bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum antibody response to carbohydrate antigens of Pasteurella haemolytica serotype 1 : Relation to experimentally induced bovine pneumonic pasteurellosis
Authors: Confer A. W. , Simons K. R. , Panciera R. J. , Mort A. J. , Mosier D. A.
Published: February 2025

The antibody responses to the capsular carbohydrate (cc) purified from Pasteurella haemolytica serotype 1 were determined by an elisa, using 135 sera from 6 calves vaccinated with phosphate-buffered saline solution, formalin-killed P haemolytica bacterins, live P haemolytica, or an extract of P haemolytica referred to as carbohydrate-protein subunit (cps). Calves vaccinated with live P haemolytica, bacterins, or cps developed serum antibodies to cc. Bacterins containing Freund incomplete adjuvant or Freund complete adjuvant induced higher antibody responses than did bacterins containing aluminum hydroxide. In 4 of 6 experiments, high antibody responses to cc were significantly (P < 0.05) correlated with resistance to transthoracic challenge exposure with P haemolytica. When calves were challenge exposed with a dose of P haemolytica that was 4.5 times greater than the standard challenge exposure dose or when calves that had been vaccinated with CPS were challenge exposed, antibody responses did not significantly (P > 0.05) correlate with resistance to challenge exposure.

The amount of serum antibodies to cps increased significantly (P < 0.05) when calves were vaccinated with live or killed P haemolytica or with cps, compared with that in calves given saline solution. In 5 of 6 experiments, correlation between high antibody responses and resistance to challenge exposure was significant (P < 0.05). The correlation between those variables was not significant (P < 0.07) for cps-vaccinated calves. In the elisa, treatment of cps with sodium m-periodate, to oxidize periodate-sensitive carbohydrate epitopes, failed to markedly alter the antibody response to cps. However, the correlation between high antibody responses to periodate-treated cps and resistance was significant (P < 0.05) for all 6 experiments.

In the elisa, periodate treatment of cc, lipopolysaccharide, and cps caused average reductions in antibody reactivity of 7.1%, 53.8%, and 34.5%, respectively. Preadsorption of sera with cc or lipopolysaccharide did not markedly reduce antibody reactivity with cps. Preadsorption of sera with cc and reaction with periodate-treated and nontreated cps indicated that for calves given phosphate-buffered saline solution vaccines, antibody reactivity was reduced 65.4 %, whereas for those vaccinated with a bacterin with aluminum hydroxide, a bacterin with Freund incomplete adjuvant, or live P haemolytica, antibody reactivity was reduced 47.1%, 40.5%, and 25.0%, respectively.

It was concluded that serum antibodies to cc are of some importance in resistance and that certain epitopes in cps that are not sensitive to periodate are of importance in resistance to bovine pneumonic pasteurellosis. There are qualitative and quantitative differences among the serum antibody responses to carbohydrate epitopes for calves vaccinated with phosphate-buffered saline solution, bacterins, or live P haemolytica.
Etiologic agents, incidence, and improved diagnostic methods of cantharidin toxicosis in horses
Authors: Ray Allen C. , Kyle Ana Laura G. , Murphy Michael J. , Reagor John C.
Published: February 2025

In addition to the 3-striped blister beetles (Epicauta equexa and E occidentalis), other sources of equine cantharidin toxicosis were identified at the Texas Veterinary Medical Diagnostic Laboratory and included E albida and E attrivittata and the previously incriminated E pardalis and E pennsylvanica. Improved methods for diagnosing cantharidin or blister beetle toxicosis involve partial purification of urine and gastric content extracts, using silica cartridges, followed by analysis, using capillary gas chromatography/mass spectrometry. During a 26-month period, 53 episodes of cantharidin toxicosis in horses were confirmed at our diagnostic laboratory. Concentrations of cantharidin in urine and gastric contents ranged from 0.0003 to 3.50 μg/g. Peak incidences were observed in late summer and early fall.
Duration of strain 2308 infection and immunogenicity of Brucella abortus lipopolysaccharide in five strains of mice
Authors: Phillips Marshall , Pugh George W. , Deyoe Billy L.
Published: February 2025

A study was conducted to compare immunogenicity of a Brucella abortus lipopolysaccharide (lps) and the duration of infection in 5 strains of mice. Mice of strains CBA/NJ, BALB/c, CD-1, C3H/HeN, and C3H/HeJ were allotted into 2 large groups (vaccinated with proteinase K-treated lps or nonvaccinated) and 6 subgroups based on the intervals between challenge exposure to B abortus strain 2308 and the week the response data were obtained. Criteria used in comparing responses between the various strains of mice as well as between vaccinated and nonvaccinated mice were splenomegaly, colony-forming units (cfu) from spleens, and antibody titers. Responses were evaluated at 1, 2, 3, 5, 8, and 12 weeks after challenge exposure.

Results indicated that all strains of mice became infected and maintained infection throughout the 12-week period, the percentages of mice infected were significantly (P < 0.05) less in vaccinated mice for the first 5 weeks after challenge exposure, and there were no direct correlations between increased immunoglobulins (IgM and IgG titers) and reduction in cfu. Vaccinated mice of strains BALB/c, CD-1, C3H/HeN, and C3H/HeJ had increased titers when challenge exposed and also had significantly (P < 0.05) smaller spleens and lower cfu. Vaccinated CBA/NJ mice did not have marked antibody titers.

The overall results indicated that vaccination with lps offers some initial protection against B abortus strain 2308 infection, but this protection disappears gradually and in various degrees in the 5 strains of mice studied.
Functional and metabolic activity of bovine pulmonary lavage cells phagocytically stimulated with pathogenic isolates of Pasteurella haemolytica
Authors: Richards Alan B. , Renshaw Harland W.
Published: February 2025

Live Pasteurella haemolytica biotype A, serotype 1 isolates (n = 3) and Escherichia coli K-12, strain W3110, were reacted with bovine pulmonary lavage cell (plc) suspensions. The comparative effects of the different bacteria on the functional and metabolic activity of alveolar macrophages (amo) in the plc suspensions were assessed simultaneously by use of 51Cr release, luminol-dependent chemiluminescence (ldcl), and amo bactericidal assays. The bovine plc responded differently to E coli, than to the 3 P haemolytica isolates in each of the 3 experimental test systems; however, responses to each of the P haemolytica isolates were not found to be significantly different.

Unopsonized live P haemolytica cells adversely affected the functional and metabolic response of plc, whereas there was no evidence of a cytotoxic (cytocidal) influence of E coli. A difference in 51Cr release for reaction mixtures containing E coli and P haemolytica was not detected at zero time; however, at each subsequent time, reaction mixtures phagocytically stimulated with P haemolytica had significantly increased amount of 51Cr release (P < 0.05), compared with those mixtures containing E coli. Bovine amo in the plc suspensions were able to effectively kill E coli in vitro, but were unable to prevent survival and subsequent growth of P haemolytica. The luminol-dependent chemiluminescence profiles for reaction mixtures phagocytically stimulated with E coli provided evidence of sustained production of oxygen radicals with antimicrobial capabilities by bovine amo in the plc. Production of these highly reactive antimicrobial oxidants appeared initially in cultures containing P haemolytica but, subsequently, their production declined precipitously and ceased altogether.
Suppression of preovulatory luteinizing hormone surges in heifers after intrauterine infusions of Escherichia coli endotoxin
Authors: Peter A. T. , Bosu W. T. K. , DeDecker R. J.
Published: February 2025

A study was conducted to test the hypothesis that high cortisol concentrations associated with products of infections (endotoxin) cause derangement in the neuroendocrine mechanism controlling ovulation in heifers. Eight Holstein heifers were given 2 injections of prostaglandin (pg), 11 days apart, to synchronize estrus. Starting from 25 hours after the second injection of pg (pg-2), the uterus of each heifer was infused with 5 ml of pyrogen-free water (control, n = 3) or Escherichia coli endotoxin (5 μg/kg of body weight) in 5 ml of pyrogen-free water (treated, n = 5), once every 6 hours for 10 treatments. Blood samples were obtained every 15 minutes via indwelling jugular catheter for an hour before and 2 hours after each infusion, then hourly until an hour before the next infusion. Ultrasonography of the ovaries was performed every 12 hours, starting 24 hours after pg-2 injection until 96 hours after pg-2 injection. Serum concentrations of luteinizing hormone and cortisol were determined by validated radioimmunoassays. Changes in cortisol concentrations were not detected in control heifers with preovulatory luteinizing hormone surges at 60 to 66 hours after pg-2 injection, followed by ovulations 72 to 96 hours after pg-2 was injected. None of the treated heifers ovulated, and the resulting follicular cysts (14 to 18 mm diameter) persisted for 7 to 21 days. In all treated heifers, serum cortisol concentrations increased (4- to 10-fold) during the first 2 hours after each infusion and then decreased gradually until the next infusion. Luteinizing hormone concentrations remained at baseline values throughout the treatment period in all treated heifers. These findings suggested that endotoxin-induced increases in cortisol concentrations during the preovulatory period of the estrous cycle prevented ovulations by blunting the preovulatory luteinizing hormone surges.
Induction of equine postanesthetic myositis after halothane-induced hypotension
Authors: Lindsay W. A. , Robinson G. M. , Brunson D. B. , Majors L. J.
Published: February 2025

Wick catheters were used to measure intracompartmental pressures of the extensor carpi radialis muscles and long heads of the triceps brachii muscles of 7 horses maintained under halothane anesthesia during controlled ventilation. Horses were positioned in left lateral recumbency on a water bed for 4 hours. Using a crossover design, 6 of the 7 horses were subjected to normotensive and hypotensive anesthesia on separate occasions. Hypotension was achieved by increasing the inspired halothane concentration. Hematologic and biochemical measurements were determined at designated intervals before, during, and for 7 days after each anesthetic episode.

Under hypotensive conditions, 2 horses developed severe, generalized myositis and were euthanatized. Three of the 5 other horses developed swelling of the downside masseter muscle, 4 demonstrated mild extensor deficits of the downside forelimb, and 1 had a severe extensor deficit of the uppermost hind limb.

As a group, the hypotensive horses had markedly increased activities of serum enzymes (creatine kinase, aspartate transaminase, and blood lactate) and abnormalities in calcium-phosphorus homeostasis. Lameness or enzyme alterations were not observed in normotensive horses.

Although the intracompartmental pressure values were markedly increased in the muscle bellies of the compressed limbs of all horses, there was a statistically significant difference in intracompartmental pressures between the downside or compressed muscle compartments of the extensor carpi radialis of hypotensive and normotensive horses.

High concentrations of halothane may predispose anesthetized horses to postanesthetic myositis, even when protective padding is used. Intracompartmental muscle pressure, as measured by the wick catheter, may not be a reliable predictor of equine postanesthetic lameness.
Turbinate perimeter ratio as an indicator of conchal atrophy for diagnosis of atrophic rhinitis in pigs
Authors: Collins Michael T. , Backstrom Lennart R. , Brim Theresa A.
Published: February 2025

Transverse sections of snouts from 171 cross-bred (principally Yorkshire × American Landrace) pigs were evaluated for evidence of turbinate atrophy by use of conventional (atrophic rhinitis [ar] score) and morphometric methods. Of the 171 pigs, 35 were clinically normal (ar score, 0), 65 had mild ar (ar score, 1), 41 had moderate ar (ar score, 2), and 30 had severe ar (ar score, 3). Turbinate cross-sectional area (ta) and the ratio of ta to nostril cross-sectional area, called turbinate area ratio (tar), had the lowest correlations (r = 0.24 to 0.55) with conventional ar score. Among clinically normal pigs, ta was greater in older pigs as expected, but the tar values also were significantly (P < 0.0001) different between 15- week-old pigs (55 kg) and 22-week-old pigs (100 kg). Turbinate penmeter and turbinate perimeeer ratio (tpr) were not influenced by pig age or source. The tpr values were closely correlated with subjective visual ar scores (r = 0.73), with ar scores derived by measuring the space between the ventral portion of the scroll and the floor of the nasal cavity (r = 0.72), and the actual size of this space in millimeters (r = 0.71). Mean tpr values for pigs assigned visual ar scores of 0, 1, 2, or 3 were 1.54, 1.25, 0.97, and 0.73, respectively. The 95% confidence intervals around these mean tpr values were discreet and did not overlap. Turbinate perimeter ratio, therefore, may be a more reliable morphometric measure of atrophic rhinitis and also provides parametric data suitable for quantitative analysis.
Oxidative metabolism of the bovine alveolar macrophage
Authors: Dyer Robert M. , Erney Susan , Spencer Pamela , Benson Charles E.
Published: February 2025

Oxidative respiratory burst activity was examined in lavage-procured bovine pulmonary alveolar macrophages. Nonstimulated alveolar macrophages released a minimal quantity of superoxide anion and had small amounts of glucose flux through the pathways of energy metabolism. Nonstimulated cells metabolized substantial amounts of glucose through the hexose monophosphate shunt. Stimulation with opsonized zymosan particles induced a tenfold increase in the release of superoxide anion and a twofold increase in the flux of glucose through the hexose monophosphate shunt and the pathways of energy metabolism. Preliminary observations also indicated that the magnitude of the burst varied between sets of bronchoalveolar cells obtained from the same calf over time.
Bioavailability, pharmacokinetics, and plasma concentration of tetracycline hydrochloride fed to swine
Authors: Kniffen T. S. , Bane D. P. , Hall W. F. , Koritz G. D. , Bevill R. F.
Published: February 2025

A 2 × 2 crossover design trial was conducted in gilts to determine the bioavailability and pharmacokinetics of tetracycline hydrochloride. The bioavailability of tetracycline hydrochloride administered orally to fasted gilts was approximately 23%. After intravascular administration, the disposition kinetics of tetracycline in plasma were best described by a triexponential equation. The drug had a rapid distribution phase followed by a relatively slow elimination phase, with half-life of 16 hours. Its large volume of distribution (4.5 ± 1.06 L/kg) suggested that tetracycline is distributed widely in swine tissues. Total body clearance was 0,185 ±0.24 L/kg/h. Other pharmacokinetic variables were estimated.

In a second trial, 3 gilts were fed a ration containing 0.55 g of tetracycline hydrochloride/kg of feed. Resulting plasma concentration of tetracycline was determined at selected times during 96 hours after exposure to the medicated feed. Plasma drug concentration peaked (0.6 μg/ml) at 72 hours after access to the medicated feed.
Somatosensory-evoked and spinal cord-evoked potentials in response to pudendal and tibial nerve stimulation in cats
Authors: Sims Michael H. , Selcer Robert R.
Published: February 2025

Somatosensory-evoked potentials (sep) and spinal cord-evoked potentials (scep) were recorded in clinically normal adult cats in response to electrical stimulation of pudendal and tibial nerves to provide normative data that can be used in a clinical evaluation of pudendal nerve function in cats after sacral or sacrococcygeal luxations or fractures. Responses to tibial nerve stimulation were included in the study as an internal control because it is usually not involved in these types of injuries and because its sep and scep are easily recorded. Evoked potentials were characterized by the latencies (ms) of positive (p or p) and negative (n or n) peaks. The sep resulting from percutaneous pudendal nerve stimulation consisted of a prominent p-N-P potential in the 30- to 80-ms range. The pudendal scep was not successfully recorded because of large muscle artifacts evoked from the sacral area. The tibial sep was similar to the pudendal sep, except that the prominent p-N-P series in the 35- to 81-ms range was preceded by a smaller p-n-p-n sequence in the 7- to 23-ms range. The tibial scep consisted of a p-N-P series in the 2- to 4-ms range.
Effects of aflatoxin, deoxynivalenol, and their combinations in the diets of growing pigs
Authors: Harvey Roger B. , Kubena Leon F. , Huff William E. , Corrier Donald E. , Clark Donald E. , Phillips Timothy D.
Published: February 2025

In 2 studies, the effects of dietary aflatoxin (af) and deoxynivalenol (don) were evaluated in growing crossbred barrows. The first study consisted of 4 treatments of 5 barrows each (6 weeks old) at dosages of 0 mg of don and af (control), 2.5 mg of don/kg of feed, 0.75 mg of af/kg of feed, and 2.5 mg of don + 0.75 mg of af/kg of feed. Pigs were fed their respective diets for 21 days. Treatment with don caused decreases in weight gains, but no other treatment-related differences could be attributed to diets. In a second study, the experimental design consisted of 4 treatments of 5 barrows each (6 weeks old) at dosages of 0 mg of don and af (control), 3 mg of don/kg of feed, 3 mg of af/kg of feed, and 3 mg of don + 3 mg of af/kg of feed fed ad libitum for 28 days. The pigs were observed twice daily for clinical signs, hematologic and serum biochemical measurements were made weekly, and body weights and feed consumption were determined weekly. Body weight gains were significantly depressed by the af and the af + DON treatments for days 7, 14, 21, and 28. Body weights and body weight gains were only slightly reduced in the don treatment. Changes in serum enzymatic activities of alkaline phosphatase, aspartate transaminase, creatine kinase, and γ-glutamyl transferase were noticed in pigs given treatments with af alone and those given af + DON. Total iron binding capacity and serum total protein, albumin, cholesterol, bun, and glucose concentrations were decreased, whereas prothrombin and activated thromboplastin times were increased by af and af + DON treatments. Lesions in the af-treated groups were compatible with a diagnosis of aflatoxicosis. The control and don-treated pigs had no abnormalities. These data provide a description of the effects of dietary af and don, singly and in combination, in growing barrows.
Circulating concentrations of trypsin-like immunoreactivity and activities of lipase and amylase after pancreatic duct ligation in dogs
Authors: Simpson Kenneth W. , Batt Roger M. , McLean Lynn , Morton David B.
Published: February 2025

The possibility that assay of circulating trypsin-like immunoreactivity (tli) could assist in the diagnosis of acute pancreatitis in dogs has been examined by assaying plasma tli concentrations after pancreatic duct ligation and comparing the results with plasma activities of lipase and amylase. Venous blood samples were obtained from 8 dogs before surgery, then daily for 5 days and at 14 days after ligation of pancreatic ducts. Plasma concentrations of tli increased within 24 hours and tended to peak before and to decrease more rapidly than activities of lipase and amylase, remaining greater than the control range for 5 days in all but 2 dogs. Plasma lipase and amylase activities increased together and remained greater than the control range in all dogs for 5 days after surgery. Regression analysis of all postoperative data indicated significant correlations between concentration of tli and lipase activity (r = 0.67, P < 0.001), concentration of tli and amylase activity (r = 0.53, P < 0.001), and between lipase and amylase activities (r = 0.74, P < 0.001). These findings suggested that assay of tli may provide an early indication of acute pancreatitis in dogs. Because tli is specifically pancreatic in origin, high plasma tli concentration may prove a more reliable indicator of clinical pancreatitis than high activities of amylase or lipase, which may be derived from extrapancreatic tissues.
Neutralizing antibody responses to bluetongue and epizootic hemorrhagic disease virus serotypes in beef cattle
Authors: Fulton Robert W. , Burge Lurinda J. , Cummins J. M.
Published: February 2025

Blood samples were obtained from sentinel beef cattle at monthly intervals, and the sera were tested for antibodies, using a bluetongue virus (btv) immunodiffusion test (idt) and virus-neutralization test (vnt), for 5 btv serotypes (2, 10, 11, 13, and 17) and 2 epizootic hemorrhagic disease virus (ehdv) serotypes (1 and 2). The cattle tested were transported from Tennessee to Texas in 1984 and 1985. All cattle were seronegative by the btv idt at the initial bleeding in Texas in 1984 and 1985. In 1984, 16 of 40 (40%) cattle seroconverted as assessed by results of the btv idt. In the 16 seropositive cattle in 1984, neutralizing antibodies were detected to btv serotypes 10 (n = 7), 11 (n = 3), and 17 (n = 11), and ehdv serotypes 1 (n = 1) and 2 (n = 7). In 1984, no cattle seroconverted to btv-2 or btv-13. In 1985, 10 of 36 (27.8%) cattle seroconverted as assessed by results of the idt. Of the 10 seropositive cattle in 1985, neutralizing antibodies were detected to btv serotypes 10 (n = 10), 11 (n = 10), 13 (n = 7), and 17 (n = 5), and ehdv serotypes 1 (n = 1) and 2 (n = 7). In 1985, no cattle seroconverted to btv-2. Clinical diseases attributable to btv or ehdv was not detected in these cattle in 1984 or 1985.
Virulence determinants of Salmonella typhimurium from animal sources
Authors: McDonough Patrick L. , Jacobson Richard H. , Timoney John F.
Published: February 2025

Two hundred seventy-eight strains of Salmonella typhimurium isolated from 1973 to 1981 from animal sources in New York State were studied for possible virulence determinants and for a serotype-specific plasmid possibly linked with virulence. Of the strains, 98% possessed type-1 fimbriae. All strains possessed flagella and were motile. One hundred twenty-three strains (44%) treated with mitomycin C tested positive for the cholera-Escherichia coli heat labile family of toxins by a kinetics-based elisa; when treated with mitomycin C and extracted with polymyxin B, 249 (90%) were positive in the kinetics-based elisa. All strains were negative in the Biken test. A smooth cell wall was found in 99% of the strains. Sixty-one percent (169) of the strains had a 62-Md plasmid. Seventy-six (27%) of the strains had detectable plasmids ranging in size from 1 to 124 Md.
Comparison of pathophysiologic changes in the lungs of calves challenge exposed with Escherichia coli-derived endotoxin and Pasteurella haemolytica, alone or in combination
Authors: Slocombe R. F. , Derksen F. J. , Robinson N. E.
Published: February 2025

Pulmonary responses to intratracheal challenge exposure with Pasteurella haemolytica, with or without Escherichia coli-derived endotoxin, E coli endotoxin alone, or saline solution were compared in anesthetized, mechanically ventilated neonatal calves. Baseline values for dynamic compliance, total pulmonary resistance, functional residual capacity, arterial blood gas tensions, hemogram, leukogram, and systemic and pulmonary arterial pressures were recorded for each calf. After baseline data were obtained, calves were challenge exposed with logarithmic-growth phase P haemolytica organisms with or without E coli endotoxin, E coli endotoxin alone, or saline solution (0.9% NaCl). Physiologic data were obtained immediately after challenge exposure and at various intervals over the next 6 hours. Calves challenge exposed with P haemolytica alone developed severe hypoxemia, had increased alveolar-arterial oxygen difference and threefold increases in total pulmonary resistance, became hypercarbic, had decreased functional residual capacity, and developed systemic hypotension without change in pulmonary arterial pressure. At necropsy, these calves had extensive multifocal areas of necrohemorrhagic and purulent pneumonia. Ratio of extravascular lung water to lung dry weight was not significantly increased in lung specimens obtained from calves challenge exposed with P haemolytica, but ratio of lung wet weight to dry weight was increased, indicating that increased lung wet weight was attributable largely to increased solids and not to fluid alone. (Extravascular lung water measurement excludes fluid from the vascular compartment.) Intratracheal challenge exposure with endotoxin failed to alter lung function and caused minor changes in lung structure consisting of focal areas of hemorrhage and edema. In addition, sequential challenge exposure with endotoxin after inoculation of P haemolytica failed to change the rate of development of physiologic abnormalities caused by P haemolytica alone. We concluded that P haemolytica inoculation leads rapidly to altered pulmonary and cardiovascular function and that similar changes could not be induced by administration of E coli endotoxin. These data suggest that endotoxin may not be responsible for the pathophysiologic derangements observed in calves with acute pneumonic pasteurellosis, unless endotoxin from E coli is markedly less pathogenic than that derived from P haemolytica.
Antagonistic effect of idazoxan on xylazine-induced central nervous system depression and bradycardia in calves
Authors: Thompson James R. , Hsu Walter H. , Kersting Karl W.
Published: February 2025

Two doses of an α2-adrenoreceptor antagonist, idazoxan, were administered to reverse the cns depressant and bradycardia effects of xylazine in calves. Once a week for 3 weeks, each of 6 calves were administered iv one treatment of: (1) 0.2 mg of xylazine/kg of body weight followed in 10 minutes by 1 ml of 0.9% NaCl, (2) 0.2 mg of xylazine/kg followed in 10 minutes by 10 μg of ida-zoxan/kg, or (3) 0.2 mg of xylazine/kg followed in 10 minutes by 30 μg of idazoxan/kg. The order of the 3 treatments in each calf was selected at random. Xylazine alone caused lateral recumbency for 27.2 ± 3.0 minutes (mean ± sem). Idazoxan administered at dosages of 10 and 30 μg/kg shortened xylazine-induced lateral recumbency to 11,5 ± 0.8 and 10.3 ± 0.2 minutes, respectively. Calves given xylazine alone stood at > 60 minutes after the onset of recumbency. Idazoxan given at dosages of 10 and 30 μg/ kg shortened the time to standing to 16.8 ± 1.7 and 11.3 ± 0.2 minutes, respectively. Idazoxan given at a dosage of 30 μg/kg also reversed xylazine-induced bradycardia. Results indicated that idazoxan should be a useful antidote for xylazine overdose in cattle.
Proadifen-induced production of prostacyclin by equine peritoneal macrophages
Authors: Morris Debra Deem , Moore James N. , Wiltshire Nancy , Fischer Kay
Published: February 2025

A study was performed to determine the effect of proadifen hydrochloride on prostacyclin (prostaglandin I2 [pgi2]) and thromboxane A2 (TxA2) synthesis by equine peritoneal macrophages and the effect of proadifen on endo-toxin-induced synthesis of pgi2 and TxA2 by equine macrophages. Peritoneal macrophages (2.5 × 106/ml) were incubated for 6 hours in tissue culture media containing 1) nothing (nontreated control), 2) proadifen hydrochloride (20, 100, 250, and 500 μmol/L, 3) endotoxin (5 ng/ ml), or 4) the calcium ionophore A23187 (0.95 μmol/L). In a second series of experiments, peritoneal macrophages were incubated with endotoxin (5 ng/ml) and proadifen (250 μmol/L), for 6 hours. Concentrations of 6-keto-prostaglandin F1α (6-keto-pgf1α) and thromboxane B2, the stable metabolites of pgi2 and TxA2, were determined in the incubation media by radioimmunoassay.

Proadifen caused increased synthesis of pgi2 by equine macrophages, without affecting TxA2 production. The increasd pgi2 production was similar to that induced by endotoxin and calcium ionophore; however, the latter 2 agents significantly stimulated TxA2 production as well (P < 0.05). There were no significant differences among mean concentrations of 6-keto-pgf1α in media from macrophages treated with 100, 250, or 500 μmol/L proadifen, but there was a significant curvilinear regression between their concentrations. The ratio of thromboxane B2 to 6-keto-pgf1α was significantly lower than baseline in incubation media from macrophages exposed to proadifen, endotoxin, and calcium ionophore. Proadifen hydrochloride did not significantly change equine peritoneal macrophage production of pgi2 or TxA2 in response to endotoxin.
Oral vaccination of dogs fed canine adenovirus in baits
Authors: Boer G. M. , Brooks R. C. , Foggin C. M.
Published: February 2025

Six groups of 5 dogs each were fed dilutions of canine adenovirus-2, either as raw liquid or after insertion into cornmeal baits. By the fourth week after vaccination, 29 of the 30 dogs developed high titers of serum-neutralizing antibodies to the virus.
Xeroradiographs evaluation of the equine larynx
Authors: Orsini Paul G. , Raker Charles W. , Reid Charles F. , Mann Peter
Published: February 2025

The normal radiographic anatomy of the equine larynx was determined by use of xeroradiography and dissection. The body and laminae of the thyroid cartilage, the muscular process of the arytenoid cartilages, and the dorsal lamina and arch of the cricoid cartilage had radiographic evidence of mineralization (calcification) and/or ossification in clinically normal horses. There was a significant (P < 0.01) increase in the degree of mineralization of the thyroid and arytenoid cartilages with advancing age.

Horses with diagnosis of arytenoid chondrosis (arytenoid chondral dysplasia, arytenoid chondropathy) by use of endoscopy had radiographic changes that included: enlargement with increased density of the arytenoid cartilage region, abnormal patterns of mineralization (dystrophic mineralization or osseous metaplasia), abnormal contour of the corniculate process(es) and laryngeal masses, sometimes obliterating part or all of the lateral laryngeal ventricles.
Identification of a virulence factor for Brucella abortus infection in BALB/c mice
Authors: Pugh George W. , Tabatabai Louisa B. , Bricker Betsy J. , Mayfield John E. , Phillips Marshall , McDonald Timothy J. , Zehr Emilie S.
Published: February 2025

Immunogenic or pathogenic factors of recombinant proteins (rbcsp20, rbcsp-31, and rbcsp45 of Brucella abortus strain 19) for mice were compared with factors of a proteinase K-treated lipopolysaccharide extracted from B abortus strain 2308. Mice were vaccinated with 4 products, using different inoculation schedules and were challenge exposed with a virulent culture of B abortus strain 2308. Blood samples were collected 2 weeks after vaccination and at necropsy and sera were obtained. Spleens were cultured for B abortus at necropsy (3 to 4 weeks after challenge exposure).

Mice given proteinase K-treated lipopolysaccharide alone or in conjunction with rbcsp20 or rbcsp45 proteins were protected, but mice given rbcsp31 on the same day as challenge exposure were not. Vaccination with recombinant proteins alone neither provide protection nor significantly (P > 0.05) increase the pathogenic effect of the challenge-exposure culture. Seemingly, rbcsp31 might be a virulence factor of B abortus.
Effects of intermittent and continuous administration of decoquinate on bovine coccidiosis in male calves
Authors: Fitzgerald Paul R. , Mansfield Manford E.
Published: February 2025

Male Holstein calves were each inoculated with 350,000 sporulated oocysts of Eimeria bovis. Two calves were given decoquinate (0.5 mg/kg of body weight) continuously in dry feed for 29 days, and 2 calves each were given 0.5, 1, or 1.5 mg of decoquinate/kg on an every 2nd-or 3rd-day schedule for 29 days.

Calves given decoquinate continuously did not discharge oocysts but had slightly loose feces. In general, the number of oocysts discharged increased and fecal consistency decreased as the time between feeding of medicated feed increased. Calves given 0.5 or 1.5 mg of decoquinate/kg every 3rd day discharged more oocysts and had more diarrhea than did calves given 1 mg of decoquinate/kg every 3rd day.

At postinoculation day 29, calves were euthanatized. At necropsy, intestinal tissues of calves given decoquinate were mostly normal. Apparently, reduced infections along with the elapsed time were sufficient to resolve most intestinal lesions caused by the coccidia.

Decoquinate was most effective when fed continuously at 0.5 mg/kg. However, when fed at 1 or 1.5 mg of decoquinate/kg every 2nd day or 1.5 mg of decoquinate/kg every 3rd day, oocyst production was reduced and clinical coccidiosis was prevented.
Controlled test of anthelmintic activity of a macrocyclic lactone (compound F28249-α) in lambs
Authors: Lyons E. T. , Drudge J. H. , Tolliver S. C.
Published: February 2025

A controlled blind test was performed in 1984 to evaluate the anthelmintic activity of experimental formulations of compound F28249-α against gastrointestinal parasites in lambs in Kentucky. Twenty-five lambs were allotted to 5 groups of 5 lambs/group.

The drug was administered sc to 2 groups (A, 0.2 mg/ kg of body weight; B, 0.3 mg/kg) and orally to 2 groups (C, 0.2 mg/kg; D, 0.3 mg/kg). Group E received a placebo subcutaneously. Lambs were euthanatized 7 days after treatment for necropsy and identification and enumeration of worm parasites in the gastrointestinal tract.

Group-E lambs harbored 7 genera (including 10 species) of nematodes and 1 genus of tapeworms. Worm collection data for group-A lambs indicated 97% to 100% of the mature Haemonchus, Ostertagia, Trichostrongylus, and Trichuris, and immature Haemonchus were removed; and 23% to 73% of the mature Cooperia, Nematodirus, and Strongyloides, and immature Nematodirus were removed. In group-B lambs, 94% to 100% of the mature Haemonchus, Nematodirus, Ostertagia, Trichostrongylus, and Trichuris, and immature Haemonchus were removed as were 70% to 84% of mature Strongyloides and immature Nematodirus, respectively, and 0% for mature Cooperia. The percentage of all nematodes removed in group C and D was 100%, except for Cooperia (95%) in group C and immature Nematodirus (93% and 95%), respectively.

Toxicosis was not apparent. Small fibrotic or blood streaked lesions were observed at necropsy in muscle at the injection site of 2 lambs in group B and 1 lamb in group E.
Pathogenicity of Escherichia coli O115:K“V165” strains isolated from pigs with diarrhea
Authors: Fairbrother John M. , Broes André , Jacques Mario , Larivière Serge
Published: February 2025

Eighteen strains of Escherichia coli serogroup 0115:K“V165” isolated from 1- to 8-week-old pigs with diarrhea were tested for toxigenidty, pathogenicity in pigs and mice, serum resistance, mannose-resistant hemagglutination (mrha), F165 and other surface antigens, colicin V (Col V), aerobactin, and biotype. Twelve strains were positive for heat-stable enterotoxin (STb), mrha-negative, and F 165-negative; 5 strains were enterotoxin-negative, mrha-positive, and F165-positive; and 1 strain was mrha-positive, but F165- and enterotoxin-negative. Six of the 12 STb-positive strains moderately colonized the ileum of newborn colostrum-deprived pigs within 24 hours after inoculation. Two of the colonizing strains were able to induce wateiy diarrhea. All 12 STb-positive strains were nonpathogenic for adult mice and were serum-sensitive; 11 of 12 were Col V-negative, 9 of 12 did not produce aerobactin, and 10 of 12 belonged to biotypes other than 1 or 2. All 6 enterotoxin-negative strains colonized the small and large intestines, associated with peritoneal serosal surfaces, and induced septicemia and polyserositis in newborn colostrum-deprived pigs 1 to 2 days after inoculation. In contrast, 3 STb-positive strains poorly colonized the intestines and did not induce septicemia in pigs at 3 days after inoculation. All 6 enterotoxin-negative strains were Col V-positive, produced aerobactin, and belonged to biotype 1 or 2. Of the 5 enterotoxin-negative, F165-positive strains, only 4 were pathogenic for intraperitoneally inoculated adult mice and were serum-resistant. The enterotoxin-negative, F165-negative strain was neither serum-resistant nor mouse-pathogenic. O-agglutinable mutants of the mouse-pathogenic strains were, for the most part, no longer pathogenic for adult mice, although these strains remained unchanged for biotype and production of mrha, F165, and Col V, and 3 of 4 mutant strains were serum-resistant.

Thus, E coli strains of the same serogroup isolated from diarrheic pigs may cause either intestinal or extraintestinal disease upon reinoculation of pigs, depending on the virulence attributes produced by the strains.
Prevalence of Cryptosporidium infection in dairy calves in western Washington
Authors: Ongerth Jerry E. , Stibbs Henry H.
Published: February 2025

The prevalence and intensity of Cryptosporidium infection were examined in 445 Holstein calves at 10 dairy farms in western Washington, near Seattle. Fifty-one percent (176) of calves in the 7- to 21-day-old age group (n = 342) were positive for oocysts in the feces by carbolfuchsin staining. Prevalence and intensity of infection were highest in calves 8 to 14 days old; prevalence was 60% in this group, and 48% of the Cryptosporidium-positive calves had oocyst shedding at a 4 + level. A seasonal pattern in prevalence was not evident.
Rapid decay of serum IgG recognizing gram-negative cell wall core antigens in neonatal calves
Authors: Douglas Vicki L. , Cullor James S. , Tyler Jeff W. , Thurmond Mark C. , Bushnell Robert B.
Published: February 2025

Serum immunoglobulins of the IgG isotype recognizing common gram-negative cell core epitopes were serially measured, using a direct elisa, on samples obtained from 20 neonatal Holstein calves. An R-mutant Escherichia coli (strain J5) was used as a plate antigen in this assay. Total serum IgG concentration was measured using radial immunodiffusion. Half-lives of core antigen-specific IgG (7.56 days) and total serum IgG (22.66 days) were dramatically different (P < 0.0005). This may be an indication of cross-reactive consumption of core antigen-specific immunoglobulins.
Furazolidone-induced injury in the isolated perfused chicken heart
Authors: McCallum T. , Badylak S. F. , Van Vleet J. F. , Reed W. M.
Published: February 2025

The Langendorff isolated heart preparation was adapted to determine the effect of furazolidone (0.5 and 2 μg/ml of perfusate) on hearts of 3-week-old broiler chickens. Following 115 minutes of perfusion, both concentrations of furazolidone caused approximately a two-fold increase in myocardial vascular resistance and a six-fold increase in lactate dehydrogenase release into the effluent fluid, compared with a control perfused group of isolated hearts (P < 0.01). Ultrastructural alteration differences were not found between the drug-treated and control groups. It was concluded that: (i) furazolidone, at concentrations only moderately above therapeutic plasma concentrations, caused detrimental changes in myocardial vascular resistance and lactate dehydrogenase release and (ii) the isolated chicken heart preparation is an example of a cost-effective, reliable laboratory tool for screening potential cardiotoxins.
Effect of weight loading on the coronary band interstitial fluid pressure in horses
Authors: Olivier Ann , Hood David M. , Jenkins William L. , Clark Donald R. , Williams John D. , Grosenbaugh Deborah A.
Published: February 2025

Interstitial fluid pressures, as a possible function of limb load, were measured at 2 sites within the digital coronary dermis of both cranial digits in 10 standing horses. Fluid pressure changes and digital load measurements were simultaneously detected and recorded by use of, respectively, modified wick-in-needle and force plate transducers coupled to a microcomputer.

Mean pressures, recorded at limb loads between 50 and 80 kg, were 2.29 ± 3.17 mm of Hg at the toe and 2.49 ± 5.91 mm of Hg at the heel. Mean pressures, recorded between 150 and 180 kg, were 5.01 ± 5.23 mm of Hg at the toe and 1.28 ± 7.69 mm of Hg at the heel. These data indicate that, in the static limb, no statistically significant change in interstitial fluid pressure occurs at loads up to 180 kg.
Effects of butorphanol tartrate on arterial pressure, jejunal blood flow, vascular resistance, O2 extraction, and O2 uptake in halothane-anesthetized ponies
Authors: Stick John A. , Loeffler Barbara S. , Arden Warwick A. , Chou Ching-Chung
Published: February 2025

The effects of butorphanol tartrate on arterial pressure, jejunal blood flow, vascular resistance, oxygen extraction, and. oxygen uptake were determined in 10 anesthetized ponies ventilated with a mixture of halothane and 100% oxygen using isolated autoperfused jejunal segments. Physiologic saline solution or butorphanol tartrate (0.2 mg/kg of body weight) was administered as a single bolus into the left jugular vein. By 2 minutes, butorphanol decreased arterial blood pressure and intestinal blood flow, and increased intestinal oxygen extraction. However, intestinal vascular resistance and oxygen uptake were unaffected. Results of this study indicate that butorphanol tartrate induces a hypotension that secondarily decreases intestinal blood flow, but intestinal vascular resistance and metabolism are not adversely affected. We conclude that butorphanol tartrate does not compromise intestinal viability in halothane-anesthetized ponies and, therefore, may be a good analgesic choice for the equid destined for abdominal surgery.
Blastocyst development on days 10 or 14 after consumption of zearalenone by sows on days 7 to 10 after breeding
Authors: Diekman Mark A. , Long Gerald G.
Published: February 2025

Sixteen primiparous sows were bred and fed either a control ration (n = 8) or a diet containing purified zearalenone (n = 8; 1 mg/kg of body weight) from days 7 to 10 after breeding. On day 7 after breeding, the jugular vein of each sow was cannulated and blood was collected at 20-minute intervals for 4 hours before feeding and 4 hours after feeding. On day 10 after breeding, blood samples were collected from 4 control sows and 4 zearalenone-fed sows at 20-minute intervals for 4 hours before collection of blastocysts. A similar blood sampling schedule was followed for the remaining 4 control and 4 zearalenone sows on day 14 after breeding. On day 10 after breeding, spherical blastocysts were recovered from all control sows and from 3 of 4 zearalenone-treated sows. Average diameter of blastocysts from zearalenone-treated sows were similar to that of control sows. On day 14 after breeding, blastocysts were recovered from all control sows and 3 of 4 zearalenone-treated sows. Blastocysts from the control sows were filamentous, whereas blastocysts from zearalenone-treated sows were fragmented and contained foci of necrosis. Incidence of luteinizing hormone (lh) secretory spikes per sow was less (P < 0.01) in zearalenone-treated sows (0.25 ± 0.25/4 h) than control sows (1.75 ± 0.25/4 h) on day 10 after breeding. Incidence of folliclestimulating hormone (fsh) secretory spikes was similar CP = 0.45) among treatments on days 7, 10, and 14 after breeding. Mean serum concentrations of lh were less on day 10 (F = 0.07) and day 14 (P < 0.01) in zearalenone-treated sows than in control sows. Mean serum concentrations of fsh were less (P = 0.07) on day 14 in zearalenone-treated sows than in control sows (3.3 ± 0.2 ng/ ml vs 6.2 ± 1.3). These data indicate that administration of zearalenone on days 7 to 10 after breeding altered secretory patterns of serum lh during days 10 and 14 after breeding, which may have contributed to the death of blastocysts by day 14 after breeding.
Effect of epidermal growth factor on healing of corneal endothelial cells in cats
Authors: Brogdon J. D. , McLaughlin S. A. , Brightman A. H. , Helper L. C.
Published: February 2025

Epidermal growth factor was injected intracamerally into the anterior chamber of the right eye of 9 cats. The central portion of the cornea in 8 of the 9 cats that had been cryoinjured. Effect of epidermal growth factor on the repair of endothelial cells in cats was evaluated by en-dothelial specular microscopy. Endothelial cell density and corneal thickness were studied quantitatively, as a measure of endothelial cell function. The repair process also was evaluated qualitatively by studying morphologic changes, developing as a result of reendothelialization and return to normal function. Seemingly, differences between rate of healing of cryoinjured eyes injected with epidermal growth factor and that in nontreated eyes were not significant (P = 0.86). The endothelial repair process was characterized by enlargement and migration of adjacent noninjured cells.
Immune response of the llama (Lama glama) to tetanus toxoid vaccination
Authors: Paul-Murphy Joanne , Gershwin Laurel J. , Thatcher Eileen F. , Fowler Murray D. , Habig William H.
Published: February 2025

An elisa was developed to measure serum concentrations of tetanus toxoid-specific immunoglobulins. The titers obtained with this assay were compatible with those obtained by the standard mouse toxin-neutralization test. Serum samples from 123 llamas were analyzed for elisa titers to tetanus toxoid. Of the 82 vaccinated adults 75 (91%) had titers ≥ 1:50. The vaccination status and titers of weanlings and juveniles (3 to 12 months old) varied; of the 21 vaccinated, 17 (81%) had titers ≥ 1:50 and 7 of 9 (78%) unvaccinated llamas had titers < 1:50. The elisa titers of unvaccinated llamas < 8 weeks old (crias) were matched with the maternal titers. All crias with titers < 1:50 had dams with titers ≥ 1:50.
Cytotoxin activity on Vero cells among Escherichia coli strains associated with diarrhea in cats
Authors: Abaas Saleem , Franklin Anders , Kühn Inger , Ørskov Frits , Ørskov Ida
Published: February 2025

The role of Escherichia coli as a causative agent of diarrhea in cats was investigated. Isolates of E coli from healthy and diarrheic cats were serotyped and investigated for their biochemical characters, production of cytotoxin activity on Vero cells, heat-labile enterotoxin, heat-stable enterotoxin, and hemagglutination of erythrocytes from other animal species. None of 48 investigated strains produced heat-labile enterotoxin or heat-stable enterotoxin, nor did they agglutinate erythrocytes. Most strains were hemolytic and belonged to O-serotypes 2 and 6. Cytotoxin activity on Vero cells was significantly more common and produced in greater amounts among E coli strains isolated from diarrheic cats, and was neutralized by antiShiga-like toxin I serum.