bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical aspects of experimentally induced chloride deficiency in Holstein calves
Authors: Blackmon D. M. , Neathery M. W. , Miller W. J. , Brown S. R. , Crowell W. A. , McGuire S. O. , Gentry R. P.
Published: February 2025

A severe total body chloride deficit was induced in Holstein calves by feeding a low-chloride ration (0.063% CI) and removing digesta daily from the abomasum through a surgically implanted cannula. Clinical signs of the deficit observed included polydipsia, polyuria, dehydration, anorexia, scleral injection, decreased respiratory rate, and blood and mucus in the feces. Necropsy findings included dehydration, blood in the lumen of the small intestine, and renal lesions. The most extensive histopathologic changes occurred in the renal tubular epithelium of the outer medulla where mineralization of the tubular epithelium and basement membranes was frequently seen.
Efficacy of triclabendazole against Fasciola hepatica and Fascioloides magna in naturally infected calves
Authors: Craig T. M. , Huey R. L.
Published: February 2025

Twenty calves (8 to 12 months old), naturally infected with Fasciola hepatica and Fascioloides magna, were obtained from Brazoria, Tex. They were randomly allotted to 3 treatment groups. One group (6 calves) was given the carrier without drug, the 2nd group (7 calves) was treated with triclabendazole at 6 mg/kg of body weight, and the 3rd group (7 calves) was treated with triclabendazole at 12 mg/kg. All treatments were administered as a drench. Calves given triclabendazole (either dosage level) had a 100% reduction in F hepatica burden as compared with the untreated controls. Both treatment doses also appeared to have detrimental effect on F magna infections. Viability of all flukes was determined on the basis of movement, color, and tegumental integrity. Clinical toxic reactions were not observed in the treated calves.
Idiopathic immune complex glomerulonephritis in dogs with multisystem involvement
Authors: Jeraj K. P , Vernier R. L. , Polzin D. , Klausner J. K. , Osborne C. A. , Stevens J. B. , Michael A. F.
Published: February 2025

Renal specimens obtained by biopsy and/or at necropsy from 4 dogs with nephrotic syndrome were studied using light, immunofluorescence, and electron microscopies. The glomerulonephritis observed in these dogs was considered an idiopathic immune complex glomerulonephritis associated with multisystem involvement because causes of glomerulonephritis in these dogs could not be established. Immunoglobulin A was observed in granular deposits in the mesangial and subendothelial regions of the glomeruli. The relationship of the clinical and pathologic features of this disease in dogs to various renal syndromes in human beings are described.
Susceptibility and reservoir potential of the dog to spotted fever-group rickettsiae
Authors: Norment B.R. , Burgdorfer Willy
Published: February 2025

This study was initiated to determine the degree of susceptibility of dogs to virulent and nonvirulent spotted fever-group rickettsiae and to evaluate dogs as sources of infection for ticks. Dogs were exposed either by inoculation (syringe) or by infective tick bite to the following rickettsial serotypes: (1) Rickettsia rickettsii (Wachsmuth and Sawtooth ♀ 2 strains), (2) R montana (M/5-6 B strain), and (3) R rhipicephaii (3-7- ♀6 strain). Results indicated that dogs inoculated with 1,000 or 10,000 egg infective doses of virulent R rickettsii developed a rickettsemia that was detectable as early as 4 days after inoculation to as late as 10 days. Conversely, none of the dogs inoculated with R montana (M/5-6 B) or R rhipicephali (3-7- ♀ 6) or exposed to ticks infected with these strains developed detectable rickettsemia, fever, or other observable clinical signs.

None of the 394 ticks that fed on rickettsemic dogs (R rickettsii) infected by inoculation became infected, and only 3 of 348 ticks (0.9% infection rate) were infected after feeding on dogs which had been infected by tick bite. All ticks fed on dogs exposed to R rhipicephali and R montana were shown to be free of rickettsiae.

The largest concentrations of plaque-forming units (pfu) in Vero cell culture from undiluted whole blood were found on day 6 and on day 7 in dogs that were inoculated with 10,000 and 1,000 R rickettsii, respectively, of the Sawtooth ♀ 2 strain. The highest rickettsial concentration observed for the dog infected by tick feeding was on day 9. Conversely, there were no pfu observed in Vero cell culture of undiluted whole blood of the dogs inoculated with 1,000 or 10,000 R rhipicephali (3-7- ♀ 6 strain) or exposed to infective Rhipicephalus sanguineus.

On the basis of these data, it would appear that the dog, under natural conditions, is not an efficient reservoir for infecting ticks with either virulent or nonvirulent spotted fever-group rickettsiae.
Efficacy of vaccination of sows with serologically related coronaviruses for control of transmissible gastroenteritis in nursing pigs
Authors: Woods R. D.
Published: February 2025

Three groups of pregnant sows were vaccinated at 8 and 2 weeks before parturition with tissue culture-adapted feline infectious peritonitis (fip) virus, porcine transmissible gastroenteritis (tge) small-plaque (sp) virus from a persistently infected cell line, or noninfected cell culture fluids (controls). Pigs nursing vaccinated sows were orally challenge exposed with virulent tge virus when they were 1 to 3 days old. The morbidity of the nursing pigs was 48% in the sp-tge group, 82% in the fip group, and 93% in the controls. The survival rate among the nursing pigs was 77% in the sp-tge groups, 48% in the fip group, and 14% in the controls. Virus-neutralizing antibodies of immunoglobulin A were detected in colostrum and milk of the sp-tge group, but not in the fip or control groups.
Endocrine pathogenesis of postweaning anestrus in swine: Response of the persistently anestrous sow to hormonal stimuli
Authors: Dial G. D. , BeVier G. W. , Hixon J. E. , Gustafsson B. K.
Published: February 2025

The endocrine function of the individual components of the hypothalamo-hypophyseal-ovarian axis of the postweaning anestrous sow was evaluated by monitoring the sow's response to exogenous estradiol, gonadotropin releasing hormone (GnRH), and gonadotropins. Sows (4 to 6/group) not returning to estrus by 42.8 ± 3.1 days after weaning were assigned to 1 of the following treatments; 10 μg of estradiol benzoate (eb)/kg of body weight; 200 μg of GnRH, 1,000 IU of pregnant mare's serum gonadotropin (pmsg); 1,000 IU of human chorionic gonadotropin (hcg); or 4 ml of saline solution plus 2 ml of corn oil. A preovulatory-like surge of luteinizing hormone [(lh) > 12 hours in duration] was observed in all weaned sows treated with eb. All eb-treated sows exhibited estrus and ovulated but none conceived. Sows given GnRH had transiently increased (< 3 hours) lh concentrations that were not associated with estrus or ovulation. Treatment with pmsg caused an increase in peripheral concentrations of 17β-estradiol that was followed by an lh surge, estrus, ovulation, and conception. Treatment with hcg caused an increase in circulating concentrations of 17β-estradiol that was accompanied by a surge of lh in some sows and ovulation in all sows. Not all sows treated with hcg exhibited estrous behavior, but conception occurred in 2 of 3 sows that were mated at estrus. None of the sows treated with saline plus corn oil had consistent changes in circulatory concentrations of 17β-estradiol or lh and none exhibited estrus or ovulated. Seemingly, the components of the hypothalamo-hypophyseal-ovarian axis were functional in the persistently anestrous sow. In addition, pmsg appeared to be the only hormone effective in inducing a fertile estrus.
Counterimmunoelectrophoresis for identification of equine urine
Authors: Edwards Karen E. , Stevens Suzanne , Woodward Clifford B. , Tweeten Kathleen A.
Published: February 2025

Counterimmunoelectrophoresis was evaluated as a method to distinguish urine of human origin from that of equine origin. The procedure used anti-equine serum and anti-human serum antibodies that had been solid-phase absorbed to eliminate species cross-reactivity. Counterimmunoelectrophoresis reliably detected contamination of equine urine by human urine to a level of 10% with a minimum sensitivity to about 2% contamination. Compared with double diffusion, counterimmunoelectrophoresis was approximately 10 to 15 times more sensitive in the detection of urine proteins.
Moraxella bovis hemolysin
Authors: Ostle A. G. , Rosenbusch R. F.
Published: February 2025

Moraxella bovis hemolysin was readily filterable through polycarbonate membrane filters, but not through nitrocellulose filters. The hemolysin was filterable through polycarbonate filters with pore diameters of ≥ 0.015 μm (apd). Of the hemolytic activity of cell-free filtrates, 74% could be pelleted by ultracentrifugation at 100,000 × g for 2½ hours. Hemolytic activity could be demonstrated in preparations of outer membrane fragments isolated from log-phase cultures. Hemolysin in M bovis broth cultures reached a maximum concentration in late logarithmic phase (4.5 hours after inoculation) and declined thereafter. Hemolysin was inactivated by heat, trypsin, formalin, and lyophilization.
In utero infection of swine fetuses with infectious bovine rhinotracheitis virus (bovine herpesvirus-1)
Authors: Joo H. S. , Dee S. A. , Molitor T. W. , Thacker B. J.
Published: February 2025

The pathogenesis of infectious bovine rhinotracheitis (ibr) virus (bovine herpesvirus-1) was studied in porcine fetuses after in utero inoculation. Laparotomies were performed on 8 seronegative pregnant sows at 34 to 86 days of gestation, and all fetuses in 1 uterine horn of each sow were exposed to ibr virus via inoculation into the amniotic sacs. Fetuses in the other horn served as controls. Clinical signs of infection were not observed in the sows, except for 2 sows that aborted at postinoculation days (pid) 11 and 15. Fetuses of the remaining 6 sows were collected at slaughter on pid 15 to 28. Fetuses were examined for gross abnormalities, presence of ibr virus in tissues, and the formation of neutralizing antibodies to ibr virus.

Of 33 inoculated fetuses from 6 sows, 10 were mummified, 11 were hemorrhagic and/or edematous, and 12 were alive. Necrotic lesions were observed on the skin and in the liver of dead and live fetuses. Virus was recovered from 29 of 33 inoculated fetuses. Infectious bovine rhinotracheitis virus was isolated from fetal skin, liver, lungs, kidney, spleen, stomach contents, brain, amniotic fluid, and placenta. Virus was isolated from 4 of 11 fetuses recovered from 1 aborting sow. Antibodies to ibr virus were not detected in sera from the sows. However, antibodies were detected in 6 of 15 fetuses inoculated at 63 to 86 days of gestation and collected at slaughter at 86 to 112 days of gestation. The youngest fetus with detectable ibr antibody was estimated to be 74 days of gestation by measuring crown-rump length of the fetus.
Antimicrobial susceptibility of coagulase-positive staphylococci isolated from Louisiana dogs
Authors: Cox Hollis Utah , Hoskins Johnny D. , Roy Alma F. , Newman Susan S. , Luther D. Gene
Published: February 2025

Disk diffusion susceptibility tests were done on 1,178 clinical strains of coagulase-positive staphylococci (cps) isolated from dogs during a 7-year period. Relative decreases of 7% to 33% were found in the percentages of cps sensitive to 8 antimicrobics. Relative percentages of cps sensitive to 9 other antimicrobics were increased or decreased < 5%. Sensitivity to the β-lactam antibiotics showed the least relative change. Regression analysis demonstrated that the greatest change in percentage sensitivity of cps occurred to gentamicin and cephalothin and the least change occurred to penicillin and ampicillin.

Recent canine clinical isolates of cps, specifically identified as Staphylococcus intermedius (n = 109), were uniformly sensitive to novobiocin, amikacin, tobramycin, spectinomycin, and amoxicillin-clavulanic acid. Twenty-two isolates were also sensitive to 17 other antimicrobics, Eighty-seven isolates were resistant to 1 or more antimicrobics tested. Resistance was most common to sulfonamides, penicillin G, ampicillin, tetracycline, and streptomycin. Differences in susceptibility results between S intermedius and unspecified cps were not statistically significant.
Injection of iron in newborn beef calves: Erythrocyte variables and weight gains with newborn-dam correlations
Authors: Reece William O. , Self H. L. , Hotchkiss Donald K.
Published: February 2025

Iron injection in beef calves during the 1st week after birth increased their pcv, hemoglobin (Hb) concentrations, mean corpuscular volumes (mcv), and mean corpuscular Hb (mch). These increases persisted between weeks 2 and 12. The rbc count during the 1st week after birth had a positive correlation with the pcv and Hb concentrations and a negative correlation with the mcv and mch. There was a positive correlation between the serum iron concentration of the dams and their mcv and mean corpuscular Hb concentration. There was also a positive correlation between the mcv and mch of the dam and their calf's mch. Seemingly, iron injection did not affect weight gain during the first 18 weeks of life.
An apparatus for quantitative collection of urine from male cattle, sheep, and swine
Authors: Paulson Gaylord D. , Cottrell Daniel J.
Published: February 2025

An apparatus for quantitative collection of urine from male cattle, sheep, and swine was designed. The apparatus was constructed of elastic, waterproof cloth, fabric fastener, and a waterproof bag. The apparatus was lightweight, easily installed on the animal, resulted in no apparent discomfort to the animal, and could be used for extended collection periods.
Cystometry in dogs under oxymorphone and acepromazine restraint
Authors: Barsanti J. A. , Mahaffey M. B. , Crowell W. A. , Barber D. L.
Published: February 2025

Cystometry was performed in 12 dogs under oxymorphone and acepromazine restraint. A detrusor reflex occurred in 10 of 12 dogs (83%). Mean threshold pressure and volume were 31 cm H2O and 22 ml/kg, respectively. Tonus limb II varied inversely with threshold volume. Threshold volume varied directly with body weight; threshold pressure was independent of body weight.
Feline malignant lymphoma: Log-linear multiway frequency analysis of a population involving the factors of sex and age of animal and tumor cell type and location
Authors: Slayter M. V. , Farver T. B. , Schneider R.
Published: February 2025

A method appropriate for the analysis of multiway frequency tables is described. This multivariate approach was used to evaluate the relationship between age, sex, cell type, and tumor location based on information available from 1,733 cases of feline malignant lymphoma. The analysis identified 6 bivariate relationships to be statistically significant, P < 0.001; there were no significant higher order interactions observed. Emphasis was placed on 3 interactions; age to tumor location, age to sex, and tumor location to cell types.
Feline giardiasis: Observations on natural and induced infections
Authors: Kirkpatrick Carl E. , Farrell Jay P.
Published: February 2025

The excretion of Giardia sp cysts in the feces of naturally and artificially infected cats fluctuated sporadically, and cysts were undetectable several times during 7 weeks of observation. The mean prepatent period for Giardia infection in 7 cats was 9.6 days (range, 5 to 16 days). The amount of the cyst inoculum did not appear to affect the length of the prepatent period.

Six of 11 cats had clinical signs consistent with those of giardiasis. Clinical signs and cyst excretion were eliminated after treatment with metronidazole or furazolidone. Moderate oral or parenteral doses of corticosteroids produced little, if any, alteration in the infection.

Postmortem examination of 1 inoculated cat revealed Giardia trophozoites in the jejunum and upper portion of the ileum but not in the duodenum, lower portion of the ileum, cecum, or colon.

Giardia cysts isolated from cat feces produced infection in Mongolian gerbils but not in C57BL/6J mice.
Serum and colostrum antibody to Pasteurella species in dairy cattle
Authors: Gresham C. N. , Confer A.W. , Bush L. J. , Rummage J. A.
Published: February 2025

A survey of antibody to Pasteurella haemolytica and P multocida, using a fluorometric immunoassay, was conducted on sera collected from 264 dairy cattle from 3 herds. Serum antibody titers to P haemolytica were 0 to 270 with low titers (< 25) seen in 48.1% of the cows and heifers. Serum antibody titers to P multocida were 0 to 380 and the frequency of distribution of these titers were more even than for P haemolytica. Mean serum antibody titers to P haemolytica were significantly (P < 0.005) higher in cattle from an open dairy herd when compared with those from 2 closed herds.

Antibody titers to these organisms was determined in 7 colostrum samples. Pasteurella haemolytica antibody titers varied, depending on the whey separation technique used. Passive transfer of colostrum-derived antibody in 5 neonatal calves resulted in a maximum mean serum antibody titer at 20 hours after birth for P haemolytica and at 8 hours after birth for P multocida. Serum titers were higher overall for P multocida than for P haemolytica. Serum titers for P haemolytica declined rapidly. A significant (P < 0.05) increase in antibody to P multocida was observed at 5 days of age.
Rapid detection of canine parvovirus in feces using monoclonal antibodies and enzyme-linked immunosorbent assay
Authors: Mildbrand M. M. , Teramoto Y. A. , Collins J. K. , Mathys A. , Winston S.
Published: February 2025

Monoclonal antibodies were used to develop a double antibody enzyme-linked immunosorbent assay for the detection of canine parvovirus (cpv) antigen in fecal samples. The assay was specific for the hemagglutinating protein of cpv and detected as little as 1.5 ng of virus within a 15-minute incubation period. The use of monoclonal antibodies against epitopes on the cpv antigen permitted the simultaneous addition test sample and enzyme-conjugated antibody, thus considerably simplifying the manipulations required for the assay. Results were visually determined without special instrumentation Clinical studies revealed > 95% correlation between enzyme-linked immunosorbent assay results and hemagglutination titers.
Effect of bambermycins, in vitro, on plasmid-mediated antimicrobial resistance
Authors: George Beverly A. , Fagerberg Diane J.
Published: February 2025

The potential of bambermycins (a growth-promoting antimicrobial approved for turkeys, broilers, and swine) to overcome or control plasmid-mediated antimicrobial resistance was determined in a series of in vitro experiments. Four possible modes of action of bambermycins were studied: synergistic effect with 12 other antimicrobials, elimination of resistance (R) plasmids from Escherichia coli, selective killing or inhibition of E coli carrying R plasmids, and inhibition of R plasmid transfer. Bambermycins had no synergistic activity with the other drugs tested and had little effect on eliminating plasmids from host bacteria. Dependent on plasmid type, bambermycins decreased or increased transfer frequency of R plasmids. Bambermycins also selectively inhibited growth of bacteria harboring certain R plasmids.
Dosage requirement of pancuronium in halothane-anesthetized ponies: A comparison of cumulative and single-dose administration
Authors: Hildebrand S. V. , Howitt G. A.
Published: February 2025

Cumulative vs single-bolus administration of pancuronium was studied in halothane-anesthetized ponies. Dosage levels were determined by giving small increments (0.01 to 0.04 mg/kg of body weight) until the desired relaxation occurred (0.125 ± 0.038 mg/kg for 90% to 99% reduction of prerelaxant twitch height), then an additional 0.037 ± 0.024 mg/kg for obliteration of twitch response. The dosage level defined by cumulative administration was then administered as a single bolus 2 more times, once on each of 2 days. Dosage requirements for the 2 methods correlated well.

The difference in duration of paralysis caused by doses of different magnitude was compared, 1 dose to produce discernible surgical relaxation (90% to 99% reduction of twitch height) and a larger dose that obliterated discernible twitch height. The larger dose produced a significantly (P < 0.05) longer duration of paralysis until a 10% recovery of prerelaxant twitch height was attained. The recovery phase, defined as the duration from 10% to 75% recovery of prerelaxant twitch tension, was not significantly different in ponies given either dose. Seemingly, after relaxant recovery began, the larger dose did not slow recovery. Duration of maximum paralysis until 10% recovery took 41 ± 16 minutes for the larger dose and 10 ± 5 minutes for the smaller dose. The recovery phase (10% to 75%) took 12 ± 3.2 minutes and 11 ± 4 minutes for the large and smaller doses, respectively.
Biochemical and serologic characterization of Klebsiella strains from bovine mastitis and the environment of the dairy cow
Authors: Nonnecke Brian J. , Newbould F. H. S.
Published: February 2025

Klebsiella strains isolated from the cow and its environment were biochemically and serologically characterized and evaluated for their susceptibility to normal bovine serum. Thirty-one different biotypes of Klebsiella were identified among 288 cattle and environmental strains. Of these, 56.2% were indole-positive, a greater percentage than expected for Klebsiella. Biotypes 1/1/1 and 5/ 1/1, most frequently isolated and constituting about 37% of the total isolates, would be considered K pneumoniae by standard biochemical typing procedures. Of 65 cattle and environmental strains studied serologically, 11 serotypes, 14 biotypes, and 29 bioserotypes were identified, indicating the diversity of Klebsiella strains present in the herd. When strains from mastitic milk (n = 19) and the environment (n = 22) were compared, no bioserotype distinction or grouping that related to isolation source was obvious. The predominant bioserotype from both sources was 5/1/1-K35 (21.0% and 22.7% of the strains from mastitic milk and the environment, respectively). The growth inhibition by bovine serum of strains isolated from mastitic milk, the environment, and udder skin was similar. However, strains isolated from the mouth and rectum of the cow were significantly (P < 0.05) more inhibited by serum.
Bovine pneumonic pasteurellosis: Effect of culture age of Pasteurella haemolytica used as a live vaccine
Authors: Confer A. W. , Panciera R. J. , Corstvet R. E. , Rummage J. A. , Fulton R. W.
Published: February 2025

Five experiments were conducted that compared aerosol immunization of calves with live Pasteurella haemolytica from logarithmic (6 hour) or stationary (20 to 22 hour) phase cultures. Calves were challenge exposed by transthoracic injection with P haemolytica. In 4 experiments, calves inoculated with 6-hour cultures had slightly lower mean lesion scores (indicating greater resistance to challenge exposure) than those inoculated with 20- to 22-hour cultures. High antibody titers, as detected by a quantitative fluorometric immunoassay or the indirect hemagglutination test, correlated directly with lung resistance (based on lesion scores) regardless of the age of the culture used as the immunogen.
The pentobarbital anesthetized dog: An animal model for assessing chemically induced changes in renal function and ultrastructure
Authors: Koechel Daniel A. , Bretz Nancy S. , Sanzenbacher Richard L. , Tarloff Joan B. , Budd G. Colin
Published: February 2025

An experimental procedure was devised using the pentobarbital-anesthetized dog that could be used for the comprehensive evaluation of the renal effects of chemicals. After iv or renal arterial administration of 0.9% saline solution (vehicle), 12 renal function determinants were continuously monitored for periods of 2 and 6 hours. At the completion of the 2 or 6 hours of study, the kidneys of a number of dogs (usually between 1 and 7) in each vehicle-treated group were subjected to a modification of the intravascular perfusion-of-fixative technique to evaluate the ultrastructural status of the outer cortical, inner cortical, and outer medullary tissue. The remaining dogs (at least 3) in each vehicle-treated group were given a nonnephrotoxic, but maximally effective, diuretic dose of ethacrynic acid, which enabled an assessment of the functional integrity of the thick ascending limb of Henle's loop.

Renal function and glomerular and tubular ultrastructure remained stable in the pentobarbital-anesthetized dog for up to 6 hours after administration of vehicle. Sustained infusion of inulin (included in the procedure to estimate glomerular filtration rate) throughout the duration of the experiments, and pentobarbital anesthesia of various durations did not alter the morphologic status of the canine nephron. The procedure used for the renal perfusion of fixative circumvented any manipulation of the kidneys before fixation and allowed for the acquisition of normal (unaltered) appearing tissue from all areas of the kidneys. The responses of pentobarbital-anesthetized dogs to ethacrynic acid administration were similar when given 2 and 6 hours after the vehicle administration. This latter finding indicated that the functional status of the thick ascending limb of Henle's loop had not deteriorated under the conditions of the experiments. Therefore, the canine model cited herein may be used to assess the acute effects of a chemical on renal function and allows for the concurrent evaluation of the morphologic status of the glomerulus and of the entire nephron from the proximal convoluted tubule to the collecting system.
Circulatory and respiratory effects of methoxyflurane in dogs: Comparison of halothane
Authors: Steffey E. P. , Farver T. B. , Woliner M. J.
Published: February 2025

Circulatory and respiratory effects of 3 alveolar concentrations (representing 1.0, 1.5, and 2.0 times the minimal alveolar concentration, mac) of methoxyflurane in O2 were compared with similar mac multiples of halothane in 02. Eight adult mixed breed dogs that were healthy and nonmedicated were studied in cross-over fashion with both agents during conditions of controlled ventilation (cv; averaged 34 to 38 mm of Hg) and spontaneous ventilation (sv). When ventilation was controlled, methoxyflurane similar to halothane caused dose-related cardiovascular depression. Except for a greater heart rate and lesser stroke volume with methoxyflurane, little difference was noticed between the anesthetics at equivalent doses during cv. There was less dose-related circulatory depression during sv with both agents but particularly with methoxyflurane. During sv, increased progressively with increases in alveolar concentrations of methoxyflurane and halothane. Methoxyflurane caused significantly greater (P < 0.05) hypoventilation than halothane only at 2.0 mac. Except for a greater respiratory gas flow and inspiratory-expiratory gas flow ratio and a lesser inspiratory-expiratory time ratio with methoxyflurane, there was no anesthetic- or dose-response effect on respiratory variables.
Linear regression to determine the relationship between F-wave latency and limb length in control dogs
Authors: Steiss Janet E.
Published: February 2025

Minimal latencies of F waves were determined for the ulnar and sciatictibial nerves in 17 dogs of various breeds, weighing between 8 to 25 kg. A linear regression model was fitted to the data (r = 0.78 and 0.87, respectively), so that latencies could be predicted despite the large variation in limb lengths among different breeds of dogs.
Acute toxoplasmosis in hamsters and mice: Measurement of pathogenicity by fever and weight loss
Authors: Elwell Michael R. , Frenkel J. K.
Published: February 2025

Infections with 4 strains of Toxoplasma gondii were studied in mice and hamsters. In mice, infections with strains RH, T-1, and T-45 were always fatal, but strain ts-4 infection was not (ie, the mice survived). In hamsters, the RH strain always gave rise to a fatal infection and the T-1 strain killed about 90% of the hamsters, but as many as 106 tachyzoites of the T-45 and ts-4 strains failed to cause fatal infection. The lesions of the ts-4 infection in hamsters were limited to mononuclear inflammation and a scar at the injection site. Also, only the ts-4 strain did not produce chronic infection in hamsters. To evaluate degrees of pathogenicity of the strains, percentages of mortality, survival time, and such subtle changes as fever and weight loss can be used.
Surgical transplantation of adult Dirofilaria immitis to study heartworm infection and disease in dogs
Authors: Rawlings Clarence A. , McCall John W.
Published: February 2025

Heartworm infections were established in dogs by surgical transplantation of adult heartworms into the external jugular vein. The heartworms were obtained from donor dogs that had been infected with large numbers of infective larvae. This heartworm model standardized the infection with a known number of heartworms of a known age and sex. This paper presents the methods for obtaining heartworms from donor dogs, for selection of recipient dogs, and for transplantation of heartworms.
Electroencephalographic patterns of clinically normal, sedated, and tranquilized newborn foals and adult horses
Authors: Mysinger Pat W. , Redding Richard W. , Vaughan John T. , Purohit Ram C. , Holladay John A.
Published: February 2025

To establish a clinically practical procedure for recording the equine eeg, 25 healthy adult horses and 6 newborn foals were used. Recordings were taken with the animals alert and tranquilized, confined in metal stocks, or physically restrained.

The dominant alert waveforms of adult horses were fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 μv-dominant 10 to 15 μv). Underlying this fast activity was slower (0.5 to 4.0 Hz) activity with medium-to-low voltages (10 to 40 μv). Twelve of the 25 adult horses had eeg frequencies in the α frequency range (10 to 15 Hz, 10 to 50 μv). Eight horses were given xylazine and 17 were given acetylpromazine. Those given xylazine had generalized slowing with several distinct frequency patterns (25 to 40 Hz, 5 to 30 μv; 10 to 15 Hz, 10 to 80 μv; and 0.5 to 4.0 Hz, 10 to 90 μv). Horses given acetylpromazine had fast activity (25 to 40 Hz) with medium-to-low voltages (5 to 40 μv). Underlying this activity were slower waveforms (1 to 4 Hz) with medium-to-low voltages (5 to 10 μv). Occasional well-formed spindle activity was observed (10 to 14 Hz, 10 to 50 μv). Acetylpromazine had little effect on the eeg recording, whereas xylazine exerted a substantial effect. All leads were synchronous with lower voltages in the left frontal, right frontal, and transfrontal leads.

The alert pattern of a newborn foal was characterized by low frequency (2 to 6 Hz) with medium-to-high voltages (20 to 90 μv). Superimposed over this slow activity was some faster activity (20 to 30 Hz) with medium-to-low voltages (5 to 25 μv). As foal maturation proceeded, the faster (20 to 30 Hz) activity became more apparent. Relaxed patterns were characterized by irregular waveforms with slow to medium frequencies (1 to 6 Hz and 8 to 10 Hz) and medium-to-high voltages (10 to 60 μv to 50 to 200 μv), respectively. Sedated patterns had slow waveforms (1 to 3 Hz) with high voltages (10 to 200 μv). Some well-formed spindle activity was seen in relaxed and tranquilized patterns. The transfrontal lead had low voltage.
Electrophoretic comparison of myosins from masticatory muscles and selected limb muscles in the dog
Authors: Shelton G. Diane , Bandman Everett , Cardinet George H.
Published: February 2025

Myosins from canine limb muscles (triceps brachii [medial and long heads], anconeus, and extensor carpi radialis) were compared biochemically with myosins from canine masticatory muscles (temporalis and masseter). Compared with the limb muscles, the temporalis and masseter muscles had: a unique myosin isoform pattern as determined by nondenaturing pyrophosphate gel electrophoresis; unique light chains as determined by 1-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis, 2-dimensional gel electrophoresis, and peptide mapping; and a unique heavy chain as determined by peptide mapping.
Effect of virus-induced destruction of villous epithelium on intestinal secretion induced by heat-stable Escherichia coli enterotoxins and prostaglandin E1 in swine
Authors: Whipp S. C. , Moon H. W. , Kemeny L. J. , Argenzio R. A.
Published: February 2025

Villous atrophy and crypt hyperplasia were induced in the jejunal epithelium of thirteen 3-week-old pigs by inoculation with transmissible gastroenteritis virus. The responses (changes in net fluid movement) induced in ligated intestinal loops of these pigs by intraloop injections of prostaglandin E1 (pge1) or Escherichia coli broth culture filtrates containing either or both E coli heat-stable enterotoxins (sta and stb) were compared with the responses induced by these preparations in littermates not inoculated with virus. Villous atrophy was associated with a marked decrease in response to preparations containing sta, stb, or sta + stb, but the response to pge1 was undiminished. These results were consistent with the reports of others that the response to cyclic adenosine monophosphate-mediated secretogogues (pge1) is a function of crypt epithelium; however, the present results also suggest that the secretory response to sta and to stb is dependent on the integrity of the villous epithelium. In the present study, loss of villous epithelium was associated with loss of response to sta and stb, but not to pge1.
Impact and shear resistance of turf grass racing surfaces for Thoroughbreds
Authors: Zebarth B. J. , Sheard R. W.
Published: February 2025

The 2 dominant processes involved in the horse hoof-to-racing surface interaction are the shock loading of the horse’s leg upon impact with the racing surface and rotation of the horse’s hoof into the racing surface. These processes were measured as impact resistance (ie, the peak deceleration of a moving body upon impact with the test surface) and as resistance to shear.

The objective of the present study was to measure physically (under a variety of conditions) those soil and turf factors related to the 2 processes. It was concluded that thatch accumulation and mowing height of the turf did not have a significant (P < 0.05) effect on racing surface hardness (therefore, turf management should optimize turf growth and recovery), that turf roots were responsible for an increase in impact resistance and in resistance to shear, that control over soil moisture through irrigation and drainage allowed modification of racing surface hardness, and that soil materials tend to have lower impact resistance (ie, lower shock loading of the horse’s leg) and higher resistance to shear (ie, greater resistance to hoof rotation) than do sand materials.
Comparative studies on three isolates of Breda virus of calves
Authors: Woode G. N. , Saif L. J. , Quesada M. , Winand N. J. , Pohlenz J. F. , Gourley N. Kelso
Published: February 2025

Three isolates of Breda virus of calves were compared morphologically and antigenically. The isolates demonstrated similar morphology and shared common antigens, as determined by enzyme-linked immunosorbent assay and immunoelectron microscopy. On the basis of results of the hemagglutination-inhibition test, enzyme-linked immunosorbent assay, and immunoelectron microscopy, the 3 isolates were further subdivided into 2 serotypes; serotype 1 (Breda virus 1) represented by the Iowa isolate 1; and serotype 2 (Breda virus 2), by the Ohio isolate and the Iowa isolate 2. The 3 isolates caused diarrhea in gnotobiotic calves.
Pathologic effects of intrauterine deposition of pseudorabies virus on the reproductive tract of swine in early pregnancy
Authors: Bolin Carole A. , Bolin Steven R. , Kluge John P. , Mengeling William L.
Published: February 2025

Pseudorabies virus was inoculated into the uterus of 15 gilts within 6 hours after natural breeding, and gilts were necropsied at postbreeding days (pbd) 3, 6, 10, 14, and 28; 3 control gilts were treated similarly, except for inoculation with pseudorabies virus and were necropsied at pbd 6, 10, and 14. Tissues were collected for virus isolation, fluorescent antibody staining, and histopathologic examination. Pseudorabies virus was isolated from the reproductive tract up to day 14. Lesions in the reproductive tract consisted of multifocal to diffuse lymphohistiocytic vaginitis and endometritis, and lymphoplasmacytic aggregates in the corpora lutea. Multiple ulcers were seen in the vagina or endometrium of several gilts at pbd 3, 6, and 10. Corpora lutea of 1 gilt were necrotic at pbd 14 and contained large numbers of inflammatory cells. Focal aggregates of lymphocytes and plasma cells were seen in vagina and endometrium of 3 gilts and in the ovary of 1 gilt at day 28.
Dose-titration studies of ivermectin against experimental Ancylostoma caninum and Uncinaria stenocephala infections
Authors: Egerton J. R. , Eary C. H. , Suhayda D.
Published: February 2025

Dose-titration trials of ivermectin were conducted on pups with dual experimental infections of 4th-stage larvae or adult Ancylostoma caninum and Uncinaria stenocephala. Ivermectin was administered orally or subcutaneously at dosages of 0.006, 0.012, or 0.024 mg/kg of body weight. Maximal or near maximal (≥ 96% to 100%) anthelmintic effect was observed for both stages of development for each hookworm species by either route of administration at a dosage of 0.024 mg/kg. Responses for all of the aforementioned categories were linearly related to increasing log dosage of ivermectin, with common slopes (regression coefficients). Regression analysis also provided estimates of the minimal dosages required to produce maximal reduction in worm burden for each stage, species, and route of administration. The estimated ivermectin dosages for maximal efficacy ranged from a low of 0.014 mg/kg for adult A caninum by oral treatment to 0.044 mg/kg for 4th-stage larvae of U stenocephala by oral treatment.
Lipids of normal and osteochondritic cartilage of the immature canine humeral head
Authors: Kincaid Steven A. , Rudd Ray G , Evander Sharon A.
Published: February 2025

Specimens of cartilage removed from the shoulder joint of dogs with osteochondritis dissecans were compared with the articular-epiphyseal cartilage from the same location of healthy dogs. The pathologic cartilage lost the lamination pattern of articular-epiphyseal cartilage from healthy dogs. Chondrocytes of healthy and pathologic cartilage contained lipid inclusions. However, in pathologic samples, the lipid inclusions were more prominent, particularly in the superficial region of the presumptive articular cartilage. Lipids in the interterritorial matrix of the pathologic cartilage were observed. The pathologic cartilage contained large groups of chondrocytes and areas of mineralization of variable magnitude. Although lipid inclusions were found in the chondrocytes of cartilage of healthy dogs, the increase in magnitude of lipids in the cartilage from dogs with osteochondritis dissecans was considered to result from a metabolic response of the chondrocyte to an altered microenvironment. The loss of sudanophilic lipids in areas of chondrolysis may be used to explain the retardation of osteogenesis of chondrolytic cartilage.
Effect of in vitro inoculation of bovine respiratory syncytial virus on bovine pulmonary alveolar macrophage function
Authors: Trigo E. , Liggitt H. D. , Evermann J. F. , Breeze R. G. , Huston L. Y. , Silflow R.
Published: February 2025

Viruses may predispose the respiratory tract to the development of secondary bacterial pneumonia by impairing functions of alveolar macrophages. The effects of bovine respiratory syncytial virus (brsv) on selected functions of bovine pulmonary alveolar macrophages (pam) were examined in vitro. Alveolar macrophages were obtained from nonsedated cattle, using a polypropylene tube passed intranasally into the lung. The pam lavaged from the lung were allowed to adhere to glass coverslips or plastic tissue culture plates, and were exposed to brsv for 2 hours. Control and brsv-inoculated pam were compared at intervals over a 72-hour period for their abilities to phagocytize and kill Staphylococcus epidermidis, rosette with and phagocytize antibody-coated sheep rbc: (srbc), phagocytize latex particles, and influence lysosomal enzyme activity. Challenge exposure with brsv did not affect the ability of pam to adhere and did not affect cell viability. There were numerical differences between control and brsv-inoculated cell populations in phagocytosis and killing of S epidermidis, but these were not significant (P > 0.05). There was < 5% difference in the abilities of control and brsv-challenged pam to phagocytize latex beads. When Fc-receptor-mediated phagocytosis of antibody-coated srbc was compared with controls, brsv-challenged pam had significantly (P < 0.05) impaired phagocytic function, which was maximal 72 hours after brsv inoculation; the phagocytic impairment occurred in spite of normal Fc-receptor function, as determined by resetting with antibody-coated srbc. Lysosomal enzyme activity, measured as intracellular acid phosphatase, was similar between control and brsv-challenged cell populations at 2, 24, and 48 hours after brsv inoculation; at 72 hours, enzyme levels in brsv-challenged cells were nearly twice those of control cells. Replication of brsv in pam and bovine turbinate (bt) cells was followed for a 60-hour period. There was no evidence of extracellular virus or cell-associated virus detected from pam over the 60-hour postinoculation period. However, extracellular and cell-associated brsv was detected over a 60-hour period after brsv inoculation of bt cells. Immunofluorescence studies at 72 hours after inoculation indicated that approximately 10% of brsv-inoculated pam contained brsv antigen. In contrast, approximately 70% of brsv-inoculated bt cells were fluorescent positive by 72 hours. These results indicated that, although bovine pam are not permissive to brsv infection, in vitro challenge with this virus did impair selected pam functions.
Ultrastructure of the intraerythrocytic stage of Cytauxzoon felis
Authors: Simpson Charles F. , Harvey John W. , Carlisle J. W.
Published: February 2025

The erythrocytes of 2 cats experimentally infected with Cytauxzoon felis were examined by light and electron microscopy. In stained blood smears, parasitized erythrocytes usually contained a single, roundish organism, but occasionally up to 4 were present in a cell. Chains of these roundish organisms also were seen. Elongated parasites, sometimes with ear-like projections, were present in a few erythrocytes.

By electron microscopy, the parasite contained a poorly defined nucleus, rough endoplasmic reticulum, ribosomes, nonplicated mitochondria, food vacuoles, and a cytostome on its limiting membrane. Usually, the parasite was oval, but budding forms also were evident. Crystalloid inclusions were present in parasitized and nonparasitized erythrocytes.
Efficacy and safety of clorsulon used concurrently with ivermectin for control of Fasciola hepatica in Florida beef cattle
Authors: Courtney C. H. , Shearer J. K. , Plue R. E.
Published: February 2025

The safety and anthelmintic efficacy of clorsulon (7 mg/kg of body weight, orally) given concurrently with ivermectin (0.2 mg/kg, subcutaneously) for control of Fasciola hepatica were evaluated in 75 crossbred beef cattle. Twenty-three control animals were given only ivermectin. Fluke egg counts were significantly lower (P < 0.0001) in clorsulon-treated animals by day 14 after treatment than before treatment (base line) and were significantly lower (P < 0.005) after treatment in clorsulon-treated animals than in controls. There was no significant change in fluke egg counts of controls after treatment. The efficacy of clorsulon in reducing F hepatica egg counts was 99%. Clorsulon showed poor efficacy against paramphistomes. Adverse reactions were not observed.
Tympanographic volume measurements of the canine ear
Authors: Forsythe William B.
Published: February 2025

External ear canal volumes of 50 dogs were measured by tympanography. Comparison between each dog’s weight and ear volume revealed a linear increase in volume with increasing weight up to 10 kg. At weights > 11 kg, ear volumes did not increase. After ear canal measurement, the tympanic membranes of 30 of the dogs were punctured, permitting determination of the combined volumes of the external ear canal and middle ear. This combined volume increased with increasing weight.
Induction of cleft palate in newborn pigs by maternal ingestion of poison hemlock (Conium maculatum)
Authors: Panter K. E. , Keeler R. F. , Buck W. B.
Published: February 2025

Cleft palates were induced in newborn pigs of gilts fed Conium maculatum seed or plant during gestation days 30 through 45. Twelve of 23 newborn pigs born to 3 gilts given Utah-grown C maculatum seed and 9 of 12 newborn pigs born to a single gilt given the fresh Utah spring-growth C maculatum plant had cleft palates. The cleft palates ranged from a unilateral cleft, involving only 1 side of the palate, to a full bilateral cleft. Brachygnathia was also observed in some of these newborn pigs with cleft palate. Other malformations were not observed.

Chemical analysis of seed and plant samples indicated that γ-coniceine was the responsible teratogenic alkaloid. A daily dose of plant or seed that provided ≥ 1.07 mg of γ-coniceine/kg of body weight fed to gilts during the 30th through the 45th day of pregnancy resulted in teratogenic effects.
Suppression of mitogenic response of bovine lymphocytes during experimental ketosis in calves
Authors: Targowski Stanislaw P. , Klucinski Wlodzimierz , Littledike E. Travis , Hoy Derrel A.
Published: February 2025

Experimental ketosis was induced by feeding calves a diet containing 1,3 butanediol for 9 or 10 days. Blood β-hydroxybutyrate was significantly (P < 0.05) elevated during clinical ketosis. The mitogenic response of the lymphocytes collected during ketosis was significantly (P < 0.01) suppressed, and the suppression persisted for 2 weeks. During ketosis, all calves fed a 1,3 butanediol diet had clinical signs of an upper respiratory tract infection. Possible relationships between the suppressed function of lymphocytes, the increased concentration of 1,3 butanediol, and the increased susceptibility of the calves to infections during ketosis were considered.