bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation and trypsin-enhanced propagation of turkey enteric (bluecomb) coronaviruses in a continuous human rectal adenocarcinoma cell line
Authors: Dea Serge , Garzon Simon , Tijssen Peter
Published: February 2025

Turkey enteric coronavirus (tcv) from intestinal contents of diarrheal poults was isolated and serially propagated in hrt-18 cells, an established cell line derived from a human rectal adenocarcinoma. In these cells, tcv induced cytopathic changes, including polykaryocytosis, which depended on trypsin in the medium and incubation at 41 C. Viral antigens could be demonstrated in the cytoplasm by immunofluorescence, and extracellular virus was detected by an elisa and negative electron microscopy. The cell-free virus had characteristics of tcv: shape, surface projections, buoyant density of 1.18 to 1.20 g/ml in sucrose, and hemagglutination of rat RBC. The one-step growth curve was complete by postinoculation hours 14 to 16, and maximal titers reached 9 to 9.5 log10 tcid50/ml during 5 passages, after which the titer remained stable.

Electron microscopic examination of infected cell monolayers revealed budding of typical coronavirus particles through intracytoplasmic membranes and accumulation of complete virus in cytoplasmic vesicles. Late in the infection, aggregated progeny vial particles were detected near the outer surface of infected cells. One-day-old turkey poults inoculated orally with tissue culture-adapted tcv isolates developed mild to severe diarrhea.
Evaluation of diets cocontaminated with aflatoxin and ochratoxin fed to growing pigs
Authors: Harvey Roger B. , Huff William E. , Kubena Leon F. , Phillips Timothy D.
Published: February 2025

The effects of dietary aflatoxin and ochratoxin, fed singly and in combination, were evaluated in growing crossbred pigs. Five barrows (7 weeks old at beginning of study) per group were fed either control feed, 2.0 mg of aflatoxin (af)/kg of feed, 2.0 mg of ochratoxin (oa)/kg of feed, or 2.0 mg of af and 2.0 mg of oa/kg of feed for 28 days. Production performance, serum biochemical, hematologic, and pathologic evaluations were made. Body weights were reduced by the combination treatment, whereas body weight gain was decreased by all toxin treatments. The effect of af and oa in combination on body weight gain was additive. Liver weights were increased by the combination treatment, whereas kidney weights were increased only in the oa group. Aflatoxin caused decreases in serum calcium, sodium, phosphorus, urea nitrogen, cholesterol, and glucose concentrations, whereas oa alone caused decreases in serum phosphorus, cholesterol, and hematologic values. The af-oa treatment induced decreases in mean corpuscular volume, packed cell volume, and in serum concentrations of phosphorus, cholesterol, and urea nitrogen. The af-oa treatment increased serum alkaline phosphatase activities and triglycerides. It was concluded that af and oa, singly or in combination, can affect clinical performance, serum biochemical and hematologic values, and organ weights of barrows. Although values of some measurements were affected more by the combination than by either toxin alone and suggested synergism or antagonism, the toxic interactions could best be described as additive.
Rapid presumptive diagnosis of anaerobic infections in animals by gas-liquid chromatography
Authors: van den Bogaard A. E. J. M. , Hazen M. J. , Maes J. H.
Published: February 2025

The detection of volatile fatty acids (vfa) by gas chromatography of 85 purulent specimens from abscesses or pyogenic infections in cats, dogs, rodents, and ruminants was compared with the results of bacteriologic culturing, and proved to be a rapid means of presumptively diagnosing anaerobic infections. Of 83 bacteriologically positive specimes, 52 (61%) yielded obligate anaerobes and in 50 specimens, 1 or more vfa (butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, or isocaproic acid) was detected. Forty-six specimens were positive for culturing of anaerobes and for detection of 1 or more of these vfa. By contrast, pus from infections caused by (facultative) aerobic microorganisms contained no vfa or only acetic and/or propionic acid.
Differentiation of avian adenovirus type-II strains by restriction endonuclease fingerprinting
Authors: Zhang Chunlin , Nagaraja K. V.
Published: February 2025

Three serologically indistinguishable viruses from the avian adenovirus type-II splenomegaly virus of chickens, marble spleen disease virus of pheasants, and hemorrhagic enteritis virus of turkeys, were analyzed by restriction endonuclease fingerprinting. The dna from these viruses were examined with 6 restriction endonucleases (Bgl II, EcoRI, HindIII, Hha I, Xho I, and BamHI). Markedly different dna cleavage patterns were found in these virus isolates with all the 5 enzymes, except with BamHI, suggesting genetic differences between isolates of adenovirus type II. Restriction endonuclease analyses were found to provide a method for distinguishing genetically different, and yet serologically similar, strains of avain adenovirus type II.
Antigenic comparisons of selected avian reoviruses by use of the plaque-reduction neutralization assay
Authors: Nersessian Bedros N. , Lukert Phil D. , Goodwin Mark A.
Published: February 2025

The antigenic interrelatedness of 3 clone-purified turkey reoviruses (ng-Turkey, 82-88, and nc-tev) to each other and to 4 clone-purified chicken reoviruses (S1133, Co8, Fahey-Crawley, and avian type 2) was determined in reciprocal cross-neutralization tests, using polyclonal antisera and the plaque-reduction technique. The morphologic features of plaques formed under agar were studied for all 7 reoviruses, and size comparisons for turkey vs chicken isolates were made.

All 3 turkey reoviruses (with the exception of ng-Turkey vs Fahey-Crawley chicken reovirus) formed plaques significantly (P < 0.05) smaller than plaques produced by their chicken counterparts.

The 3 turkey reoviruses were closely related to each other and to chicken reovirus CO8. The antigenic differences between turkey reoviruses 82-88 and nc-tev and chicken reovirus S1133 were slight (minor subtype); however, the latter and ng-Turkey were serotypically distinct. The ng-Turkey and 82-88 turkey reoviruses were more related (minor subtype) to the Fahey-Crawley and avian type 2 chicken reoviruses, than was nc-tev turkey reovirus (major subtype).
Inhibition of pregnancy in heifers, using a repositol formulation of melengestrol acetate
Authors: Floyd James G. , Ott Randall S. , Weigel Ronald M. , Zinn Gene M. , Hixon James E.
Published: February 2025

Efficacy of a repositol formulation of melengestrol acetate (mga) for inhibition of pregnancy was determined in one hundred 14- to 16-month-old beef heifers. Nonpregnant heifers were allocated on the basis of weight into 5 groups of 20 heifers each and were given 0, 30, 60, 90, or 120 mg of repositol mga, sc, on day 0. Four bulls, determined to be satisfactory potential breeders, were pastured with the heifers from postinjection days (pid) 7 to 177. The day of gestation was estimated for each heifer by rectal palpation at pid 59, 91, 134, 177, and 225. Heifers not pregnant by pid 177 were assigned a day of conception of > 177.

For heifers given 0, 30, 60, 90, and 120 mg of mga, respectively, the percentage pregnant at pid 177 was 95, 95, 50, 15, and 15%, and the median day of estimated conception was pid 21, 87, 175, > 177, and > 177. Repositol mga significantly (P < 0.001) affected the distribution of conception times over all doses. Average daily gain (± sem) for 178 days was 0.28 ± 0.04 kg, 0.24 ± 0.03 kg, 0.33 ± 0.04 kg, 0.40 ± 0.03 kg, and 0.35 ± 0.03 kg for heifers given 0, 30, 60, 90, and 120 mg of mga, respectively. Increased dose of repositol mga was associated with increased average daily gain, but this effect was not apparent when days pregnant were taken into account. Repositol mga was an effective contraceptive for pastured heifers and the duration of its effect was dose-dependent.
Variations of serum vitamin E, cholesterol, and total serum lipid concentrations in horses during a 72-hour period
Authors: Craig A. M. , Blythe L. L. , Lassen E. D. , Rowe K. E. , Barrington R. , Slizeski M.
Published: February 2025

Fluctuations of serum vitamin E (α-tocopherol), cholesterol, and total lipids were monitored in 12 horses at 3-hour intervals for 72 hours. Mean coefficients of variation were 12, 5, and 15%, respectively. Statistical analyses were used to conclude that instrumentation error was accountable for only a small portion of the vitamin E variation. Results indicated that a single serum sample assay is an unsatisfactory indicator of vitamin E status in horses. These data have clinical application in the evaluation of horses suspected to be affected with equine degenerative myeloencephalopathy. The large variance of serum total lipids and the lack of correlation of it with serum vitamin E over time preclude the use of vitamin E/serum total lipids ratio in assessing vitamin E status.
Effects of idazoxan, tolazoline, and yohimbine on xylazine-induced respiratory changes and central nervous system depression in ewes
Authors: Hsu Walter H. , Hanson Chip E. , Hembrough Frederick B. , Schaffer David D.
Published: February 2025

We compared the ability of 3 α2-adrenoreceptor antagonists, idazoxan (0.05 mg/kg), tolazoline (2 mg/kg), and yohimbine (0.2 mg/kg) to reverse xylazine (0.3 mg/kg)-induced respiratory changes and cns depression in 6 ewes. Once weekly, each ewe was given a random iv treatment of xylazine, followed in 5 minutes by either an antagonist or 0.9% NaCl solution. Xylazine alone caused recumbency for 54.2 ± 5.3 minutes (mean ± sem). Xylazine also increased respiratory rate and decreased Paco2 for at least 45 minutes, but did not significantly change arterial pH or Paco2. Idazoxan and tolazoline were equally effective in reversing the respiratory actions of xylazine; however, yohimbine was less effective in reducing the respiratory rate and was ineffective in antagonizing the decreased Pao2. Idazoxan and tolazoline decreased the duration of xylazine-induced recumbency to 6.3 ± 0.6 and 9.5 ± 2.3 minutes, respectively, whereas yohimbine did not significantly change this effect of xylazine. Thus, at the dosages studied, idazoxan and tolazoline appeared to be more effective than yohimbine in reversing the respiratory and cns depressant actions of xylazine in sheep.
Controlled dosage titration of febantel paste in naturally parasitized cattle
Authors: Blagburn Byron L. , Hendrix Charles M. , Hanrahan Lynn A. , Lindsay David S. , Arther Robert G. , Drane J. Wanzer
Published: February 2025

A controlled anthelmintic trial was conducted to determine the efficacy of febantel paste (45.5%) at dosage of 2.5, 5.0, 7.5, and 10.0 mg/kg in calves harboring natural gastrointestinal nematode infections. Dosages of 5.0, 7.5 and 10.0 mg of febantel/kg of body weight were > 96% effective in removing adults of Haemonchus contortus, Ostertagia spp, Cooperia spp, and Oesophagostomum radiatum. The 2.5 mg/kg dosage was considered suboptimal because of low efficacy against Ostertagia and Cooperia spp. Efficacies against Trichostronglylus axei, Trichuris spp, Bunostomum phlebotomum, and Stronglyloides papillosus were difficult to determine because fewer numbers of these nematodes were recovered. Efficacies of febantel paste against immature bovine parasites ranged from 83.62% to 97.72%.
Enzyme-linked immunosorbent assay for the detection of circulating antigens of Toxoplasma gondii in the serum of cats
Authors: Lappin Michael R. , Greene Craig E. , Prestwood A. K. , Dawe Donald L. , Tarleton Rick L.
Published: February 2025

An elisa was developed to detect circulating antigens of Toxoplasma gondii in the serum of cats. For the experiment, toxoplasmosis was induced in a group of cats by oral administration of bradyzoites. An elisa that detects anti-Toxoplasma IgG, an elisa to detect circulating antigens, and fecal examinations were performed on samples from each cat for 1 year after inoculation. When coupled with IgG-class antibody measurement, antigen detection can aid in the diagnosis of some cases of subclinical feline toxoplasmosis.
Modulation of the cellular immune responses to T-cell-dependent and T cell-independent antigens in lambs with induced bovine viral diarrhea virus infection
Authors: Lamontagne Lucie , Lafortune Pierre , Fournel Marielle
Published: February 2025

Functional interaction between lymphoid cells and lymphotropic viruses is particularly evident for bovine viral diarrhea virus (bvdv) in cattle and its closely related virus, the border disease virus (bvdv) in sheep. The most important aspect of acute or chronic phases of bvdv or bdv infection was the host's increased susceptibility to secondary bacterial or viral infection. To study the ability of bvdv to alter the development of the cellular immune responses to concomitant inoculation with T cell-dependent and T cell-independent antigens, lambs were inoculated twice with rabbit rbc and Escherichia coli lipopolysacharide (lps) and then were infected with a cytopathic strain of bvdv at postinoculation day 3. Leukopenia characterized by lymphopenia developed after bvdv infection. Increased [3H]thymidine incorporation was observed in resting or lectin-stimulated blood mononuclear cells in the first weeks after inoculation in bvdv-infected lambs, but was followed by decreased [3H]thymidine incorporation after the second inoculation for up to 8 weeks after initial inoculation. In contrast, transient decrease of blastogenic responses, associated with toxic effect of lps, was detected in inoculated noninfected lambs, but was followed by stimulation of cellular immune responses. Inoculated noninfected lambs had good in vitro cellular immune response to rabbit rbc and lps antigens, whereas lymphocytes from bvdv-infected lambs could not mount lasting cellular immune responses to antigens or bvdv. Results suggest that bvdv infection in lambs modulates the ability of lymphocytes to respond to lectins or antigenic stimuli according to the time after infection. This mechanism of bvdv-induced immunodepression may contribute to susceptibility of infected animals to secondary bacterial or viral infection.
Serum amylase and lipase activities after exploratory laparotomy in dogs
Authors: Bellah Jamie R. , Bell Grahame
Published: February 2025

Serum amylase and lipase activities and creatinine concentration were determined before surgery, and at 1 and 2 days after exploratory laparotomy in 24 dogs. Examination of all viscera was done during each laparotomy, but a surgical procedure was not performed. The mean serum activities for lipase were: before surgery, 0.71 (0.0 to 2.0) Cherry Crandall units (ccu)/L; 1 day after surgery, 2.1 (0.0 to 4.5) ccu/L; and 2 days after surgery, 1.19 (0.0 to 3.9) ccu/L. The mean serum activities for amylase were: before surgery, 1,958 (1,027 to 3,426) IU/ L; 1 day after surgery, 1,538 (937 to 2,659) IU/L; and 2 days after surgery, 1,663 (1,066 to 2,274) IU/L. Serum creatinine concentrations before surgery, 1 day after surgery, and 2 days after surgery were 0.88 (0.2 to 1.7) mg/dl, 0.78 (0.4 to 1.3) mg/dl, and 0.78 (0.3 to 1.3) mg/dl, respectively. Mean preoperative, day-1, and day-2 serum amylase activities and serum creatinine concentrations did not differ significantly from each other. Mean preoperative and day-2 serum lipase activities did not differ significantly; however, mean serum lipase activity was significantly greater when day 1 activities were compared with preoperative activities (P = 0.0002). Postmortem examinations revealed no gross or histologic evidence of pancreatitis in any dog. The results of this study show that a 3 or more fold increase in serum lipase activity may occur after routine exploratory laparotomy in dogs without clinical signs or gross evidence of pancreatitis. Histologic evidence of pancreatitis was not found in the right pancreatic lobes in any dog.
Experimental prevention of bitterweed (Hymenoxys odorata) poisoning of sheep
Authors: Calhoun M. C. , Baldwin B. C. , Kuhlmann S. W. , Kim H. L.
Published: February 2025

To examine the effects on bitterweed toxicity of dietary factors known to increase thiol concentrations in the body, 36 lambs were fed one of the following diets (12 lambs/diet) for a minimum of 9 days prior to bitterweed administration: diet 1, 10% crude protein; diet 2, 20% crude protein, 0.5% methionine, 0.5% sodium sulfate, and 1,102 IU of vitamin E/kg; and diet 3, diet 2 with 0.5% ethoxyquin hydrochloride added. Four lambs fed each diet were euthanatized prior to bitterweed administration (initial euthanasia group). Four lambs fed each diet were administered bitterweed (0.68% hymenoxon, air-dried basis) at a rate of 0.25% of live weight for 5 consecutive days. The remaining four lambs on each diet served as unchallenged controls. In the initial euthanasia group, diet 2 increased extracellular blood thiol concentrations (1.12 vs 0.94 mg of sh/dl, P < 0.10), rumen fluid thiol concentrations (4.46 vs 1.88 mg of sh/dl, P < 0.05), and liver thiol concentrations (263.6 vs 109.3 μg sh/g of wet wt, P < 0.05), compared with diet 1. Ethoxyquin hydrochloride (diet 3) reduced blood thiol concentrations (0.94 vs 1.12 mg of sh/dl, P < 0.10) and liver thiol concentrations (151.6 vs 263.6 μg of sh/g of wet wt, P < 0.05), compared with diet 2. Kidney thiols were unaffected by treatments. In lambs fed diet 1, bitterweed increased serum creatinine (P < 0.05) and urea nitrogen (P < 0.10) concentrations and γ-glutamyltransferase (P < 0.05) and aspartate transaminase (P < 0.05) activities; whereas, only serum creatinine (P < 0.05) and urea nitrogen (P < 0.05) concentrations were increased by bitterweed in lambs fed diet 2 and none of these serum constituents were increased by bitterweed in lambs fed diet 3. These results demonstrate that dietary components that increase thiol concentrations protect against bitterweed poisoning. However, this does not appear to explain the additional benefit from including ethoxyquin hydrochloride in the diet.
Latent infection and subsequent reactivation of pseudorabies virus in swine exposed to pseudorabies virus while nursing immune dams
Authors: Mengeling W. L.
Published: February 2025

The ability of pseudorabies virus (prv) to infect and establish latency in pigs with passively acquired (maternal) antibody for prv was tested by exposing such pigs to the virus and subsequently attempting to reactivate latent virus by administering large doses of dexamethasone. Pigs of each of 4 litters that had nursed gilts with relatively high (512, gilts 1 and 2), moderate (32, gilt 3), and no (< 2, gilt 4) serum titers of virus-neutralizing (vn) antibodies for prv were allotted to 3 treatment groups (A, B, C) when they were 2 weeks old. Group-A pigs were separated from littermates and dam and thereafter kept in isolation; group-B pigs were experimentally exposed oronasally to prv and 1 hour later returned to their dam; group-C pigs were kept with their dam and potentially exposed to prv by contact with littermates of group B. Sera obtained from pigs at selected intervals until they were 17 weeks old were tested for vn activity and for precipitating activity for radiolabeled viral proteins.

All group-A pigs remained clinically normal throughout the experiment. Depending on the initial amount of passively acquired antibody, little or no serum vn or precipitating activity remained by the time these pigs were 17 weeks old. Group-B and -C pigs, with relatively high amounts of passively acquired antibody when exposed to prv, also remained clinically normal. However, most became latently infected as subsequently evidenced by either dexamethasone-induced or noninduced virus reactivation. Noninduced reactivation may have been initiated by weaning the pigs when they were about 8 weeks old. Group-B and -C pigs, with no or moderate amounts of passively acquired antibody when exposed to prv, had severe clinical signs. These pigs either died or recovered but remained stunted in growth. Virus was reactivated in all of the recovered pigs by treatment with dexamethasone. Quantitative and qualitative changes in serum precipitating activity, especially for viral proteins of relatively low molecular weight (< 46,000), were a more consistent indication of virus reactivation than were either increased vn titers or virus isolation. Results with litters 1 and 2 clearly indicate that latent infection of young pigs with highly virulent prv can develop in the absence of clinical signs.
Technique for transrectal ultrasonography of the cranial mesenteric artery of the horse
Authors: Wallace K. D. , Selcer B. A. , Becht J. L.
Published: February 2025

Transrectal ultrasonography was successfully used to image the cranial mesenteric artery and its branches in 23 adult horses. The artery could be imaged from its origin at the aorta distally to identify several bifurcations. The method for transrectal imaging of the cranial mesenteric artery and its major branches required 3 distinct transducer positions. One position was used to locate the cranial mesenteric artery by imaging the caudal portion of the aorta from the aortic bifurcation cranially to the level of the cranial mesenteric artery. The second position was used to image the origin of the cranial mesenteric artery. The third position was used to image the major branches of the cranial mesenteric artery.
Transrectal ultrasonography of the cranial mesenteric artery of the horse
Authors: Wallace K. D. , Selcer B. A. , Tyler D. E. , Brown J.
Published: February 2025

Transrectal ultrasonography was performed on the cranial mesenteric artery and its major branches in 23 conscious adult horses. Ultrasonographically, 25 arterial segments were classified as either normal or abnormal. These ultrasonographic classifications were later compared with the gross and histologic evaluations of each artery following necropsy of each horse. In this study, transrectal ultrasonography as a diagnostic test for verminous arteritis had a 90% sensitivity for detecting normal arteries and an 86% specificity for detecting abnormal arteries, suggesting that ultrasonography may be useful in the antemortem diagnosis of verminous arteritis.
Epithelium- and mucosa-dependent relaxation and contraction of normal equine trachealis muscle in vitro
Authors: Olson L. E. , Perkowski S. Z. , Mason D. E. , Muir W. W.
Published: February 2025

Strips of trachealis muscle were dissected from the midcervical portion of the trachea from horses that were free of respiratory tract disease. The epithelium and mucosa were removed from one group of tissues and were left intact in a second group of tissues. Each tissue was suspended in a bath filled with Krebs-bicarbonate solution that was aerated with 5% CO2 in oxygen and maintained at 37 C. Isometric tension was continuously recorded. The contractile response to square-wave electrical stimulations increased as frequency (3, 5, 10, 15, 20, 25, and 30 Hz), voltage (10, 15, 18, and 25 V), and pulse duration (0.2, 0.5, 1.0, 1.5, and 2.0 ms) increased in tissues with the epithelium and mucosa intact. A stimulus of 18 V, 20 Hz, and 0.5 ms induced maximal contraction. Atropine (10−6M) abolished the response to 18 V and 0.5 ms at all frequencies. The increase in active isometric tension was concentration dependent when acetylcholine (10−9 to 10−4M) was added to the baths in 0.5-logarithmic increments. Tissues that were contracted in response to acetylcholine (10−5M) had a concentration-dependent decrease in active isometric tension when isoproterenol was added to the baths in 0.5-logarithmic increments (10−9 to 10−4M). The contraction and relaxation curves were qualitatively similar, but quantitatively different in tissues with and without the epithelium and mucosa. Removing the epithelium and mucosa increased the contractile response to acetylcholine at bath concentrations of 3.1 × 10−7M and 10−6M. The presence of epithelium and mucosa enhanced the magnitude of isoproterenol-induced relaxations. We concluded that electrical stimulation released acetylcholine from isolated equine trachealis muscle, that isoproterenol induced relaxation of the trachealis muscle, and that the magnitude of the responses to exogenous agonists depended on the presence of epithelium and mucosa.
Bioavailability of gentamicin in dogs after intramuscular or subcutaneous injections
Authors: Wilson Robert C. , Duran Sue H. , Horton Charles R. , Wright Lila C.
Published: February 2025

Healthy adult mixed-breed dogs, assigned to 2 groups of 6 dogs each, were given 3 mg of gentamicin sulfate/kg of body weight on 3 injection days 7 days apart. Group 1 was given gentamicin by rapid iv injection, by injection into the belly of the longissimus muscle at the first lumbar vertebrae (im site 1), and by injection in the belly of the biceps femoris muscle (im site 2). Group 2 was given gentamicin by rapid iv injection, by sc injection into the space over the cranial angle of the scapula on the midline (sc site 1), and by sc injection just caudal to the crest of the ilium (sc site 2).

Pharmacokinetic values (mean ± sd) from 12 dogs given gentamicin iv were 54.4 ± 15.4 minutes for the effective half life, 2.29 ± 0.48 ml/kg/min for clearance, and 172 ± 25.4 ml/kg for volume of distribution at steady state. Bioavailability (93.92 to 96.65%) and peak plasma gentamicin concentration (9.43 to 10.89 μg/ml) were independent of injection site, but time to peak concentration when gentamicin was given at sc site 2 (43.33 minutes) was significantly (P < 0.05) longer than that when gentamicin was given at im site 1 (27.50 minutes). Absorption half-life was shorter after injections were given at both im sites (8.9 and 9.8 minutes) than after injection was given at sc site 2 (18 minutes).
Breed, age, and gender differences in plasma antithrombin-III activity in clinically normal young horses
Authors: Johnstone I. B. , Physick-Sheard P. , Crane S.
Published: February 2025

Plasma antithrombin-III activity was quantitated in plasma samples obtained from 165 clinically normal horses 3 years old or younger. In the horses as a group, antithrombin-III activity ranged from 63 to 131% of a species-specific reference plasma. Thoroughbred horses had significantly higher antithrombin-III activity (103.3 ± 18.3; mean ± sd) than did Standardbred horses (92.3 ± 14.2). The plasma antithrombin-III activities were significantly lower in horses younger than 16 months old when compared with those in more mature horses (3 years old). There was no statistically significant gender-related effect on plasma antithrombin-III activity. Breed and age factors should therefore be taken into consideration when interpreting plasma antithrombin-III activity in horses.
Transmission of bovine leukemia virus by Tabanus Fuscicostatus
Authors: Foil L. D. , French D. D. , Hoyt P. G. , Issel C. J. , Leprince D. J. , McManus J. M. , Seger C. L.
Published: February 2025

Bovine leukemia virus (blv) was transmitted by horse flies, Tabanus fuscicostatus, from a cow with a lymphocyte count of 31,500/mm3 to goats and dairy calves. As few as 10 and 20 flies transmitted blv to goats and calves respectively, but the minimal number of flies required to transmit the infection was not established. Groups of 150 and 100 T fuscicostatus transmitted blv to beef calves from a cow with a lymphocyte count of 14,600/mm3. These results support a role for horse flies in the horizontal transmission of blv.
Methods of clinical electrophysiologic study in pigs
Authors: Wheeler S. J. , Wells G. A. H. , Hawkins S. A. C.
Published: February 2025

Methods of estimating motor nerve conduction, sensory nerve conduction, and f-wave latency in pigs were determined. The sciatic-tibial nerves were used for motor nerve conduction and f-wave response and the superficial peroneal nerve was used for sensory nerve conduction.
Enzyme-linked immunosorbent assay for measurement of allergen-specific IgE antibodies in canine serum
Authors: Kleinbeck Michael L. , Hites Mark J. , Loker Jeffrey L. , Halliwell Richard E. , Lee Kenneth W.
Published: February 2025

A micro-elisa, using horseradish peroxidase-conjugated anti-canine IgE and polystyrene microtitration wells for detection of allergen-specific IgE in canine serum, was developed. Specificity of anti-canine IgE was confirmed by reversed cutaneous anaphylaxis evaluations, gel-precipitation reactions, immunoelectrophoresis, immunoaffinity chromatography, and heat inactivation. Individual allergen blanks were used to account for variable nonspecific binding among various allergens, and results were normalized using 4 reference sera. Coefficients of variation for intra-assay and interassay variability ranged from 0.77 to 5.66% and 3.15 to 9.83%, respectively. Results observed with wells coated with mixtures of various allergen extracts yielded results approximately equal to results (average) of wells containing individual components. Agreement between elisa and skin test results ranged from 43 to 64%, depending on allergen used.
Effects of single intravenously administered doses of dexamethasone on response to the adrenocorticotropic hormone stimulation test in dogs
Authors: Kemppainen R. J. , Sartin J. L. , Peterson M. E.
Published: February 2025

The effects of single iv administered doses of dexamethasone on response to the adrenocorticotropic hormone (acth) stimulation test (baseline plasma acth, pre- acth cortisol, and post-acth cortisol concentrations) performed 1, 2, and 3 days (experiment 1) or 3, 7, 10, and 14 days (experiment 2) after dexamethasone treatment were evaluated in healthy Beagles. In experiment 1, acth stimulation tests were carried out after administration of 0, 0.01, 0.1, 1, and 5 mg of dexamethasone/kg of body weight. Dosages ≥ 0.1 mg of dexamethasone/kg decreased pre-acth plasma cortisol concentration on subsequent days, whereas dosages ≥ 1 mg/kg also decreased plasma acth concentration. Treatment with 1 or 5 mg of dexamethasone/kg suppressed (P < 0.05) post-acth plasma cortisol concentration (on day 3 after 1 mg of dexamethasone/kg; on days 1, 2, and 3 after 5 mg of dexamethasone/kg). In experiment 2, iv administration of 1 mg of dexamethasone/kg was associated only with low (P < 0.05) post- acth plasma cortisol concentration in dogs on day 3. In experiment 2, pre-acth plasma cortisol and acth concentrations in dogs on days 3, 7, 10, and 14 and post-acth plasma cortisol concentration on days 7, 10, and 14 were not affected by dexamethasone administration.

The results suggest that, in dogs, a single iv administered dosage of ≥ 0.1 mg of dexamethasone/kg can alter the results of the acth stimulation test for at least 3 days. The suppressive effect of dexamethasone is dose dependent and is not apparent 7 days after treatment with 1 mg of dexamethasone/kg. The magnitude of the decrease in post-acth plasma cortisol concentration did not exceed 35% (compared with control values), regardless of the dose of dexamethasone used.
Cell proliferation kinetics of epidermis, hair follicles, and sebaceous glands of Cocker Spaniels with idiopathic seborrhea
Authors: Kwochka Kenneth W. , Rademakers Adriana M.
Published: February 2025

Cell proliferation kinetic values were established for the epidermis, hair follicle epithelium, and sebaceous glands of 8 Cocker Spaniels with primary idiopathic seborrhea. Values were established by intradermal pulse labeling injections of tritiated thymidine followed by cutaneous biopsy and autoradiography. The epidermal basal cell-labeling index was 4.96 ± 0.97%, and the epidermal nucleated cell-labeling index was 3.33 ± 0.71%. Calculated epidermal cell renewal time for the viable layers of the epidermis was 7.85 ± 1.80 days. The hair follicle infundibulum basal cell-labeling index was 5.48 ± 2.01%, and the sebaceous gland basal cell-labeling index was 5.94 ± 4.15%. When compared with previously reported cell kinetic values for Cocker Spaniels and Beagles with healthy skin, these data indicate accelerated cellular proliferation in all 3 cutaneous structures in seborrheic Cocker Spaniels.
Further phenotypic characterization of target cells for bovine leukemia virus experimental infection in sheep
Authors: Aida Y. , Miyasaka M. , Okada K. , Onuma M. , Kogure S. , Suzuki M. , Minoprio P. , Levy D. , Ikawa Y.
Published: February 2025

To determine the phenotype of target cells for bovine leukemia virus (blv) infection in sheep, we analyzed blood lymphocytes from blv-infected clinically healthy and leukemic sheep by use of monoclonal antibodies. In clinically healthy and leukemic sheep that were blv-infected, the blood concentration of T lymphocytes was within normal values, but the number of B lymphocytes was increased in several cases. In addition, the number of blood lymphocytes expressing the blv antigen correlated well with that of B lymphocytes. Double immunofluorescence staining demonstrated that lymphocytes expressing blv antigens bore B-cell but not T-cell surface markers. Moreover, neoplastic cells in the lymph nodes of leukemic sheep were stained immunohistochemically with an anti-B monoclonal antibody but not with any of anti-T monoclonal antibody tested, indicating that tumor cells are of B-lym-phocyte origin. Collectively, these results show that blv antigen-positive cells obtained from blv-infected sheep that have no clinical signs and blv-induced lymphosarcoma cells belong to the B-lymphocyte lineage.
Rotavirus replication in colostrum-fed and colostrum-deprived pigs
Authors: Shaw Daniel P. , Morehouse Lawrence G. , Solorzano Robert F.
Published: February 2025

A porcine rotavirus isolate was titrated in neonatal colostrum-fed and colostrum-deprived pigs. The stock rotavirus suspension had a titer of 10−6.5/ml and was in its fifteenth cell culture passage in MA-104 cells. Fourteen colostrum-fed pigs were orally inoculated with dilutions of the stock virus suspension ranging from undiluted to 10−5. These pigs did not develop notable clinical signs during the 7-day experimental trial and no pathologic changes were found in intestine, liver, lung, kidney, spleen, or brain. However, rotavirus was detected in feces of the colostrum-fed pigs, using virus isolation and electron microscopic techniques. Rotavirus was also isolated from lung, brain, or spleen of 4 of 12 of these pigs. Sixteen colostrum- deprived pigs were orally inoculated with dilutions of the stock virus suspension ranging from 10−1 to 10−8. Diarrhea developed in 10 of 12 pigs that were given up to the 10−6 dilution. Seven of these 12 pigs died because of the severity of diarrhea. Pigs that died of rotavirus-induced diarrhea had severe villus loss in the jejunum and ileum. Villi of the small intestine of colostrum-deprived pigs that survived the severe diarrhea were within normal limits at the end of the 7-day trial. The colostrum-deprived pigs that were inoculated with a dilution < 10−6 and survived past 96 hours underwent seroconversion. Rotavirus was detected by virus isolation and electron microscopy in the feces of all colostrum-deprived pigs that survived beyond 18.5 hours after inoculation. Virus was isolated from lungs, brain, or spleen of 12 of 16 colostrum-deprived pigs.
Characterization of osteosarcoma cells from two sibling large-breed dogs
Authors: Norrdin R. W. , Powers B. E. , Torgersen J. L. , Smith R. E. , Withrow S. J.
Published: February 2025

Neoplastic cells were isolated from 2 sibling Great Dane/ Labrador Retriever mixed-breed dogs in which telangiectatic type osteosarcomas arose concurrently. Cells from various sites in the same osteosarcoma appeared similar in culture, but there were differences between the 2 osteosarcomas in growth characteristics and appearance of cells. Cells from 1 osteosarcoma had a small, but significant (P < 0.05), cyclic adenosine monophosphate response to parathyroid hormone stimulation, indicating a low order of osteoblastic differentiation. Cells from the other osteosarcoma had no response to parathyroid hormone stimulation. Cells from both osteosarcomas and a concentrated cell-free filtrate from the osteosarcoma with osteoblastic differentiation were injected into nude mice, but osteosarcomas were not induced. Results of ultra- structural examination of osteosarcoma samples for viral particles were negative and supernatant fluids from cultured cells were considered negative for viral reverse transcriptase activity.
Immunohistochemical diagnosis of Neospora caninum in tissue sections
Authors: Lindsay David S. , Dubey J. P.
Published: February 2025

An avidin-biotin-peroxidase complex immunoperoxidase staining method was developed to detect Neospora caninum in formalin-fixed, paraffin-embedded tissue sections. Specific antiserum to N caninum was made in rabbits and used to probe tissues from dogs naturally and experimentally infected with N caninum. The test detected tachyzoites and bradyzoites of N caninum. A reaction was not observed to Toxoplasma gondii, Hammondia, hammondi, Sarcocystis cruzi, S capricanis, S tenella, Besnoitia jellisoni, Caryospora bigenetica, Hepatazoon canis, Atoxoplasma sp, or the organism causing canine dermal coccidiosis. When antiserum made in rabbits to T gondii was used in the test, reaction to N caninum was not observed.
Serum biochemical indicators of liver function in neonatal foals
Authors: Bauer John E. , Asquith Richard L. , Kivipelto Jan
Published: February 2025

Serum biochemical indicators of liver function were determined in healthy, age-matched foals during the first 270 days of life. Values were compared with those of healthy adult horses and with those determined on the day of birth (< 12 hours old).

Serum alkaline phosphatase, γ-glutamyl transferase, and l-iditol dehydrogenase activities were increased during the first 2 weeks of life. Serum cholesterol, triglyceride, and total and unconjugated bilirubin concentrations peaked during this same period. During the early neonatal period (<12 hours old), globulin concentrations (mainly β2 and γ fractions) were low and albumin/globulin ratios were high. However, individual values for all analytes were varied.
Effects of halothane and isoflurane on baroreflex sensitivity in horses
Authors: Hellyer Peter W. , Bednarski Richard M. , Hubbell John A. E. , Muir William W.
Published: February 2025

Baroreflex sensitivity (bs) was used to quantitatively assess the effects of halothane and isoflurane on the heart rate/arterial pressure relationship during steady-state (10 minutes) and dynamic pressure changes in adult horses. Arterial pressure was decreased in response to nitroglycerin or sodium nitroprusside and increased in response to phenylephrine HCl. Mean (± sem) bs in awake horses was 28.9 ± 2.6 and 13.2 ± 2.0 ms/mm of Hg during steady-state decreases and increases in systolic arterial pressure (sap), respectively. Halothane and isoflurane either significantly (P < 0.05) decreased or eliminated bs during steady-state decreases in sap, with no significant differences detected between anesthetic agents. During steady-state decreases in sap, significant (P < 0.05) correlation between r-r interval and arterial pressure was not observed for 6 of 10 and 4 of 11 halothane and isoflurane anesthesia periods, respectively. Halothane significantly (P < 0.05) decreased bs during steady-state increases in sap to 7.9 ± 0.6 and 6.5 ± 1.1 ms/mm of Hg during low and high minimal alveolar concentration (mac) multiples, respectively. Isoflurane decreased bs during steady-state increases in sap to 9.6 ± 1.5 and 6.6 ± 1.1 ms/mm of Hg during low and high mac anesthesia, respectively, with high mac of isoflurane decreasing bs significantly (P < 0.05), compared with awake and low mac values.

Plasma catecholamine (epinephrine and norepinephrine) concentrations increased significantly (P < 0.05), compared with baseline values during steady-state vasodilator infusions in halothane- and isoflurane-anesthetized horses. Steady-state infusions of phenylephrine in anesthetized horses resulted in arrhythmia development, with premature atrial and ventricular complexes seen in halothane-anesthetized horses and increased heart rate and atrial premature complexes seen less frequently in isoflurane-anesthetized horses.

Dynamic bs was 25.0 ± 4.5 and 20.1 ± 2.8 ms/mm of Hg for decreasing and increasing sap, respectively, in awake horses. The r-r interval and sap were linearly correlated during dynamic decreases in sap in 7 of 9 halothane and 8 of 10 isoflurane anesthesia periods. Baroreflex sensitivity decreased to 15.0 ± 6.8 and 13.3 ± 3.5 ms/mm of Hg during anesthesia with low mac of halothane and isoflurane, respectively. High mac of halothane and isoflurane significantly (P < 0.05) decreased bs during dynamic decreases in sap in 7.8 ± 1.8 and 7.2 ± 1.3 ms/mm of Hg, respectively. There were no significant differences in bs depression between halothane and isoflurane.
Clinical electromyographic studies of canine X-linked muscular dystrophy
Authors: Valentine B. A. , Kornegay J. N. , Cooper B. J.
Published: February 2025

Clinical electromyographic studies were performed in dogs (6 weeks to 5.5 years old) with a degenerative myopathy analogous to Duchenne muscular dystrophy. Spontaneous activity, consisting primarily of complex repetitive discharges (pseudomyotonic discharges), was found in all dogs tested, but was most prominent in dogs ≥ 10 weeks old. Myotonic discharges also were found, but were less frequent. Motor unit potentials were generally abnormally brief and frequently polyphasic. Ulnar nerve conduction velocities determined in two 4-month-old dogs were similar to those of unaffected littermates. It was concluded that canine X-linked muscular dystrophy is a primary myopathic process in which complex repetitive discharges and myotonic discharges are a prominent feature. The basis for this spontaneous activity is not known.
Interleukin-1β as an articular process joint intra-articular model induces synovitis and signs of acute neck pain in horses
Authors: Story Melinda R. , King Melissa , Nout-Lomas Yvette S. , Barrett Myra F. , Kawcak Christopher , Frisbie David , McIlwraith C. Wayne , Haussler Kevin K.
Published: February 2025

Objective

To develop and define a model of acute neck pain in an equine cervical articular process joint (APJ) using recombinant equine IL-1β (reIL-1β).

Methods

12 horses in this experimental study received a randomly assigned, unilateral intra-articular injection of 50 ng (n = 6) or 100 ng (n = 6) of reIL-1β and saline (contralateral side as control) into the C5-to-C6 APJ. Blinded ultrasonographic, clinical, and biomechanical parameters were evaluated between 4 hours and 14 days.

Results

There was a significant increase in APJ effusion on ultrasonographic examination that peaked at 24 hours (P = .0256; effect size, 0.8312; CI, 1.0594 to 0.629). There was a time effect on the clinical examination score (myofascial pain and stiffness) and a significant decrease in stride length and velocity at 24 hours. There was an adverse event (extravasation of injectate) in 1 horse.

Conclusions

Ultrasonographic evidence of the presence and severity of APJ effusion was readily identified and tracked over time. Unilateral injection of the APJ with reIL-1β induced clinical signs of myofascial pain, neck stiffness, and gait adaptations. Using individual control horses, rather than a contralateral saline injection within the same horse, would improve our understanding of the clinical presentation of acute APJ pain using this model.

Clinical Relevance

Diagnosing the presence, localization, and clinical effects of neck pain in horses remains challenging and would benefit from the establishment of an experimental model. The induction of acute synovitis using reIL-1β within the C5-to-C6 APJ opens the door for future studies to ultimately better understand equine cervical pain and dysfunction.
Preoperative screening thoracic radiographs yield few significant abnormalities in dogs with no history or exam findings suggestive of thoracic disease
Authors: Moss Kristine M. , Gauthier Christopher M. , Randall Elissa K.
Published: February 2025

Objective

To evaluate the utility of routine preanesthetic screening thoracic radiographs in dogs without a specific clinical indication for this test.

Methods

All patients presented for elective tibial plateau leveling osteotomy between January 1, 2022, and December 31, 2022, were enrolled if there were no clinical signs or history of neoplasia or cardiopulmonary or thoracic disease. Three-view thoracic radiographic studies were performed and evaluated by the attending surgeon and a board-certified veterinary radiologist. The incidence of radiographic abnormalities and agreement between the attending clinician and the radiologist were analyzed.

Results

Of the 281 cases evaluated in this study, 10 (3.6%) were found to have radiographic abnormalities that were likely to affect the clinician's decision to proceed with elective surgery. There was no association between patient age and the probability of diagnosing a significant radiographic abnormality. There was poor agreement between the findings of the clinician and radiologist for cardiovascular and pulmonary abnormalities. There was slight agreement between the findings of the clinician and the radiologist for extrathoracic abnormalities.

Conclusions

Our data suggest that the utility of preoperative screening thoracic radiographs in dogs with no specific clinical indications for this test appears to be low. Given the poor agreement between clinician and radiologist findings, clinicians should consider routine evaluation of thoracic radiographs by a radiologist.

Clinical Relevance

These findings should be considered by a clinician when deciding whether to recommend thoracic radiographs as a screening tool for a patient without history or physical examination findings suggestive of intrathoracic disease.
Time but not storage of equine plasma in silicate-coated tubes affects adrenocorticotropic hormone stability
Authors: Johnston Taylah J. , Stewart Allison J. , Dryburgh Elizabeth L. , Bertin François-René
Published: February 2025

Objective

Pituitary pars intermedia dysfunction (PPID) is diagnosed by measuring the ACTH concentrations. Due to the reported instability of ACTH, it is recommended to transfer centrifuged plasma into cryovials; however, in practice, cryovials are infrequently used, and serum (red-top) tubes are used instead. This study investigated whether this procedure affects ACTH concentrations and the diagnosis of PPID.

Methods

This was a cohort study. Blood was collected into EDTA tubes from 9 horses with PPID and 7 controls. After centrifugation, plasma was either aliquoted into a cryovial or into a serum tube. Samples were stored at 4 and 20 °C with ACTH concentrations measured using a chemiluminescent assay at 2, 24, and 48 hours after collection. Data were analyzed using a 2-way repeated measures ANOVA with P < .05 considered significant.

Results

There was a significant effect of time on ACTH concentrations in horses with PPID at 4 and 20 °C and in all horses at 20 °C with decreasing ACTH concentrations over time; however, no significant effect of storing plasma in a serum tube was detected. Three horses diagnosed with PPID would have had a different classification if the samples had been kept at 20 °C for 24 or 48 hours.

Conclusions

Time but not storage of plasma in serum tubes decreases the measured ACTH concentration in horses with PPID.

Clinical Relevance

Transferring plasma into serum tubes does not significantly alter the measured ACTH concentrations; however, time between collection and analysis might lead to erroneous diagnoses.
Combined Immunodeficiency of Arabian Horses: Confirmation of Autosomal Recessive Mode of Inheritance
Authors: Perryman Lance E. , Torbeck Richard L.
Published: February 2025

A 3-year prospective breeding trial was designed to verify the mode of inheritance of combined immunodeficiency (cid) in Arabian horses. Twenty-six mares that had previously produced foals with cid were mated to a stallion that had sired foals with cid. Of 53 foals obtained, 15 (28.3%) had cid. The ratio of female to male foals was 28:25, and the ratio of female cid to male cid foals was 8:7. The results of this trial confirmed a suggestion that cid in Arabian horses is inherited as an autosomal recessive trait.