bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxicity of pyrrolizidine alkaloids from Riddell groundsel (Senecio riddellii) to cattle
Authors: Molyneux Russell J. , Johnson A. Earl , Olsen John D. , Baker Dale C.
Published: January 2024

The toxicity of Riddell groundsel (Senecio riddellii) gavaged to calves at a known lethal rate was compared with the toxicity of riddelliine and riddelliine N-oxide, the pyrrolizidine alkaloids isolated from the plant, which were fed by intraruminal infusion. Doses of the alkaloids were adjusted to the amount determined to be in the plant and fed individually and in combination. The relative toxicosis in the calves was measured by clinical signs, serum enzyme changes, survival time to morbidity, and histologic changes.

Calves fed Senecio riddellii by gavage for 20 consecutive days to provide 45 mg of total pyrrolizidine alkaloids/kg of body weight/d developed clinical signs and serum enzyme changes typical of seneciosis, with 100% morbidity. However, calves receiving riddelliine at 4.5 mg/kg/d for 20 days had neither serum enzyme changes nor clinical signs of pyrrolizidine alkaloidosis. Calves treated with riddelliine N-oxide (40.5 mg/kg/d), and with riddelliine (4.5 mg/kg/d) and riddelliine N-oxide (40.5 mg/kg/d) in combination, had 100% morbidity, although the latter group had fewer liver lesions.

These results establish that the N-oxide form of the alkaloid alone is capable of inducing typical Senecio toxicosis in cattle and that the free base level of the plant cannot be considered to be the sole factor in assessing the toxicity of S riddellii.
Effects of divergent selection for limb weakness on bone and muscle cross-sectional areas in Duroc swine
Authors: Draper D. D. , Rothschild M. F. , Christian L. L.
Published: January 2024

The relationship of muscle and bone structure to limb weakness was examined in 60 Duroc pigs from 3 lines divergently selected for thoracic limb weakness. The lines were designated high, control, or low, with the low line having inferior thoracic limb structure. At approximately 100 kg, 10 pigs of each line and gender were scored for thoracic limb structure and movement. Right and left thoracic limbs were collected at slaughter. A computerized morphometric image analysis system was used to determine cross-sectional areas of muscles, bones, and soft tissues at levels through the brachium, antebrachium, metacarpus, and digits. The statistical model that was used to analyze the data included the effects of line, sire, gender, and side (left vs right), with weight as a covariate.

Total bone area was similar for all 3 lines of pigs at all cross-sectional levels, but significant differences in muscle and other soft tissue areas were observed, including significantly greater extensor area for the antebrachium (P < 0.001) in low-line pigs than in control- and high-line pigs, smaller total area (P < 0.05) of the metacarpus in low-line pigs than in control and high-line pigs, and less total area of the medial digit (P < 0.01) in low-line pigs than in control- or high-line pigs. Total area of bone and soft tissue for each cross-sectional region was significantly greater (P < 0.05) in boars than in gilts. Side differences also were observed in total cross-sectional areas of bone and soft tissue of the antebrachium, metacarpus, and digits. Pigs selected for inferior thoracic limb structure had less total soft tissue cross-sectional areas in distal limb regions than did control- or high-line pigs. Limb weakness may be related to altered distribution of soft tissue supporting structures of the thoracic limb.

Limb weakness, characterized by lameness, is a common problem in most swine herds and causes an economic loss in the commercial and seed stock swine industries. In boars, culling losses range from 10 to 40%.1-4 The swine industry would benefit considerably if the causes of limb weakness could be determined.

Several factors may contribute to limb weakness, including microbial infections,5-8 nutritional imbalances or deficiencies, 2,7,9,10 skeletal lesions, 1,11,12 and trauma.13 A hereditary contribution to limb weakness also has been suggested. 2,14-16 Three lines of pigs that differed genetically in their expression of limb weakness were developed from a five-generation divergent selection experiment. 16 These 3 lines of pigs provided an unusual opportunity to examine the relationship between muscle and bone structure and limb weakness. The purpose of the study reported here was to determine whether there were differences in the areas of muscles, bones, and other tissues at cross-sectional levels through the brachium, antebrachium, metacarpus, and digits among the 3 lines of Duroc swine differing in degree of limb weakness.
Ability of a mutagenized virus variant to protect young lambs from Rift Valley fever
Authors: Hubbard Kathryn A. , Baskerville Arthur , Stephenson John R.
Published: January 2024

A live attenuated vaccine virus variant of Rift Valley fever (rvf) virus was developed by passaging a human isolate in tissue culture under the influence of the mutagen 5-fluorouracil. This virus variant (MV P12) has been assessed in this study as to its suitability as a vaccine, by testing its pathogenicity in young lambs and measuring its ability to induce a protective immune response.

Even high doses of the vaccine virus failed to induce any of the clinical or histopathologic changes associated with classical rvf virus infection. Although the vaccine induced mild pyrexia when given in high doses, viremia was not induced. Neutralizing antibody and a protective immune response was elicited with even low doses of vaccine virus.

These data, along with data of other workers on the lack of abortigenicity of this virus variant, indicate that the MV P12 variant of rvf virus is an excellent candidate for a safe and effective vaccine against rvf.
Evaluation of use of dimethyl sulfoxide for intra-articular lavage in clinically normal horses
Authors: Adair Henry S. , Goble Dallas O. , Vanhooser S. , Blackford J. T. , Rohrbach B. W.
Published: January 2024

The antebrachiocarpal and tarsocrural joints of 10 adult horses were randomly assigned to 1 of 4 groups. Groups were formulated and were treated as follows: group 1, control (arthrocentesis only); group 2, buffered lactated Ringer solution; group 3, 10% dimethyl sulfoxide (dmso; w/v) in lactated Ringer solution; and group 4, 30% dmso (w/v) in lactated Ringer solution. Joints were lavaged once with the respective solution. Prior to lavage and on days 1, 4, and 8 after lavage, all horses were evaluated for lameness and joint effusion; synovial fluid total and differential wbc counts, synovial fluid total protein concentration, and mucin clot quality were determined. Horses were euthanatized on day 8, and joints were evaluated grossly, histologically, and histochemically.

Significant difference was not observed in effect of lactated Ringer solution, 10% dmso, and 30% dmso on any measured variable. At 24 hours after treatment, significant (P < 0.05) difference in synovial fluid wbc numbers and total protein concentration was detected between control and treated joints. Eighty percent of lavaged joints had effusion 24 hours after treatment, compared with 30% of control joints.

Gross, histopathologic, or histochemical differences were not detected between treated and control joints. Results of the study indicate that buffered lactated Ringer, 10% dmso, and 30% dmso solutions induce similar inflammatory changes in articular structures and significantly greater inflammatory reaction than does arthrocentesis alone.
Mechanical and morphometric analysis of the third carpal bone of Thoroughbreds
Authors: Young David R. , Richardson Dean W. , Markel Mark D. , Nunamaker David M.
Published: January 2024

The third carpal bone (C3) was collected from both forelimbs of 27 Thoroughbreds. On the basis of age, training, and history, specimens were assigned to 1 of 5 groups: yearling, untrained horses (group 1, n = 4); 2- to 3-year-old, untrained horses (group 2, n = 7); trained 2-year-old horses (group 3, n = 6); trained 3-year-old horses (group 4, n = 6); and 3-year-old, trained horses with carpal pathologic features (group 5, n = 4). A transverse section of subchondral bone 5-mm thick was cut in a precise fashion 10 mm below the proximal articular surface of all specimens. After high-detail radiography was done, indentation testing was performed on the proximal surface of the section at points 5 mm apart. The stiffness of the subchondral cancellous bone was determined from the slope of the load vs displacement curve. Topographic plots of stiffness measurements were compared with radiographs of each specimen. Point determinations were averaged to derive measures for the radial and intermediate facets, and for regions 5, 10, 15, and 20 mm from the dorsal margin of C3. Area fraction (1-p; p = porosity) was measured for the radial and intermediate facets, using an automated image analysis system.

Significant (P < 0.05) increases in stiffness and area fraction were found in the C3 from trained horses (groups 3 to 5), compared with untrained horses (groups 1 to 2). Stiffness and area fraction of the radial facet of pathologic C3 were significantly higher than the same variables measured in C3 from any other group. A typical profile of regional subchondral stiffness was identified in C3 from normal horses, with maximal stiffness measured 10 mm from the dorsal articular margin. A different pattern was found in pathologic C3, with significantly greater stiffness 15 and 20 mm from the dorsal articular margin when compared with normal horses. A highly significant (P < 0.0001) direct linear correlation between stiffness and area fraction at the radial facet was found. Topographic and radiographic analysis demonstrated good correlation between stiffness and radiographic density of the bone sections. The observed patterns of normal and pathologic C3 were contrasted. In particular, a large gradient in subchondral stiffness was identified in pathologic C3 at the dorsomedial aspect of the bone.
Efficacy of nitroscanate against naturally acquired infection with Ancylostoma caninum, Dipylidium caninum, and Trichuris vulpis in dogs
Authors: Craig T. M. , Mercer S. H. , Wade C. G. , Lynn R. C.
Published: January 2024

Eighteen dogs with naturally acquired helminth infections were used to evaluate the efficacy of nitroscanate against Ancylostoma caninum, Dipylidium caninum, and Trichuris vulpis. Approximately 15 minutes before treatment, the dogs were given 100 to 200 g of canned dog food. Ten dogs were treated with nitroscanate (50 mg/kg of body weight, po), and 8 dogs were given placebo tablets po. The dogs were euthanatized and necropsied 10 days after treatment and helminths were recovered from the small intestine and cecum. On the basis of the number of worms recovered from treated dogs vs the number recovered from control dogs, we determined the efficacy of nitroscanate to be 99.6% against A caninum, 99.8% against D caninum, and 0% against T vulpis.
Steady-state response characteristics of a pulse oximeter on equine intestine
Authors: Schmotzer Wayne B. , Riebold Thomas W. , Rowe Kenneth E. , Scott Edward A.
Published: January 2024

The steady-state response characteristics of a pulse oximeter were evaluated on intestinal segments of seven clinically normal halothane-anesthetized horses. Arterial oxygen tension > 200 mm of Hg, end tidal carbon dioxide from 30 to 35 mm of Hg, and systemic mean arterial pressure > 70 mm of Hg were maintained throughout the recording periods. Values for percentage of pulse oximeter oxygen saturation, pulsatile blood flow, and percentage of signal strength were recorded from jejunum, ileum, cecum, left ventral colon, left dorsal colon, and descending colon. Probe placement on intestinal segments was recorded as over or not over visible subserosal or transmural vessels. There was no significant difference between median values on the basis of vessel codes for pulse oximeter oxygen saturations, pulsatile flow, and signal strength. Median values recorded for pulse oximeter oxygen saturation were 93% from jejunum and ileum and 95% from cecum, left ventral colon, left dorsal colon, and descending colon; median values for pulsatile flow were 576 from jejunum, 560 from ileum, 560 from cecum, 574 from left ventral colon, 578 from left dorsal colon, and 560 from descending colon; median values for signal strength were 50% from jejunum, 67.5% from ileum, 60% from cecum, 75% from left ventral colon, 50% from left dorsal colon, and 52.5% from descending colon. Median values obtained from each anatomic location were not significantly different for pulsatile flow or signal strength. Median pulse oximetry oxygen values recorded from jejunum and ileum were significantly lower than values obtained from other intestinal segments. When calculated arterial oxygen saturation was compared with oxygen saturation determined by the pulse oximeter, pulse oximeter oxygen saturation was consistently lower by 6.7% (jejunum and ileum) and 4.7% (cecum, left ventral colon, left dorsal colon, and descending colon). Equine and human absorption spectra were generated and compared for reduced hemoglobin and oxyhemoglobin at wavelengths of 600 nm (red) to 950 nm (infrared). Extinction coefficients calculated at wavelengths used by the pulse oximeter (660 nm and 940 nm) were nearly identical. The pulse oximeter is a self-calibrating instrument that displays oxygen saturation, heart rate, plethysmographic waveform, and signal strength indicator. Probe application was rapid and easy. Response time for the appear ance of a plethysmographic waveform ranged from 5 to 25 seconds.
Cardiovascular effects of halothane anesthesia after diazepam and ketamine administration in beavers (Castor canadensis) during spontaneous or controlled ventilation
Authors: Greene Stephen A. , Keegan Robert D. , Gallagher LeRoy V. , Alexander Jack E. , Harari J.
Published: January 2024

Fourteen adult beavers (Castor canadensis) weighing 16.5 ± 4.14 kg (mean ± sd) were anesthetized for surgical implantation of radio telemetry devices. Beavers were anesthetized with diazepam (0.1 mg/kg) and ketamine (25 mg/kg) administered im, which provided smooth anesthetic induction and facilitated tracheal intubation. Anesthesia was maintained with halothane in oxygen via a semiclosed circle anesthetic circuit. Values for heart rate, respiratory rate, esophageal temperature, direct arterial blood pressure, end-tidal halothane concentration, and end-tidal CO2 tension were recorded every 15 minutes during the surgical procedure. Arterial blood samples were collected every 30 minutes to determine pH, PaO2, and PaCO2. Values for plasma bicarbonate, total CO2, and base excess were calculated. Ventilation was spontaneous in 7 beavers and controlled to maintain normocapnia (PaCO2 approx 40 mm of Hg) in 7 others. Vaporizer settings were adjusted to maintain a light surgical plane of anesthesia. Throughout the surgical procedure, all beavers had mean arterial pressure < 60 mm of Hg and esophageal temperature < 35 C. Mean values for arterial pH, end-tidal CO2, PaO2, and PaCO2 were significantly (P < 0.05) different in spontaneously ventilating beavers, compared with those in which ventilation was controlled. Respiratory acidosis during halothane anesthesia was observed in spontaneously ventilating beavers, but not in beavers maintained with controlled ventilation. All beavers recovered unremarkably from anesthesia.
Isolation of a major form of pepsinogen from gastric mucosa of horses
Authors: Khittoo G. , Vermette L. , Nappert G. , Lariviere N.
Published: January 2024

In mammalian species studied previously, pepsinogen consisted of biochemically different groups of isozymogens. By use of gel filtration chromatography and electrophoresis, we isolated a predominant pepsinogen from the gastric mucosa of a horse. Peptide mapping with V8 protease revealed differences with its porcine homologue. However, porcine and equine pepsinogens, when activated to pepsin, had a similar pattern of activity when hemoglobin was used as substrate. Those results suggest that differences must exist in the primary structure of the pepsinogens of the 2 species.
Evaluation of flow cytometric counting procedure for canine reticulocytes by use of thiazole orange
Authors: Abbott David L. , McGrath John P.
Published: January 2024

An automated reticulocyte counting method that used a flow cytometer and the nucleic acid staining dye, thiazole orange, was developed. Anticoagulated (edta) blood specimens were suitable for flow cytometric reticulocyte counting when stored at 4 C for 96 hours after collection. Thiazole orange-stained samples were stable for 5.5 hours after staining when stored capped at 20 C and protected from light. Flow cytometric and manual microscopic reticulocyte counts were compared for counts in the 0.27 to 5.32% range (as determined by flow cytometry) and 0.10 to 4.90% range (as determined by 1 technician). Although the results of flow cytometric analysis generally correlated well (r = 0.821) with manual counts, there was poor correlation between the procedures for counts ≤ 2.0% (r ≤ 0.272). Linearity of flow cytometric counts over the range 0.27 to 14.46% was excellent (r = 0.999). Withinrun precision of flow cytometric counts (% coefficient of variation [cv] = 3 to 5) was superior to manual microscopic counts obtained by one technician (% cv = 19 to 23) and to manual microscopic counts, which were an average of counts done by 3 technicians (% cv = 8 to 18). Comparable flow cytometric counts were obtained by counting 50,000 or 100,000 blood cells in the flow cytometer.
Proteoglycan synthesis and content in articular cartilage and cartilage repair tissue in horses
Authors: Richardson Dean W. , Clark Charles C.
Published: January 2024

Hexosamine concentration, dna concentration, and [35S]sulfate incorporation for articular cartilage obtained from various sites in the metacarpophalangeal and carpal joints of horses were measured. The same measurements were made on the repair tissue filling full-thickness articular defects in the intermediate carpal bone and on cartilage surrounding partial-thickness defects 6 weeks after the defects were created arthroscopically.

Cellularity (measured as dna concentration), proteoglycan content (measured as hexosamine concentration), and proteoglycan synthesis (measured as [35S]sulfate incorporation) varied according to the site sampled. Cartilage from the transverse ridge of the head of the third metacarpal bone and the radial facet of the third carpal bone had the lowest hexosamine concentration, whereas rate of proteoglycan synthesis was lowest in cartilage from the transverse ridge of the head of the third metacarpal bone and the distal articular surface of the radial carpal bone.

Repair tissue filling a full-thickness cartilage defect at 6 weeks was highly cellular. It was low in proteoglycan content, but was actively synthesizing these macromolecules. In contrast, the cartilage surrounding a partial-thickness defect was unchanged 6 weeks after the original defect was made.
Concentrations of amino acids in the plasma of neonatal foals with septicemia
Authors: Zicker Steven C. , Spensley Michael S. , Rogers Quintan R. , Willits Neil H.
Published: January 2024

Concentrations of amino acids in the plasma of 13 neonatal foals with septicemia were compared with the concentrations of amino acids in the plasma of 13 age-matched neonatal foals without septicemia. Analysis of the results revealed significantly lower concentrations of arginine, citrulline, isoleucine, proline, threonine, and valine in the plasma of foals with septicemia. The ratio of the plasma concentrations of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine), was also significantly lower in the foals with septicemia. In addition, the concentrations of alanine, glycine, and phenylalanine were significantly higher in the plasma of foals with septicemia. Therefore, neonatal foals with septicemia had significant differences in the concentrations of several amino acids in their plasma, compared with concentrations from healthy foals. These differences were compatible with protein calorie inadequacy and may be related to an alteration in the intake, production, use, or clearance of amino acids from the plasma pool in sepsis.
Celiac trunk cannulation for obtaining abomasal lymph from cattle
Authors: Baker David G. , Gershwin Laurel J. , Snider Theron G.
Published: January 2024

Cannulation of the celiac trunk was surgically performed in 26 Holstein steers. The procedure was successful in 23 (88.5%) of the steers. Twenty-two of the steers were infected either naturally or experimentally with the abomasal nematode, Ostertagia ostertagi and/or other gastrointestinal parasites. The remaining 4 steers were not infected. Lymph obtained after surgery was used in various immunologic and biochemical assays. Daily lymph flow rate and total and differential wbc counts were determined after surgeiy in 4 of the infected and 3 of the noninfected steers. Steers were euthanatized for tissue specimen collection 7 days after surgery. At the time of euthanasia, lymph was still flowing from the cannula of 13 (56.5%) of the steers in which surgeiy was successful. This surgical procedure represents a valuable technique for studying at the local level, immunologic and physiologic responses of cattle to infection with O ostertagi.
Assessment of toxicosis induced by high-dose administration of milbemycin oxime in Collies
Authors: Tranquilli Wm. J. , Paul A. J. , Todd K. S.
Published: January 2024

Fifteen Collies, previously having mild reactions to ivermectin challenge (120 μg/kg of body weight; 20 times the recommended dosage level), were studied to evaluate the effects of milbemycin oxime administration at 5 and 10 mg/kg (10 and 20 times the manufacturer's recommended dosage). Five replicates, comprising 3 dogs each, were formed on the basis of body weight. Within replicates, each dog was randomly allocated to treatment with 5 or 10 mg of milbemycin/kg or served as a untreated control. Dogs were examined repeatedly for signs of toxicosis for 4 days after treatment and daily thereafter. Two of 5 dogs treated at 5 mg/kg (10 × ) developed signs of mild depression on the day of treatment, but were normal 24 hours after treatment. All 5 dogs treated at 10 mg/kg (20 × ) developed signs of mild depression and ataxia by 6 hours. Signs persisted for 24 hours in 3 dogs. Two of these dogs also had mydriasis, whereas 3 salivated excessively. All dogs recovered completely by day 2 after treatment. The results of this study demonstrated that Collies sensitive to the effects of 120 μg of ivermectin (20 × )/kg show similar sensitivity to the effects of milbemycin oxine administered at 10 mg/kg (20 x). We conclude that ivermectin and milbemycin commercial formulations have similar margins of safety and that milbemycin toxicosis appears to be dose-dependent in Collies with a demonstrated sensitivity to ivermectin.
Location of open reading frames coding for equine herpesvirus type-1 glycoproteins with homology to gE and gI of herpes simplex virus
Authors: Elton Debra M. , Bonass William A. , Killington Richard A. , Meredith David M. , Halliburton Ian W.
Published: January 2024

The dna fragments representing the entire short unique region and part of the repeat sequences of the equine herpesvirus type-1 genome were cloned into plasmid vectors. The approximate positions of the junctions between the short unique region and the inverted repeats were then located by restriction endonuclease mapping. Two open reading frames coding for potential glycoproteins have been identified within the short unique region, using dna sequence analysis. The predicted amino acid sequences of these open reading frames had extensive homology to the herpes simplex virus glycoproteins gE and gl and the related glycoproteins of pseudorabies virus and varicella-zoster virus.
Effect of diet on gentamicin-induced nephrotoxicosis in horses
Authors: Schumacher J. , Wilson R. C. , Spano J. S. , Hammond L. S. , McGuire J. , Duran S. H. , Kemppainen R. J. , Hughes F. E.
Published: January 2024

Gentamicin sulfate-induced nephrotoxicosis was compared in 2 groups of horses fed different rations. Four horses were fed only alfalfa hay, and 4 other horses were fed only whole oats. Seven days after initiation of the diet, all horses were given gentamicin iv (5 mg/kg of body weight) every 12 hours for 22 days. Urinary-y-glutamyltransferase to urinary creatinine (uggt:UCr) ratio was calculated daily, and serum concentration of gentamicin was measured at 1 and 12 hours after drug administration. Results indicated that horses fed oats had greater renal tubular damage than did horses fed alfalfa. Mean uggt:UCr for horses fed alfalfa was 47.1 ± 18.8 and was 100.0 ± 19.0 for horses fed oats (P = 0.007). The uggt:UCr in horses fed oats was > 100 for a total of 54 days; horses fed alfalfa had uggt:UCr > 100 for only 7 days. Two horses not given gentamicin were fed only oats and 2 were fed only alfalfa. These horses had mean uggt:UCr of 17.6 ± 2.2 and 30.5 ± 3.0, respectively. Mean peak and trough concentrations of gentamicin were statistically different for horses fed oats and those fed alfalfa (peak 23.16 ± 1.87 and 14.07 ± 1.79 μg/ml, respectively [P = 0.0001], and trough, 1.81 ± 0.69 and 0.71 ± 0.70 μg/ml, respectively [P = 0.0270]). Mean half-lives of gentamicin (estimated from peak and trough concentrations) for horses fed alfalfa (2.58 ± 0.26 hours) and horses fed oats (2.88 ± 0.27 hours) were not significantly different. Horses fed only oats had greater degree of gentamicininduced nephrotoxicosis than did those fed only alfalfa.
Tumor necrosis factor as a potential mediator of acute metabolic and hormonal responses to endotoxemia in calves
Authors: Kenison Dale C. , Elsasser Theodore H. , Fayer Ronald
Published: January 2024

The effects of coliform endotoxin (e) and recombinant bovine tumor necrosis factor α (tnf) were compared with respect to clinical signs of disease and changes in plasma metabolite and pituitary and pancreatic hormone concentrations in calves. In addition, changes in plasma tnf concentration during each challenge exposure were quantitated by use of radioimmunoassay. Healthy Holstein bull calves with mean body weight of 90 kg were each given, in order, on different days, saline solution (5.0 ml, iv, day 1, n = 4), e (type 055:B5, 1.0 μg/kg of body weight iv, day 2, n = 4) and tnf (5.0 μg/kg iv, day 9, n = 3). Jugular venous blood samples, rectal temperature reading, and pcv were obtained at hourly intervals before (2 hours) and after challenge exposure. The pcv increased (P < 0.05) after e and tnf administrations for the first 5 hours, then returned to normal in calves given E, but decreased and remained low in calves given tnf through 24 hours. Plasma triglyceride and nonesterified free fatty acids concentrations were increased through 10 hours (P < 0.05) after e administration, whereas triglyceride and nonesterified free fatty acids concentrations were not significantly affected by tnf administration. Increase in blood glucose concentration at 1 hour after administration of e and tnf was followed by prolonged hypoglycemia that lasted through 6 hours. Changes in plasma insulin concentration paralleled the observed changes in glucose concentration, initially increased at 2 hours after e and tnf (P < 0.05) administrations, but then tended to decrease below control values thereafter. Plasma growth hormone and luteinizing hormone concentrations decreased after e and tnf administrations to almost nondetectable values through 4 hours after dosing, returning to normal values by 8 hours. The data indicate similarities in physiologic response of calves to e and tnf and suggest a role for acute production of tnf as a mediator of e responses.
Erythrocyte cation content and sodium transport in Siberian Huskies
Authors: Wilson Owen , Dixon Earl
Published: January 2024

Adult mixed-breed dogs and Siberian Huskies were used to study erythrocyte cation and water contents, as well as sodium transport kinetics. Erythrocyte sodium, potassium, and water contents, as well as sodium efflux and influx kinetics, were measured. Lithium efflux studies were also performed, because previous studies reported involvement of this ion in sodium transport kinetics. Sodium, potassium, and water contents in erythrocytes from mixed-breed dogs were significantly (P < 0.05) different from those of Siberian Huskies when cells were washed in an isotonic sodium-free medium. Lithium efflux in hypertonic choline chloride was found to be significantly (P < 0.048) different in erythrocytes obtained from Siberian Huskies, compared with those from mixed-breed dogs. Additionally, sodium efflux in isotonic choline chloride was significantly (P < 0.01) lower in erythrocytes isolated from Siberian Huskies. Under these experimental conditions, sodium efflux was inhibited by 10 mM LiCl in erythrocytes of both groups. Amiloride (0.2 mM) was found to be a potent inhibitor of Na+ and Li+ efflux. These data indicate that Na+ metabolism may be altered in erythrocytes of Siberian Huskies, and may provide important insight into some of the erythrocyte transport abnormalities associated with specific human diseases in which erythrocyte cation content and sodium transport kinetics are altered.
Treatment of left laryngeal hemiplegia in Standardbreds, using a nerve muscle pedicle graft
Authors: Fulton I. C. , Derksen F. J. , Stick J. A. , Robinson N. E. , Walshaw R.
Published: January 2024

The efficacy of a nerve muscle pedicle (nmp) graft in restoring upper airway function was evaluated in exercising horses with induced left laryngeal hemiplegia. The nmp graft was created from the first cervical nerve and the omohyoideus muscle and transplanted into the left cricoarytenoideus dorsalis muscle. Seven adult Standardbreds were trained to exercise on a treadmill inclined at 6.38°. With the horses at rest and exercising at 4.2 and 7.0 m/s, the following variables were recorded: peak inspiratory and expiratory transupper airway pressures (defined as the pressure difference between a lateral tracheal catheter and a mask catheter), peak inspiratory and expiratory air flow, inspiratory and expiratory impedance, tidal volume, minute ventilation, heart rate, and respiratory frequency. Measurements were made before left recurrent laryngeal neurectomy (lrln), 28 days after lrln, and 12, 24, and 52 weeks after the nmp graft (n = 5) or sham operation (n = 2). Before lrln, exercise increased inspiratory and expiratory air flow and transupper airway pressure, whereas the impedance was unchanged. After lrln, transupper airway inspiratory pressure and impedance were significantly greater and inspiratory air flow was significantly less than baseline values at 7.0 m/s. The sham operation did not improve airway function. Twelve weeks after insertion of the nmp graft, inspiratory impedance and inspiratory air flow were significantly different (improved) from lrln values. Twenty-four weeks after insertion of the nmp graft, inspiratory impedance was not significantly different from lrln values. Fifty-two weeks after insertion of the nmp graft, inspiratory impedance was not significantly different from the baseline value and was significantly less than the value after lrln. We conclude that the nerve muscle pedicle graft can restore upper airway function within 52 weeks in horses with induced left laryngeal hemiplegia.
Effect of vaccination with the R mutant Escherichia coli (J5) antigen on morbidity and mortality of dairy calves
Authors: Daigneault J. , Thurmond M. , Anderson M. , Tyler J. , Picanso J. , Cullor J.
Published: January 2024

A prospective cohort study was undertaken to determine the efficacy of Escherichia coli 0111:B4 (J5) vaccination in dairy calves. Calves on 2 units were vaccinated when they were 2 to 3 days old and 2 weeks later with the J5 antigen or they were left unvaccinated, and were observed during the first 60 days of age for morbidity and mortality. Events recorded were death, the first case of illness, the first sign of a respiratory tract condition, the first sign of diarrhea, and the first treatment. The time to death or to a morbid event was examined as a function of vaccination status, using the Cox model of survival analysis, where serum IgG concentration at 2 to 3 days of age and gender of the calf were included to control confounding. Signs of morbidity in 517 calves were followed, 189 from unit 1 and 328 from unit 2. Vaccination was associated with a 2.15-fold reduction in risk of death on unit 2 (P = 0.042), but with a 2.43-fold increase in risk of death on unit 1 (P = 0.0035). The only association found between vaccination and morbidity was a 1.34-fold reduction in risk of respiratory tract signs for vaccinated calves on unit 2 (P = 0.055). Necropsy results and clinical investigations indicated that calves on unit 1 were poorly nourished and emaciated. Antibodies to J5 2 weeks after vaccination were significantly (P = 0.0002) lower in calves on unit 1 than in calves on unit 2. The findings offered a possible explanation for the adverse vaccination effect in calves on unit 1. Results suggested that vaccination with J5 antigen may be highly beneficial in preventing deaths of reasonably well-managed calves, but may be contraindicated in poorly managed calves.
Effects of mild cardiac hypertrophy, induced by volume overload in turkeys, on myocardial sarcoplasmic reticulum calcium-pump and calcium-channel activities and on the creatine kinase system
Authors: Shen Hua , Mirsalimi S. Mehdi , Weiler Janice E. , Julian Richard J. , O'Brien Peter James
Published: January 2024

Recent studies indicate that in animals with marked cardiac hypertrophy, there is depressed function of Ca2+ sequestration by myocardial sarcoplasmic reticulum (sr) because of down regulation of the Ca2+-ATPase gene. However, in several animal models we have observed enhancement of myocardial Ca2+ sequestration in response to chronic cardiac stimulation. We tested the hypothesis that in animals with mild cardiac hypertrophy, there is enhanced Ca2+-cycling activity by the sr Ca2+ pump and Ca2+-release channel. Because creatine kinase activity is consistently decreased in cardiomyopathy, we also determined whether enhanced Ca2+ cycling was accompanied by down regulation or inhibition of the creatine kinase system. Mild cardiac hypertrophy was induced by volume overload; 2% salt was added to the diet of 2-week-old turkey poults for 4 weeks.

Compared with age-matched controls, volume overload resulted in 14.3% increase in heart weight and 21.5% increase in heart-to-body weight ratios. The hypertrophied heart had approximately 20% increased activities of the sr Ca2+ pump and the sr Ca2+ channel. Net Ca2+ transport was increased by 16.5%. Compared with controls and in contrast to several other myocardial enzymes, creatine kinase activity was diminished in the hypertrophied hearts by 23% and creatine content was decreased by 8%. Differences between groups were not detected for lactate dehydrogenase, aspartate transaminase, and alanine transaminase.

We concluded that an early adaptation of the myocardium undergoing hypertrophy in compensatory response to functional overload is an enhancement of Ca2+ cycling activity by the Ca2+ pump and Ca2+ channel of the sr. In contrast to late-stage hypertrophy, there is no evidence for down regulation of the Ca2+-ATPase gene. However, creatine kinase activity and creatine content are diminished by mild cardiac hypertrophy.
Early clinical and morphologic alterations in the pathogenesis of furazolidone-induced toxicosis in ducklings
Authors: Webb Dale M. , Van Vleet John F.
Published: January 2024

Clinical and pathologic alterations during the development of furazolidone-induced toxicosis were investigated in a group of 35 newly hatched male Pekin ducklings fed a ration containing 700 mg of furazolidone/kg of feed for 27 days. A control group (n = 25) was fed the same ration without added furazolidone. Every 3 days, ducklings were weighed and palpated for ascites and 3 were chosen at random for euthanasia to determine the severity of lesions and to obtain hearts for gross measurements and ultrastructural study. Clinical alterations in treated ducklings consisted of decreased feed consumption with lower weight gain and nervous signs. Gross pathologic alterations included cardiomegaly with dilatation of all chambers and thinning of the myocardium, pericardial effusion, pulmonary edema and congestion, ascites, and testicular enlargement. Gross lesions were not observed before day 8. The earliest lesion (day 9) was cardiac chamber dilatation, with the left ventricle and left atrium most commonly and most severely dilated. Hearts from ducklings euthanatized on days 6, 12, 18, 24, and 27 were examined ultrastructurally. Myofibrillar lysis was first observed on day 12 in 1 duckling (of 3) and in at least 1 duckling from subsequent euthanasia periods. Myofibrillar lysis did not appear to be uniform among the cardiac chambers.
Association of environmental air contaminants with disease and productivity in swine
Authors: Donham Kelley J.
Published: January 2024

A cross-sectional epidemiologic study associating air quality with swine health was conducted on 28 swine farms in southern Sweden. Correlation of housing air environment to swine diseases and productivity (data collected over the preceding 12 months) were investigated.

The most prevalent swine health problems detected at slaughter were pneumonia and pleuritis. In farrowing and nursery operations, the most prevalent problem was neonatal pig mortality. Several air contaminants (dust, ammonia, carbon dioxide, and microbes) were found to be correlated with these swine health problems. Maximal safe concentrations of air contaminants were estimated on the basis of dose-response correlation to swine health or human health problems. Recommended maximal concentrations of contaminants were: dust, 2.4 mg/m3; ammonia, 7 ppm; endotoxin, 0.08 mg/m3; total microbes, 105 colony-forming units/m3; and carbon dioxide, 1,540 ppm.

The overall quality of the ventilation system was correlated with lower concentration of ammonia, carbon dioxide, microorganisms, and endotoxin, but not with dust concentrations.

High animal density was related to high ammonia and air microbe concentrations. Animal density measured as kilograms of swine per cubic meter (compared with kilograms of pig weight or swine per square meter) had the highest correlation to animal health and air contaminants.
Routes and prevalence of shedding of psittacine beak and feather disease virus
Authors: Ritchie Branson W. , Niagro Frank D. , Latimer Kenneth S. , Steffens W. L. , Pesti Denise , Ancona Joni , Lukert Phil D.
Published: January 2024

Psittacine beak and feather disease (pbfd) virus was recovered from the feces and crop washings from various species of psittacine birds diagnosed with pbfd. High concentrations of the virus also could be demonstrated in feather dust collection from a room where 22 birds with active cases of pbfd were being housed. The virions recovered from the feces, crop, and feather dust were confirmed to be pbfd virus by ultrastructural, physical, or antigenic characteristics. Virus recovered from the feather dust and feces hemagglutinated cockatoo erythrocytes. The specificity of the agglutination was confirmed by hemagglutination inhibition, using rabbit antibodies against pbfd virus. During the test period, 26% (8 of 31) of the birds screened were found to be excreting pbfd virus in their feces, and 21% (3 of 14) of crop washings were positive for pbfd virus. Some birds in the sample group had active cases of diarrhea, whereas others had normal-appearing feces. Diarrhea was found to be the only significant indicator of whether a bird was likely to be excreting virus from the digestive tract. These findings suggest that exposure of susceptible birds to pbfd virus may occur from contact with contaminated feather dust, feces, or crop secretions. Viral particles that were morphologically similar to parvovirus (20- to 24 nm-icosahedral nonenveloped virions) also were recovered from feces of some of the birds.
Characterization and classification of Actinobacillus (Haemophilus) pleuropneumoniae plasmids
Authors: Ishii Hiroshi , Hayashi Fujio , Iyobe Shizuko , Hashimoto Hajime
Published: January 2024

Actinobacillus (Haemophilus) pleuropneumoniae plasmids were characterized and classified. They were isolated from A pleuropneumoniae strains different in serotype, year isolated, or location from which isolated. Six of 8 plasmids encoded streptomycin (Sm) and sulfonamide (Su) resistance (SmSu). One of the other plasmids, pVM105, encoded ampicillin (Ap) resistance and another, pHM0, encoded no drug resistance. All SmSu plasmids were transferred to Escherichia coli strains by transformation. Among them, pABO and pMS260 were 8.1 kb and incompatible with each other; they were stable in E coli. The other SmSu plasmids, pHM1, pVM104, pVM106, and pKD25, were 4.3 kb and did not replicate stably in E coli. The former SmSu plasmids were mobilized in E coli strains by a plasmid RP4, which belonged to incompatibility (Inc) group P, but the latter plasmids were not. Further, each 8.1-kb SmSu plasmid and each 4.3-kb plasmid had the same respective restriction pattern. These results indicated that there were at least 2 types of SmSu plasmids in A pleuropneumoniae. The 2 types were classified in 2 groups: H1(pMS260 and pABO) and H2(pHM1, pVM104, pVM106, and pKD25). The H1 and H2 plasmids belonged to different Inc groups, and H2 plasmids belonged to a different Inc group from that of pHM0 and pVM105.
Replacement of chloride deficit by use of 1.8% NaCl to correct experimentally induced hypochloremic metabolic alkalosis in sheep
Authors: Fubini S. L. , Smith D. F. , Grohn Y. T. , Levine S. A. , Deuel D. M.
Published: January 2024

Five adult 40- to 50-kg female sheep were surgically fitted with a reentrant cannulae placed in the proximal part of the duodenum just distal to the pylorus. By diversion of abomasal outflow, this model has been shown to produce hypochloremic metabolic alkalosis accompanied by dehydration, hypokalemia, and hyponatremia. Each sheep was subjected to 3 separate, 12-hour iv treatment trials, in each case preceded by a control period of 48 hours, and a diversion period of 36 to 96 hours, during which a hypochloremic (Cl− ≤ 60 ± 2 mEq/L) metabolic alkalosis with hypokalemia and hyponatremia was produced.

Treatment 1, consisting of 6 L of isotonic Na gluconate, was designed to replace volume without replenishing the Cl− deficit. Although hydration improved, plasma Cl− decreased further, and the sheep became increasingly weak and depressed. Treatment 2, consisting of 2 L of 1.8% NaCl, was designed to replace the Cl− deficit without replacing total volume. Plasma Na+ and Cl− concentrations returned to normal during the 12 hours of treatment; acid-base balance and plasma K+ concentrations returned to normal within 36 hours of treatment. During treatment 3 (control, no treatment), measured metabolic values changed minimally. We concluded that the iv replacement of Cl− without K+ is effective in the correction of experimentally induced hypochloremic metabolic alkalosis in sheep.
Ultrasonographic examination of the right kidney in cows
Authors: Braun U.
Published: January 2024

To determine the position, dimensions, and structure of the right kidney in cattle by use of ultrasonography, the right kidney of 11 healthy Brown Swiss cows was examined 10 times within 2 weeks. A 3.5- and 5.0-MHz linear and convex transducer was placed on the right side of the cow in the lumbar region, in the paralumbar fossa, and in the last intercostal space. The echogenicity of various renal structures differed. The lobulation of the kidney in cattle could be visualized ultrasonographically; however, the cortex and medulla could not be differentiated. The distance between body surface and the right kidney was almost 3 times larger (5.3 ± 1.71 cm, mean ± sd) in the lumbar region than in the paralumbar fossa (1.8 ± 0.52 cm). The vertical diameter of the kidney was remarkably smaller (5.1 ± 0.47 cm) than the horizontal diameter (9.4 ± 0.98 cm). In 7 cows, the thickness of the renal cortex and medulla was between 1.9 and 2.1 cm. The medullary pyramids could be visualized when the transducer was placed in the paralumbar fossa. Fourteen of 19 variables measured had a coefficient of variation between 8 and 14%. It was concluded that the ultrasonographic values determined in this study can be used as references for the diagnosis of morphologic changes in the right kidney of domestic dairy cattle.
Comparison of high-performance liquid chromatography with a radiometric assay for determination of the effect of intra-articular administration of corticosteroid and saline solution on synovial fluid hyaluronate concentration in horses
Authors: Tulamo Riitta-Mari
Published: January 2024

Two recently developed direct methods, radioassay—125I-labeled hyaluronic acid binding protein (125I-habp)—and high-performance liquid chromatography (halc), were used to assess and compare the concentration of hyaluronate (ha) in synovial fluid of horses. Also determined were changes in the ha concentration in an experimental treatment model involving physiologic saline solution (pss)-irrigated or methylprednisolone acetate-injected tarsocrural joints of clinically normal horses. Serum ha concentration was determined simultaneously, using the 125I-habp assay.

Synovial fluid ha concentration values obtained by use of the hplc method were approximately double the values obtained by use of 125I-habp assay. Correlation (r = 0.819) between the 2 methods was highly significant (P < 0.001; linear regression analysis) for all samples studied and for various experimental subgroups. When pure ha standards were used, correlation between the 2 methods was close to 1 (r = 0.965; P < 0.001), with higher values obtained by use of the 125I-habp assay. It is suggested that the ha binding protein derived from endogenous cartilage proteoglycan interferes with the 125I-habp assay on synovial fluid, resulting in excessively low values, compared with those obtained using the hplc procedure.

Intra-articular injection of methylprednisolone acetate significantly (P < 0.01) increased synovial fluid ha concentration at 24 hours after injection. Increase was also detected after pss irrigation, but owing to wide intersubject variation, this increase was not significant. The hplc procedure, which provides simultaneous information about the concentration and degree of polymerization of ha, is recommended for the study of synovial fluid, whereas the 125I-habp assay is more suitable for serum ha analysis.
Comparison of antigens of Pasteurella haemolytica serotype 1 grown in vitro and in vivo
Authors: Confer Anthony W. , Durham Janet A. , Clarke Cyril R.
Published: January 2024

To determine whether antigenic differences exist in Pasteurella haemolytica serotype 1 grown in different culture conditions, the bacteria was grown on solid enriched medium, in broth culture, and in tissue chambers subcutaneously implanted in the flanks of calves. The organisms obtained by each culture method were comparable with respect to encapsulation and lipopolysaccharide content. In the bacteria grown in vivo, several unique high molecular-mass (> 150 kDa) protein antigens were found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein immunoblotting. Bacteria grown in vitro had higher concentrations of a 49- and a 26-kDa protein than the organisms grown in vivo. The concentration of several major proteins (30, 42, 55, 71, and 100 kDa) were similar among the organisms grown by the three cultural conditions. Although the high molecular-mass antigens were unique for the chamber-grown bacteria, they were recognized by serum from a calf that had been vaccinated with formalin-killed, solid medium-grown P haemolytica and were resistant to challenge exposure with the live organism. This recognition of antigens by serum from the P haemolytica-resistant calf that had been vaccinated with solid-medium-grown bacterium indicates that the high molecular-mass antigens from chamber-grown P haemolytica may be precursors of or share antigenic determinants with other P haemolytica proteins and may not be important for consideration in vaccine formulation.