinical and necropsy specimens were used for the technique. From 171 milk samples, 80 (46.8%) were positive by cie (73 samples with Mycoplasma bovis and 7 with Mycoplasma arginini) and 77 (45%) were positive by biochemical and growth inhibition tests (70 samples with Mycoplasma bovis and 7 with Mycoplasma arginini). From 36 mycoplasma culture-positive clinical and necropsy specimens, cie identified 5 different mycoplasma species and from 3 mycoplasma culture-positive specimens, the technique identified coinfection by 2 mycoplasma species. The cie is a reliable, specific, sensitive, and rapid technique for the diagnosis of mycoplasmosis in the bovine.
Long-term study on the effects of electroejaculation on seminal characteristics of the domestic cat
Authors: Pineda M. H. , Dooley M. P. , Martin P. A.
Published: February 2025

Semen was collected by electroejaculation from 9 random-source cats. There were 22 seminal collections over 32 weeks. An electroejaculate was defined as the seminal fluid and spermatozoa collected during the application of 60 electrical stimuli—the 1st 40 stimuli at 2.0 V, and immediately afterward, 20 stimuli at 3.0 V. Four sequential electroejaculates were obtained from each cat at each seminal collection. The volume and number of spermatozoa for each electroejaculate were determined. There was a significant (P < 0.005) effect of cat and sequence of electroejaculate for both the volume and number of spermatozoa in the electroejaculate. There was no effect of week of collection; however, there was a trend (P < 0.1) for the volume of electroejaculate to increase with time. The interactions of cat × week of collection and electroejaculate sequence × week of collection for the volume and for the number of spermatozoa per electroejaculate were not significant (P > 0.05).

The volume of the 1st electroejaculate of the sequence was lower (P < 0.01) and the number of spermatozoa in the 2nd of the sequential electroejaculates was higher (P < 0.05). There was considerable variation within and between cats in the volume and number of spermatozoa. Repeated anesthesia and electrical stimulation did not appear to alter the ejaculatory capacity of the cat.
Morphology of bovine viral diarrhea virus
Authors: Chu Hsien-Jue , Zee Yuan Chung
Published: February 2025

The morphology of bovine viral diarrhea virus (bvdv) was studied by electron microscopy. The NADL strain of bvdv was plaque purified 3 times, concentrated by polyethylene glycol precipitation, and purified by centrifugation to equilibrium in continuous potassium tartrate density-gradients. The virus was examined by negative-stain electron microscopy in the presence or absence of specific antiserum. The density of bvdv was between 1.101 g/cm3 and 1.174 g/cm3, with the peak at maximum infectivity at 1.122 g/cm3. Oval to pleomorphic viral particles, 120 (± 30) nm in diameter, were enriched in the peak of maximum infectivity. The detailed structure of virions was revealed: a 5- to 7-μm thick unit membrane-like envelope layer with numerous projecting knobs, 4 to 5 nm in diameter, surrounding an interior core-like structure. Viral particles measuring 120 (± 30) nm were found in large aggregates in the presence of specific antiserum.
Effects of dopamine and serotonin on eructation rate and ruminal motility in sheep
Authors: Sorraing Jean-Marc , Fioramonti Jean , Bueno Lionel
Published: February 2025

The relationships between forestomach motility and eructation rate were studied during dopamine infusion (2 sheep) and serotonin infusion (2 sheep). The sheep were chronically fitted with strain gauges on the reticulorumen and with a cannula in the dorsal sac of the rumen. A tracheotomy was performed to intercept the eructated gases and to permit measurement of their volume. To maintain a regular rate of eructation during the control periods, experiments were performed with a moderately increased intraruminal pressure obtained by continuous ruminal insufflation of nitrogen. Dopamine and serotonin were infused (iv for 10 minutes) at rates of 25, 50, and 100 μg/kg/min and 4, 8, and 16 μg/kg/min, respectively.

Dopamine and serotonin both decreased the frequency of primary contractions. Dopamine reduced the amplitude of secondary contractions, whereas serotonin increased the forestomach tone and suppressed secondary contractions which were replaced by unpropagated eructative contractions. These motility changes were associated with a decrease in eructation rate during dopamine infusion and an increase in the eructation rate during serotonin infusion. After dopamine infusion was stopped, rebounds of eructation rate and rumen motility were observed which disappeared when a constant intraruminal pressure was maintained, indicating that the rumen reacts to its own distention.

Sulpiride, but not phentolamine or propranolol, blocked the effects of dopamine. The effects of serotonin were abolished by methysergide, but were unaffected by imipramine. Therefore, seemingly dopamine acts through specific dopaminergic receptors and serotonin impinges on smooth muscle serotoninergic receptors.

Finally, the use of dopamine and serotonin revealed that close relationships exist between the eructation rate and the pattern of ruminoreticular motility which may be preponderant against the cardia tone in the elimination of ruminai gases.
Determination of the oral toxicity of Sesbania drummondii seeds in chickens
Authors: Flory Wayne , Hebert Charles D.
Published: February 2025

Extracts of Sesbania drummondii administered to chickens by oral intubation are lethal within several days. Effects are dose-dependent; a dose of 1% of body weight is uniformly lethal in 5 days. Signs of poisoning include weakness, depression (cns), anorexia, diarrhea, ruffled feathers, cold feet, and rapid loss of body weight. Microscopic examination indicates damage to kidney glomeruli and leakage of protein into the kidney tubules. Packed cell volume and plasma glucose concentrations show no difference between controls and treated chickens; however, creatine kinase is increased and plasma cholinesterase and total plasma protein values are severely depressed in poisoned birds. Neither a specific toxin nor a mechanism of action for toxicity has yet been identified.
Combined effects of deoxycorticosterone and furaltadone on Escherichia coli infection in chickens
Authors: Gross W. B.
Published: February 2025

After low antibody-response line chickens were challenge exposed with Escherichia coli, 10% of the controls, 35% of those fed furaltadone, 37% of those fed deoxycorticosterone (doc), and 92% of those fed furaltadone and doc gained weight. Concentrations of doc above or below the optimal concentration (40 mg/kg of feed) were less effective, eg, when 100 mg of doc/kg of feed was fed with furaltadone, 45% of low antibody-response line birds gained weight as compared with 85% of the birds when furaltadone was fed alone. However, the optimal amount of doc did vary among genetic stocks and with environment. Stocks of birds also differed in their response to the concentration of furaltadone and doc. Socialization increased the effectiveness of furaltadone.
Monoclonal antibodies to Brucella surface antigens associated with the smooth lipopolysaccharide complex
Authors: Schurig Gerhardt G. , Hammerberg Craig , Finkler Beth R.
Published: February 2025

Hybridomas producing antibodies to determinants associated with the lipopolysaccharide (lps) of Brucella abortus and B melitensis were obtained by polyethylene glycol fusion of the SP2/0 myeloma cell line with B lymphocytes harvested from a Sprague-Dawley-derived rat previously immunized with whole B abortus strain 1119 organisms. Two clones, BRU38 and BRU28, were selected for their ability to react with whole B abortus organisms and purified smooth-lps (f5p). The BRU38 monoclonal antibodies were absorbed with live, rough strain 45/20 and smooth strains of B abortus and B melitensis organisms, whereas only smooth strains absorbed the antibody activity from BRU28. Complete inhibition of the monoclonal's activity could be achieved with crude smooth-lps, purified f5p fraction, and a water-soluble acid degraded polysaccharide. Absorption of BRU38 and BRU28 with rough Brucella lps, polysaccharide-B antigen, keto-deoxyoctanoic acid, or with several sugars and fatty acids known to be components of the Brucella lps complex had no effect on the monoclonals. The data indicate that antigenic determinants are associated with the smooth lps complex, probably with the O-side chain, and are expressed patchwise and in different quantities on several strains of B abortus and B melitensis. The B abortus rough strain 45/20 contains surface determinants which lead to the agglutination of smooth strain 1119 organisms, The potential use of monoclonals in competitive enzyme-linked immunosorbent assays for diagnostic purposes is discussed.
Efficacy of fenbendazole against migrating Ascaris suum larvae in pigs
Authors: Stewart T. B. , Bidner T. D. , Southern L. L. , Simmons L. A.
Published: February 2025

Twenty-four weanling crossbred pigs were inoculated with 10,000 embryonated Ascaris suum eggs. The infection was aborted in 1 group (n = 8 pigs) with fenbendazole (3 mg/kg of body weight) given on postinfection days 2, 3, and 4 and in a 2nd group (n = 8 pigs) given fenbendazole at the same rate on postinfection days 6, 7, and 8; a 3rd group (n = 8 pigs) was not treated with fenbendazole. All pigs were necropsied at 24 days after they were inoculated. Fenbendazole was 99% effective against A suum larvae in the 2 treated groups. Early treated pigs had significantly higher daily weight gains (P < 0.05) and were 22% more efficient in feed conversion than were nontreated pigs. Lung weights increased linearly with length of exposure to migrating A suum larvae (P < 0.10). Liver weights were greater in treated pigs than in non-treated pigs (P < 0.01). A negative correlation existed between number of liver lesions and liver weights of all pigs (P < 0.05).
Reproduction in feral horses: An eight-year study
Authors: Keiper Ronald , Houpt Katherine
Published: February 2025

The reproductive rate and foal survival of the free-ranging ponies on Assateague Island National Seashore were studied for 8 years, 1975 to 1982. Most (52%) of the 86 foals were born in May, 13% were born in April, 22.6% in June, 10.4% in July, and < 1% in August and September. The mean foaling rate was 57.1 ± 3.9% and the survival rate was 88.3 ± 3.6%. Forty-eight colts and 55 fillies were born (sex ratio 53% female). Mares < 3 years old did not foal and the foaling rate of 3-year-old mares was only 23%, that of 4-year-old mares was 46%, that of 5-year-old mares was 53%, and 6-year-old mares was 69%. The relatively poor reproduction rate was believed to be a consequence of the stress of lactating while carrying a foal when forage quality on the island was low. The hypothesis was supported by the higher reproductive rate (74.4 ± 24%) of the ponies in the Chincoteague National Wildlife Refuge on the southern part of the island. Their foals are weaned and sold in July each year. Despite the low reproductive rate on Assateague Island National Seashore, the number of ponies increased from 43 to 80, a 90% increase in the 8-year period or > 10%/yr. There were 24 deaths and 8 dispersals from the study area.
Prevalence of Anoplocephala perfoliata and lesions of Draschia megastoma in Thoroughbreds in Kentucky at necropsy
Authors: Lyons Ε. T. , Drudge J. H. , Tolliver S. C. , Swerczek T. W. , Crowe M. W.
Published: February 2025

A total of 396 Thoroughbreds (86 males, 293 females, and 17 geldings) in Kentucky, 1 to 30 years of age, were examined at necropsy for presence of Anoplocephala perfoliata (2 female horses were not examined) in the cecum and for lesions of Draschia megastoma in the stomach, during the 1-year period of Mar 1,1982 through Feb 28,1983. Prevalence of A perfoliata was 53% and of lesions of D megastoma was 63%.

All lesions of D megastoma were partially or entirely in the glandular region of the stomach. Distances of the midpoint of these lesions from the margo plicatus varied from 0 to 290 mm. The center of about 88% of the lesions was within 50 mm of the margo plicatus. Measurements of the size of the lesions, exclusive of masses, indicated that about 95% were ≤ 50 mm in diameter. There appeared to be a higher infection rate of lesions of D megastoma in younger horses (81% in 1 to 7 year olds) than in older horses (41% in 8 to 30 year olds) with a few exceptions.
Characterization of bovine herpesvirus-1 isolated from trigeminal ganglia of clinically healthy cattle
Authors: Rodriguez Luis L. , Homan E. Jane , Easterday Bernard C.
Published: February 2025

Isolates of bovine herpesvirus-1 (bhv-1) recovered from tissue explants of trigeminal ganglia of clinically healthy cattle were studied in vitro and in an animal model, and their characteristics were compared with those of vaccine and field strains of bhv-1. The isolates could be distinguished by their plaque size on cell monolayers, but were not significantly different in their thermal inactivation profiles at 48 C. Temperature-sensitive mutants were not found among the isolates when they were grown at 41 C. Selected isolates had different pathogenicity when inoculated in young rabbits.
Leukokinesis in bovine ostertagiasis: Stimulation of leukocyte migration by Ostertagia
Authors: Washburn S. Michelle , Klesius Phillip H.
Published: February 2025

A blind-well chemotaxis chamber method was used to indicate migration stimulation of bovine neutrophil and eosinophil polymorphonuclear leukocytes and macrophages as related to ostertagiasis. Live exsheathed Ostertagia ostertagi 3rd-stage larvae (L3) and soluble L3 antigen (sla), prepared by freeze thawing and sonic disruption of L3, enhanced cellular migration for eosinophils, but not for neutrophils and macrophages. Products of Lymphocytes cultured with sla for 3 to 6 hours were also examined, using lymphocytes from peripheral blood of helminth-free cattle and cattle infected with O ostertagi or Trichostrongylus axei. Lymphokines that enhanced cellular migration of neutrophils, eosinophils, and macrophages were present in culture supernatants of sla-stimulated lymphocytes from O ostertagi-infected cattle, but not from cattle infected with T axei or helminth-free cattle. Seemingly, L3 and sla were stimulants of eosinophil migration. Further, neutrophil, eosinophil, and macrophage migration was modulated by lymphokines produced by sla-stimulated lymphocytes from cattle with ostertagiasis.
Canine inherited hypertrophic neuropathy: Clinical and electrodiagnostic studies
Authors: Cooper Barry J. , deLahunta Alexander , Cummings John F. , Lein Donald H. , Karrema Grace
Published: February 2025

Clinical and electrodiagnostic features of acute and chronic canine-inherited hypertrophic neuropathy were studied in 20 affected dogs. The age of onset was consistently between 7.5 and 10 weeks of age. Affected pups had rapidly developing limb weakness accompanied by muscle hypotonia and hyporeflexia. There was no clinical evidence of cranial nerve dysfunction. Pups that did not develop limb contractures later regained some strength and became clinically stable for long periods, although they always remained weak.

Progressive slowing of nerve conduction velocities occurred during the development of clinical signs of limb weakness. Temporal dispersion of evoked muscle action potentials was present in more chronically affected dogs. Transient spontaneous activity was present in muscles of affected dogs examined by electromyography.

An autosomal recessive mode of inheritance was supported by the results of breeding studies.
Serologic pattern of canine heartworm (Dirofilaria immitis) infection
Authors: Glickman Lawrence T. , Grieve Robert B. , Breitschwerdt Edward B. , Mika-Grieve Marcia , Patronek Gary J. , Domanski Linda M. , Root Charles R. , Malone John B.
Published: February 2025

A total of 602 dogs at the Louisiana State University Veterinary Teaching Hospital were tested for antibodies to Dirofilaria immitis by enzyme-linked immunosorbent assay (elisa), using a purified adult dirofilaria-derived antigen. Most dogs also were evaluated for heartworm infection by a complete wbc count and a Knott test for circulating microfilariae. The serologic prevalence of heartworm infection was 34.7%; prevalence increased significantly (P = 0.0003) with age up to 8 years and then decreased. Dogs usually kept indoors were significantly (P = 0.005) less likely to be infected, as were dogs given diethylcarbamazine therapy (P = 0.0004). Coat length, sex, breed, and presence of intestinal parasites were not associated (P > 0.05) with a positive heartworm elisa result. The elisa titers showed a positive relationship with both eosinophil and basophil counts.

A total of 99 dogs evaluated radiographically were grouped according to results of the Knott test and radiographic examination as follows: (i) negative Knott test and negative radiographic examination (14 dogs), (ii) negative Knott test and positive radiographic examination (57 dogs), and (iii) positive Knott test and positive radiographic examination (28 dogs). The serologic prevalences of D immitis infection in each of these groups were 35.7%, 56.1%, and 85.7% for groups (i), (ii), and (iii), respectively. The elisa, when used in conjunction with the Knott test results, record of exposure, clinical signs, laboratory results, and radiographic changes, was found to be useful for studying serologic patterns and identifying risk factors for canine heartworm infection.