bluuebunny/crossref_metadata_2025 huggingface dataset:
Susceptibility of Chinese Meishan and European Large White pigs to enterotoxigenic Escherichia coli strains bearing colonization factor K88, 987P, K99, or F41
Authors: Duchet-Suchaux Marion F. , Bertin Anne M. , Menanteau Pierrette S.
Published: January 2024

Conventionally raised Chinese Meishan and European Large White pigs were intragastrically challenge exposed with 2.1 × 1010 enterotoxigenic Esherichia coli strains bearing colonization factor K88, 987P, F41, or F41 plus K99. In response to challenge exposure with the K88-positive (K88+ ) organisms, 96% of Large White pigs died within 48 hours, whereas none of the Meishan pigs died. Both breeds of pigs had similar susceptibility to strains bearing 987P or F41. Lastly, Meishan pigs were found to be more susceptible than Large White pigs to a strain expressing K99 and F41. In pigs with diarrhea, challenge-exposure strains intensively colonized the jejunum (108 to 1010 bacteria/g of tissue) and, to less extent, the duodenum (except K88+ strain, which comprised 108/g). In most cases, jejunal concentrations of the challenge-exposure strains were substantially lower in pigs that did not have diarrhea. Half the resistant Meishan pigs eliminated the K88+ strain from the intestines. Colostral antibody titer that agglutinated challenge-exposure strains did not differ between Meishan and Large White gilts. Results indicate that resistance of pigs to the K88+ strain did not extend to enterotoxigenic strains bearing other well-known factors. They indicate, in addition, that genetic resistance to K88+ strains described in pigs in Europe may exist in pigs in China.
Efficacy of ivermectin administered via sustained-release bolus against gastrointestinal nematodes in cattle
Authors: Zimmerman Gary L. , Mulrooney Donna M. , Wallace Dennis H.
Published: January 2024

Twelve calves (mean weight, 175.5 kg) were used to confirm efficacy of ivermectin delivered from a prototype sustained-release bolus against naturally acquired gastrointestinal nematodes including early fourth-stage (inhibited) larvae of Ostertagia ostertagi. The calves were allocated by restricted randomization on weight to 1 of 2 groups: controls, to which a placebo bolus was given orally, and treated calves, to which a sustained-release bolus designed to deliver 8 mg of ivermectin/day at a steady rate was given orally. After treatment, the 2 groups were housed in separate pens with concrete flooring. Twenty-eight days after treatment, all calves were euthanatized and necropsied. The ivermectin-treated calves had no larval or adult Ostertagia spp and significantly (P < 0.01) fewer adult Trichostrongylus axei and adult Cooperia (C oncophora, C punctata and C surnabada) than control calves. Efficacy of ivermectin was > 99% for Cooperia spp, and 100% for other parasites. Drug-related adverse reactions were not observed.
Hypertonic saline/dextran resuscitation of dogs with experimentally induced gastric dilatation-volvulus shock
Authors: Allen David A. , Schertel Eric R. , Muir William W. , Valentine A. K.
Published: January 2024

We investigated small-volume (5 ml/kg) 7% NaCl in 6% dextran 70 (HS/D70) as an alternative to large-volume (60 ml/kg) 0.9% NaCl for treatment of experimentally induced canine gastric dilatation-volvulus (gdv) shock. The stomach was surgically displaced and then distended with an intragastric balloon in 11 dogs anesthetized with pentobarbital. All dogs were subjected to gdv for 180 minutes before partial decompression and resuscitation. Hemodynamic values, blood gas values, and plasma volume were measured during control, shock, and resuscitation periods. Resuscitation started with 1 group (n = 6) receiving 5 ml of HS/D70/kg, iv, over 5 minutes, and the other group (n = 5) receiving 60 ml of 0.9% NaCl/kg, iv, over 60 minutes. Both groups received a surgical maintenance dosage (20 ml/kg/h) of 0.9% NaCl after initial resuscitation. Resuscitative effects of small-volume HS/D70 were similar to large-volume 0.9% NaCl during the first hour of treatment; however, cardiac output was significantly higher in the HS/D70 group for the last 2 hours of resuscitation. Changes in heart rate, left ventricular pressure change, and systemic vascular resistance appeared to be responsible for improved perfusion. Mixed venous oxygen partial pressure data supported improved perfusion in the HS/D70 group. Packed cell volume remained higher in the HS/D70 group, indicating less hemodilution and improved oxygen delivery. Resuscitation of this gdv-induced shock model was better sustained with small-volume HS/D70, compared with conventional large-volume 0.9% NaCl.
Serodiagnosis of bovine paratuberculosis by use of a dot enzyme-linked immunosorbent assay
Authors: Woodruff T. S. , Shulaw W. P. , Bech-Nielsen S. , Hoffsis G. F. , Spangler E. , Heider L. E.
Published: January 2024

A dot elisa was developed for detection of antibodies to Mycobacterium paratuberculosis. The assay was evaluated by testing sera from cattle that were determined, by bacteriologic culturing of feces, to be infected with M paratuberculosis and were suspected of having clinical disease. Further evaluation involved testing sera from cattle in which M paratuberculosis had not been isolated from feces on several attempts. Results of the dot elisa were positive for sera from 86 of 101 infected cattle, and results were negative for sera from 64 of 64 noninfected cattle. Results of conventional elisa and agar gel immunodiffusion (agid) tests were positive for 79 of 99 and for 51 of 101 infected cattle, respectively.

The dot elisa also was evaluated by comparing results of testing 708 sera with results of bacteriologic culturing of matched fecal samples from 262 cattle in 3 central Ohio dairy herds known to include cattle infected with M paratuberculosis. Results of the dot elisa were positive for 25 of 39 sera from cattle with positive results on culturing of concurrently obtained fecal specimens. The dot elisa results were negative for 661 of 669 sera from cattle with negative results to culturing of concurrently obtained fecal specimens. The 39 sera from cattle with positive results on bacteriologie culturing of matched fecal specimens had positive results for elisa and the agid test 25 and 14 times, respectively. The 669 sera from cattle with concurrently negative results on bacteriologie culturing of feces had negative results to elisa and the agid test 559 and 668 times, respectively.
Evaluation of an indirect enzyme-linked immunosorbent assay for screening antibody against aflatoxins
Authors: Holladay S. D. , Brownie C. F. , Corbett W. T. , Talley D. D.
Published: January 2024

Enzyme-linked immunosorbent assay screening of antibody produced against aflatoxin was accomplished by a new and simple procedure. To demonstrate the new indirect elisa technique used, antibody against aflatoxin M1 was produced in female BALB/CJ mice by immunization with an aflatoxin M1-bovine serum albumin conjugate. Instead of coating test-plate wells with purified antibody (direct elisa) or synthesizing a second protein-aflatoxin conjugate (aflatoxin M1-poly-l-lysine) to coat test-plate wells, wells were coated with the readily available aflatoxin M1-bovine serum albumin and aflatoxin B1-bovine serum albumin. This method, applicable for any aflatoxin conjugated by the common cyclopentano-carboxymethoxyl-oxime technique, eliminates the more time-consuming and technically difficult portions of earlier direct and indirect elisa. The new technique can be valuable in continued efforts toward development of new and improved immunoassays against aflatoxin metabolites.
Use of a computerized system for evaluation of equine spermatozoal motility
Authors: Varner Dickson D. , Vaughan Scott D. , Johnson Larry
Published: January 2024

Three ejaculates from each of 3 stallions were used to evaluate a computerized system (Hamilton-Thorn motility analyzer; htma) for measuring equine spermatozoal motility. Variance components (ejaculate-within-stallion, chamber-within-ejaculate, and microscopic field-within-chamber) were determined for each stallion after diluting ejaculates to 25 × 106 spermatozoa/ml with a skim milk-glucose seminal extender. The htma was compared with frame-by-frame playback videomicrography (video) for determining: percentage of spermatozoal motility and spermatozoal number in microscopic fields; curvilinear velocity and straight-line velocity of individual spermatozoa for 5 track types; and repeatability of those velocity measurements. The effect of spermatozoal number per microscopic field on incidence of intersecting spermatozoa and the outcome of intersecting spermatozoa also were evaluated. Greatest variability in motility measures was generally attributed to the microscopic field-within-chamber component. The htma was highly correlated with video for estimation of spermatozoal numbers per microscopic field (r = 0.99; P < 0.001) and motility (r = 0.97; P < 0.001); however over the entire range of spermatozoal numbers, the htma yielded higher spermatozoal numbers per microscopic field (P < 0.05) and higher motility (P < 0.05) than did video. The htma- and video-derived measurements of curvilinear and straight-line velocities were highly correlated for all spermatozoal track types, but both measures were higher (P < 0.05) by use of the htma than by use of video for most track types. For 3 of 5 track types, measurements of curvilinear and straight-line velocities were less variable (P < 0.05), using the htma, rather than video. Using the htma, the number of intersecting spermatozoa was highly correlated with spermatozoal numbers per microscopic field (r = 0.97; P < 0.001). The percentage of erroneous track interpretations involving intersecting spermatozoa was high (85.3 ± 2.7%). The htma was a reliable system for determining percentage of spermatozoal motility and velocity measures in video recordings of equine semen diluted to spermatozoal concentration of 25 × 106/ml prior to evaluation.
Effects of heparin treatment on colonic torsion-associated hemodynamic and plasma eicosanoid changes in anesthetized ponies
Authors: Provost P. J. , Stick J. A. , Patterson J. S. , Hauptman J. G. , Robinson N. E. , Roth R.
Published: January 2024

Large colon torsion frequently is a fatal condition in horses. The purpose of the study reported here was to determine systemic arterial pressure, plasma eicosanoid concentrations, colonic blood flow, vascular resistance, tissue pH, and morphologic features associated with large colon torsion and detorsion, and to evaluate the effects of sodium heparin (80 IU/kg of body weight, iv) treatment on these values. Values were determined in 20 anesthetized ponies that were randomly assigned into 4 equal groups: control; control/heparin; torsion; torsion/heparin. Torsions were created by a 720° rotation of the cecum and colon around their long axes at the sternal and diaphragmatic flexures. After 1 hour of torsion, the torsion was corrected and the colon was allowed to reperfuse for 1 hour. Heparin was administered 30 minutes into the experiment. Parametric data were analyzed (P ≤ 0.05), using split-plot analysis of variance, with differences between means evaluated with a modified Bonferroni t test; histopathologic data were analyzed (P ≤ 0.05) with a Kruskal-Wallis one-way analysis of variance by ranks. Heparin prevented colonic detorsion-induced hypotension and increases in vascular resistance and thromboxane concentration, and it significantly increased colonic blood flow for 40 minutes during reperfusion. Heparin did not alter prostacyclin concentration or the histologic appearance of the large colon.
Radioimmunoassay of parathyroid hormone in cats
Authors: Flanders James A. , Reimers Thomas J.
Published: January 2024

A radioimmunoassay for measurement of midmolecule parathyroid hormone (pth) concentration in serum from dogs was validated for use on serum from cats. The assay detected an increase in serum concentration of pth after iv infusion of Na2 edta in healthy cats. Infusion of calcium chloride caused a decrease in measured pth. Accuracy of the assay was demonstrated by quantitative recovery of a feline parathyroid gland extract added to pooled feline sera. Mean interassay and intra-assay coefficients of variation were 0.13 and 0.07, respectively. Sensitivity of the assay was 0.1 ng of pth/ml. The median pth concentration measured in 40 adult cats was 3.5 ng/ml, with a range of 1.16 to 11.0 ng/ml.
Antagonism of ketamine-xylazine anesthesia in rats by administration of yohimbine, tolazoline, or 4-aminopyridine
Authors: Komulainen Anna , Olson Merle E.
Published: January 2024

Antagonism of ketamine-xylazine (85 mg of ketamine/ kg of body weight and 15 mg of xylazine/kg, im) anesthesia in rats by yohimbine (yoh; 1, 5, 10, and 20 mg/kg, ip), tolazoline (tol; 10, 20, or 50 mg/kg, ip), 4-aminopyridine (4-AP; 1 or 5 mg/kg, ip), or a combination of yohimbine and 4-aminopyridine (yoh:4-AP, 1 mg/kg: 1 mg/kg or 5 mg/kg: 1 mg/kg, ip) was studied. All dosages of yoh, tol, 4-AP, and yoh:4-AP reduced the time to appearance of corneal and pedal reflexes. Only tol was effective in reducing time to appearance of the crawl reflex and recovery time. Yohimbine, 4-AP, yoh:4-AP, and tol were effective in reversing respiratory depression caused by ketamine-xylazine anesthesia, but anesthetic-induced hypothermia was not antagonized. When given to nonanesthetized rats, the antagonists had little influence on respiratory rate, but all antagonists caused significant (P < 0.05) reduction in core body temperature for at least 90 minutes. When yoh was used as an anesthetic antagonist at dosage of 20 mg/kg, 20% mortality was observed and was attributable to acute respiratory arrest. The use of 4-AP and yoh:4-AP at the dosages studied induced moderate to severe muscular tremors. In conclusion, tol at dosage of 20 mg/kg given ip, appears to be an appropriate antagonist for ketamine-xylazine anesthesia in rats.
Cardiovascular effects of xylazine and detomidine in horses
Authors: Wagner Ann E. , Muir William W. , Hinchcliff Kenneth W.
Published: January 2024

The cardiovascular effects of xylazine and detomidine in horses were studied. Six horses were given each of the following 5 treatments, at 1-week intervals: xylazine, 1.1 mg/kg, iv; xylazine, 2.2 mg/kg, im; detomidine, 0.01 mg/ kg, iv; detomidine, 0.02 mg/kg, iv; and detomidine, 0,04 mg/kg, im. All treatments resulted in significantly decreased heart rate, increased incidence of atrioventricular block, and decreased cardiac output and cardiac index; cardiac output and cardiac index were lowest following iv administration of 0.02 mg of detomidine/kg. Mean arterial pressure was significantly reduced for various periods with all treatments; however, iv administration of 0.02 nig of detomidine/kg caused hypertension initially. Systemic vascular resistance was increased by all treatments. Indices of ventricular contractility and relaxation, + dP/dt and − dP/dt, were significantly depressed by all treatments. Significant changes were not detected in stroke volume or ejection fraction. The pcv was significantly reduced by all treatments. Respiratoiy rate was significantly decreased with all treatments, but arterial carbon dioxide tension did not change. Arterial oxygen tension was significantly decreased briefly with the 3 iv treatments only.
Plasma free cortisol concentrations in dogs with hyperadrenocorticism
Authors: Kemppainen R. J. , Peterson M. E. , Sartin J. L.
Published: January 2024

Unbound or free cortisol constitutes a small fraction of total plasma cortisol, but is believed to represent the biologically active portion of this circulating glucocorticoid. We tested the hypothesis that the percentage free cortisol was altered in plasma from dogs with hyperadrenocorticism, which could account for a greater target tissue response to this circulating hormone. The percentage free cortisol in plasma samples from human beings, healthy dogs, and dogs with hyperadrenocorticism was estimated, using centrifugal ultrafiltration-dialysis. Total cortisol concentrations were determined by use of radioimmunoassay. Total cortisol concentrations appeared greater in plasma from human beings than in plasma from either group of dogs. However, the percentage free cortisol was lower in plasma from human beings, resulting in a calculated concentration of free cortisol that was quite similar between plasma from human beings and healthy dogs. Total plasma cortisol concentrations were greater (P < 0.01) in samples from dogs with hyperadrenocorticism (190 ±113 nmol/L; mean ± SD) than in healthy dogs (102 ± 85 nmol/L), but the percentage free cortisol was not different between these 2 groups (dogs with hyperadrenocorticism, 16 ± 9%; healthy dogs, 13 ± 6%). However, plasma free cortisol concentrations (product of total and the percentage of free cortisol) were greater (P < 0.01) in samples from dogs with hyperadrenocorticism (36 ± 41 nmol/L) than in those from healthy dogs (16 ± 9 nmol/ L). Significant (P < 0.001) positive linear relationships were found between total cortisol concentrations and percentage free cortisol in plasma samples from healthy dogs and dogs with hyperadrenocorticism. Furthermore, the slope of these lines was not different between the 2 groups, providing no evidence for alterations in cortisol binding associated with hyperadrenocorticism. The higher total cortisol concentrations in dogs affected with this disease do, however, result in greater concentrations of free cortisol in circulation, contributing to the development of clinical signs observed in this disease.
Acute hemolytic anemia after oral administration of L-tryptophan in ponies
Authors: Paradis Mary Rose , Breeze R. G. , Bayly W. M. , Counts D. F. , Laegreid W. W.
Published: January 2024

The hematologic and pathologic effects of orally administered l-tryptophan and indoleactic acid and of l-tryptophan administered iv were studied in ponies. Sixteen adult Shetland ponies were allotted into 4 experimental groups. Group 1 consisted of 5 ponies (1-5) given 0.6 g of tryptophan/kg of body weight in a water slurry via stomach tube. Group 2 included 4 ponies (6-9) given 0.35 g of tryptophan/kg orally. Group-3 ponies (10—13) were given 0.35 g of indoleacetic acid/kg orally. Group 4 consisted of 3 ponies (14—16) given a single 4-hour iv infusion of 0.1 g of tryptophan/kg.

Restlessness, increased respiratory rate, hemolysis, and hemoglobinuria were detected in 4 of the 5 group-1 pomes. Only pony 7 in group 2 developed hemolysis, hemoglobinuria, and a significant increase in respiratory rate. Renal pathologic lesions, consistent with hemoglobinuric nephrosis, were seen in ponies 2, 4, 5, and 7. Bronchiolar degeneration was evident in 4 of 9 ponies given tryptophan orally. The importance of these respiratory lesions was unknown. Clinical or pathologic abnormalities were not noticed in the ponies of groups 3 and 4.

Mean plasma tryptophan values increased significantly in groups 1 and 2 at 6 hours after dosing. A second peak of tryptophan was detected in both groups at 12 hours. Values returned to predose values by 48 hours. Plasma indole and 3-methylindole concentrations were detectable in only 2 ponies (4 and 7). In vitro incubations of cecal fluid from ponies 6, 8, and 9 yielded a percentage conversion of tryptophan to indole of 16.75%, 5.84%, and 7.96%, respectively. 3-Methylindole was not produced. These results suggested that indole was the major metabolite of orally administered tryptophan in these ponies.
Use of embryonating eggs for isolation of Campylobacter species from intestines of swine with proliferative enteritis
Authors: Ward Gilbert E. , Harp Karin J. , Jones Gary F.
Published: January 2024

Intestinal tissues from swine affected with proliferative enteritis were ground, filtered through a 0.65-μm pore membrane filter, diluted, and injected into 7-day-old embryonated hens’ eggs via the yolk sac. At 2, 4, and 7 days later, yolk sac swab specimens taken from live embryos were cultured for Campylobacter species. Campylobacter hyointestinalis was recovered from eggs injected with tissues of swine with acute hemorrhagic proliferative enteritis at dilutions up to 10−4. Campylobacter mucosalis was recovered from eggs injected with tissues of swine with chronic proliferative enteritis at dilutions up to 10−6. Campylobacter coli was recovered from several specimens without lesions of proliferative enteritis and also from some specimens with lesions of proliferative enteritis. Two previously undescribed hemolytic Campylobacter species designed as hemolytic number 1 and hemolytic number 2 were recovered from normal and experimentally inoculated swine tissues. Few contaminating organisms grow in eggs and these were usually recovered at dilutions of 10−2 or less. Recovery of Campylobacter species by use of these techniques was seldom successful in tissues stored at −70 C for more than 6 months.
Phagocytosis and erythrocyte antibody-rosette formation by three populations of mononuclear phagocytes obtained from dogs treated with glucocorticoids
Authors: DeBowes Linda J. , Anderson Neil V.
Published: January 2024

The effect of systemic administration of glucocorticoids was evaluated on 3 populations of macrophages obtained from healthy dogs. Phagocytic and Fc-receptor activities were determined for mononuclear phagocytes from blood and pulmonary and peritoneal lavage fluids. Samples were collected from 12 dogs before treatment and again on the same dogs after glucocorticoid administration. Thirty or more days were allowed between treatment periods.

Twelve hours after combined prednisolone sodium succinate and dexamethasone sodium phosphate administration, the percentage of phagocytosing cells decreased for blood monocytes and increased for pulmonary macrophages. The percentage of pulmonary macrophages positive for erythrocyte antibody-rosette formation (Fcreceptor activity) increased. After 7 days of oral administration of prednisone, the percentage of phagocytosing peritoneal macrophages increased, whereas the percentage of blood monocytes with Fc-receptor activity increased.

Results indicate that significant (P < 0.05) changes in macrophage function occur after systemic administration of the glucocorticoid doses used in this study. Also, the effect of systemic administration of glucocorticoids on mononuclear phagocytes varies, depending on the specific cell location.
Evaluation of the oral vitamin E absorption test in horses
Authors: Craig A. M. , Blythe L. L. , Rowe K. E. , Lassen E. D. , Walker L. L.
Published: January 2024

An oral vitamin E absorption test used in human beings was modified for use in horses. The most appropriate techniques with which to measure gastrointestinal tract absorption of vitamin E (α-tocopherol) in horses were developed. Vitamin E was administered orally, and serum values of α-tocopherol were measured by use of high-performance liquid chromatography at 0, 3, 6, 9, 12, and 24 hours after vitamin E administration. Variables included comparison of 2 dosages (45 and 90 IU/kg of body weight), routes of administration, and absorption dynamics of 3 preparations of dl-α-tocopherol. Absorption of the 2 doses of dl-α-tocopherol acetate indicated a dose response; the area under the curve at 24 hours (AUC24) was 4.3 μg-h/ ml for the 45-IU/kg dose and 32.2 μg-h/ml (P < 0.01) for the 90-IU/kg dose. Maximal absorption was apparent when vitamin E was naturally consumed in grain, compared with administration of identical preparations by stomach tube or paste. In the same horses, dl-α-tocopherol and dl-α-tocopherol acetate plus polyethylene glycol had statistically similar absorption curves and both had significantly greater AUC24, compared with dl-α-tocopherol acetate; values for the 3 compounds were 23.6, 25.8, and 12.6 μg-h/ml, respectively. The AUC24 varied between individual horses, but time of peak value was consistently observed between 6 and 9 hours.

On the basis of the data from this study, the recommended technique for performing the oral vitamin E absorption test in horses would be administration of 90 IU of the free form of dl-α-tocopherol/kg, mixed in 1 L of grain to horses from which food has been withheld for 12 hours, followed by allowing the horses ad libitum access to hay immediately after administration of the vitamin E. Three baseline serum α-tocopherol values should be obtained within 24 hours prior to the test, with the last sample being obtained just prior to administration of the test dose of vitamin E. Heparinized plasma also may be used for this testing procedure. α-Tocopherol concentration should be measured at 3, 6, 9, 12, and 24 hours after vitamin E administration.
Effects of intra-articular administration of dimethylsulfoxide on chemically induced synovitis in immature horses
Authors: Welch R. D. , Watkins J. P. , DeBowes R. M. , Leipold H. W.
Published: January 2024

The effects of intra-articular administration of dimethylsulfoxide (dmso) on chemically induced synovitis in the middle carpal joint of 6 weanling horses were evaluated. Following aseptic collection of synovial fluid, the middle carpal joint of each forelimb was injected with 50 mg of Namonoiodoacetate to induce synovitis. Eight days after injection, synovial fluid was obtained and the right middle carpal joints were injected with 2 ml of 40% dmso in lactated Ringer solution. The corresponding joints of the left limb (control) were injected with 2 ml of lactated Ringer solution. Sampling and treatments were repeated on postinjection days 11 and 14, for a total of 3 treatments. Horses were visually evaluated daily for lameness and joint effusion. Synovial fluid was evaluated for color and clarity, differential and total WBC count, total protein content, and hyaluronic acid concentration. The Kaegi gait analysis system provided an objective assessment of lameness prior to inducing synovitis, again on day 7, and on day 17. At necropsy (day 17), synovial fluid, synovial membrane, and articular cartilage specimens were collected.

Joint effusion was evident 12 hours after injection of Namonoiodoacetate in all joints. Mild lameness was evident at 24 hours; however, the lameness resolved by 72 hours. Objective assessment of lameness did not reveal significant differences between treatment or control limbs. Hyaluronic acid concentrations increased significantly (P = 0.023) above baseline values in most joints over the study period. Synovial fluid wbc counts increased significantly (P = 0.002) following Na-monoiodoacetate injection and remained significantly (P = 0.002) above baseline values throughout the study. There was a significantly greater decrease (P = 0.04) in total wbc counts between the pretreatment and final sampling period in the dmso-treated joints, compared with the controls. Histologic evaluation of synovial membrane samples revealed a significantly less inflammatory response in 4 of 6 dmso-treated joints, compared with that in the controls. Histochemical staining of articular cartilage did not reveal any observable difference between treated or control specimens.
Clinical, clinicopathologic, and parasitologic observations of trypanosomiasis in dogs infected with North American Trypanosoma cruzi isolates
Authors: Barr Stephen C. , Gossett Kent A. , Klei Thomas R.
Published: January 2024

Nineteen purebred Beagles of various ages (4, 5, 13, and 47 weeks) were inoculated with North American Trypanosoma cruzi isolates obtained from an opossum (Tc-O), an armadillo (Tc-A), or a dog (Tc-D). Dogs were grouped on the basis of clinical outcome of infection. During the acute stage of disease, dogs of group 1 (n = 7 inoculated with Tc-O or Tc-A) died or were euthanatized because of the severity of disease. Dogs of group 2 (n = 5 inoculated with Tc-O or Tc-A) developed acute disease, but survived to develop chronic disease. Dogs of group 3 (n = 7 Tc-Dinoculated dogs) developed neither acute nor chronic disease. Dogs of group 4 (n = 4—2 dogs 13 weeks old and 2 dogs 47 weeks old) served as noninoculated controls.

Clinical signs associated with severe acute myocarditis developed in dogs of groups 1 and 2 between postinoculation day (pid) 15 and 28. Generalized lymphadenopathy and lymphocytosis were observed in all dogs of groups 1, 2, and 3 between pid 14 and 17. Serum alanine transaminase and aspartate transaminase activities and urea nitrogen concentration were high, and glucose concentration was low prior to death of dogs in group 1. Serum activities of isoenzymes of creatine kinase were significantly (P < 0.05) high in only 1 dog (group 1), whereas serum lactate dehydrogenase isoenzyme activities were not significantly high in any dog. Parasitemia was detected by examination of thick blood smears as early as pid 3, peaked by pid 17 in most dogs, and was not detected by pid 33 in dogs of groups 1 and 2. Parasitemia was documented by blood culture results in dogs of groups 2 and 3 at various times throughout the study. Dogs infected at an older age generally had lesser degree of parasitemia and higher survival rate than did dogs infected at a younger age.

Dogs of group 2 did not manifest clinical signs of disease for 27 to 120 days prior to onset of chronic disease. Ventricular-based arrhythmias and exercise intolerance developed in all dogs of group 2 at various times by pid 120. Two dogs developed signs of biventricular heart failure.
Effects of conditioning and maximal incremental exercise on oxygen consumption in sheep
Authors: Mundie Thomas G. , Januszkiewicz Adolph J. , Rayburn Daniel B. , Martin Dale G. , Ripple Gary R.
Published: January 2024

To assess the suitability of sheep for exercise studies, the effect of incremental exercise and conditioning on oxygen consumption (Vo2) was studied. Six sheep were adapted to a treadmill and subsequently trained 8 weeks. The sheep were then studied, in random order, using 3 incremental exercise protocols (ex-1, ex-2, and ex-3). The protocols were chosen to approximate high (ex-1), moderate (ex-2), and low (ex-3) intensity exercise by varying treadmill speed and incline. The sheep were then conditioned for an additional 12 weeks and retested on the ex- 2 protocol. During exercise, Vo2, gas exchange ratio (R), and rectal temperatures (Tb) were recorded. All 3 protocols resulted in significant increases in Vo2, R, and Tb (P < 0.05). Maximum Vo2 for ex-1, 49.9 ± 5.0 ml/min/kg of body weight, was significantly greater than maximum Vo2 for ex-2 and ex-3, 37.8 ± 6.5 and 42.3 ± 6.0 ml/min/kg, respectively (P < 0.05), whereas maximum R and maximum Tb were similar. After the additional 12-week conditioning, time on the treadmill increased 40% from 9.58 ± 0.87 to 13.4 ± 0.44 minutes, and maximum V02 increased 27% to 48.1 ± 9.1 ml/min/kg. These data indicated that maximum Vo2 varied with intensity of the exercise, 12 weeks of maximal exercise conditioning was sufficient to produce a measurable training effect (ie, increase endurance and maximum oxygen consumption) and sheep are suitable for maximal exercise studies where Vo2 measurements are desired.
Enzyme-linked immunosorbent assay for the detection of Salmonella enteritidis infection in chickens
Authors: Kim C. J. , Nagaraja K. V. , Pomeroy B. S.
Published: January 2024

An elisa was developed and tested for its ability to detect antibodies against Salmonella enteritidis in chickens. Various features of the elisa were evaluated and optimized. The outer membrane protein antigens selected by use of the protein immunoblotting method made the assay specific and sensitive. The assay was evaluated in chickens experimentally infected with S enteritidis. Blood samples collected at weekly intervals after experimental infection with S enteritidis were analyzed by elisa. Results of the elisa were compared with those of conventional serum plate and microagglutination tests. The elisa was more sensitive and specific in the detection of S enteritidis infection than the other 2 conventional tests.
Evaluation of carbohydrate malassimilation and intestinal transit time in cats by measurement of breath hydrogen excretion
Authors: Muir P. , Papassouliotis K. , Gruffydd-Jones T. J. , Cripps P. J. , Harbour D. A.
Published: January 2024

Techniques for the measurement of breath hydrogen excretion have been evaluated in dogs and the breath hydrogen test has been shown to be useful for clinical diagnosis and as a research tool. A simple method was developed for collection of expired air and measurement of breath hydrogen concentrations in cats, which enabled demonstration of carbohydrate malassimilation. Breath hydrogen concentrations were measured in healthy cats after food was withheld and after xylose and lactulose administration. Breath samples were collected by use of an open flow system with the cat confined in an acrylic plastic chamber. Breath hydrogen excretion did not exceed 0.53 ml of hydrogen/h in cats not fed. Breath hydrogen concentrations after the ingestion of xylose, a pentose sugar given orally at 0.75 g/kg of body weight, were not significantly higher from those of cats not fed. After ingestion of 3.35 g of lactulose, a nonabsorbable disaccharide, breath hydrogen excretion increased and breath hydrogen concentrations were significantly higher by 45 minutes (P < 0.05) and 60 minutes (P < 0.01) from breath hydrogen concentrations measured in cats not fed and after xylose administration. Administration of lactulose at an increased dosage resulted in further significant (P < 0.01) increases in breath hydrogen excretion. In this study, mouth-to-cecum transit times were variable. A mean ± sem- mouth-to-cecum transit time of 86 ± 6 minutes was calculated from measurement of breath hydrogen excretion after oral administration of 3.35 g of lactulose.

Measurements of breath hydrogen concentrations after breath collection by open-flow and closed-flow sampling systems were highly correlated and both variables followed log-normal distributions. The dilution of expired air by the open flow sampling system was not excessive and the results of this correlation study suggested that differences in the assimilation of xylose in healthy cats and dogs may well exist.
Effects of xylazine butorphanol on cecal arterial blood flow, cecal mechanical activity, and systemic hemodynamics in horses
Authors: Rutkowski Judith A. , Eades Susan C. , Moore James N.
Published: January 2024

A chronic model with an ultrasonic transit time blood flow probe and strain gauge force transducers implanted on the cecum was used to evaluate cecal mechanical activity and cecal arterial blood flow in 4 conscious adult horses. Intravenous administration of xylazine (1.1 mg/kg of body weight) significantly decreased heart rate and cardiac output, but significantly increased diastolic pulmonary arterial pressure, mean pulmonary arterial pressure, carotid arterial pressure, and central venous pressure. Lateral cecal arterial blood flow after xylazine administration was decreased substantially more than was cardiac output, suggesting that xylazine caused constriction of the cecal vasculature. This effect of xylazine may have resulted from either a direct effect of xylazine on the cecal vasculature or from reflex vasoconstriction attributable to reduced cardiac output. Intravenous administration of butorphanol tartrate (0.1 mg/kg) did not significantly alter the hemodynamic responses to xylazine. Cecal mechanical activity, as measured by the motility index, was decreased for 120 minutes after administration of xylazine and for 150 minutes after administration of xylazine/butorphanol.
Serologic enzyme-linked immunosorbent assay responses of calves vaccinated with a killed Mycobacterium paratuberculosis vaccine
Authors: Spangler E. , Heider Lawrence E. , Beck-Nielsen Steen , Dorn C. Richard
Published: January 2024

The purpose of this study was to document the effect of calfhood vaccination for Mycobacterium paratuberculosis on a serologic elisa. Fifteen calves vaccinated with a killed paratuherculosis vaccine and 5 unvaccinated control calves were tested from the first through the fifteenth month of life. Age of vaccination ranged from 5 to 40 days. Blood samples were collected prior to vaccination and periodically thereafter. Serum antibody was analyzed by use of the elisa. All calves were elisa-negative prior to vaccination. Thirteen of 15 vaccinated calves became elisapositive between 2 and 6 months after vaccination. The unvaccinated cohort remained elisa-negative. Widespread use of vaccine may interfere with diagnosis of paratuberculosis and with control programs that are based 0n serologic tests that measure humoral antibody.
Use of corticosterone and ampicillin for treatment of Streptococcus faecalis infection in chickens
Authors: Gross W. B.
Published: January 2024

Chickens were selectively bred for either high-antibody (ha) or low-antibody (la) response to sheep erythrocytes. From 6 to 31 days after Streptococcus faecalis challenge exposure, la-line chickens maintained a greater percentage of the prechallenge-exposure body weight and had lower heterophil-to-lymphocyte ratio than did ha-line chickens. The optimal dose of corticosterone (30 mg/kg of feed) was effective in maintaining postchallenge-exposure body weight greater than that of controls. Ampicillin (20 mg/d) alone was ineffective in almost all experiments. Treatment with 30 mg of corticosterone/kg of feed plus ampicillin resulted in increased body weight response to S faecalis infection when treatment was initiated 1 day before or 2 days after challenge exposure. Treatment with corticosterone was more effective in ha- than in la-line chickens. Treatment before challenge exposure was more effective than treatment 2 days after challenge exposure.
Effects of amnion and live yeast cell derivative on second-intention healing in horses
Authors: Bigbie R. B. , Schumacher J. , Swaim S. F. , Purohit R. C. , Wright J. C.
Published: January 2024

Equine amnion and live yeast cell derivative were evaluated as a biological dressing and as a topical wound medicament respectively, in the treatment of granulating wounds of the distal portion of the limbs of horses. Wounds measuring 2.5 × 2.5 cm were created on the dorsomedial aspect of the metacarpal and metatarsal region of all 4 limbs of 9 horses. Each wound was assigned randomly to 1 of 3 treatment groups: group C, treated with a nonadherent bandage as a control; group A, treated with amnion beneath a nonadherent bandage; and group L, treated with live yeast cell derivative beneath a nonadherent bandage. Rates of contraction and epithelialization were not significantly different among groups. Percentage of epithelialization for group A was significantly greater throughout the study than for the other groups. Number of days to complete healing was significantly less in group A and significantly greater in group L than in group C. Incidence and severity of exuberant granulation tissue were significantly less in group A than in the other 2 groups. Group L had more frequent and severe cases of exuberant granulation tissue than the other 2 groups.
Comparison of flunixin meglumine and flurbiprofen for control of ocular irritative response in dogs
Authors: Millichamp Nicholas J. , Dziezyc Joan
Published: January 2024

Dogs were treated with the cyclo-oxygenase inhibitors flunixin meglumine iv or flurbiprofen topically. Acute inflammation was induced in the eyes by disruption of the anterior lens capsule, using a neodymium:yttrium aluminum garnet laser. Pupil diameter and intraocular pressure were measured before and after inducing ocular inflammation. Both drugs maintained mydriasis and increased intraocular pressure in the inflamed eyes, compared with untreated controls.
Multiplanar quantitative computed tomography for bone mineral analysis in dogs
Authors: Markel Mark D. , Morin Richard L. , Wikenheiser Mark A. , Robb Richard A. , Chao Edmund Y. S.
Published: January 2024

The purpose of this study was to determine the precision and accuracy of quantitative computed tomography bone mineral analysis in dogs in coronally reconstructed images. Nonhomogeneous tissues, such as bones with fractures or deformities, may be better analyzed if multiplanar reconstruction of the transaxial data could be performed without degradation of information. Our analysis demonstrated that coronal reconstruction of quantitative-computed tomography data was precise (1.2 to 4.7%) and accurate (1.3 to 7.5%) in vitro. The technique displays high-quality images, which can be analyzed at any location within the volume scanned. Quantitative computed tomography of canine osteotomy healing in vivo accurately determined bone mineral density of selected regions of interest. Bone mineral density correlated highly with calcium content of the tissue (R2 = 0.76, P < 0.0001).
Functional deficiency of polymorphonuclear leukocytes in simian acquired immunodeficiency syndrome
Authors: Cheung Anthony T. W. , Gardner Murray B.
Published: January 2024

The functional characteristics of polymorphonuclear leukocytes (pmn), considered to be the first line of host defense against infections, from rhesus macaques confirmed to have simian retrovirus (srv)-induced simian acquired immunodeficiency syndrome (saids), were evaluated. The pmn from srv antibody-positive macaques without clinical signs were chemotactically responsive. Their phagocytic and killing capabilities were normal, and their cell membranes were highly deformable. However, pmn from srv antibody-positive macaques and with persistent lymphadenopathy, as well as having at least 3 of the 11 common clinical signs of saids, were chemotactically nonresponsive. Their phagocytic and killing capabilities were compromised, and their cell membranes were rigid and nondeformable. In general, pmn from macaques with clinically confirmed saids were functionally deficient. The results are similar to those obtained in other retroviral infections and can be clinically significant, because the host defense deficiency may be responsible for the recurrent and opportunistic infections in saids.
Evaluation of urine and serum metabolites in Miniature Schnauzers with calcium oxalate urolithiasis
Authors: Lulich Jody P. , Osborne Carl A. , Nagode Larry A. , Polzin David J. , Parke Mary Lou
Published: January 2024

To evaluate underlying causes of calcium oxalate urolithiasis, 24-hour excretion of urine metabolites was measured in 6 Miniature Schnauzers that formed calcium oxalate (CaOx) uroliths during periods when they were fed a standard diet and during periods when food was withheld. Serum concentrations of parathyroid hormone and 1,25-dihydroxyvitamin D also were evaluated. Serum calcium concentrations were normal in all 6 affected Miniature Schnauzers; however, during diet consumption, mean 24-hour urinary excretion of calcium was significantly (P = 0.025) higher than calcium excretion when food was withheld. In 1 dog, urinary calcium excretion was lower during the period of food consumption, compared with the period when food was withheld. Compared with clinically normal Beagles, Miniature Schnauzers that formed CaOx uroliths excreted significantly greater quantities of calcium when food was consumed (P = 0.0004) and when food was withheld (P = 0.001).

Miniature Schnauzers that formed CaOx uroliths excreted significantly less oxalate than clinically normal Beagles during fed (P = 0.028) and nonfed (P = 0.004) conditions. Affected Miniature Schnauzers also excreted abnormally high quantities of uric acid. Excretion of citrate was not different between Miniature Schnauzers with CaOx urolithiasis and clinically normal Beagles.

In 5 of 6 Miniature Schnauzers with CaOx urolithiasis, concentrations of serum parathyroid hormone were similar to values from age- and gender-matched Miniature Schnauzers without uroliths. The concentration of serum parathyroid hormone in 1 dog was > 4 times the mean concentration of clinically normal Miniature Schnauzers. Mean serum concentrations of 1,25-dihydroxyvitamin D in Miniature Schnauzers with calcium oxalate urolithiasis were similar to concentrations of clinically normal Miniature Schnauzers.
Pharmacokinetics of rifampin in adult sheep
Authors: Jernigan Antoinette D. , St. Jean Guy D. , Rings D. Michael , Sams Richard A.
Published: January 2024

Pharmacokinetics and bioavailability of rifampin in adult sheep were investigated by use of high-performance liquid chromatography for determination of serum concentrations. Eight adult ewes were given rifampin po at the rate of 50 mg of rifampin/kg of body weight. Three weeks after the first experiment, the sheep were given rifampin po and iv at the rate of 20 mg/kg in a cross-over design, with 1 week between treatments. Serum obtained over a 36-hour period was analyzed for rifampin and a potential metabolite, 25-desacetyl-rifampin, using reverse-phase chromatography with uv detection at 254 nm. Data were analyzed by compartmental and noncompartmental models. Analysis by the noncompartmental model of rifampin serum concentrations after iv administration yielded a mean ± sd total body clearance of 1.16 ± 0.21 ml/min/kg, apparent volume of distribution at steady state of 0.45 ± 0.06 L/kg, and terminal elimination rate constant of 0.15 ± 0.04 hour−1. The harmonic mean of the elimination half-life was 4.56 hours. Because of incomplete and continuing absorption, bioavailability was extremely variable after oral administration. Desacetylrifampin was not detected. On the basis of pharmacokinetic values, serum concentrations measured in this study, and published minimal inhibitory concentrations, the dosage of 20 mg of rifampin/kg, po, every 24 hours should provide adequate serum concentrations for treatment of rifampin-susceptible bacterial infections in sheep.
Preclinical evaluation of l-asparaginase and methotrexate administered at intermediate doses in dogs
Authors: Bortnowski Hattie B. , Rosenthal Robert C.
Published: January 2024

The role of l-asparaginase (l-asp) in limiting signs of methotrexate (mtx) toxicosis was studied. Eight dogs were randomly allotted to 2 groups of 4 dogs. All dogs were given 400 iu of l-asp/kg of body weight im, on day 1. On day 10, group-1 dogs were given 3 mg of mtx/kg, iv, and group-2 dogs were given 6 mg of mtx/kg, iv. All dogs were given 400 iu of l-asp/kg, im, 24 hours later (on day 11). One group-2 dog was euthanatized on day 16 because of severe gastrointestinal signs that were unresponsive to treatment. A second dose of mtx, identical to that given on day 10, was given on day 20 to each surviving dog, followed by l-asp on day 21. On day 67, the 7 surviving dogs were given 3 mg of mtx/kg, iv. Adverse reactions observed were vomiting, diarrhea, and weight loss. Gastrointestinal side effects of mtx were not attenuated with l-asp and would be a serious limitation to use of mtx administered at an intermediate dose in the treatment of lymphoma in dogs.
Effect of vaccination with a monovalent Leptospira interrogans serovar hardjo type hardjo-bovis vaccine on type hardjo-bovis infection of cattle
Authors: Bolin Carole A. , Cassells James A. , Zuerner Richard L. , Trueba Gabriel
Published: January 2024

Effectiveness of 2 concentrations of a monovalent vaccine containing Leptospira interrogans serovar hardjo type hardjo-bovis was evaluated for protection of heifers from infection with type hardjo-bovis. Nine heifers were given 2 doses of low-dose vaccine (8.32 × 108 cells/dose); 9 heifers were given 2 doses of high-dose vaccine (8.32 × 109 cells/dose); and 1 steer and 1 heifer were maintained as nonvaccinated controls. Groups of vaccinated cattle were challenge-exposed with serovar hardjo type hardjo-bovis at 7 (n = 6), 11 (n = 6), or 15 (n = 6) weeks after completion of vaccination. All cattle were challenge-exposed by conjunctival instillation of 1 × 105 hardjo-bovis cells on 3 consecutive days. Both control and all vaccinated cattle became infected and shed serovar hardjo type hardjo-bovis in their urine. Leptospires were detected in 15 of 16 (94%) urine samples from control cattle and in 124 of 143 (87%) samples from vaccinated cattle. Leptospires were detected in kidneys of 17 of 18 vaccinated cattle and 2 of 2 control cattle and in the uterus or oviducts of 13 of 18 vaccinates and the 1 control heifer.