bluuebunny/crossref_metadata_2025 huggingface dataset:
Safety of a temperature-sensitive vaccine strain of bovine viral diarrhea virus in pregnant cows
Authors: Lobmann M. , Charlier P. , Klaassen C. L. , Zygraich N.
Published: February 2025

Safety tests were conducted in 78 pregnant cows vaccinated with a commercial preparation of a temperature-sensitive vaccine strain of bovine viral diarrhea (bvd) virus. After vaccination, seroconversion was detected in 33 (97%) of 34 cattle that did not have antibodies against bvd virus. Overall, 43 (91%) of 47 cows with prevaccination titers ≤ 4 seroconverted. During the test period, cows did not become naturally infected with bvd virus, and bvd-associated reactions to the vaccine were not observed in vaccinated cows. Calves born to vaccinated cows did not have clinical signs of fetal bvd. Precolostral blood samples collected from the progeny of cows that were seronegative at vaccination were free of antibody against bvd virus. Bovine viral diarrhea virus was not isolated from the cattle evaluated in the present study.
Standardization of enzyme-linked immunosorbent assay for avian influenza virus antibodies in turkeys
Authors: Abraham Albert , Sivanandan V. , Halvorson D. A. , Newman J. A.
Published: February 2025

The signal-to-noise ratio was useful in determining the optimal dilution of rabbit anti-turkey conjugate. Optimum dilution for rabbit anti-turkey conjugate to be used in the enzyme-linked immunosorbent assay (elisa) was 1:1,000. The avian influenza virus antigen concentration was 128 hemagglutinating units (0.3 μg of protein) per well, as determined by checkerboard titration. Bovine serum albumin fraction V increased nonspecific binding of conjugate and was not used to coat the plates in subsequent tests. Using elisa, nonspecific binding to avian influenza virus-coated plates were not found with antibodies to Newcastle disease virus, infectious bursal disease, Salmonella, or Escherichia coli. Chromogens o-phenenediamine, and 2,2′-azino-di-(3-ethyl-benz-thiazoline sulfonic acid) were almost equal in sensitivity for detecting released oxygen from the H2O2. The substrate plate was more sensitive than was the polystyrene plate. Dual wavelength was reliable in reading elisa results.
Genotypic characterization of type-2 variants of canine adenovirus
Authors: Hamelin Claude , Jouvenne Patricia , Assaf Robert
Published: February 2025

Two canine adenovirus (cav) isolates, apparently distinct from type-1 (Utrecht) and type-2 (Toronto A26/61) reference strains in their biochemical and/or immunologic properties, were submitted to DNA-restriction endonuclease analysis. Both isolates, designated IAF-81-2116 and IAF-75-95, appeared as genotypic variants of cav-2. Isolate IAF-81-2116 was recovered from the intestine of a young pup with diarrheal disease. Seemingly, relatively small changes in the original cav-2 DNA sequence allowed the virus to replicate at an unusual site in the dog.
Pharmacokinetics of minocycline hydrochloride in clinically normal and hypoproteinemic sheep
Authors: Wilson Robert C. , Green Nancy K.
Published: February 2025

Eight adult sheep were given 2.2 mg of minocycline hydrochloride/kg of body weight iv before and after blood was collected to induce hypoproteinemia. The blood collection produced a significant (P < 0.01) reduction in pcv, hemoglobin, and total serum protein values. Pharmacokinetic evaluation of the serum drug concentration vs time data was performed, using a noncompartmental model based on statistical moment theory. Pharmacokinetic values obtained from the sheep with normal serum protein were 5.94 ± 1.78 ml/kg/min for clearance, 1.32 ± 0.16 L/kg for the steady-state volume of distribution, and 3.89 ± 0.80 hours for mean residence time. Significant differences were not found in these values obtained from the sheep when they were hypoproteinemic. The effective half-life, reported as the harmonic mean, increased from 2.57 hours in sheep before blood collection to 2.91 hours in sheep when they were hypoproteinemic. The 2.2 mg of minocycline/kg administered once or twice daily would not be expected to produce adequate serum concentrations for most susceptible microorganisms. Some evidence that minocycline disposition may follow zero-order kinetics is presented.
Pharmacokinetics and body fluid and endometrial concentrations of cephapirin in mares
Authors: Brown Murray P. , Gronwall Ronald R. , Houston A. E.
Published: February 2025

Six healthy adult horse mares were each given a single injection of sodium cephapirin (20 mg/kg of body weight, iv), and serum cephapirin concentrations were measured serially over a 6-hour period. The mean elimination rate constant was 0.78 hour−1 and the elimination half-life was 0.92 hour. The apparent volume of distribution (at steady state) and the clearance of the drug were estimated at 0.17 L/kg and 598 ml/hour/kg, respectively. Each mare was then given 4 consecutive im injections of sodium cephapirin (400 mg/ml) at a dosage level of 20 mg/kg. Cephapirin concentrations in serum, synovial fluid, peritoneal fluid, csf, urine, and endometrium were measured serially. After im administration, the highest mean serum concentration was 14.8 μg/ml 25 minutes after the 4th injection. The highest mean synovial and peritoneal concentrations were 4.6 μg/ml and 5.0 μg/ml, respectively, 2 hours after the 4th injection. The highest mean endometrial concentration was 2.2 μg/g 4 hours after the 4th injection. Mean urine concentrations reached 7,421 μg/ml. Cephapirin did not readily penetrate the csf. When cephapirin was given im at the same dose, but in a less concentrated solution (250 mg/ml), serum concentrations peaked at 25.0 μg/ml 20 minutes after injection, but the area under the serum concentration-time curve was not significantly different (P > 0.05). The bioavailability of the drug was ≥ 95% after im injection.
Pathogenesis of simian AIDS in rhesus macaques inoculated with the SRV-1 strain of type D retrovirus
Authors: Maul Donald H. , Lerche Nicholas W. , Osborn Kent G. , Marx Preston A. , Zaiss Conrad , Spinner Abigail , Kluge J. D. , MacKenzie Malcolm R. , Lowenstine Linda J. , Bryant Martin L. , Blakeslee James R. , Henrickson Roy V. , Gardner Murray B.
Published: February 2025

Type D retrovirus was isolated from rhesus macaques with simian acquired immunodeficiency syndrome (saids) and transmitted to healthy rhesus macaques with tissue culture medium containing the virus. The clinical, immunologic, and lymph node morphologic changes were observed in 9 rhesus macaques for 52 weeks after inoculation. A spectrum of clinical signs developed including early death, persistent saids, and apparent remission. Animals that died or developed persistent saids had characteristic lymphoid depletion, persistently depressed peripheral blood mononuclear cell (pbmc) mitogenic response, and decreased serum immunoglobulins. The saids retrovirus (srv) was recovered from pbmc of 8 of the animals after inoculation. Virus could not be recovered from pbmc of one animal in remission, but this animal developed serum-neutralizing antibodies to srv after inoculation. Seven of the animals seroconverted to srv after inoculation, all 9 were seronegative for human T-lymphotropic virus-III, and 5 animals tested were seronegative to human T-lymphotropic virus-I. These findings support the etiologic role of the type D retrovirus in saids and further define the pathogenesis of this disease.
Efficacy of ivermectin against Dirofilaria immitis larvae in dogs 30 and 45 days after induced infection
Authors: Paul Allan J. , Todd Kenneth S. , Sundberg John P. , DiPietro Joseph A. , McCall John W.
Published: February 2025

Forty-two Beagles, 14 to 15 weeks of age, were injected subcutaneously with 50 infective larvae of Dirofilaria immitis and were allotted by weight, within sex, to 6 treatment groups. Group 1 served as nonmedicated vehicle-treated controls; groups 2 through 5 were given an oral tablet form of ivermectin at dosages of 0.3 μg/kg, 1.0 μg/kg, 2.0 μg/kg, and 3.3 μg/kg at 30 days after inoculation; group 6 was given the 2.0 μg/kg dosage at 45 days after inoculation. Dogs were euthanatized and necropsied 154 days after treatment (day 139 for dogs in group 6) and examined for heartworms. On the numerical bases of helminths recovered in the groups, the efficacies for preventing heartworm maturation were 0% (group 2), 53.2% (group 3), 97.2% (group 4), 98.1% (group 5), and 63.8% (group 6). Drug-related adverse reactions were not detected.
Effect of yohimbine hydrochloride on serum prolactin concentration in the rat: Possible antagonist for fescue toxicosis
Authors: Jernigan Antoinette D. , Booth Nicholas H. , Robbins J. D. , Zahner Joanne M.
Published: February 2025

Yohimbine hydrochloride is an indole alkaloid which blocks α2-adrenergic and dopamine receptors and stimulates serotonergic receptors. Yohimbine was selected for testing as a possible antagonist in fescue toxicosis. Reduced body weight gains in cattle with chronic fescue toxicosis may be due to ergot alkaloids produced by fungi which infect the fescue grass. Ergot alkaloids stimulate dopamine receptors, antagonize serotonin, and lower serum prolactin concentrations. It was hypothesized that yohimbine may reverse or counteract the effects of the toxic fescue. Investigation was made of the treatment effects of multiple doses of yohimbine given in rats by intraperitoneal and oral routes. Given intraperitoneally once a day for 8 days, yohimbine hydrochloride increased serum prolactin concentrations. When given orally in feed for 7 days, the drug decreased the serum prolactin concentration. The effects of yohimbine on prolactin concentrations were dependent on the dosages and routes of administration. The inability of yohimbine, when given orally, to increase serum prolactin levels decreased its potential usefulness for prolonged treatment of fescue toxicosis.
Morphologie changes induced by photoperiod in eyes of turkey poults
Authors: Davis G. S. , Siopes T. D. , Peiffer R. L. , Cook C.
Published: February 2025

Large White commercial torm poults were grown from 1 day to 8 weeks of age in the following light treatments: (i) continuous incandescent light (24LL); (ii) 23 hours of incandescent light and 1 hour of darkness/day (23L:1D); (iii) 12 hours of incandescent light and 12 hours of darkness/day (12L:12D); or (iv) natural decreasing day lengths (natural). At 8 weeks of age, significant (P < 0.05) morphologic changes in eyes occurred. Poults exposed to the 24LL or 23L:1D had heavier eyes than did poults exposed to the 12L:12D or natural day length. In addition, the eye size (anterior to posterior diameter and horizontal width) exposed to the 24LL treatment was greater than those exposed to 23L:1D, 12L:12D, or natural day length. Cornea heights of poults exposed to 24LL or 23L:1D were smaller than cornea heights of those exposed to 12L:12D or natural day length. Marked differences did not occur in intraocular pressure among treatments.
Tidal breathing flow-volume loop analysis for clinical assessment of airway obstruction in conscious dogs
Authors: Amis Terence C. , Kurpershoek C.
Published: February 2025

Using a mask, pneumotachograph, and X-Y recorder, tidal breathing flow-volume loops (tbfvl) were evaluated in 33 healthy dogs and in 18 dogs with acquired obstructive respiratory tract disease. The loops were evaluated for qualitative shape, tidal volume (VT), respiratory rate, peak and midtidal inspiratory flow (pif and if50, respectively), peak and midtidal expiratory flow (pef and ef50, respectively), inspiratory and expiratory flow at end expiratory volume plus 25% VT (if25 and ef25, respectively), inspiratory time, and expiratory time. Indices of loop shape were developed by division of flow measurements (eg, pef/pif and if50/if25). Twenty healthy dogs had the same tbfvl (type 1). Typically, pef occurred at the beginning of expiration, and pif occurred toward the end of inspiration. Three other tbfvl types were identified in the remaining dogs. Mean coefficients of variation for tbfvl indices ranged from 7% to 18%. Dogs with a fixed-type upper airway obstruction (pharyngeal or laryngeal mass, n = 7) had tbfvl abnormalities, indicating inspiratory and expiratory phase flattening. Concavity or late expiratory phase flattening was detected in tbfvl from dogs with chronic bronchitis/tracheal collapse (n = 11). The tbfvl were easily evaluated in conscious dogs and were useful in the functional assessment of airway obstruction.
Forestomach epithelial receptor activation by rumen fluids from sheep given intraruminal infusions of volatile fatty acids
Authors: Crichlow E. C. , Leek B. F.
Published: February 2025

Forty-four reticuloruminal epithelial receptors were tested with rumen fluids obtained from 12 sheep before they were intraruminally infused with 4.0M acetic acid (8 sheep) or 4.0M butyric acid (4 sheep; preinfusion rumen fluid) and with rumen fluids obtained at the onset of ruminai stasis (abolition rumen fluid). The preinfusion rumen fluids from the 8 acetic acid-infused sheep (mean pH, 6.55) contained 1.7 mM nondissociated volatile fatty acids (vfa)/L and excited none of the 25 receptors tested. Preinfusion rumen fluids from the 4 butyric acid-infused sheep (mean pH, 6.98) contained 0.3 mM nondissociated vfa/L and also did not evoke responses in any of the 19 receptors tested.

Abolition rumen fluids from sheep treated with acetic acid excited 17 of the 25 receptors tested and contained 89.4 mM nondissociated vfa/L, of which nondissociated acetic acid comprised 85.0 mM/L. Abolition rumen fluids from sheep treated with butyric acid activated 14 of the 19 receptors tested and contained 61.1 mM nondissociated vfa/L, of which 38.7 mM/L was nondissociated butyric acid.

Preinfusion rumen fluids whose pH values were adjusted to that of abolition rumen fluids with HCl contained nondissociated vfa levels ranging from 16.3 mM/L (acetic acid-treated sheep) to 20.6 mM/L (butyric acid-treated sheep) and elicited responses in 4 of 30 receptors tested. Preinfusion rumen fluids whose pH values were adjusted to the pH value of abolition rumen fluid with acetic acid contained 29.5 mM nondissociated vfa/L and excited 7 of 13 tested receptors. Preinfusion rumen fluids whose pH values were adjusted to the pH of abolition rumen fluid with butyric acid had 66.0 mM nondissociated vfa/L and evoked responses in 14 of the 17 tested receptors.

Abolition rumen fluids whose pH values were adjusted (with NaOH) to the pH of preinfusion rumen fluids showed decreased concentrations of nondissociated vfa: from 63.6 mM/L to 5.6 mM/L in the acetic acid-treated sheep and from 61.1 mM/L to 0.8 mM/L in the butyric acid-treated sheep. These abolition rumen fluids with adjusted pH only activated 3 of the 36 receptors, whereas before pH was adjusted to preinfusion rumen fluid values, they had activated 28 receptors.
Conduction velocities and reflexes of the proximal and distal parts of the saphenous nerve of the dog
Authors: Whalen L. R. , Spurgeon T. L. , Carsten R. E. , Gould D. H.
Published: February 2025

The maximal conduction velocities of compound-action potentials in the proximal and distal parts of the saphenous nerve were determined by averaging potentials evoked and recorded through needle electrodes. Antidromic, triphasic compound-action potentials unipolarly recorded from the distal part of the saphenous nerve were of the same minimal latency as potentials having 4 phases which were recorded bipolarly from the same site. However, the unipolarly recorded potentials were of greater amplitude. Monophasic compound-action potentials were recorded through bipolar chlorided silver electrodes from the surface of fascicles of the distal part of the saphenous nerve. The maximal conduction velocity of these potentials was in agreement with the conduction velocity of compound-action potentials of the distal part of the saphenous nerve which were evoked and recorded through subcutaneous needle electrodes. The specificities of the stimulating and recording sites were verified by recording before and after the saphenous nerve was cut between the stimulating and recording sites. Mean conduction velocities were 62.3 ± 2.0 m/s for the distal part of the saphenous nerve and 66.3 ± 2.2 m/s for the proximal part of the saphenous nerve. Reflex-evoked muscle activity was elicited in the ipsilateral tensor muscle of the fascia lata and semimembranous muscle after electrical stimulation of the saphenous nerve through subcutaneous needle electrodes. The effects of various stimulus intensities on the latency and duration of these reflex-evoked muscle potentials were determined.
Effects of acetylpromazine on the hemodynamics of the equine metatarsal artery, as determined by two-dimensional real-time and pulsed Doppler ultrasonography
Authors: Walker Michael , Geiser Dennis
Published: February 2025

Heart rate, blood velocity, volumetric blood flow, and arterial diameter for 10 horses given acetylpromazine were determined from measurements of the dorsal metatarsal artery 3 (the great metatarsal artery), using 2-dimensional real-time and gated pulsed Doppler ultrasonography. Acetylpromazine induced significant increases in arterial diameter (P < 0.01) and volumetric flow rate (P < 0.05)—all compatible with adrenergic blockade. There was a trend indicating that there was increased blood velocity. Heart rate was unchanged.
Adrenal cortical necrosis caused by T-2 mycotoxicosis in female, but not male, mice
Authors: Thurman J. D. , Creasia D. A. , Quance J. L. , Johnson A. J.
Published: February 2025

Experimentally, adrenal cortical parenchymal cell necrosis was induced by T-2 mycotoxin in female, but not male, mice. The lesion occurred in the adrenal glands in 11 of 11 female and 0 of 10 male mice given a nose-only aerosol exposure to T-2 mycotoxin. The necrosis, restricted to the zona fasciculata, began at the X zone interface and extended peripherally to involve 15% to 70% of the zone. Both light and transmission electron microscopies were used to determine whether the cellular and subcellular damage involved parenchymal cells of the zona fasciculata. Extensive necrosis of cortical thymocytes and necrosis of lymphoid cells in follicles of the spleen, lymph nodes, and intestine-associated lymphoid tissue were observed in both sexes. This is the first report to describe adrenal gland necrosis associated with exposure to T-2 mycotoxin.
Lymphocyte blastogenesis and neutrophil function in cattle persistently infected with bovine viral diarrhea virus
Authors: Roth James A. , Bolin Steven R. , Frank Dagmar Ε.
Published: February 2025

Neutrophil function and mononuclear cell proliferative responses to mitogens were determined in healthy cattle and in cattle persistently infected with bovine viral diarrhea (bvd) virus. Uptake of [3H]thymidine by resting and mitogen-stimulated peripheral blood mononuclear cells was significantly lower in cattle persistently infected with bvd virus than in healthy cattle. Neutrophils from cattle persistently infected with bvd virus had significantly impaired capability to ingest Staphylococcus aureus, but were normal in respect to random migration under agarose, cytochrome C reduction, iodination, and antibody-dependent cell-mediated cytotoxicity. Impairment of neutrophil function in cattle persistently infected with bvd virus differs from impairment of neutrophil function reported in healthy cattle mounting an immune response to recent bvd virus infection.
Cloning and characterization of a canine oral papillomavirus
Authors: Sundberg John P. , O'Banion M. Kerry , Schmidt-Didier Elizabeth , Reichmann Manfred E.
Published: February 2025

A papillomavirus, isolated from oral papillomas in young Beagles, was used to produce a live-virus vaccine. After the im use of this vaccine, some dogs developed squamous cell carcinomas at the inoculation site. The virus was isolated from the original vaccine and was cloned into pBR322. A detailed restriction map of the viral genome was generated.
Etiologic significance of bacterial isolates from rams with palpable epididymitis
Authors: Lozano E. A.
Published: February 2025

Identified and partly identified bacterial isolates were obtained from 48 rams of various breeds that had unilateral or bilateral epididymitis. Most of the animals were approximately 1 year of age; a few were older. Brucella ovis, Actinobacillus spp, Corynebacterium spp, Haemophilus spp, Acinetobacter spp, Escherichia coli, Moraxella spp, Staphylococcus spp, Pasteurella spp, Streptococcus spp, and Chlamydia psittaci were isolated.

A vaccine strain of B ovis, isolated species of bacteria, and mixtures of isolates of tissue homogenates containing all isolates except B ovis and C psittaci were inoculated via the mucous membranes of the eyes, nares, and prepuce. Palpable epididymitis was not produced by the inoculations. The vaccine strain of B ovis induced complement-fixation reactions in 11 of 20 rams.
Induction of ovulation in anestrous mares with pulsatile administration of gonadotropin-releasing hormone
Authors: Johnson A. L.
Published: February 2025

Four seasonally anestrous mares (Standardbred), housed under a nonstimulatory photoperiod of 8 hours light:16 hours dark, were administered gonadotropin-releasing hormone (GnRH) in a pulsatile pattern (50 or 250 μg of GnRH/hour) for 8 to 18 days during February and March 1985. Treatment with GnRH, irrespective of dose or month, induced an increase in serum luteinizing hormone from a mean pretreatment value typical of anestrus (0.58 ± 0.02 ng/ml ± SE) to 10.84 ± 1.27 ng/ml on day 8 of GnRH treatment. Ovulation in the 4 mares occurred 8.8 ± 0.7 days after the initiation of pulsatile GnRH administration. In each instance, ovulation was followed by a functional corpus luteum, as indicated by a luteal phase (defined as the number of days on which serum levels of progesterone were greater than 1.0 ng/ml) which lasted 14.5 ± 0.6 days. These results indicate that infusion of GnRH in a pulsatile pattern is effective in inducing follicular development and ovulation in anestrous mares in the absence of a stimulatory photoperiod.
Diarrhea and malabsorption in calves associated with therapeutic doses of antibiotics: Absorptive and clinical changes
Authors: Rollin Ruth E. , Mero Kendall N. , Kozisek Peter B. , Phillips Robert W.
Published: February 2025

Of 28 healthy, nondiarrheal, colostrum-fed neonatal calves, 22 developed diarrhea after they were given (orally) for 3 to 5 days maximally recommended doses of chloramphenicol, neomycin, ampicillin, or tetracycline. Ampicillin-, neomycin-, or tetracycline-treated calves had significantly (P < 0.05) decreased and delayed glucose absorption during oral glucose tolerance tests. Chloramphenicol-treated calves had significantly (P < 0.05) higher base-line plasma glucose concentrations during the non-test period and had no significant increase in blood glucose concentrations during the tolerance tests compared with those in control calves.
Comparison of diluents for maintaining the viability of Cowdria ruminantium
Authors: Birnie E. F. , Endris R. G. , Logan L. L.
Published: February 2025

Thirteen solutions were compared to determine the optimal diluent for preservation of the viability of the Kwanyanga isolate of Cowdria ruminantium. They included the 2 diluents commonly used with C ruminantium and diluents proved effective with other rickettsiae. The capability of each diluent to maintain the viability of C ruminantium over a 3-hour period at room temperature was assessed by comparing the survival distributions of groups of outbred albino mice after they were inoculated iv with infected liver homogenates. The results indicated that the Snyder I diluent was significantly better at maintaining the viability of C ruminantium than were the other diluents studied.
Antifungal activity of ketoconazole with emphasis on zoophilic fungal pathogens
Authors: Gabal M. A.
Published: February 2025

The antifungal activity of ketoconazole was studied against fungal pathogens associated with various mycotic infections in animals. A concentration of 10 μg of ketoconazole/ml of medium proved fungicidal to Trichophyton verrucosum. The same concentration acted as a strong fungistat against the majority of the tested dermatophytes.

Yeasts were generally more sensitive than yeast-like pathogens. Ketoconazole also proved fungicidal against Pityrosporon canis and strongly inhibitory on Cryptococcus neoformans and Torulopsis famata at the lowest used concentration. Candida albicans, Candida tropicalis, and Aspergillus fumigatus required a higher concentration in order for the drug to demonstrate some gross changes. However, variable serious microscopic effects were detected. The most marked effect of ketoconazole was in connection with the dimorphic fungi. The action was fungicidal or strongly inhibitory on both the mycelial form and the tissue phase, respectively.

The effect of the drug involved both gross morphologic and microscopic changes of the fungi. The mechanism of action of the drug is described in detail. The results are promising and encouraging for the use of ketoconazole in veterinary medicine.
Preliminary evidence for a diagnostic immunoglobulin G1 antibody response among culture-positive cows vaccinated with Brucella abortus strain 19 and challenge exposed with strain 2308
Authors: Butler J. E. , Seawright G. L. , McGivern P. L. , Gilsdorf M.
Published: February 2025

The sera of cows inoculated with Brucella abortus have a characteristically high titer of immunoglobulin (Ig) G1 antibodies to a soluble brucella antigen compared with sera of noninoculated vaccinated cattle. Concentrations of antigen-specific IgG1 were > 10-fold higher than those for IgG2, even though total IgG2 concentrations were higher than total IgG1 concentrations. Increases in IgG1 antibodies to Brucella abortus soluble antigen were detected shortly after vaccination in those cows from which strain 19 was isolated and by 28 weeks in cows from which strain 2308 was isolated. Increases in specific antibodies were not paralleled by increases in either total IgG1 or total IgG2 concentrations. Rather, there was a 15-fold to > 200-fold increase in specific activity, with up to 16% of the IgG1 specific for the brucella antigen used in the assay. Thus, measurement of changes in total IgG1 concentrations is not a reliable method to identify brucellosis-associated anti-Brucella abortus soluble antigen activity. Only one cow in a panel of 10 selected for detailed study showed a false-positive IgG1 titer, whereas some serologic assays showed as many as 4 or 5 false-positives. Results of the complement-fixation test, among the battery of serologic tests used for detection of brucellosis, best agreed with the occurrence of increased IgG1 antibody levels.
Characterization of lectin-binding lymphocytes in goats with caseous lymphadenitis
Authors: Hedden Jane A. , Thomas Cynthia M. , Songer J. Glenn , Olson George B.
Published: February 2025

Numbers of lymphoid cells bearing markers for peanut agglutinin, wheat germ agglutinin, and anti-immunoglobulin G in healthy goats and in goats with caseous lymphadenitis were determined by use of immunofluorescent techniques. Results indicated that, when compared with healthy goats, diseased goats had normal numbers of anti-immunoglobulin G-positive cells (B cells), had significantly reduced numbers of peanut agglutinin-positive cells (T cells), and had fewer cells with receptor sites for Lens culinaris agglutinin and concanavalin A. Compared with healthy goats, numbers of peanut agglutinin-positive cells in goats with caseous lymphadenitis indicated that the goats may have had a compromised cell-mediated immunity.
Light microscopic and electron microscopic changes in the livers of cats with extrahepatic bile duct obstruction
Authors: Center S. A. , Castleman W. , Roth L. , Baldwin B. H. , Tennant B. C.
Published: February 2025

Light microscopic and transmission electron microscopic changes were studied in the livers of 6 cats at 25 to 54 days after their extrahepatic bile ducts were experimentally obstructed. Histologic findings included various degrees of bile duct dilatation, ductular proliferation, and peribiliary fibrosis. Concentric layers of dense, birefringent connective tissue surrounded midsized bile ducts. The degrees of bile duct proliferation, hepatocellular degeneration, and bile retention were similar in each cat, but the amount of periductular connective tissue increased with chronicity of bile duct obstruction.

Ultrastructural changes included marked swelling of endoplasmic reticulum and mitochondrial inner compartments, marked dilatation and distention of the canaliculi by bile casts, and numerical reduction of canalicular microvilli. Microvilli were often swollen and blunt. Mitochondria were swollen and long, and the cristae lacked normal distribution and density. Cytoplasmic accumulations of granular, electron-dense material and concentrically laminated arrays of material indicative of bile substances were also observed.
Cellular inflammatory response in the lungs of calves exposed to bovine viral diarrhea virus, Mycoplasma bovis, and Pasteurella haemolytica
Authors: Lopez Alfonso , Maxie M. Grant , Ruhnke Louise , Savan Milton , Thomson Reginald G.
Published: February 2025

Three, 5, or 7 days after inoculation with bovine viral diarrhea (bvd) virus (n = 12) or Mycoplasma bovis (n = 12), groups of calves were exposed to aerosols of Pasteurella haemolytica and were euthanatized 4 hours later. Histologic lesions in the lungs and the ratios of neutrophils to alveolar macrophages, collected by bronchoalveolar lavage, were compared with those of clinically healthy calves (n = 8) and calves inoculated with bvd virus only (n = 4), M bovis only (n = 4), or Ρ haemolytica only (n = 2). Inoculation with bvd virus or M bovis did not have a significant (P > 0.05) effect on the neutrophil/macrophage ratio in the bronchoalveolar lavage. Aerosol exposure to Ρ haemolytica induced a marked and significant (P < 0.01) change in the neutrophil/macrophage ratio (from < 1:9 to > 9:1). The reversed neutrophil/macrophage ratio in calves exposed to Ρ haemolytica correlated well with the histologic changes in which small bronchi and bronchioles were plugged with purulent exudate. Inoculation with bvd virus did not induce gross or microscopic lesions in the lungs. Inoculation with M bovis resulted in a severe peribronchial lymphoid hyperplasia with mild exudation of neutrophils and macrophages into the cranioventral parts of the lungs.
Rapid and specific serodiagnosis of western equine encephalitis virus infection in horses
Authors: Calisher C. H. , Al-D. Mahmud M. I. , El-Kafrawi A. O. , Emerson J. K. , Muth D. J.
Published: February 2025

Paired sera from 28 nonvaccinated horses with serologically confirmed western equine encephalitis (wee) virus infections were evaluated for immunoglobulin (Ig)M and IgG directed against wee virus, by use of enzyme immunoassay. Twenty-one of the horses developed ≥ 4-fold increases or decreases in serum IgM titers in paired serum samples, confirming the diagnosis of wee in these horses. Of the remaining 7 horses, 1 had stable IgM titers, 1 had a 2-fold increase in IgM titer between paired sera, 2 had 2-fold decreases in IgM titer, and for 3 horses adequate volumes were not available for both sera of the pair. Twenty-nine of 56 blood samples collected from these 28 horses had been collected within the first 3 days after clinical disease was recognized; all 28 horses and 48 of 53 available serum samples had IgM antibody to wee virus. Immunoglobulin M also was detected in sera of 27 of 45 other nonvaccinated horses that had illnesses clinically compatible with wee. Sera with IgM did not have cross-reacting IgM against eastern equine encephalitis virus. Therefore, the sensitivity, specificity, and lack of persistence of IgM was useful in the rapid diagnosis of wee virus infections in horses.
Thiacetarsamide in dogs: Disposition kinetics and correlations with selected indocyanine green kinetic values
Authors: Holmes Robert A. , Wilson Robert C. , McCall John W.
Published: February 2025

The pharmacokinetic values of thiacetarsamide (2.2 mg/kg) were determined in 6 healthy dogs after iv injection. A semilogarithmic plot of serum concentration vs time indicated that the 2-compartment open model best described thiacetarsamide disposition. A least-squares log linear regression microcomputer program was used to calculate the pharmacokinetic values. The mean elimination-phase half-life and clearance rate were 43 minutes and 200 ml/kg/min, respectively. Wide ranges in values were seen for the half-life (20.5 to 83.4 minutes) and the clearance rate (80.0 to 350.0 ml/kg/min).

Before thiacetarsamide was given to the dogs, indocyanine green (icg), an anionic dye that is eliminated almost entirely by hepatobiliary excretion, was administered iv at a dosage of 0.5 mg/kg of body weight. The half-life of icg was 7.4 minutes, and the clearance rate was 8.43 ml/kg/min. There was a significant (P < 0.01) correlation between the half-lives of thiacetarsamide and icg, but not between the clearance rates. The variations in icg half-lives and clearance rates were less than those seen for thiacetarsamide.
Doxapram: Cardiopulmonary effects in the horse
Authors: Wernette K. M. , Hubbell J. A. E. , Muir W. W. , Sams R. A.
Published: February 2025

The cardiopulmonary effects of 3 dosages of doxapram hydrochloride (0.275 mg/kg, 0.55 mg/kg, and 1.1 mg/kg, iv) were studied in 6 adult horses. Doxapram given iv significantly (P < 0.05) decreased PaCO2 and increased respiratory rate, cardiac output arterial blood pressures (systolic, mean, and diastolic) arterial pH, and PaO2 at 1 minute after each dose was administered. Heart rate and mean and diastolic pulmonary arterial blood pressure were significantly (P < 0.05) increased 1 minute after the 2 larger dosages of doxapram were given (0.55 mg/kg and 1-1 mg/kg, iv), but not after the smallest dosage was given. All measurements, except heart rate and cardiac output, had returned to base line by 5 minutes after each dosing. Heart rate remained significantly (P < 0.05) increased 10 minutes after the 0.55 mg/kg dosage was given and 30 minutes after the 1.1 mg/kg dosage. Cardiac output remained significantly (P < 0.05) increased at 10 minutes, 5 minutes, and 30 minutes after the 0.275, 0.55, and 1.1 mg/kg dosages, respectively, were given.
Biochemical characterization of the leukotoxins of three bovine strains of Fusobacterium necrophorum
Authors: Scanlan C. M. , Berg J. N. , Campbell F. F.
Published: February 2025

The biochemical characteristics of the leukotoxins of 3 bovine isolates of Fusobacterium necrophorum which represent biotypes A, AB, and B were compared. Two methods were used for the production of the leukotoxins: (1) medium M-l continuous dialysis sac cultures and (2) brainheart infusion agar plate cultures. The supernatant cultural fluids were fractionated sequentially by membranepartition chromatography, using ultrafilters with approximate molecular weight (mol wt) exclusion limits of 100,000,10,000, 2,000, and 500. The ultrafiltrates (< 500 mol wt) were fractionated by gel-permeation chromatography, using G-10 Sephadex. The leukotoxins of the 3 F necrophorum strains were estimated to have a molecular weight between 350 and 450. The leukotoxins in the ultrafiltrates (< 500 mol wt) were stable at 60 C for 4 hours and at 100 C for 30 minutes, stable to extremes of pH (3 to 11), and stable to degradative enzymes including trypsin, protease, a-amylase, lipase, deoxyribonuclease, and ribonuclease. Significant differences were not observed in the biochemical characteristics of the leukotoxins produced in vitro by the 3 F necrophorum biotypes. These assays were done, using monolayers of mouse peritoneal macrophages. The monolayers were exposed to the 4 ul-trafiltrates of both the continuous dialysis sac and brain-heart infusion agar cultures (pH 7.2) for 4 hours at 4 C, 25 C, and 37 C. Maximal cytotoxic activity in the assays was at 37 C.
Isolation and biological characterization of two lipopolysaccharides and a capsular-enriched polysaccharide preparation from Haemophilus pleuropneumoniae
Authors: Fenwick B. W. , Osburn B. I. , Olander H. J.
Published: February 2025

A smooth-type lipopolysaccharide (HpS-lps), a rough-type lipopolysaccharide (HpR-lps), and a capsular-en-riched polysaccharide preparation (HpC-ps) were ex-tracted and purified from Haemophilus pleuropneumoniae serotype 5, strain J45, by the use of phenol-water (HpS- lps) and phenol-chloroform-petroleum-ether (HpR-lps) techniques. Chemical analysis of the HpS-lps and HpR- lps indicated that they contained 0.7% and 4.4% (w/w) 2- keto-3-deoxyoctonate, 11.8% and 10.4% phosphate, 0.8% and 0.8% nucleic acid, and 0.8% and 1.1% protein, re-spectively. The HpC-ps contained 0.3% 2-keto-3-deoxy-octonate, 1.4% phosphate, 0.2% nucleic acid, and 0.8% protein. With sodium dodecyl sulfate-polyacrylamide-gel electrophoresis, the HpS-lps banded as a smooth-type lps and the HpR-lps banded as a rough-type lps. Electrophoresis of HpC-ps indicated the presence of a broad high molecular weight band. Gelation of Limulus amoebocyte lysate developed at a minimum concentration of 8 ng/ml of HpS-lps, 0.3 ng/ml of HpR-lps, and 35 ng/ml of HpC- ps. The lipopolysaccharide preparations provoked a positive dermal Shwartzman reaction in rabbits and swine, a biphasic febrile response in rabbits, and a monophasic response in swine. Responses were typical of endotoxic activity with swine having greater sensitivity than rabbits. The chick embryo 50% lethal dose was calculated to be 7.3 ng for HpS-lps, 1.6 ng for HpR-lps, 5.1 ng for the lipopolysaccharide of Escherichia coli 0111:B4; and the HpC-ps was not toxic. In all assays, HpR-lps was significantly more toxic than was HpS-lps. The HpC-ps preparation was not toxic, even at high concentrations. Intrabronchial infusion of HpS-lps and HpR-lps in pigs induced lesions typical of those found in pigs dying in the acute stages of H pleuropneumoniae infections, thus indicating the possible involvement of endotoxin in the pathogenesis of porcine pleuropneumonia. The HpC-ps preparation did not induce clinical illness or pulmonary lesions in pigs.
Immunomodulation in weanling swine with dietary selenium
Authors: Blodgett D. J. , Schurig G. G. , Kornegay E. T.
Published: February 2025

The capability of dietary selenium (Se) to augment the immune response was evaluated in 96 crossbred weanling swine. Six groups of 16 pigs were fed diets with Se supplemented as sodium selenite at 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mg/kg. The basal diet contained 0.068 mg of Se/kg. Weight gain, feed consumption, and feed efficiency were similar for all diets. Whole blood concentrations of Se linearly increased as the dietary concentrations of Se increased. The humoral response was monitored by immunoglobulin G titers to lysozyme and ribonuclease, using an enzyme-linked immunosorbent assay. Although no significant difference in immunoglobulin G titers to either antigen was detected among diets, a similar trend in antibody response was noted. The diet with 0.9 mg of added Se/kg produced the highest antibody response to both antigens, whereas the diet with 0.3 mg of added Se/kg produced the lowest titers for both antigens. Cell-mediated immunity was evaluated in the pigs by the dermal response to phytohemagglutinin. Significant difference was not detected in pigs fed the various diets in terms of the mean diameters of their dermal reactions to phytohemagglutinin injections. Although blood concentrations of Se were increased, rate and efficiency of weight gain and humoral and cell-mediated immunity were not significantly improved by adding 0.3 to 1.5 mg of Se/kg to diets.
Distinguishing between ovine abortion and ovine arthritis Chlamydia psittaci isolates with specific monoclonal antibodies
Authors: DeLong Walter J. , Magee Wayne E.
Published: February 2025

Monoclonal antibodies to Chlamydia psittaci were prepared by both in vivo and in vitro immunization methods, using an abortion strain of C psittaci as the immunizing antigen. Seven of the 8 monoclonal antibodies produced were genus-specific by the enzyme-linked immunosorbent assay and immunofluorescence test. The genus-specific antibodies were reactive with a protease-resistant, periodate-sensitive antigen of < 14 kilodaltons. The remaining monoclonal antibody, 10D7, was specific for ovine abortion strains of C psittaci and nonreactive with 2 strains isolated from the joints of lambs with polyarthritis. The type-specific antigen was protease sensitive, but could not be detected in the immunoblot assay.
Effects of bolus injection of epinephrine and norepinephrine on systolic time intervals in stress-resistant and stress-susceptible pigs
Authors: Malo D. , DeRoth L.
Published: February 2025

Systolic time intervals were measured in 15 stress-susceptible (ss) pigs to derive regression equations to determine to what extent their ventricular functions differed from those of stress-resistant (sr) pigs. Regression analysis revealed that the RR interval was the variable that was significantly (P < 0.01) related to electromechanical systole and left ventricular ejection time. The preejection period (pep) was independent of the RR interval. A normal increase of all systolic time intervals with age, independent of the RR interval, was also observed in sr and ss pigs. The 55-kg ss pigs had a higher noradrenergic tone than did 15-kg and 90-kg ss pigs, because their mean arterial blood pressure was higher and because their index values for electromechanical systole and their pep were shorter than those of sr pigs of the same body weights. The cardiovascular responses to biogenic amines were also different according to the degree of development and stress susceptibility. Changes in mean arterial pressure and pep were not as pronounced after injections of epinephrine and norepinephrine (10-8 mol/kg of body weight) were given. Subsequently, a decrease in cardiovascular responses to epinephrine and norepinephrine injections in 90-kg ss pigs were recorded. These results indicate that 55-kg ss pigs have a higher level of circulating catecholamines and that the myocardium becomes less sensitive to epinephrine and norepinephrine after it is chronically exposed to these amines.
Radiographic assessment of laryngeal reflexes in ketamine-anesthetized cats
Authors: Robinson E. P. , Johnston G. R.
Published: February 2025

The competence of the laryngeal closure reflexes of cats anesthetized with ketamine was assessed. Radiographic evaluations of the respiratory and digestive tracts were made after colloidal barium suspension was instilled into the pharynges of conscious and ketamine-anesthetized cats. There was a significant ketamine dose-related response of spread of contrast medium into the supraglottic laryngeal area and into the stomach 2 minutes after contrast medium was instilled into the pharynx (P < 0.05). Cats did not aspirate contrast medium into the lower respiratory tract. Three ketamine-anesthetized cats aspirated contrasst medium into the subglottic area of the larynx, and 2 of these cats also aspirated the material into the cranial part of the trachea. This material was coughed up and swallowed within 5 minutes. Transit time of contrast medium into the stomach seemed to be increased in 11 of the 15 cats given the larger dosages of ketamine (24, 36, 48 mg/kg of body weight), compared with that in conscious cats and those given ketamine at 12 mg/kg. Competent laryngeal protective reflexes in cats can be maintained with ketamine anesthesia. Contrast radiography could be used as a diagnostic aid in ketamine-anesthetized cats suspected of laryngeal reflex abnormalities.
Concentrations of gentamicin in serum, milk, urine, endometrium, and skeletal muscle of cows after repeated intrauterine injections
Authors: Haddad Nadim S. , Pedersoli W. M. , Carson R. L. , Ravis W. R.
Published: February 2025

Healthy mature cows (n = 6) were injected intrauterinally (iu) with gentamicin (50 ml of a 5% injectable solution) daily for 3 consecutive days. Venous blood and milk samples were collected at postinjection (initial) hours (pih) 1, 3, 6, 9, 12, 24, 28, 31, 34, 37, 48, 51, 54, 57, 60, and 71, and endometrial biopsies were performed at pih 6, 25, 48, 73, 95, and 119. Skeletal muscle biopsy samples were taken at pih 25 and 73, and urine was collected every 1 or 2 hours during 12 consecutive hours after the first iu injection. Serum, milk, urine, and tissue concentrations of gentamicin were measured by radioimmunoassay. The highest mean serum concentration of gentamicin occurred during the 3 hours after each injection (2.49 ± 1.46, 6.60 ± 5.47, and 4.98 ± 2.70 μg/ml). The mean peak concentration of gentamicin in milk occurred 3 to 6 hours after each injection. Mean peak urine concentration of gentamicin (256.8 ± 127.9 μg/ml) was measured at pih 6. The mean percentage of the first dose of gentamicin excreted in the urine within 12 hours was 14.78 ± 3.56. The highest concentration of gentamicin in endometrial tissue (639.16 ± 307.22 μg/g) was measured at pih 6, decreasing to 9.64 ± 3.55 μg/g before the next iu dose. Gentamicin was still detectable in endometrial tissue (0.86 ± 0.43 μg/g) 71 hours after the 3rd (last) iu injection.
Surgical treatment of endometriosis in 50 rhesus monkeys
Authors: Fanton John W. , Yochmowitz Michael G. , Wood David H. , Salmon Yolanda L.
Published: February 2025

Surgical treatment of endometriosis was attempted in 50 female rhesus monkeys (Macaca mulatta). Endometriosis was clinically staged as minimal (8% of the monkeys), moderate (18%), or massive (74%). Elective euthanasia was performed in 15 (30%) of the monkeys. Total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed in 30 (60%) of the monkeys, and bilateral salpingo-oophoretomy alone was performed in 5 (10%) monkeys. Statistical differences were not found in Kaplin-Meier survival curves between the different stages of endometriosis (P = 0.6297).
Efficacy of clorsulon against mature, naturally acquired Fasciola hepatica infections in cattle and sheep
Authors: Zivmerman Gary L. , Wallace Dennis H. , Schons Debra J , Hoberg Eric P.
Published: February 2025

Clorsulon (3.5 or 7 mg/kg of body weight) was given orally to mature cows (dairy or beef) and to mature mixed-breed sheep harboring patent infections of Fasciola hepatica. Eighteen animals of each species were assigned to a control group (drug vehicle) or to 1 of 2 treatment (3.5 or 7.0 mg/kg) groups of 6 animals each. On posttreatment days 8 (cows) or 14 (sheep), the animals were slaughtered for recovery of flukes. In cows, the efficacy (P values for treatment groups vs control) of clorsulon against infections of mature F hepatica was 99.21% (P ≤ 0.0065) at 3.5 mg/kg and was 100% (P ≤ 0.0039) at 7 mg/kg. In sheep, the efficacy was 93.33% (P ≤ 0.0104) at 3.5 mg/kg and was 100% (P ≤ 0.0039) at 7 mg/kg. These results indicate that clorsulon is a highly effective compound for the treatment of mature F hepatica in cows and sheep.
Pressure-induced changes in fibular motor nerve conduction velocity and fibularis (peroneus) tertius muscle-evoked potentials in a goat model of the downer cow syndrome
Authors: Onapito John S. , Raffe Marc R. , Cox Victor S.
Published: February 2025

A study was conducted to determine the acceptable fibular motor nerve conduction velocity (ncv) in goats and to characterize pressure-induced changes in conduction velocity and muscle-evoked potentials (mep). The acceptable motor ncv in the adult goat was determined to be 95.9 ± 6.8 m/s. Limb compression in recumbent cows was modeled by application of external compression to the goat pelvic limb to increase im pressure to a minimum of 50 mm of Hg. This pressure, when applied for a 6-hour period, caused a 30% to 100% reduction of fibular motor ncv and a 10% to 100% reduction of amplitude of mep measured from fibularis (peroneus) tertius muscle. The reduction of motor ncv and mep was associated with clinically evident limb dysfunction. The changes detected by the electrodiagnostic tests were proportional to the magnitude and duration of the locomotor deficits. The limb dysfunction was accompanied by muscular damage indicated by an increase of serum creatine kinase activity.