bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystalloids versus colloids: Implications in fluid therapy of dogs with intestinal obstruction
Authors: Allen Douglas , Kvietys Peter R. , Granger D. Neil
Published: February 2025

Responses of jejunal transcapillary and transmucosal fluid fluxes to iv infiision of crystalloid or colloid solutions were evaluated in 12 dogs. One isolated intestinal segment in each dog was used as the control segment, and 2 segments were distended to a intraluminal hydrostatic pressure of 10 cm of H2O. The artery supplying 1 of the 2 distended (autoperfused) segments was cannulated and perfused with blood from the femoral artery. One of the 2 distended segments was autoperfused from the femoral artery. Intraluminal pressure was increased in the autoperfused segment and in 1 other segment for three, 20-minute periods after administration of the crystalloid or colloid solution. Net transmucosal fluid flux was estimated, using a volume recovery method. In each autoperfused segment, blood flow, capillary pressure, lymph flow, and plasma protein and lymph protein concentrations were measured during each 20-minute distention period. Systemic arterial pressure was monitored throughout the procedure. Plasma and tissue oncotic pressures were calculated from the plasma protein and lymph protein concentrations. Total vascular resistance and precapillary and postcapillary resistances were determined.

Capillary pressure increased after infusion with colloids and crystalloids, with the effects being more prolonged in the colloid group. Plasma oncotic pressure transiently increased after infusion with colloids and decreased after infusion with crystalloids. Lymph flow increased only in crystalloid-treated dogs. Due to alterations in transcapillary fluid filtration, crystalloids induced a net loss of fluid into the intestinal lumen, whereas the fluid absorptive capacity of the jejunum was unaltered by colloid treatment. Results of the present study indicate that colloids are the solution of choice when large volumes of fluid are required for volume expansion in dogs with small intestinal obstruction.
Percentage of glycosylated hemoglobin and serum concentration of glucose in the blood of Japanese macaques and in three exotic ruminant species
Authors: Richter Nadine A.
Published: February 2025

Serum glucose concentrations and percentages of glycosylated hemoglobin (GHb) were determined m 16 Japanese macaques and in 19 exotic ruminants (4 markhor, 5 mouflon, 10 aoudad). Mean (± sd) serum glucose concentration and GHb percentage in the Japanese macaques were 73 ± 21.8 mg/dl and 4.7 ± 0.82%, respectively. Serum glucose concentration was considered within the normal range for this species. The mean GHb percentage was within the normal range for man, indicating that GHb may be a valid indicator of long-term mean serum glucose concentration in the Japanese macaque. Mean serum glucose concentrations in the markhor, mouflon, and aoudad were 110 ± 23.2, 111.4 ± 37.1, and 132.5 ± 38.5 mg/dl, respectively, and were considered within the normal ranges for these species. Mean GHb percentages for each of the 3 ruminant species were 0.425, 1.04, and 0.74%, respectively, which may have been below the range of accuracy for the testing procedure used, probably due to low erythrocyte permeability to glucose rather than to a shortened erythrocyte lifespan.
Ultrastructural study of the equine cecum during onset of laminitis
Authors: Krueger Ann S. , Kinden D. A. , Garner H. E. , Sprouse R. F.
Published: February 2025

The morphologic and pathologic changes which occurred within the cecal mucosa of 4 horses during the onset of laminitis were determined from cecal biopsy materials obtained via a cecal fistula; the laminitis was induced with carbohydrate overload. The cecal epithelial mucosa specimens were obtained at 0 (base line), 24, 32, 48, and 72 horn's after horses were given carbohydrate overload, and these were fixed and subsequently photographed. Changes in the cecal epithelium were examined by transmission electron and scanning electron microscopies. These histopathologic changes indicated that the mucosal barrier was substantially damaged by the carbohydrate overload.
Effects of exogenous iron on Escherichia coli septicemia of turkeys
Authors: Bolin Carole A.
Published: February 2025

The effect of inoculation with Escherichia coli on serum iron concentrations of turkeys and the effect of exogenous iron, as ferric ammonium citrate, on E coli septicemia in turkeys were determined. Inoculation of air sacs with E coli produced hypoferremia in 18-day-old turkeys. Administration of iron with E coli significantly (P < 0.01) increased mortality, frequency and degree of bacteremia, and severity of lesions in inoculated turkeys, compared with those in turkeys given E coli but not given iron. Similar results were seen whether iron was inoculated at the same location as E coli or at a different location.
Effect of zearalenone on dairy cows
Authors: Weaver Gary A. , Kurtz Harold J. , Behrens Jerome C. , Robison Thomas S. , Seguin Bradley E. , Bates Fern Y. , Mirocha Chester J.
Published: February 2025

Doses of 99% pure zearalenone (0.0, 31.25, 62.5, 125.0, 250.0, or 500.0 mg) in gelatin capsules were given once a day per os to 18 nonpregnant, nonlactating, multiparous dairy cows for 2 consecutive estrous cycles. There was no effect (P < 0.10) on serum progesterone concentrations, rbc, wbc, pcv, hemoglobin, and estrous cycle length. Differential cell counts, clinical health, and sexual behavior were not affected by the zearalenone. One cow from each of the groups given zearalenone and a control were euthanatized at the end of the study. The zearalenone had no effect on the terminal bone marrow smears and did not induce any gross lesions discernible at necropsy or any microscopic lesions in representative samples of 30 tissues/cow.

Rectal palpation of the reproductive tracts once a week indicated that the corpora lutea were small in cows given zearalenone. There was a general trend to increased hemoglobin concentrations in cows given the larger doses of zearalenone.

Zearalenone of and by itself does not seem to be an important factor in dairy cow health.
Comparison of metrizamide and iohexol for cisternal myelographic examination of dogs
Authors: Puglisi Tony A. , Green Ronald W. , Hall Charles L. , Read W. K. , Green Robert A. , Tangner Cecil H. , Mann F. A. , Hobson H. Phil
Published: February 2025

A double-blind study, using metrizamide, iohexol, or Ringer's solution (control) as cisternal myelographic agents, was performed on 25 dogs. Before myelographic examination was done, each dog was subjected to physical, clinical pathologic, and neurologic examinations, as well as examinations by electroencephalography and computerized tomography. These were repeated 24 hours after completion of the myelographic examination. The group of dogs given metrizamide (group II) had a significantly greater occurrence of seizure activity (6 of 10) than did the control dogs (group I; 0 of 5) or dogs given iohexol (group III; 0 of 10; P < 0.003). In group n, the csf microprotein concentration was significantly greater 24 hours after myelography was done than were the values in groups I and III (P < 0.003). Myelograms of the group II dogs (metrizamide) and group III dogs (iohexol) had similar diagnostic qualities. At 24 hours after myelographic examination was done, computerized tomography scan revealed that each dog given metrizamide and iohexol had myelographic contrast material in the brain and cervical spinal cord parenchyma. Seemingly, iohexol has good diagnostic quality, but is less epileptogenic than metrizamide when used in cervical myelographic examinations of dogs.
Genotypic and phenotypic variation of biotypes coexisting in the Hickman strain of Newcastle disease virus
Authors: McMillan Blair C. , Hanson Robert P.
Published: February 2025

Many Newcastle disease virus strains are composed of several biotypes which coexist in the wild and in laboratory cultures. We have studied some of the phenotypic and genotypic properties of 6 virus clones from the coexisting biotypes of the Hickman strain of Newcastle disease virus. These clones were readily distinguishable from the parent virus strain and from each other by their RNA fingerprints. Fingerprints of the most virulent clones (Hi/LC, Hi/MC, and Hi/LR) contained 61% to 77% of the oligoribonucleotides present in the fingerprint of the Hickman parent strain. None of the clones killed chickens as rapidly as did the parent strain, although some clones killed embryonating eggs as rapidly as did the parent strain.
Comparison of the antigens associated with saline solution, potassium thiocyanate, and sodium salicylate extracts of Pasteurella haemolytica serotype 1
Authors: Durham J. A. , Confer A. W. , Mosier D. A. , Lessley B. A.
Published: February 2025

Pasteurella haemolytica antigenic extracts were made, using saline solution, potassium thiocyanate (kscn), and sodium salicylate (ss) extraction procedures. Of the 3 techniques, saline solution extraction resulted in the lowest protein concentration and lowest ribonucleic acid-to-protein ratio. The extracts varied in protein:carbohydrate ratios, with the kscn extract being highest and the saline solution extract the lowest. Each extract contained lipopolysaccharide, as determined by detectable quantities of 2-keto, 3-deoxyoctonate. The saline solution extract contained the fewest protein bands by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis, but contained the highest molecular weight proteins.

All 3 extracts were reasonably similar antigenically, as detected by immunoblotting. Many of the protein bands present in the kscn or ss extracts did not seem to be antigenic. Each extract was subjected to chromatofocusing, and the greatest antigenic peak, for each extract, failed to bind to the exchanger. These highly antigenic peaks, designated as saline solution, kscn, or ss antigens, were similarly high in carbohydrate content, had similar antigenic-profiles, and contained high molecular weight (> 200,000) antigenic material, most likely carbohydrate in nature, as detected by immunoblotting.

Inoculation of mice with 1 of the 3 extracts or the saline solution antigen resulted in marked antibody responses; however, protection against intraperitoneal challenge exposure to P haemolytica was minimal.
Breath hydrogen concentration and small intestinal malabsorption in calves
Authors: Holland R. E. , Herdt T. H. , Refsal K. R.
Published: February 2025

Breath hydrogen concentrations were measured to assess intestinal carbohydrate malabsorption in preruminating calves. Oral administration of 1.25 g of lactulose (a nonabsorbable carbohydrate)/kg to calves produced breath hydrogen concentrations significantly (P < 0.001) higher than values determined after calves were fed milk and before the treatment was given. This indicates that, in the calf, fermentation of nonabsorbed carbohydrates results in increased breath hydrogen values. To induce small intestinal malabsorption, chloramphenicol was administered orally at 50 mg/kg, 2 times a day, to 5 calves for 3 days. Before therapy was started, each calf was fitted with a duodenal cannula to facilitate collection of intestinal mucosal biopsy samples during treatment. Chloramphenicol therapy significantly (P < 0.001) increased breath hydrogen concentrations from those values measured after calves were fed milk alone. Concurrently, chloramphenicol administration significantly decreased intestinal villous length (P < 0.001) and d-xylose absorption (P < 0.05), compared with those values before treatment was given. These results demonstrate that decreased intestinal absorptive capacity is associated with an increase in breath hydrogen concentrations and that breath hydrogen may be useful in evaluating malabsorption in calves with naturally occurring enteric disease.
Evaluation of lasalocid as a coccidiostat in calves: Titration, efficacy, and comparison with monensin and decoquinate
Authors: Foreyt William J. , Rice Daniel H. , Wescott Richard B.
Published: February 2025

Two experiments were conducted to evaluate lasalocid as a coccidiostat in Holstein calves and to compare lasalocid with monensin and decoquinate. In experiment 1, calves in 3 groups (6 calves/group) were each inoculated with 500,000 sporulated oocysts, 88% of which were Eimeria bovis and 12% were E zuernii. Calves in each group were given lasalocid-medicated feed at 0.50 (group 3), 0.75 (group 4), or 1 mg/kg (group 5) of body weight/day for 45 days. Two control groups (6 calves/group) were also evaluated; calves in control group 2 were inoculated and nontreated, and calves in control group 1 were noninoculated and nontreated. At 0.50, 0.75, or 1 mg/kg/day, lasalocid was equally effective in preventing induced coccidiosis (E bovis and E zuernii) in calves. Compared with inoculated nontreated controls, treated calves had significantly (P < 0.05) fewer oocysts in feces and had fewer clinical signs of coccidiosis from days 16 to 30 after inoculation.

Experiment 2 was conducted to compare the effectiveness of monensin, lasalocid, and decoquinate for the prevention of experimentally induced coccidiosis. Calves (n = 48) were allotted into 4 groups (12 calves/group); each was inoculated orally with 275,000 sporulated oocysts, predominantly E bovis and E zuernii, and each was given nonmedicated feed (group 6) or feed medicated with 33 mg of lasalocid (group 7), decoquinate (group 8), or monensin (group 9)/kg of feed for 46 days. Calves given medicated rations had significantly (P < 0.05) fewer oocysts in their feces and fewer clinical signs of coccidiosis than did calves given nonmedicated rations. Monensin, lasalocid, and decoquinate effectively reduced oocysts numbers in the feces of calves and prevented clinical coccidiosis. In both experiments, significant differences in average daily gain, feed consumed, or feed-conversion rates were not found among treated and nontreated groups.
Chloramphenicol concentrations in calf muscle tissue
Authors: Epstein R. L. , Ashworth R. B. , Simpson R. M.
Published: February 2025

Twenty-five 9- to 11-week-old calves were administered 2 doses of chloramphenicol prepared in propylene glycol (13.6 mg/kg of body weight iv; 6.8 mg/kg im; or 13.6 mg/kg im) at 24-hour intervals. Calves were euthanatized at designated times from 2 to 72 hours after the last dose was administered. Muscle tissues were collected immediately after euthanasia, and chloramphenicol concentrations in the tissues were determined.
Cardiovascular and pharmacokinetic effects of isoxsuprine in the horse
Authors: Matthews Nora S. , Gleed Robin D. , Short Charles E. , Burrows Katey
Published: February 2025

Isoxsuprine (0.6 mg/kg) administered iv to 6 standing horses produced substantial, transient decreases in systemic blood pressure, systemic vascular resistance, and stroke volume. It also produced substantial, transient increases in heart rate, cardiac output, and purposeful movement. Plasma concentrations of isoxsuprine peaked soon after the drug was administered iv and then decreased over a 12-hour period in a biexponential manner, with distribution and elimination half-lives of 14 minutes and 2.67 hours, respectively. Total body clearance and steady-state volume of distribution were calculated to be 53.8 ml/min/kg and 10.5 L/kg, respectively. When a recommended therapeutic dosage regimen (0.6 mg/kg 2 times a day, per os) was used in 4 of these horses, changes were not detected. Isoxsuprine was not detected in plasma after the drug was given orally. We conclude that 0.6 mg of isoxsuprine/kg given orally every 12 hours is not likely to produce cardiovascular changes in the resting horse and that this is probably because plasma concentrations are not high enough to do so.
Evaluation of 99mTc-diethylenetriaminepentaacetic acid nuclear imaging for quantitative determination of the glomerular filtration rate of dogs
Authors: Krawiec Donald R. , Badertscher Robert R. , Twardock A. Robert , Rubin Stanley I. , Gelberg Howard B.
Published: February 2025

Thu suitability of 99mTc-diethylenetriaminepentaacetic acid (99mTc-dtpa) as an agent to assess glomerular filtration rate (gfr) in dogs was evaluated. Glomerular filtration rates of 12 healthy dogs were determined on the basis of creatinine and/or inulin clearance. Glomerular filtration rates also were determined in 7 dogs after induction of acute renal failure by administration of amphotericin B. The healthy dogs and the amphotericin B-treated dogs were given 99mTc-dtpa (1 to 2 mCi) iv. The percentage of the 99mTc-dtpa dose in the kidneys (percentage dose) was determined, with background activity subtracted from total activity at 15-s intervals 0 to 6 minutes after 99mTc-dtpa infusion. Linear regression analyses (lra) were performed to determine whether the percentage dose at various time intervals after injection correlated with gfr calculated on the basis of creatinine and inulin clearance data. One to 3 minutes after 99mTc-dtpa administration appeared to be the best period for analysis of the data. The percentage dose of 99mTc-dtpa (corrected for kidney depth differences) was determined and lra against gfr were performed. The percentage dose correlated better with inulin clearance (r = 0.94) than with endogenous creatinine clearance (r = 0.83). Only inulin clearance correlations improved with kidney depth correction. The lra was used to derive an equation that could be used to calculate gfr on the basis of the percentage dose. The equation derived from inulin regression was: gfr (milliliter/minute/kilogram of body weight) = 0.194 (depth-corrected percentage dose) − 0.37; the equation derived from the creatinine regression was: gfr (milliliter/minute/kilogram) = 0.171 (depth-corrected percentage dose) − 0.15. Therefore, 99mTc-dtpa can be used as an agent for the rapid, noninvasive, and accurate determination of gfr in dogs.
Effects of ketanserin on pulmonary hemodynamics, lung mechanics, and gas exchange in endotoxemic pigs
Authors: Olson N. C. , Grizzle M. K. , Anderson D. L.
Published: February 2025

The effects of ketanserin on pulmonary hemodynmmics, lung mechanics, and gas exchange were determined in anesthetized 10- to 14-week-old pigs after they were endotoxemic for 1 or 4.5 hours. Saline solution was given to controls (group 1). Escherichia coli endotoxin (055-B5) was infused iv at a dosage of 5 μg/kg for 1 hour (group 2). In group 3, endotoxin was infused at 5 μg/kg the first hour plus a continuous infusion of endotoxin at 2 μg/kg/hr. Ketanserin, a specific serotonin receptor antagonist, was infused iv (300 μg/kg) after pigs were endotoxemic for 1 or 4.5 hours (groups 2 and 3, respectively). At 1 hour of endotoxemia, mean pulmonary artery pressure and pulmonary vascular resistance were increased, and cardiac index was decreased. Ketanserin caused a small attenuation of the increases in mean pulmonary artery pressure and pulmonary vascular resistance, indicating that serotonin may have a small role in the endotoxin response at 1 hour. At 4.5 hours of endotoxemia, mean pulmonary artery pressure, pulmonary vascular resistance, alveolar dead space ventilation, and alveolar-arterial oxygen gradient were increased, and cardiac index and lung dynamic compliance were decreased; ketanserin significantly attenuated the endotoxin-induced changes in cardiac index, mean pulmonary artery pressure, pulmonary vascular resistance, and lung dynamic compliance. Ketanserin also decreased the blood temperature after pigs were endotoxemic for 4.5 hours. However, the endotoxin-induced increases (at 4.5 hours) in alveolar-arterial oxygen gradient and alveolar dead space ventilation were not acutely reversed by ketanserin. These findings indicate that serotonin contributes significantly to the pulmonary vasoconstriction and, to a lesser extent, to the bronchoconstriction observed in pigs that were endotoxemic for 4.5 hours.
Pattern of breathing in brachycephalic dogs
Authors: Amis Terence C. , Kurpershoek C.
Published: February 2025

The pattern of breathing was assessed in 19 brachycephalic dogs, using tidal breathing flow-volume loop (tbfvl) analysis. Fifteen dogs had tbfvl consistent with a fixed-type upper airway obstruction, whereas 4 dogs had a tbfvl indicative of a nonfixed upper airway obstruction. The dogs did not have a tbfvl shape the same as that considered normal for healthy nonbrachycephalic dogs. Tidal breathing flow-volume loops from brachycephalic dogs that were considered to have a normal respiratory tract (n = 11) were similar to those of dogs with clinical signs of upper airway obstruction (n = 8). Respiration was monitored continuously for short periods (20 to 50 minutes) in 3 brachycephalic dogs resting in a cage in a quiet, darkened laboratory; 2 of these dogs had periodic breathing patterns characterized by multiple episodes of alternating hypopnea and arousal. Brachycephalic dogs may be at risk for the development of disordered breathing during sleep.
Recording uterine motility in the nonanesthetized bitch
Authors: Wheaton Lynn G. , Rodriguez-Martinez Heriberto , Weston Patricia G. , Ko Chih-Heng , Gustafsson Borje K.
Published: February 2025

Spontaneous and drug-induced uterine motility (um) was recorded in 5 nonanesthetized bitches for 2 to 4 days. Catheter-tip pressure transducers were surgically implanted in 1 uterine horn, tunneled subcutaneously to exit from the skin over the dorsal lumbar area, and protected by a bandage. On the day after implantation, spontaneous um was recorded in the awake bitch. Effects of iv prostaglandin (pg) F2α (5 μg/kg of body weight) and oxytocin (0.05 USP U/kg) and im pgf2α (25 μg/kg) were measured. Estradiol (1 to 25 μg/kg) was administered and the study was repeated 24 hours later. In awake bitches, spontaneous um was 190% greater than um in anesthetized bitches. Uterine motility was increased by more than 100% after iv pgf2α or oxytocin and by 52% after im pgf2α. Estradiol abolished spontaneous um, but did not affect drug-induced responses. Seemingly, spontaneous and drug-induced um can be documented in the nonanesthetized bitch.
Onchocerca gutturosa and Onchocerca lienalis in cattle: Effect of age, sex, and origin on prevalence of onchocerciasis in subtropical and temperate regions of Florida and Georgia
Authors: Ferenc S. A. , Copeman D. B. , Turk S. R. , Courtney C. H.
Published: February 2025

Evaluation of 845 cattle from Florida and Georgia for onchocerciasis indicated a significantly higher prevalence of infection with Onchocerca gutturosa and a significantly lower prevalence of infection with Onchocerca lienalis in the southern portion of Florida (subtropical region) than in the northern portion of Florida or in Georgia (temperature region). In all regions, prevalence of infection with O gutturosa was significantly higher than infection with O lienalis. In the temperate region, bulls were infected more often with O lienalis than were cows. Other sex-related differences in infection with either filariid was not found. Prevalence of infection with O lienalis was similar between age groups in all regions. Rates of infection with O gutturosa differed between age groups within and between subtropical and temperate regions.

Examination of cervical and umbilical skin specimens for microfilariae detected an additional 6.6% of infected animals that had not been found by examination for adult worms. However, microfilariae were not found in 21.4% of animals that were positive for adult worms.
Evidence of paratuberculosis in Ohio's white-tailed deer, as determined by an enzyme-linked immunosorbent assay
Authors: Shulaw William P. , Gordon John C. , Bech-Nielsen Steen , Pretzman Charles I. , Hoffsis Glen F.
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) was developed and used to detect antibodies to Mycobacterium paratuberculosis in serum samples obtained in December of 1983 from 954 hunter-killed white-tailed deer (Odocoileus virginianus) in 13 Ohio counties. Positive or negative status was determined by calculating a signal-to-noise ratio, a ratio between the optical density of the test serum and negative reference sera; a ratio of ≥ 3.0 was considered positive. Twenty-four samples (2.5%) were found to be assay positive, using this method. A statistically significant difference among age groups was found, with those ≤ 6 months of age having a lower proportion of positives. Differences by sex were not observed.

To determine the validity of the elisa in deer, serum samples from 46 fallow (Dama dama) and axis deer (Axis axis) harvested from a known infected population were tested by elisa and agar-gel immunodiffusion. The agar-gel immunodiffusion test showed evidence of exposure of the deer to M paratuberculosis or a related antigen. The elisa closely approximated the prevalence of paratuberculosis infection as previously determined by fecal culture in this population. As a result of these tests, it was concluded that free-ranging Ohio deer have been infected with M paratuberculosis or exposed to a closely related antigen.
Ultrasonographic evaluation of normal boar testicles
Authors: Cartee Robert E. , Powe Thomas A. , Gray Bruce W. , Hudson Robert S. , Kuhlers Daryl L.
Published: February 2025

The testicles of 14 Landrace boars (7 at 9 months of age and 7 at 15 months of age) were measured and examined by routine physical examination. Semen analysis was done. The testicles were then examined and measured by B-mode ultrasonography. The ultrasonographic appearance and measurements were compared with the physical measurements and the semen analysis. Seminiferous epithelial area (sea) data were obtained after the testicles were surgically removed. These data were compared with the ultrasonographic data and the other physical data. A correlation could not be found between semen analysis and either physical or ultrasonographic data or between sea data and semen analysis. Significant differences were found between the 9-month-old and the 15-month-old boars relative to 5 measurements: sea, tunica albuginea thickness, testicular diameter, testicular length, and epididymal diameter. A ratio of 4:1 was found between each of the average physical measurements (scrotal diameter, testicular-epididymal circumference, testicular-epididymal length) and ultrasonographic measurements of testicular diameter. A ratio of 2.6:1 was found between testicular diameter and epididymal tail diameter (cranial to caudal).
Characterization of Tritrichomonas foetus antigens, using bovine antiserum
Authors: Hall Mark R. , Huang Juch-Chin , Ota Ronald , Redelman Doug , Hanks Donald , Taylor Robert E. L.
Published: February 2025

Tritrichomonas foetus antigens were identified, using the serum of an Angus heifer that had been repeatedly immunized with suspensions of 1 × 108 organisms in Freund's complete adjuvant. Antibody activity against T foetus was determined by dot-blot analysis, using horseradish peroxidase-conjugated anti-bovine immunoglobulin to detect bound antibody. The antiserum contained antibodies against surface and flagellar components of live or fixed T foetus, as determined by use of immunofluorescence. The antiserum reacted with approximately 38 proteins in a pool of 55 to 60 components resolvable by polyacrylamide-gel electrophoresis of T foetus extracts.
Clinical survey of antibodies against red blood cells in horses after homologous blood transfusion
Authors: Wong P. L. , Nickel L. S. , Bowling A. T. , Steffey E. P.
Published: February 2025

Serum samples of 20 horses were evaluated for antibodies against rbc after homologous blood transfusion. Transfusion-associated antibodies against rbc were detected in 10 horses. Antibodies recognizing horse blood group antigens Aa, Ae, Db, and Dc were identified. Antibodies against Aa were found in all samples from Aa-negative horses that were transfused with Aa-positive rbc. Antibodies against Aa persisted for at least 1 year after transfusion. Antibodies against Ae were detected in 7 of 8 horses transfused with Ae-positive rbc. Initial appearance and persistence of antibodies against Ae differed among the horses; antibodies were initially detected 1 week to 154 weeks after transfusion and disappeared as early as 4 weeks after transfusion. Antibodies against Db or Dc were detected in ≤ 33% of the horses that lacked Db or Dc antigens and were transfused with Db- or Dc-positive rbc. Antibodies against Db and Dc were initially detected in sera later than were the A-system antibodies.

Three mares with transfusion-associated antibodies subsequently produced healthy offspring. Two foals had rbc antigens corresponding to their dam's alloantibodies; maternal colostrum with antibodies against Aa was withheld from the Aa-positive foal. The Db-positive foal remained healthy after nursing the mare with serum antibodies against Db.
Pharmacokinetics and endometrial tissue concentrations of ticarcillin given to the horse by intravenous and intrauterine routes
Authors: Spensley Michael S. , Baggot J. Desmond , Wilson W. David , Hietala Sharon K. , Mihalyi Judith E.
Published: February 2025

Plasma and endometrial tissue concentrations of ticarcillin were measured in healthy mares. In the first of the 3 separate phases comprising the study, ticarcillin disodium (30 mg/kg) was administered iv. The mean peak concentration in endometrial tissue, 12.9 μg/g, was attained at 30 minutes. The plasma half-life of the drug in the 6 mares was 0.83 ± 0.22 hour.

Six grams of the drug was diluted in 250 ml of sodium chloride injection USP (2nd phase) and in 60 ml of sodium chloride injection USP (3rd phase). These dilutions were administered by intrauterine infusion. In phase 2, the mean peak concentrations of the drug in plasma and endometrium were 2.76 μg/ml and > 150 μg/g, respectively, at 60 minutes after it was administered. Endometrial concentrations > 150 μg of ticarcillin/g persisted through 2 hours after the drug was administered. Mean peak plasma and endometrial concentrations of the drug in phase 3 were 2.78 μg/ml and > 150 μg/g at 45 and 30 minutes after administration was done, respectively.

At 1 hour after the drug was administered, endometrial concentrations of ticarcillin were significantly higher (P < 0.01) after the drug was infused intrauterinely in the 250-ml volume than those after the 60-ml volume was infused. It was concluded that the volume of fluid in which the drug was infused into the uterus markedly influenced the duration of concentrations > 20 μg/g in endometrial tissue.
Sulfamethazine blood/tissue correlation study in swine
Authors: Ashworth R. B. , Epstein R. L. , Thomas M. H. , Frobish L. T.
Published: February 2025

Seventy market-weight hogs (90 to 113 kg) were used in a feeding study to determine the correlation of serum sulfamethazine concentrations with sulfamethazine concentrations in liver and muscle at time of slaughter. Test groups were fed medicated feeds prepared from commercial medicated premixes containing 110 g of sulfamethazine/metric ton for 30 days. Fifteen days before hogs were slaughtered, test groups were given maintenance feeds containing 1.1 to 13.9 g of sulfamethazine/metric ton and were fed these diets until slaughtered.

Comparison of data from positive- and negative-control groups indicated that total withdrawal of sulfamethaziner in the feed was not necessary for the liver to contain less than the allowed tolerance of 0.1 mg of sulfamethazine/kg of liver at slaughter. Feed concentrations of up to 2 g of sulfamethazine/metric ton could be tolerated in withdrawal feeds before liver sulfamethazine values exceeded 0.1 mg/kg of liver. Serum/tissue sulfamethazine ratios were erratic in hogs given 1.1 to 2.7 g of sulfamethazine/metric ton, but became less variable in hogs given > 5.7 g/metric ton. Feed concentrations > 8 g of sulfamethazine/metric ton produced values >0.1 mg/kg of muscle and values of about 0.4 mg/kg of liver.

When serum sulfamethazine concentrations alone were used as a predictor for tissue sulfamethazine values, 100% of the liver values exceeded 0.10 mg/kg of liver when sulfamethazine in serum was > 0.45 mg/L. However, 57.4% of samples having serum concentrations between 0.10 and 0.45 mg/L had associated sulfamethazine values >0.1 mg/kg of liver. All hogs having serum sulfamethazine concentrations < 0.1 mg/L had sulfamethazine concentrations < 0.1 mg/kg of liver.
Comparison of the susceptibility of Brucella abortus isolates obtained before and after cows were treated with oxytetracycline and streptomycin
Authors: Guerra Marta A. , Nicoletti Paul
Published: February 2025

Eight isolates of Brucella abortus were obtained from cows before and after they were treated with oxytetracycline and streptomycin. The susceptibility to these antibiotics was determined by broth-dilution minimal inhibitory and minimal lethal concentrations. Differences were not found in the minimal lethal concentrations of oxytetracycline or streptomycin in isolates obtained from cows before and after they were treated. This indicates that treatment failures in the cows were not the result of development of resistance to the antibiotics by B abortus.
Comparison of single-dose and conventional trimethoprim-sulfadiazine therapy in experimental Staphylococcus intermedius cystitis in the female dog
Authors: Turnwald Grant H. , Gossett Kent A. , Cox Hollis Utah , Kearney Michael T. , Roy Alma F. , Thomas David E. , Troy Gregory C.
Published: February 2025

Cystitis was produced in 4 groups of 6 female dogs each, using salicylic acid, ethanol, and Staphylococcus intermedius. Group-I dogs served as nontreated controls. Starting 2 days after infection was induced, group-II dogs were treated with trimethoprim-sulfadiazine at a dosage of 15 mg/kg given orally 2 times a day for 21 days; groups-III and -IV dogs were treated with single oral dosages of the antibiotic at 60 mg/kg and 90 mg/kg, respectively.

Group-I dogs (controls) remained infected for the 26-day duration of the study. The response to therapy seen in group-II dogs was better than the therapeutic responses in groups-III and -IV dogs (P < 0.05).

Results of the present study do not support the efficacy of single-dose therapy for this model of cystitis.
Experimentally induced infections in turkeys with Cryptosporidium baileyi isolated from chickens
Authors: Lindsay David S. , Blagburn Byron L. , Hoerr Frederic J.
Published: February 2025

Oocysts of Cryptosporidium baileyi isolated from chickens were inoculated by different routes into 3 groups of turkey poults. Intratracheal inoculation of oocysts produced clinical signs of respiratory tract disease, deaths, and gross lesions of airsacculitis. Parasites developed in the microvillous border of the nasopharynx, larynx, trachea, bronchi, and air sacs. Oral and intracloacal inoculations of oocysts caused no deaths or clinical signs of disease, but did produce patent infections. Respiratory tract infections limited to the nasopharynx, larynx, and trachea occurred in 3 orally inoculated poults. Respiratory tract infections were not observed in intracloacally inoculated poults. The mode of inoculation did not influence the distribution of C baileyi in the digestive tract. The cloaca was parasitized in 100% of the birds with intestinal infections, and the bursa of Fabricius was parasitized in 72.7%.
Assessment of bovine mammary gland macrophage oxidative burst activity in a chemiluminescence assay
Authors: Harmon Barry G. , Adams L. G.
Published: February 2025

A major bactericidal mechanism of neutrophils and macrophages is the generation of toxic oxygen-free radicals upon phagocytosis of microbes. Studies were conducted to assess the oxidative metabolism of bovine mammary gland macrophages. Bovine mammary gland macrophages were challenge exposed with a variety of phagocytic stimuli in an in vitro, luminol-assisted chemiluminescence assay. A measurable oxidative burst was observed when macrophages were challenge exposed with heat-aggregated bovine immunoglobulin, opsonified zymosan, and nonopsonified zymosan. Addition of superoxide dismutase decreased mammary gland macrophage chemiluminescence in a dose-dependent manner. Brucella abortus, when opsonified with antiserum, lacteal antibody, or normal serum, produced an oxidative event, whereas nonopsonified B abortus did not. When challenge exposed with phagocytic stimuli, mammary gland macrophages produced an oxidative burst similar to that produced by other phagocytes for which an oxidative event is known to be bactericidal.
Effect of aspirin on ex vivo generation of thromboxane in healthy horses
Authors: Baxter Gary M. , Moore James N.
Published: February 2025

Different dosages of aspirin were administered (by nasogastric tube) to 3 groups of 5 healthy adult horses to determine the minimal effective dosage needed to decrease serum thromboxane B2 (TxB2) concentrations and to determine the duration of this decrease. When compared with their base-line serum TxB2 concentrations, horses in group 1 (given 5 mg/kg) had a 71% decrease in TxB2 concentrations at 24 hours after aspirin was given and a 86% decrease at 48 hours; serum TxB2 concentrations were back to base-line values by 120 hours. Horses in group 2 (given 10 mg/kg) had a 60% decrease in TxB2 concentrations at 24 hours after aspirin was given, an 84% decrease at 48 hours, a 48% decrease at 96 hours, and an 18% decrease at 6 days. Horses in group 3 (given 20 mg/kg) had a 68% decrease in TxB2 concentrations at 24 hours, a 93% decrease at 72 hours, an 87% decrease at 96 hours, and a 70% decrease at 6 days after aspirin treatment was given. All groups had a statistically significant decrease in TxB2 concentrations (P < 0.05) by 12 hours after aspirin was given, which persisted 96 hours for group 1 and throughout the study for groups 2 and 3.

The maximal TxB2 decrease was similar among the 3 groups (90% decrease from base line), and there were no significant differences among the TxB2 concentrations between 24 and 72 hours after treatment was given. However, beginning 96 hours after aspirin was given, there was a statistically significant (P < 0.005) dose-dependent increase in duration of aspirin activity. As the aspirin dosage was increased, the rate of return of TxB2 concentrations toward base line significantly decreased.
Contribution of whole blood L-lactate, pyruvate, D-lactate, acetoacetate, and 3-hydroxybutyrate concentrations to the plasma anion gap in horses with intestinal disorders
Authors: Gossett K. A. , Cleghorn B. , Adams R. , Church G. E. , McCoy D. J. , Carakostas M. C. , Flory W.
Published: February 2025

Increased anion gap (ag) was due, in part, to l-lactic acidosis in 14 of 14 horses with intestinal disorders. In a few horses, increased whole blood concentrations of d-lactate made a minor contribution to the ag. However, the increase in ag was often greater than the sum of the increases in these 2 acid anions. This unexplained increase was not a result of increases in whole blood pyruvate, 3-hydroxybutyrate, or acetoacetate concentrations or serum albumin or phosphate concentrations. Identification of other anions causing increased ag could lead to better understanding, diagnosis, and treatment of metabolic imbalances in critically ill horses.
Uptake of channel catfish virus from water by channel catfish and bluegills
Authors: Nusbaum Kenneth E. , Grizzle John M.
Published: February 2025

Radiolabeled channel catfish virus entered the gills of juvenile channel catfish (Ictalurus punctatus) and was then concentrated in the gut and the liver over 48 hours. Diminution of radioactivity was not detected in these tissues over the course of the experiment. Bluegills (Lepomis macrochirus) were capable of clearing the virus during a period of 48 hours. [3H]Thymidine alone had a different distribution in the channel catfish than did labeled virus.
Pharmacokinetics and renal clearance of sulfamethazine, sulfamerazine, and sulfadiazine and their N4-acetyl and hydroxy metabolites in horses
Authors: Nouws J. F. M. , Firth E. C. , Vree T. B. , Baakman M.
Published: February 2025

Plasma disposition, protein binding, urinary recovery, and renal clearance of sulfamethazine (smz), sulfamerazine (smr), and sulfadiazine (sdz) and their N4-acetyl and hydroxy derivatives were studied in 4 horses in a crossover trial. The plasma concentration-time curves of the metabolites paralleled those of the parent drug in the elimination phase. Sulfamethazine and smr were extensively metabolized. In plasma and urine, the main metabolite of the 3 sulfonamides tested was the 5-hydroxypyrimidine derivative, which was highly glucuronidated. Difference in elimination half-life of smz, smr, and sdz could be related to difference in metabolism and renal clearance values. Metabolism speeds drug elimination, producing compounds with higher renal clearance values than those of the parent drug. Methyl substitution in the pyrimidine side chain increased hydroxylation of the parent drug, but prolonged the persistence of the sulfonamides studied in the body. The high concentration of N4-acetyl and hydroxy metabolites of smz and smr in plasma and urine decreased the potential antibacterial activity of the parent drugs. Sulfadiazine was less metabolized, and microbiologically determined sdz concentrations in plasma and urine were slightly lower than those measured by high-performance liquid chromatography.
Healing of experimentally induced corneal ulcers in horses
Authors: Neaderland M. H. , Riis R. C. , Rebhun W. C. , Erb H. N.
Published: February 2025

Corneal ulcers to the depth of the anterior third of the stroma were created surgically in both eyes of 10 ponies. One eye in each pony was treated topically with chloramphenicol and 1% atropine ophthalmic ointments 3 times per day; the contralateral eye was not treated topically. All ponies were given phenylbutazone orally for relief of ocular pain.

Fluorescein-stained ulcers were measured once a day. The median healing time of the treated eyes (11 days) and the median healing time of the nontreated eyes (13.5 days) were found not to be significantly different. Clinically, however, more severe complications arose in the nontreated eyes.
Experimental crush of the equine recurrent laryngeal nerve: A study of normal and aberrant reinnervation
Authors: Duncan I. D. , Baker G. J.
Published: February 2025

Experimental reinnervation of the equine larynx in healthy ponies was studied after the recurrent laryngeal nerve was crushed, using endoscopic, electromyographic, and microscopic techniques. In 12 ponies, the recurrent laryngeal nerve was crushed unilaterally in the midcervical area. All showed postoperative paralysis of the larynx on the operated side. In 8 ponies, recovery of movement of the vocal folds occurred at different times (2.5 to 8 months) after surgical operation was done. These movements, which were often abnormal, included trembling and asynchronism. In 2 of these ponies, complete return of normal vocal fold function occurred. Return of function was due to reinnervation, as determined by electromyographic examination of the laryngeal muscles and microscopic evaluation of these muscles and the recurrent laryngeal nerves. In the muscles, there was evidence of fiber-type grouping, and the nerves showed regenerative activity. In 3 ponies, there was evidence of aberrant reinnervation, with adductor or abductor muscles discharging during an inappropriate phase of the respiratory cycle. Further evidence that reinnervation occurred in the larynges of these ponies was determined in microscopic sections of the recurrent laryngeal nerves and muscles, which showed regenerative activity and muscle fiber-type grouping, respectively. The endoscopic abnormalities in these ponies were compared with those seen in horses with spontaneous subclinical laryngeal paralysis. However, the possibility that the abnormal endoscopic findings in this latter group of horses are due to aberrant reinnervation is thought to be unlikely.
Passage of exogenous L-thyroxine and triiodothyronine into bovine ejaculate
Authors: Eiler Hugo , Armstrong-Backus Cindy S.
Published: February 2025

The metabolic effects of thyroxine (T4) and triiodothyronine (T3) on spermatozoa metabolism and male anatomy have been demonstrated. The metabolic effects of T3 and T4 could affect the physiologic characteristics of the spermatozoa. There are little data on the passage of T4 and T3 into the ejaculate from blood. The passage of exogenous T4 and T3 from the blood into semen was measured after T4 (45 mg) or T3 (37.5 mg) was injected iv into 8 bulls. Blood and electroejaculate were obtained simultaneously at 20, 40, 60, 120, and 180 minutes and 24 hours after bulls were injected to determine T3 and T4 concentrations compared with base-line values. Blood T3 and T4 concentrations were increased (P < 0.05) at 20 minutes after bulls were injected (1.1 ± 0.25 to 598 ± 76.3 ng/ml and from 66 ± 5 to 1,318 ± 105 ng/ml, respectively). Seminal concentrations of T4 were unchanged until 120 minutes after bulls were injected, when they increased (P < 0.05) from < 1.2 ng/ml to 4.7 ± 1.9 ng/ml. However, seminal concentrations of T3 were increased (P < 0.05) from < 0.1 ng/ml to 0.5 ± 0.2 ng/ml at 20 minutes and to 12.5 ± 2.9 ng/ml at 120 minutes after bulls were injected. It was concluded that exogenous thyroid hormones passed into the ejaculate from blood, with T3 passing faster than T4.
Porcine malignant hyperthermia: False negatives in the halothane test
Authors: Gallant Esther M. , Rempel William E.
Published: February 2025

Purebred Pietrain pigs presumed (on the basis of pedigree) to be homozygous for malignant hyperthermia (mh) susceptibility were subjected to a 3% halothane challenge test. A few (6%) pigs that should have been mh susceptible on the basis of parental genotype did not develop muscle rigidity in response to repeated halothane tests. Three of these animals were brought into the laboratory, and muscle biopsy specimens were obtained for in vitro analysis.

Bundles of intact muscle cells dissected from biopsy specimens were electrically stimulated, and mechanical responses were monitored during exposure to halothane. In all instances, the muscle bundles from the halothane-negative (ie, not sensitive to halothane), but genetically susceptible, pigs gave in vitro responses that were similar to those of halothane-positive mh-susceptible pigs in that tetanic tension was depressed, tetanus relaxation was slowed, and small contractures were produced upon halothane exposure. Thus, the presence of a halothane-sensitive abnormality in the skeletal muscles, in and of itself, is not always sufficient for development of in vivo muscle rigidity during a brief halothane test. Furthermore, when the halothane testing of pigs is conducted by recommended techniques, false negatives still occur in a small percentage of the genetically mh-susceptible animals.
Effect of electroejactuation on progesterone and Cortisol excretion in bovine semen
Authors: Eiler Hugo , Armstrong-Backus Cindy S. , Smalling John D.
Published: February 2025

Artificial vagina (av) and electroejaculation (ee) are the 2 methods used to obtain semen from bulls. The purpose in the present study was to evaluate these 2 methods of collection when 2 markers, Cortisol and progesterone, were injected iv.

During period 1 (control measurement), semen was obtained by ee at 0, 20, 60, 120, and 180 minutes. In period 2, bulls were injected (3 days later) with a mixture of Cortisol (113 mg) and progesterone (100 mg), and then samples were obtained by ee. In period 3, Cortisol and progesterone were injected (3 weeks later), and samples were obtained by av.

Seminal plasma concentrations of Cortisol and progesterone were maximal at 20 minutes in ee and av collections. Seminal plasma concentrations of progesterone and Cortisol were roughly 50% less in ee than in av collection. However, the total excretion of progesterone and Cortisol per collection was similar in both techniques. Excretion of Cortisol was 14 to 33 times greater than that of progesterone.

It was concluded that concentrations of markers in the ee were significantly less than those in av collection. For this reason, total excretion and concentration of marker in semen should be accounted for when conducting excretion studies.