bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of monensin on selenium status and related factors in genetically hypo- and hyperselenemic growing swine
Authors: Horvath Christopher J. , Stowe Howard D. , Miller Elwin R.
Published: January 2024

Monensin is an ionophoretic antibiotic, which selectively transports alkali metal cations across biological membranes. In growing swine, monensin toxicosis causes acute, degenerative cardiac and skeletal myopathy resembling vitamin E-selenium deficiency. Selenium is an essential trace element incorporated in glutathione peroxidase (gsh-Px), an antioxidant enzyme system that protects subcellular membranes. In our study, we examined the effects of monensin on body weight, Se balance, antioxidant status, and serum concentrations of selected minerals in growing pigs that were genetically hypo- or hyperselenemic (hypo-Se and hyper-Se, respectively). Three groups of eight 8-week-old pigs, each comprised of 4 hypo-Se and 4 hyper-Se pigs (76.4 ± 3.0 and 106.3 ± 10.3 ng of Se/ml of serum, respectively), were fed standard diets containing 0.1 mg of supplemental Se/kg of body weight, and either 0, 200, or 400 mg of monensin/kg for a 77-day period, followed by a 28-day monensin withdrawal period. On days 0, 7, 28, 56, 70, and 98, all pigs were weighed and blood was collected for determination of serum gsh-Px, creatine phosphokinase, and aspartate transaminase values, as well as serum concentrations of vitamin E, Se, Ca, Cu, Fe, K, Mg, Na, P, and Zn. Significance of main effects of monensin treatment, genetic Se status, and their interactions was tested by Fisher's variance ratio test, followed by conditional comparison of treatment means with a Bonferroni test. Signs of monensin toxicosis were not observed and monensin consumption had no effect on body weight, or serum creatine phosphokinase, aspartate transaminase, or Se values. However, pigs consuming monensin had consistently higher serum gsh-Px activities, possibly because of increased synthesis of this adaptive antioxidant enzyme. Interactions were not found between monensin and genetic Se status. Hyperselenemic pigs were heavier and had higher serum Se and gsh-Px values than hypo-Se pigs. Furthermore, hypo-Se and hyper-Se pigs were hypo- and hypercupremic, respectively, suggesting genetic regulation of copper status. It is likely that pigs with inadequate antioxidant status (hyposelenemia, hypocupremia) are more susceptible to diseases associated with cellular membrane damage, such as vitamin E-Se deficiency disease and monensin toxicosis.
Neuromuscular and cardiovascular effects of atracurium in isoflurane-anesthetized chickens
Authors: Nicholson Anthony , Ilkiw Jan E.
Published: January 2024

Atracurium besylate, a nondepolarizing neuromuscular blocking agent, was administered to 24 isoflurane-anesthetized domestic chickens. Birds were randomly assigned to 4 groups, and atracurium was administered at dosage of 0.15, 0.25, 0.35 or 0.45 mg/kg of body weight. The time of onset of twitch depression, the amount of maximal twitch depression, and the duration of muscular relaxation were recorded. After return to control twitch height, atracurium was further administered to achieve > 75% twitch depression. When twitch depression reached 75% during noninduced recovery, 0 5 mg of edrophonium/kg was administered to reverse the muscle relaxation. Throughout the experimental period, cardiovascular, arterial blood gas, and acid-base variables were monitored.

The effective dosage of atracurium to result in 95% twitch depression in 50% of birds, (ed95/50) was calculated, using probit analysis, to be 0.25 mg/kg, whereas the ed95/95, the dosage of atracurium to result in 95% twitch depression in 95% of birds, was calculated by probit analysis to be 0.46 mg/kg. The total duration of action at dosage of 0.25 mg/kg was 34.5 ± 5.8 minutes; at the highest dosage (0 45 mg/kg), total duration increased 0 47.8 ± 10.3 minutes. The return to control twitch height was greatly hastened by administration of edrophonium. Small, but statistically significant changes in heart rate and systolic blood pressure, were associated with administration of atracurium and edrophonium. These changes would not be clinically relevant.

In this study, atracurium was found to be safe and reliable for induction of muscle relaxation in isoflurane-anesthetized chickens.
Cerebrospinal fluid changes after iopamidol and metrizamide myelography in clinically normal dogs
Authors: Widmer William R. , DeNicola Dennis B. , Blevins William E. , Cook James R. , Cantwell H. Dan , Teclaw Robert F.
Published: January 2024

Cerebrospinal fluid samples from 2 groups of clinically normal dogs were compared after iopamidol (n = 9) and metrizamide (n = 8) myelography. Iopamidol (200 mg of I/ml) and metrizamide (170 mg of I/ml) were administered by cerebellomedullary injection at dosage of 0.45 ml/kg of body weight. In dogs of both groups, postmyelographic csf changes included high specific gravity, Pandy score, protein concentration, and wbc count. The high specific gravity and Pandy score were false-positive effects attributed to nonionic contrast media. Although postmyelographic protein concentration and total wbc count were greater in csf samples from dogs given metrizamide than in those given iopamidol, differences were not statistically significant. The differential wbc counts were consistent with mild, acute leptomeningitis; these findings were supported by results of histologic examination. Iopamidol and metrizamide should be considered low-grade leptomeningeal irritants in dogs.
Evaluation of the Doppler ultrasonic method of measuring systolic arterial blood pressure in cats
Authors: Grandy J. L. , Dunlop C. I. , Hodgson D. S. , Curtis C. R. , Chapman P. L.
Published: January 2024

The accuracy of the Doppler technique for indirect systolic blood pressure measurement was assessed in 16 anesthetized cats. Eight cats were anesthetized with isoflurane and 8 were anesthetized with halothane. Anesthetic depth and mode of ventilation were varied to obtain a wide range of arterial blood pressure. A Doppler transducer was placed on the palmer surface of the left forelimb over the common digital branch of the radial artery to detect blood flow, and a blood pressure monitoring cuff with a width 37% the limb circumference was placed half way between the elbow and the carpus. To enable direct arterial pressure measurements, the left femoral artery was catheterized and the blood pressure waveforms recorded simultaneously.

Systolic blood pressure measured by use of the Doppler ultrasonic technique was significantly lower than that obtained from the femoral artery catheter. Using linear regression, we determined a clinically useful calibration adjustment for Doppler indirect blood pressure measurement in cats: femoral systolic pressure = Doppler systolic pressure + 14 mm of Hg.
High-resolution computed tomography of the mammalian lung
Authors: Chen Qihang , Klein Jeffrey S. , Gamsu Gordon , Webb W. Richard
Published: January 2024

High-resolution computed tomography (HRCT) was performed in 21 isolated animal lungs, from 4 mammalian species (pigs, rabbits, dogs, sheep). Gross and subgross central and peripheral lung morphology was determined by HRCT. Three distinct types of lungs can be identified, principally based on the extent of interlobular septal development; the relationship of major vessels to airways; and the thickness of the visceral pleura. Type-I lung is found in pigs, sheep, and cattle; type-II lung is found in rabbits, dogs, cats, and monkeys; and type-IH lung is found in human beings and horses.1 These mammalian lungs were compared with human lungs. The potential use of HRCT to investigate specific human lung diseases in the aforementioned species also was considered.
Characteristics of L-glutamine transport in equine jejunal brush border membrane vesicles
Authors: Salloum Rabih M. , Duckworth Donna , Madison John B. , Souba Wiley W.
Published: January 2024

The sodium-dependent transporter system responsible for L-glutamine uptake by brush border membrane vesicles prepared from equine jejunum was characterized. Vesicle purity was ascertained by a 14- to 17-fold increase in activity of the brush border enzyme markers. Glutamine uptake was found to occur into an osmotically active space with negligible membrane binding. The sodium-dependent velocity represented approximately 80% of total uptake and demonstrated overshoots. Kinetic studies of sodium-dependent glutamine transport at concentrations between 5 μM and 5 mM revealed a single saturable high-affinity carrier with a Michaelis constant of 519 ± 90 μM/ and a maximal transport velocity of 3.08 ± 0.97 nmol/mg of protein/10 s. Glutamine uptake was not affected by changes in environmental pH. Lithium could not substitute for sodium as a contransporter ion. 2-Methylaminoisobutyric acid inhibited the sodium-dependent carrier only minimally, but marked inhibition (> 90%) was observed in the presence of histidine, alanine, cysteine, and nonradioactive glutamine. Kinetic analysis of the sodium-independent transporter revealed it to have a Michaelis constant = 260 ± 47 μM and a maximal transport velocity of 0.32 ± 0.06 nmol/mg of protein/10 s. We conclude that glutamine transport in equine jejunal brush border membrane vesicles occurs primarily via the system B transporter and, to a lesser extent, by a sodium-independent carrier.
Fetal heart rate patterns and the influence of myometrial activity during the last month of gestation in cows
Authors: Jonker F. H. , van Oord H. A. , van der Weyden G. C. , Taverne M. A. M.
Published: January 2024

Five cows in the last month of gestation, provided with uterine electrodes and in which catheters had been chronically installed in the fetal aorta, were used to study patterns of fetal heart rate (fhr) and the influence of periods of myometrial electrical activity during gestation (contractures) on fhr. The fhr was calculated by counting the number of blood pressure pulses on the tracings during alternate periods of 12 seconds. Three 1-hour recordings without contractures and 10 recordings during the time of a contracture were randomly selected for each cow. The calculated data points were plotted on a graph to display fhr patterns.

In 41 periods associated with single contractures, fhr data points were taken every 72 seconds. Changes in absolute and relative fhr in these periods were determined to analyze a possible effect of contractures on fhr.

Three types of variation in fhr patterns could be distinguished: a short-term, low-amplitude variation of basal FHR; a second type in which the duration was < 4 minutes and the amplitude was ≥ 15 beats/ min; and prolonged periods with increased or decreased fhr values (> 4 minutes and ≥ 15 beats/ min). The relationship between these types of variation and fetal activity states remains to be established for cows. During the 60 hours of recordings that were analyzed, a period of several minutes during which fhr values were extremely high (> 180 beats/min) was found 3 times. There were no significant differences in absolute or relative fhr before, during, or after a contracture.
Elbow arthroscopy in clinically normal dogs
Authors: Van Ryssen Bernadette , van Bree Henri , Simoens Paul
Published: January 2024

After a detailed anatomic study to determine puncture sites, 10 cadaver elbows from 5 dogs were examined arthroscopically to study the normal intraarticular anatomy, as viewed from the medial side. Subsequent dissection revealed absence of neurovascular injury and only minor iatrogenic damage to the cartilage. The technique was clinically applied and evaluated in 13 dogs (26 joints). The dogs recovered without complications. The technique proved to be safe and reliable for direct examination of nearly the entire joint. More specifically, it allowed systematic inspection of the medial and lateral humeral condyles, the medial and lateral coronoid processes, the caudal and middle parts of the head of the radius, the olecranon (including the anconeal process), and the medial collateral ligament.
Intraosseous pressure and pathologic changes in horses with navicular disease
Authors: Pleasant R Scott , Baker Gordon J. , Foreman Jonathan H. , Eurell Jo Ann C. , Losonsky John M.
Published: January 2024

Navicular bone intraosseous pressure, gross pathologic, histologic, and histochemical data were collected from 8 horses with navicular disease and 4 control horses. Simultaneous navicular bone intraosseous, medial palmar arterial, and saphenous venous pressures were measured for the left and right forelimbs of each horse under general anesthesia. Gross pathologic evaluation included grading of changes on the flexor surface of the navicular bone. Safranin-O-fast green-stained sections were used for histologic-histochemical grading of the hyaline articular and fibrocartilage surfaces of the navicular bones. Hematoxyhn and eosin-stained sections were used for morphologic evaluation of the marrow spaces of navicular bones. Mean navicular bone intraosseous pressure for horses with navicular disease was significantly (P< 0.001) higher than that for controls. Differences in medical palmar arterial or saphenous venous pressures were not significant between groups. The median flexor surface gross pathologic and histologic-histochemical fibrocartilage scores for horses with navicular disease were significantly (P< 0.001) more severe than those for control horses. The histologic-histochemical hyaline cartilage scores for control horses and those for horses with navicular disease were not significantly different. Fibrosis of the marrow spaces beneath the flexor cortex of horses with navicular disease was more pronounced than that of control horses.
Detection of bluetongue virus from blood of infected sheep by use of an antigen-capture enzyme-linked immunosorbent assay after amplification of the virus in cell culture
Authors: Mecham James O.
Published: January 2024

An antigen-capture elisa was used to detect bluetongue virus (btv) from blood of infected sheep. A rabbit-origin capture antibody and a mouse-origin detection antibody combined with biotin-avidin amplification were used for the assay. The antigen-capture elisa could not detect virus directly from the blood of infected sheep because of low virus titer. To enhance detection, virus from infected blood was amplified in cell culture. Virus could then be detected from cell culture supernatant fluids, using the elisa. This amplification step increased the sensitivity of the assay comparable to that of assays performed in cell culture measuring cytopathic effects. The elisa procedure was specific for btv and did not mistakenly identify the antigenically related epizootic hemorrhagic disease virus. The antigen-capture elisa permitted indirect quantitation and identification of btv from the blood of infected sheep.
Effect of Corynebacterium pseudotuberculosis phospholipase D on viability and chemotactic responses of ovine neutrophils
Authors: Yozwiak Michael L. , Songer J. Glenn
Published: January 2024

Corynebacterium pseudotuberculosis phospholipase D (PLD) significantly affected viability of ovine neutrophils after 24 hours' exposure. This effect was more marked in cells that ingested PLD emulsified in oil. Treatment of neutrophils with PLD significantly (P < 0.05) reduced the ability of these cells to migrate toward activated sheep serum. The PLD was not chemotactic, but it activated normal sheep serum, producing factors that were chemotactic for neutrophils.
Transcutaneous oxygen monitoring for predicting skin viability in dogs
Authors: Rochat Mark C. , Pope Eric R. , Payne John T. , Pace Lanny W. , Wagner-Mann Colette C.
Published: January 2024

Transcutaneous oxygen (PO2-TC) monitoring is commonly used in human medicine for evaluating skin viability. The application of transcutaneous monitoring for evaluating skin viability in dogs was investigated.

The changes in PO2-TC values were measured from 16 avascular skin flaps created along the lateral hemithoraces of 4 dogs. Transcutaneous oxygen values were serially recorded from the vascular base and avascular apex of each flap for 12 hours after surgery. A single transcutaneous measurement was obtained from each flap base and apex 24 hours after surgery. Serial arterial blood gas analyses were obtained to compare central oxygen values with PO2-TC values. Full-thickness skin biopsy specimens were harvested from the base and apex of each flap 24 hours after surgery. The flaps were observed for 4 days and then excised for histologic examination. A subjective grading scale was used to assess histologic changes.

Throughout the 12-hour period and at 24 hours, a statistically significant difference was found between the PO2-TC values for apices and bases of the flaps. The mean PO2-TC for all bases was 90.9 mm of Hg ± 3.3 SEM, and the mean PO2-TC for all apices was 21.2 mm of Hg ± 1.8 SEM. The mean regional perfusion index (apex PO2-TC/base PO2-TC) was 0.23 ± 0.02. The subjective numbers assigned to the biopsy specimens were statistically evaluated by using a paired Student's t test and a Wilcoxon signed-rank test. A significant difference was found between the numbers for the collective bases and apices with both tests. A statistically significant difference was found between the numbers for the apex biopsy specimens taken 24 hours after creation of the skin flap and those taken when the flap was excised, whereas no difference was found between the numbers for the base biopsy specimens. On the basis of our findings, PO2-tc monitoring is a useful technique for assessing skin viability in dogs.
Relation between reduced glutathione content and Heinz body formation in sheep erythrocytes
Authors: Goto Ikuo , Agar N. S. , Maede Yoshimitsu
Published: January 2024

To clarify the oxidant defense functions of reduced glutathione (gsh) in erythrocytes, the effect of gsh deficiency on in vitro oxidant defense was studied, using gsh-deficient sheep erythrocytes (low-gsh cells). The formation of Heinz bodies in low-gsh cells was higher than that in high-gsh cells when the cells were incubated with an oxidant drug, acetylphenylhydrazine (aph). Artificial depletion of gsh by 1-chloro-2,4-dinitrobenzene in high-gsh cells resulted in increased Heinz body formation in these cells incubated with aph. Furthermore, high negative correlation was observed between Heinz body formation and gsh content in sheep erythrocytes exposed to aph. These results clearly indicate that erythrocyte gsh is indispensable for erythrocyte defense against oxidative damage induced by aph, and support the previous observations that sheep with low-gsh erythrocytes were more susceptible to oxidative agents than were sheep with high-gsh erythrocytes.
Comparison of excretory urography and ultrasonography for detection of experimentally induced pyelonephritis in dogs
Authors: Neuwirth L. , Mahaffey M. , Crowell W. , Selcer B. , Barsanti J. , Cooper R. , Brown J.
Published: January 2024

Pyelonephritis was experimentally induced in 10 clinically normal dogs by nephropyelocentesis and introduction of Proteus mirabilis into the randomly chosen right or left renal pelvis. Dogs were examined by nephrosonography and excretory urography before and 2 weeks after infection.

The major nephrosonographic findings of pyelonephritis were renal pelvic dilatation, usually with proximal ureteral dilatation, and a hyperechoic mucosal margin line within the renal pelvis, proximal portion of the ureter, or both. In addition, at least one or more of the following were observed: generalized hyperechoic renal cortex, focal hyperechoic areas within the medulla, and focal hyperechoic or hypoechoic cortical lesions.

Interpretation of excretory urograms resulted in 3 false-negative and 1 false-positive conclusions, compared with the histologic findings. Interpretation of nephrosonograms resulted in 2 false-negative and no false-positive conclusions. Of the kidneys with histologic evidence of pyelonephritis, 73% were detected by excretory urography, whereas 82% were detected by nephrosonography.

Nephrosonography appeared to be useful for detection of mild to moderate cases of acute pyelonephritis that may be be interpreted as such by excretory urography.
Possible involvement of protein kinase C with induction of haptoglobin in cows by treatment with dexamethasone and by starvation
Authors: Yoshino Kazuhiro , Katoh Norio , Takahashi Kiyoshi , Yuasa Akira
Published: January 2024

Haptoglobin (Hp), an acute-phase protein, is detected in serum of cows with hepatic lipidosis (fatty liver). To assess the relevance of Hp in fatty liver, induction of Hp was examined, using conditions similar to those involving development of fatty liver in cows. Induction of Hp was achieved by a combination of dexamethasone administration (0.1 mg/kg of body weight) and 2 days’ starvation. Haptoglobin appearance in serum was not associated with the increase of α1-acid glycoprotein (a marker for inflammation). This treatment increased serum nonesterified fatty acids concentration and decreased serum triglycerides concentration. Protein kinase C activity was decreased in the cytosolic fractions of liver and mononuclear cells. Reduction of protein kinase C-catalyzed endogenous protein phosphorylation also was observed, particularly in the cytosolic fractions of the tissue and cells. Detection of Hp in serum of cows with fatty liver appears to be explained by the fact that Hp is induced by dexamethasone administration and starvation, which are similar to the condition responsible for fatty liver development. The change of protein kinase C-catalyzed phosphorylation was suggested to be involved in the induction of Hp in cows.
Effects of ampicillin and trimethoprim-sulfamethoxazole on the vaginal bacterial flora of bitches
Authors: Ström Bodil , Linde-Forsberg Catharina
Published: January 2024

Vaginal aerobic bacterial flora was studied in 5 healthy bitches before, during, and after a 10-day period of treatment with ampicillin and an equally long period of treatment with trimethoprim-sulfamethoxazole. Blood variables and antimicrobial drug susceptibility also were studied. Bacteria were isolated from all bitches before the first treatment period. Bitches from which only a sparse number of bacteria were isolated had flora that varied from day to day.

In most instances when bitches were given an antibiotic to which their vaginal bacterial flora was susceptible, these bacteria were eradicated after only 1 day of treatment. This was true for pasteurellae, streptococci, and, in all but one case, Escherichia coli. Staphylococcus intermedius was more difficult to eradicate, and, although susceptible in vitro, it was unaffected by antibiotic treatment in 1 bitch and it took 7 days to eradicate in another. Eradication of aerobic bacteria in the vagina was total only in the bitch that had sparse flora from the beginning. Bacteria colonized within 0 (in 4/5 bitches) to 4 days after termination of treatment with ampicillin and within 0 (in 4/5 bitches) to 3 days for trimethoprim-sulfamethoxazole.

Mycoplasmas emerged during and after both treatment periods, and E coli became apparent during treatment with trimethoprim-sulfamethoxazole. Because mycoplasmas may be genital pathogens in bitches and E coli is a common uropathogen, their appearance should be an argument against widespread use of antibiotics in healthy breeding bitches. Two bitches developed a vaginal discharge during treatment or shortly after. Blood variables did not change during the study, nor did antimicrobial drug resistance of the isolated bacteria.
Pulmonary thromboembolism and hypertension after thiacetarsamide vs melarsomine dihydrocholoride treatment of Dirofilaria immitis infection in dogs
Authors: Rawlings Clarence A. , Raynaud Jean Pierre , Lewis Robert E. , Duncan J. Robert
Published: January 2024

The severity of pulmonary thromboembolism and pulmonary hypertension induced by heartworms dying after administration of 2 adulticides was evaluated. Because melarsomine dihydrochloride (RM340) has been shown to be more effective in killing Dirofilaria immitis (heartworms) than the traditional approved adulticide, thiacetarsamide, an attempt was made to determine whether this new adulticide induced more severe lung disease. Before adulticide treatment, 32 dogs with naturally acquired heartworm infections received physical examinations, semiquantitative antigen concentration tests, cbc, platelet counts, serum biochemistry analyses, arterial blood gas determinations, thoracic radiography, pulmonary arteriography, and pulmonary hemodynamic tests. Eight dogs with a low burden and 9 dogs with a high burden of heartworms were treated with thiacetarsamide, and 7 dogs with a low burden and 8 dogs with a high burden were treated with RM340. Except for the heartworm-burden test, tests were repeated at regular intervals during the first 7 weeks after treatment. None of the dogs coughed or had dyspnea after treatment. Six of 9 dogs with high worm burdens and 4 of 8 dogs with low worm burdens had surviving heartworms after thiacetarsamide treatment, in contrast to only 3 of 15 RM340-treated dogs. Differences between the 2 adulticide treatments were minimal as determined by thoracic radiography, pulmonary hemodynamic tests, clinical laboratory analyses, pulmonary arteriography, or necropsy. The RM340 treatment was a more effective adulticide, but it did not increase the severity of hypertension and thromboembolism.
Lung tissue concentrations and plasma pharmacokinetics of danofloxacin in calves with acute pneumonia
Authors: Apley Michael D. , Upson Dan W.
Published: January 2024

Plasma and lung tissue pharmacokinetics of danofloxacin in calves with naturally induced acute pneumonia were determined in 2 separate studies. A maximal pneumonic tissue concentration of 1.17 μg/ g was achieved 1.8 hours after im injection of 1.25 mg of danofloxacin/kg of body weight. Pneumonic tissue danofloxacin concentrations were 5.5 times greater than those in plasma at 1 and 2 hours after injection. Cranioventral pneumonic tissue had significantly decreased danofloxacin concentration, compared with that of grossly normal tissue from the caudodorsal part of the lungs at 2 of 6 sample times.

After iv injection, the apparent steady-state volume of distribution was 3.44 ± 1.13 L/kg, and the elimination half-life was 6.26 ± 2.27 hours. Maximal plasma danofloxacin concentration of 0.25 μg/ml was detected 0.80 hour after im injection. Bioavailability was 91%.

Our findings indicated that a large percentage of danofloxacin is rapidly absorbed after im administration to calves with acute pneumonia. Extensive tissue penetration was suggested by a high steady-state volume of distribution and was indicated by high concentrations in pneumonic tissue.
Immunoglobulins in stimulated tears of dogs
Authors: Ginel Pedro J. , Novales Manuel , García María , Martín Eva M. , López Rocío , Molleda José M.
Published: January 2024

Immunoelectrophoresis and single radial immunodiffusion were used to identify and measure tear immunoglobulin concentrations in 50 healthy dogs. Immunoglobulin A and IgG were detected in all samples analyzed, whereas IgM was not detected in any sample. Mean IgA concentration was 25.28 ± 1.9 mg/dl, adult dogs (> 18 months) having significantly higher mean value. The IgA concentration related to age had significant (P < 0.006) positive correlation; mean IgG concentration was 23.10 ± 1.72 mg/dl. Linear correlation analysis revealed significant (P < 0.0007) correlation coefficient between tear total protein and IgA concentrations. The IgA and IgG concentrations also were significantly (P < 0.0001) correlated when expressed as milligrams per 100 mg of protein. Relation with sex was not established for either immunoglobulin.
Effect of ranitidine on healing of experimentally induced gastric ulcers in ponies
Authors: MacAllister Charles G. , Sangiah Subbiah
Published: January 2024

Thirty young ponies were examined endoscopically for evidence of gastric ulceration. Seven ponies had noninduced gastric ulcers present at the initial examination and were eliminated from the study. In an attempt to induce gastric ulcers experimentally, flunixin meglumine (1.1 mg/kg of body weight, im, q 8 h) was administered for 7 days to the 23 ponies with endoscopically normal gastric mucosa. During the 7 days of flunixin administration, 11 ponies developed gastric ulcers that were appropriate for study. The 11 ponies were randomly allotted to 2 groups. Group-A (n = 5) and group-B (n = 6) ponies received ranitidine (4.4 mg/kg, po, q 8 h) and corn syrup, respectively, until ulcers healed or for a maximum of 40 days. General anesthesia was induced every 3 to 5 days for visual evaluation of ulcer healing by use of a video endoscope. The earliest complete healing of gastric lesions observed in a corn syrup-treated pony was at 17 days. At 40 days, 3 of 5 and 3 of 6 ponies of the ranitidine and corn syrup-treated groups, respectively, had healed ulcers.

Results of this study indicate that: noninduced gastric ulcers may be common in young ponies, flunixin meglumine may be effective in inducing gastric ulcers for gastric healing studies in young ponies, and ranitidine (4.4 mg/kg, q 8 h) is not significantly effective in accelerating healing of experimentally induced gastric ulcers in ponies under conditions of this study.
Toxin production by Pasteurella multocida isolated from rabbits with atrophic rhinitis
Authors: DiGiacomo Ronald F. , Deeb Barbara J. , Brodie Scott J. , Zimmerman Thomas E. , Veltkamp Eugene R. , Chrisp Clarence E.
Published: January 2024

Naturally acquired turbinate atrophy in rabbits was associated with Pasteurella multocida infection. Several in vitro and in vivo studies were conducted to document toxin production from P multocida isolates and to determine the relation of toxin to atrophic rhinitis in rabbits. Ten isolates of P multocida serotype A:12 were obtained from adult New Zealand White rabbits with noninduced atrophic rhinitis. Specific-pathogen-free rabbits inoculated intranasally with isolates of P multocida developed rhinitis and turbinate atrophy. However, inoculation with filtrates of the same bacteria failed to induce turbinate atrophy. Cytotoxicity was observed in assays, using bovine embryonic turbinate cell cultures with extracts of P multocida, but not in agar overlay cytotoxicity assays, using bovine embryonic turbinate, bovine embryonic lung, or Vero cell cultures, or in a sandwich elisa, using monoclonal antibodies to purified P multocida toxin. Thus, turbinate atrophy was experimentally reproduced in rabbits with isolates of P multocida, but toxin was only detected in vitro by cell culture assay of P multocida extracts.
Effects of shipping, handling, adrenocorticotropic hormone, and epinephrine on α-tocopherol content of bovine blood
Authors: Sconberg Shelly , Nockels Cheryl F. , Bennett Bill W. , Bruyninckx Walter , Blancquaert Anne-Marie B. , Craig A. Morrie
Published: January 2024

In 2 studies, plasma, erythrocyte, and neutrophil α-tocopherol concentrations were monitored in beef cattle after shipping, handling, and sample collection. On the basis of α-tocopherol results, an additional 2 studies were designed to measure the effects of administration of adrenocorticotropic hormone (acth) and epinephrine on the α-tocopherol concentration in the aforementioned blood constituents and on creatine kinase (ck) activity in Holstein calves.

In the first of these studies, 15 beef cattle that had recently arrived at the feedlot consumed feed supplemented daily with 1,000 IU of dl-α-tocopheryl acetate. Values for initial blood samples indicated that ck activity was high. Although plasma α-tocopherol concentration indicated that vitamin supplementation was adequate, rbc and neutrophil α-tocopherol values were generally nondetectable. After 4 weeks of supplementation, plasma α-tocopherol concentration increased (P < 0.05), and neutrophil and rbc α-tocopherol values became measurable in most of the cattle. In the second study, 6 beef heifers had decreased (P < 0.05) plasma, rbc, and neutrophil α-tocopherol values after multiple periods of handling and blood sample collection.

In the third and fourth studies, 10 tamed Holstein heifer calves, 5 of which were administered acth and epinephrine to simulate stress effects on blood α-tocopherol concentrations and ck activity. In study 3, the vitamin E-adequate heifers had increased blood ck (P < 0.001) activity and cortisol (P < 0.01) concentration, and decreased (P < 0.05) neutrophil α-tocopherol concentration after hormone injections. In study 4, when vitamin E-deficient calves received the aforementioned hormones, ck activity increased (P < 0.05) and rbc α-tocopherol concentration decreased (P < 0.05), whereas plasma and neutrophil values did not change.

These results indicate that shipping and handling, or the stress paradigm of acth and epinephrine injections, may reduce the α-tocopherol content of plasma, rbc, and neutrophils while increasing plasma ck activity, which indicates membrane destruction.
Treatment of experimentally induced trichinosis in dogs and cats
Authors: Bowman Dwight Douglas , Darrigrand Ruth Anne , Frongillo Marguerite K. , Barr Stephen Charles , Flanders James A. , Carbone Lawrence G.
Published: January 2024

Studies were undertaken to determine the efficacy of milbemycin oxime against the enteric adult stages of Trichinella spiralis and of albendazole against the muscle stage larvae in experimentally infected dogs and cats. Specific-pathogen-free Beagle pups (n = 6) and domestic shorthair kittens (n = 6) were inoculated with 7,500 first-stage larvae of Trichinella spiralis. Physical examination (including collection of blood and fecal samples) was performed weekly. During the first week after inoculation, all animals had mild gastrointestinal tract disturbances, but stages of T spiralis were not observed in the feces. Beginning on postinoculation day (pid) 10, 3 pups and 3 kittens were treated with milbemycin oxime (1.25 mg/kg of body weight, po, q 12 h) for 10 days. Muscle biopsy specimens were taken from dogs and cats on pid 26 and 29, respectively. Mean numbers of larvae per gram of muscle were 30.3 in the control and 37.7 in the treated dogs. Mean numbers of larvae per gram of muscle in the control and treated cats were 318.7 and 89.3, respectively. Two dogs and 2 cats were removed from the study at that time. The remaining animals, 2 each of the control and milbemycin oxime-treated animals, were given albendazole (50 mg/kg, po, q 12 h) for 7 days starting at pid 31 and 34 in dogs and cats, respectively. Muscle biopsy specimens were again taken at pid 46 and 49, for dogs and cats, respectively; mean numbers of larvae recovered from muscle were 0.6 for dogs and 13.5 for cats.
Enzyme-linked immunosorbent assay for serologic detection of Salmonella dublin carriers on a large dairy
Authors: House John K. , Smith Bradford P. , Dilling George W. , Da Roden Lin
Published: January 2024

Cows and calves from a 1,600-cow drylot dairy were screened for IgG antibodies to Salmonella dublin lipopolysaccharide (lps), using an indirect elisa. The elisa was performed on milk samples from lactating cows and on sera from nonlactating cows and calves. Fecal samples were collected from calves and nonlactating cows for culture of Salmonella spp. All seropositive cattle were retested by culture and elisa 5 times at monthly intervals or until antibody concentration decreased. None of the cattle remained culture-positive and seronegative. Prior to and during the sample collection period, approximately 30% of calves < 8 weeks old died of S dublin infection. Vaccination of cows with a killed S dublin/S typhimurium vaccine at cessation of lactation was a routine management practice. The elisa-determined IgG response to vaccination had decreased by 50 days after vaccination.

Eight cows and 5 calves that maintained a high serologic response to S dublin were purchased and moved to a research facility for 6 months of intensive monitoring. Lactating cows were milked twice daily, and culture of milk and feces for Salmonella spp was performed 5 times/wk. Serum IgG antibodies to S dublin lps were measured weekly, using elisa. At the end of 6 months, all 13 cattle were necropsied and tissues were obtained for culture of Salmonella spp. All 8 cows and 5 calves maintained persistently high elisa titer for the 6 months of testing, and shed S dublin in the milk and/or feces during the same period. On this basis, they were termed S dublin carriers. Salmonella dublin was isolated from mammary tissue of 2 calves at necropsy, indicating that bacteremia may be a mode of mammary infection by S dublin.

Results of the study indicated serologic testing can be used successfully on a large dairy to identify S dublin carrier cattle. Using initial milk screening, 42 of 1,268 lactating cows were identified as suspect, requiring repeated serologic testing. One nonlactating cow, 7 of the 42 suspect lactating cows, and 5 of the 222 calves maintained an IgG response, and were found to be S dublin carriers. Carrier cows shed S dublin in 3.35% of fecal samples and 2.51% of milk samples, and carrier calves shed S dublin in 17.26% of fecal samples.
Antinociceptive effects of combining low doses of neuroleptic drugs and fentanyl in sheep
Authors: Kyles Andrew Edward , Waterman Avril Eira , Livingston Alex
Published: January 2024

Effects of low doses of the neuroleptic drugs droperidol and zuclopenthixol, combined with a sub-analgesic dose of the opioid µ-agonist, fentanyl, on mechanical nociceptive thresholds were evaluated in sheep. Intravenously administered droperidol (5 µg/kg of body weight) did not induce any change in the nociceptive thresholds when administered alone, but caused marked increase in threshold responses when combined with a subanalgesic dose of fentanyl (5 µg/kg). Similarly, a combination of IV administered zuclopenthixol (100 µg/kg) and fentanyl induced significant (P< 0.05) antinociceptive effects, whereas zuclopenthixol administered IV alone had no effect on the threshold responses. Intrathecal administration of a low dose of droperidol (5-µg total dose) combined with IV administered fentanyl also increased mechanical thresholds significantly (P< 0.05). These results indicate that interactions exist between dopaminergic and opioid systems in the processing of nociceptive information and that these effects may, at least partially, be mediated spinally.
Capacitation-like membrane changes and prolonged viability in vitro of equine spermatozoa cultured with uterine tube epithelial cells
Authors: Ellington J. E. , Ball B. A. , Blue B.J. , Wilker C. E.
Published: January 2024

Reliable capacitation of equine spermatozoa has been a major obstacle in the development of equine in vitro fertilization. Experiments were done to compare in vitro capacitation of equine spermatozoa by use of heparin/caffeine, calcium ionophore, uterine tube epithelial cell (utec)-conditioned medium, and direct culturing of spermatozoa with utec (coculturing). Capacitation-like changes, as determined by chlortetracycline membrane staining patterns, developed with utec-conditioned medium and coculturing, equivalent to that with calcium ionophore. Both of these treatments induced more (P. < 0.05) capacitation-like changes than did the control, a modified Tyrode’s medium. More (P < 0.05) spermatozoa were viable after 24 hours of utec coculturing than in the control incubation.
Leukocyte mobilization to skin lesions in dogs
Authors: Wisselink Marinus A. , Koeman Jan P. , Willemse Ton
Published: January 2024

A suction blister technique was used in 10 healthy dogs to remove the epidermis from the dermis in a standardized way. Collection chambers were attached to these skin windows and filled with autologous serum to attract exudative neutrophils. The chambers were emptied by fine-needle aspiration at 4-hour intervals and were refilled with serum for 24 hours after the last aspiration. The collected cells were counted, differentiated, and stained, using the trypan blue dye-exclusion method to determine cell viability. Multiple skin biopsy specimens obtained during the procedure were examined histologically. The chamber fluid collected after 24 hours was cultured for bacteria. Increasing numbers of viable neutrophils were collected during the 24-hour period from the induced skin windows. In all but 1 dog, sufficient viable neutrophils could be collected to perform further functional tests in vitro. Our conclusion is that this technique might be useful to study chemotaxis in vivo and to perform functional tests on exudative neutrophils.
Microbiologic changes during antimicrobial treatment and rate of relapse of distal respiratory tract infections in foals
Authors: Hoffman Andrew M. , Viel Laurent , Prescott John F.
Published: January 2024

Despite the high incidence of distal respiratory tract infection of undetermined cause on farms, to our knowledge, the microbiologic effects of conventional antimicrobial treatment for this condition have not been studied. We evaluated the possible pathogenic role of bacterial isolates from the distal airways of foals with clinical respiratory tract disease, by correlating changes in their numbers (increase or decrease) with clinical, endoscopic, and pulmonary cytologic signs of disease resolution during treatment with antimicrobial drugs. We also determined qualitative changes in in vitro antimicrobial susceptibility of bacterial isolates after 7 days of treatment and relapse rate of foals. Significant (P < 0.05) decrease in the numbers of an isolate in the airways was considered strong evidence of a pathogenic role in this disease syndrome. Foals with endoscopically confirmed distal respiratory tract infection (drti; n = 65) were selected at random for treatment (n = 56) or nontreatment (n = 9), and bronchial lavage specimens were cultured and evaluated cytologically before and after 7 days of treatment with trimethoprim-sulfamethoxazole (tms) and a β-lactam drug (penicillin, ampicillin, or sulbactam-ampicillin), the standard treatment in all foals. The effect of treatment was to abruptly reduce the clinical (nasal discharge, cough, adventitious lung sounds) and cytologic signs of airway infection. Severity of disease in nontreated foals, however, did not change or did worsen over time. Reduction in the frequency and numbers of Streptococcus zooepidemicus isolated during treatment supported a causal role for this organism in the clinical syndrome observed. On the other hand, the frequency of non-Str zooepidemicus isolates (eg, Staphylococcus epidermidis, Streptomyces spp, α-hemolytic streptococci) actually increased during treatment, compatible with a commensal or competitive role for these organisms. Significantly (P < 0.001) more pretreatment isolates were susceptible in vitro to either tms or β-lactam drugs than to β-lactam drugs alone; more posttreatment isolates were susceptible to either tms or β-lactam than to either drug alone. These data indicate that there may be some benefit to combined use of tms plus β-lactam drugs in foals with drti. Mean ± sem relapse rate was 31 ± 6% (range 0 to 57%); risk factors (clinical signs of disease, laboratory variables) for relapse could not be identified. In conclusion, treatment resulted in significant (P < 0.001) reduction in airway inflammation in foals with clinical drti. The high reinfection rate indicates that a predisposing factor, possibly age-related immunodeficiency, may predispose foals to illness and persists after treatment.
Cardiovascular effects of intravenous bolus administration and infusion of ketamine-midazolam in isoflurane-anesthetized dogs
Authors: Jacobson John D. , Hartsfield Sandee M.
Published: January 2024

Cardiovascular effects of iv administered ketamine (10 mg/kg) and midazolam (0.5 mg/kg) were determined in 12 healthy isoflurane-anesthetized (1.7% end-tidal concentration) dogs. Six dogs received a ketamine-midazolam combination (k-m) as a bolus over 30 seconds and 6 dogs received k-m as an infusion over 15 minutes. Ketamine-midazolam combination as a bolus and an infusion caused early significant (P < 0.05) reductions in mean systemic blood pressure, cardiac index, and stroke index, which returned to baseline values near the end of the study. Heart rate decreased significantly (P < 0.05) in dogs of the infusion group and returned to the baseline value near the end of the study. One dog died after k-m bolus administration. Mean maximal decreases from baseline for systemic blood pressure, cardiac index, and stroke index were significantly (P < 0.05) greater in dogs of the bolus group than in dogs of the infusion group; therefore, cardiovascular effects of k-m after infusion were less severe than those after bolus. Base excess and pHa decreased significantly (P < 0.05) in the infusion group, although similar changes occurred in both groups.

Four dogs were maintained with 1.7% end-tidal isoflurane to determine temporal effects of isoflurane; these dogs did not receive k-m. Increases in heart rate, cardiac index, stroke index, and left and right ventricular stroke work indexes were significant (P < 0.05) at various sample collection intervals, particularly during the later stages of the study.

Isoflurane anesthesia effectively blocked the cardiostimulatory properties of k-m. Ketamine-midazolam combination should be used cautiously during isoflurane anesthesia, and administration by slow infusion may be safer than by rapid bolus administration.
Effect of constant administration of a gonadotropin-releasing hormone agonist on reproductive activity in mares: Induction of ovulation during seasonal anestrus
Authors: Fitzgerald Barry P. , Meyer Steven L. , Affleck Karen J. , Silvia Pamela J.
Published: January 2024

The potential of a gonadotropin-releasing hormone (GnRH) agonist (goserelin acetate), delivered constantly for 28 days via a subcutaneous depot, to induce ovulation in seasonally anestrous mares, was investigated. Two experiments were conducted, in which a range of doses (30 to 240 µg/mare/d) was examined. Mares were selected on the basis of lack of substantial follicular development (follicle diameter < 20 mm determined ultrasonically) and low serum concentrations of luteinizing hormone (lh) and progesterone.

Constant administration of the GnRH agonist-induced ovulation in anestrous mares, but a dose-response relation was not observed. Furthermore, with identical doses tested in consecutive or alternate years, considerable variation was observed in the ovulatory response. In general, ovulation in all treated mares was accompanied by increased circulating concentrations of lh and a decrease in follicle-stimulating hormone values. Ovulation was preceded by an increase in estradiol and lh concentrations. In mares in which ovulation did not occur, concentration of lh increased during agonist treatment, whereas that of follicle-stimulating hormone either increased or did not change.

It was concluded that constant administration of GnRH agonists may induce ovulation in mares during seasonal anestrus; however, percentage of mares ovulating and the lack of reproducibility of effect indicate that this approach is inappropriate for use as a reliable method to manipulate breeding activity in commercial broodmares.
Brain stem auditory evoked potentials from bone stimulation in dogs
Authors: Strain George M. , Green Kelly D. , Twedt Alan C. , Tedford Bruce L.
Published: January 2024

Brain stem auditory evoked potential (baep) testing with air-conducted click stimuli can be used to diagnose sensorineural deafness in dogs if conductive deafness can be ruled out. Detection of conductive deafness can be performed by recording baep elicited by a vibratory stimulus transducer placed against the skull. Air- and bone-conducted baep were compared in dogs, varying bone stimulator placement, click polarity, and stimulus intensity. Optimal bone stimulator placement was determined to be over the mastoid process, followed by the mandible and the zygomatic arch. Condensation polarity clicks gave responses preferable to those elicited by rarefaction or alternating polarity. Bone-conducted baep peak latencies were significantly longer than air-conducted latencies after correction of the latencies for the air conduction time accompanying air-conducted stimuli. Significant differences between stimulus modalities were not seen for baep peak amplitudes or interpeak latencies. Latency-intensity and amplitude-intensity regressions had similar effects for both modalities: latencies decreased and amplitudes increased as stimulus intensity increased.