bluuebunny/crossref_metadata_2025 huggingface dataset:
High-frequency jet ventilation during pneumothorax in dogs
Authors: Bjorling Dale E. , Whitfield Jeff B.
Published: February 2025

Pneumothorax (45 ml of N/kg of body weight insufflated into the pleural space) in anesthetized dogs ventilated with air caused a significant (P < 0.05) increase in pleural pressure, central venous pressure, capillary wedge pressure, and venous admixture. Cardiac index (ci) and arterial O2 tensions were decreased. Ventilation with 100% O2 increased arterial O2 tensions, but did not affect calculated intrapulmonary shunting of blood or ci. Application of 10 cm of H2O-positive end-expiratory pressure in the presence of pneumothorax during positive-pressure ventilation and high-frequency jet ventilation reduced intrapulmonary shunting of blood, which remained higher than control values, and caused a further decrease in ci. Cardiopulmonary function during pneumothorax in anesthetized dogs was more profoundly affected by the application of positive end-expiratory pressure than by the form of mechanical ventilation.
Pathophysiology of small testes in beef bulls: Relationship between scrotal circumference, histopathologic features of testes and epididymides, seminal characteristics, and endocrine profiles
Authors: Veeramachaneni D. N. Rao , Ott R. S. , Heath E. H. , McEntee K. , Bolt D. J. , Hixon J. E.
Published: February 2025

Tissue sections from testes and epididymides obtained from 17 young beef bulls with scrotal circumference (sc) between 27 and 40.5 cm were studied to determine whether small testes were a manifestation of lesions or a result of less, but otherwise normal, seminiferous epithelium. The sc correlated negatively with the estimates of germinal epithelial loss and positively with seminiferous epithelial area. Four bulls with sc < 30 cm had severe lesions in their testes. Hypoplastic tubules were characterized by Sertoli's cells only with no evidence of germinal cells. Loss of germinal cells, leaving vacuolated epithelium and atrophy, were observed in degenerated tubules. Hyperplasia of Leydig's cells was observed in the vicinity of Sertoli's cell-only tubules, resulting either from degeneration or hypoplasia, and atrophy of Leydig's cells was associated with tubules devoid of Sertoli's cells. These findings indicated that Sertoli's cells may produce a factor(s) required for maintenance and regulation of Leydig's cell function. Epididymal epithelium, especially in the head, had regressed in bulls with hypoplastic and degenerative changes in their testes. Decreased sperm concentration and motility and an increased frequency of morphologic defects were observed in the 4 bulls with testicular lesions and regressed epididymal epithelium. Blood plasma profiles of cortisol, follicle-stimulating hormone, luteinizing hormone, and testosterone were determined in the 4 bulls with sc < 30 cm and 10 of the 13 bulls with sc > 30 cm. There were no statistically significant (P > 0.1) differences in the responses to exogenous gonadotropin-releasing hormone or base-line patterns of blood plasma follicle-stimulating hormone and luteinizing hormone between the 2 groups. However, in the bulls with sc < 30 cm, the mean concentration of testosterone was lower, whether spontaneous (P < 0.05) or exogenous gonadotropin-releasing hormone induced (P < 0.1). The fact that these bulls were not deficient in gonadotropins indicated that Leydig's cell function was impaired by local factors, either the factors that caused the tubular damage or those consequent to the tubular damage.
Endocrinologic, hematologic, and heart rate changes in swimming horses
Authors: Garcia M. C. , Beech Jill
Published: February 2025

Two identical experiments, using Standardbred and Thoroughbred horses (experiment A, n = 31; experiment B, n = 17) on a swimming regimen, were performed 1 week apart to evaluate short-term heart rate, hematologic, and endocrinologic changes. Horses were placed in 4 categories based on duration of swimming (1 to 5, > 5 to 10, > 10 to 15, and > 15 minutes). Heart rate, pcv, and plasma concentrations of total protein, cortisol triiodothyronine, thyroxine, insulin, and glucose of each horse were evaluated before, immediately after, and 1 hour after swimming. For experiment A, there was a main effect of time of sampling on pcv, total protein, triiodothyronine, thyroxine, and insulin. There was a main effect of duration of swimming on insulin concentration and an interaction of duration of swimming and time of blood collection on heart rate and cortisol concentration. For experiment B, there was a main effect of time of blood collection on all the variables except glucose.
Flow cytofluorometric characterization of bovine blood and milk leukocytes
Authors: Hageltorn M. , Saad M. Alaa
Published: February 2025

Flow cytometry and sorting proved to be a rapid method that facilitated the identification of different leukocyte populations in bovine blood and milk. After briefly incubating whole blood and milk samples in a hypotonic phosphate buffer, containing supravital acridine orange, 5 classes of leukocytes were found in the blood (lymphocytes, neutrophils, eosinophils, basophils, and monocytes) and 4 in the milk (lymphocytes, neutrophils, monocytes, and macrophages) by flow cytometry. Cells were morphologically identified by fluorescent microscopy after flow cytometric sorting and by light microscopy after Papanicolaous staining. Udder parenchymal and ductal tissue cells (secretory and epithelial cells) were not found in the milk samples evaluated. Large differences in the total and differential cell counts were found in the different milk secretions.
Effects of aflatoxin on the growth performance and immune responses of weanling swine
Authors: Panangala V. S. , Giambrone J. J. , Diener U. L. , Davis N. D. , Hoerr F. J. , Mitra A. , Schultz R. D. , Wilt G. R.
Published: February 2025

Aflatoxin (af)-contaminated ground com was mixed with a commercial swine ration to yield 2 concentrations (500 mg of afb1/kg of feed [A] and 300 mg of afb1/kg [B]) and was fed to 2 groups of pigs. Groups A and B were fed the af-containing ration, whereas control group C was fed the same commercial ration mixed with ground corn devoid of af. A comparative analysis of the average weight gain per pig in each of the treatment groups, compared with that in the control group, indicated a significantly (P < 0.01) greater weight gain in the control group. The average feed conversion rate was also significantly (P < 0.01) lower in group A pigs, compared with that in the control group. The humoral immune response to Erysipelothrix rhusiopathiae, measured by enzyme-linked immunosorbent assay, did not reveal a significant difference among groups; there were no consistent differences observed in the proliferative responses of lymphocytes to mitogens. In contrast, a significant (P < 0.05) reduction in complement titers was observed, whereas an increase in serum immunoglobulin G and M values occurred in the af-treated group A, compared with that in group C. Gross enlargement of the liver, substantiated by histologic evidence of toxic damage to the hepatic parenchyma, revealed that af at concentrations of 500 mg/kg of feed was toxigenic and produced an adverse effect on the growth rate, feed efficiency, and general well-being of young pigs.
Delta-aminolevulinic acid dehydratase (EC4.3.1.24) activity in erythrocytes from cattle administered low concentrations of lead acetate
Authors: Bratton Gerald R. , Childress Marilyn , Zmudzki Jan , Womac Carolyn , Rowe Loyd D. , Tiffany-Castiglioni Evelyn
Published: February 2025

Four different age groups of cattle, which had never been exposed to Pb, were used to determine normal age-related values for erythrocyte δ-aminolevulinic acid dehydratase (alad) activity. Acute or chronic Pb intoxication was experimentally induced in young calves, and their alad values were compared with the normal values. Results indicated that alad of normal bovine erythrocytes increased 2- to 3-fold from 1 week to 9 weeks of age and then slowly returned to the initial (1 week old) value by 9 months of age. Erythrocyte alad from cattle ≥ 9 months old was uniform. Because of the age-related changes in normal alad of cattle < 9 months old, the age of an animal should be carefully established and age-matched controls evaluated simultaneously when alad is used to assess calves suspected of having Pb poisoning. A significant negative correlation was found between blood Pb concentration and alad during the first 24 hours after the initial administration of Pb, indicating a high sensitivity of erythrocyte alad to Pb. However, when blood Pb concentrations reached 50 μg/dl, alad did not change further. Because single ingestions of Pb can raise blood Pb concentrations > 50 μg/dl, alad appears to have little value in differentiating acute from chronic Pb intoxication.

Within 7 days after Pb administration ceased, alad did not increase significantly, even when calves were given calcium ethylenediaminetetraacetic acid (CaNa2EDTA); however, blood Pb concentration decreased by 50%. The rapid change in blood Pb concentration gave a false indication of a positive treatment effect when no real effect was detected by alad. These findings indicated that alad may be more useful than blood Pb concentration for estimating the effectiveness of chelation treatment for Pb intoxication because the animal would have to be almost completely deleaded before alad values return to normal. The method of storing blood samples was critical to the accuracy of determining alad. Rapid freezing in liquid nitrogen for up to 10 days, refrigeration for up to 6 days, storage in wet ice for 3 days, or storage at room temperature (22 C) for 3 days adequately preserved alad, whereas freezing in a home freezer for 3 days resulted in a 50% loss of alad.
Histochemical changes in skeletal muscles of four male horses with neuromuscular disease
Authors: Andrews F. M. , Spurgeon T. L. , Reed S. M.
Published: February 2025

Skeletal muscle biopsy specimens were taken from 4 male horses with neuromuscular disease such as myotonia congenita, chronic myositis, exertional rhabdomyolysis, and shivers. Histologic and histochemical techniques were used to evaluate skeletal muscle morphologic features and fiber-type population, size, and area, as well as muscle enzyme activities (acid phosphatase, alkaline phosphatase, and esterase). A histochemical and histologic profile were described for each muscle biopsy specimen.
Induction of mycoplasmosis in goat kids by oral inoculation with Mycoplasma mycoides subspecies mycoides
Authors: DaMassa A. J. , Brooks D. L. , Holmberg C. A.
Published: February 2025

A one-time, orally administered dose of ≥ 1 × 106 colony-forming units of Mycoplasma mycoides subspecies mycoides was sufficient to induce clinical mycoplasmosis (n = 37) terminating in fatal mycoplasmemia in 73% (37 of 51) of the clinically affected kids. The pathogen was isolated from the blood samples as early as 24 hours after oral inoculation; hot, swollen joints frequently were evident by 4 or 5 days after exposure. Pyrexia (to 42.3 C) was detected in about 95% (35 of 37) clinically affected kids, although about 5% (2 of 35) died peracutely without fever or other premonitory signs. At necropsy, the cardinal lesions were a fibrinopurulent polyarthritis and red, patchy to diffuse areas of consolidation in 1 or more lung lobes. At death, usually within 4 to 16 days after oral inoculation, the concentration of M mycoides subspecies mycoides in the blood was 1 × 106 to 1 × 107 colony-forming units/ml.

Histologically, the kids had diffuse fluid leakage into pulmonary alveoli and to a lesser extent into small vessels of various other organs. Fibrinocellular thrombi of terminal occurrence were occasionally present in various organs. The meningeal, pleural, and peritoneal surfaces had vascular leakage and a minimal perivascular accumulation of leukocytes.

The disease was contagious. Of 14 noninoculated control kids in close confinement with affected kids, 8 (57%) developed mycoplasmosis in 7 to 15 days and died of mycoplasmemia. The remaining 5 noninoculated kids remained healthy, as did noninoculated kids that were kept isolated from affected kids.
Antagonism of xylazine-induced depression of shuttle-avoidance responses in dogs by administration of 4-aminopyridine, doxapram, or yohimbine
Authors: Schaffer David D. , Hsu Walter H. , Hopper David L.
Published: February 2025

The effectiveness of 4-aminopyridine, doxapram, or yohimbine as antagonists against xylazine-induced cns depression in dogs was evaluated and compared, using the 2-way shuttle-avoidance paradigm. All drugs were given iv to 5 male dogs trained to avoid mild shock by jumping over a hurdle within 10 s after initiation of an audible tone. At dosages of 1 and 2 mg/kg of body weight, xylazine abolished or significantly decreased the mean number of avoidance responses and significantly increased the mean latency of avoidance responses.

The analeptic 4-aminopyridine (0.5 mg/kg) did not significantly antagonize xylazine in all dogs. One dog convulsed both times it was given xylazine followed by 4-aminopyridine, but did not convulse when given either drug alone.

Doxapram (5.5 mg/kg), a short-acting analeptic and respiratory stimulant, was only partially effective in antagonizing xylazine, and its antagonistic actions were brief.

Yohimbine (0.1 mg/kg), an α2-adrenoreceptor-blocking agent, was superior to 4-aminopyridine and doxapram in its ability to antagonize xylazine-induced cns depression. Yohimbine consistently increased the mean number of avoidance responses to the maximum of 8 and consistently decreased the mean latency of avoidance responses to control values in dogs given 1 or 2 mg of xylazine/kg. In dogs given 2 mg of xylazine/kg, yohimbine was significantly more effective than 4-aminopyridine or doxapram in its ability to increase the mean number of avoidance responses and decrease the mean latency of avoidance responses.

Results of the present study indicated that yohimbine was superior to 4-aminopyridine and doxapram in sustaining the reversal of xylazine-induced suppression of avoidance responses in dogs and that xylazine’s suppression of the avoidance responses may be mediated by α2-adrenoreceptors.
Ketamine and the arrhythmogenic dose of epinephrine in cats anesthetized with halothane and isoflurane
Authors: Bednarski Richard M. , Majors Lynda J.
Published: February 2025

Epinephrine-induced arrhythmias were studied in 4 cats (group A), using a 4 × 4 Latin square design. Each cat was anesthetized 4 times, 1 week apart, with halothane (1.5% end expired), isoflurane (2.0% end expired), and halothane or isoflurane preceded by ketamine administered im (8.8 mg/kg). Lead II of the ecg and femoral artery pressure were recorded. Epinephrine was infused in progressively doubled rates (initial rate = 0.125 μg/kg/min) for a maximum of 2.5 minutes or until at least 4 ventricular premature depolarizations occurred within 15 s of each other. The arrhythmogenic dose of epinephrine (ade; μg/kg) was calculated as the product of infusion rate and time to arrhythmia. The ade (X ± sd) during anesthesia with halothane alone and with ketamine-halothane anesthesia were 1.33 ± 0.65 and 1.37 ± 0.59 μg/kg, respectively; during anesthesia with isoflurane alone and ketamine-isoflurane anesthesia, the ade were 9.34 ± 1.29 and 16.16 ± 3.63 μg/kg, respectively. The ade was significantly greater (P < 0.05) during isoflurane anesthesia and ketamine-isoflurane anesthesia than during halothane anesthesia. The percentages of change in systolic blood pressure (X ± sd) at the ade during halothane, ketamine-halothane, isoflurane, and ketamine-isoflurane were 31 ± 34, 41 ± 17, 127 ± 27, and 148 ± 57, respectively. The percentages of change in blood pressure during isoflurane anesthesia and ketamine-isoflurane anesthesia were significantly (P < 0.05) greater than during halothane anesthesia. The percentages of change in heart rate (X ± sd) at the ade during halothane, ketamine-halothane, isoflurane, and ketamine-isoflurane were 20 ± 15, 16 ± 14, 14 ± 18, and 0 ± 27, respectively.

Five additional cats (group B) were anesthetized on 2 occasions, 1 week apart, with halothane (1.5% end expired) and ketamine infusion (76 μg/kg/min) or isoflurane (2.0% end expired) and ketamine infusion (76 μg/kg/min). The ade was determined after the cats had been anesthetized for 4 hours. The ade (X ± sd) during ketamine infusion-halothane anesthesia and ketamine infusionisoflurane anesthesia were 0.57 ± 0.35 μg/kg and 6.63 ± 4.28 μg/kg, respectively. The percentages of change in systolic blood pressure at the ade during ketamine infusion-halothane anesthesia and ketamine infusion-isoflurane anesthesia were 35 ± 29 and 156 ± 19, respectively. The percentages of change in heart rate at the ade during ketamine infusion-halothane anesthesia and ketamine infusion-isoflurane anesthesia were 22 ± 11 and 77 ± 78, respectively.
Halothane-catecholamine arrhythmias in swine (Sus scrofa)
Authors: Tranquilli W. J. , Thurmon J. C. , Benson G. J.
Published: February 2025

The arrhythmogenic dose of epinephrine (ade) was determined in 6 pigs during steady-state anesthesia (1.5% halothane in O2) and steady-state anesthesia plus xylazine (1.1 mg·kg−1·hr−1; iv infusion) and after either prazosin (αl) or metoprolol (β1) adrenergic blockade during halothane-xylazine (h-x) anesthesia. A constant infusion (1, 2, 3, 5, and 10 μg·kg−1·min−1) of freshly mixed epinephrine (100 μg·ml−1 in saline solution) was used to determine ade. The ade was defined as the total dose of epinephrine which produced 4 or more continuous or intermittent, premature, ventricular contractions within a 15-s period. The mean epinephrine total dose values during 1.5% halothane anesthesia, h-x anesthesia alone, or h-x anesthesia after either prazosin (0.1 mg·kg−1) or metoprolol (0.5 mg·kg−1) adrenergic blockade were 3.60 ± 0.844, 2.68 ± 0.402, 11.85 ± 3.804, and 5.17 ± 0.587 μg·kg−1, respectively. Xylazine administration did not significantly decrease ade, although mean arterial pressure significantly increased. Prazosin administration significantly increased ade and was associated with an increased heart rate and a decreased mean arterial pressure. We conclude that α1-blockade with prazosin is more protective to epinephrine-induced arrhythmias in h-x-anesthetized pigs than is β1-blockade with metoprolol.
Cardiopulmonary responses of swine to intravenous infusion of guaifenesin, ketamine, and xylazine
Authors: Thurmon J. C. , Tranquilli W. J. , Benson G. J.
Published: February 2025

Swine were anesthetized with a 5% solution of dextrose in water containing 50 mg of guaifenesin, 1 mg of ketamine, and 1 mg of xylazine · ml−1 (g-k-x) infused iv at a rate of 2.2 ml · kg−1 · hr−1. Mean arterial blood pressure and systemic vascular resistance were significantly increased from base-line values throughout the 2 hours of g-k-x infusion. Cardiac index decreased significantly initially, but returned to near base line at 30 minutes. Fifteen minutes after g-k-x infusion was discontinued, cardiac index was not significantly different from base line. Heart rate decreased significantly from base line 90 minutes after infusion of g-k-x began and remained so throughout the study. However, the mean heart rate remained within the acceptable range for swine. Rate-pressure product was not significantly altered. The PaCO2 decreased, and arterial pH increased significantly from base line, supporting our clinical impression that pigs breathe well when anesthetized with g-k-x. We conclude that g-k-x is a satisfactory combination of drugs for induction and maintenance of surgical anesthesia in healthy swine for a period of 2 hours.
Influence of thyroid function on the pharmacokinetics of gentamicin in pigs
Authors: Riond Jean-Luc , Dix Lynn P. , Riviere J. Edmond
Published: February 2025

Hypothyroidism or hyperthyroidism was induced in 10 pigs (5 pigs/group) and each pig was administered gentamicin (6 mg/kg of body weight, iv). Low thyroxine and triiodothyronine resulted in a decrease in creatinine clearance (P = 0.04), an increase in serum creatinine concentration (P = 0.003), and a decrease in gentamicin systemic clearance (P = 0.002), compared with findings in control pigs (n = 5). These effects probably were secondary to a decreased glomerular filtration rate associated with hypothyroidism. A strong correlation among the 3 treatment groups was found between gentamicin systemic clearance and creatinine clearance (r = 0.72; P = 0.004) and between gentamicin systemic clearance and serum creatinine concentration (r = −0.77; P = 0.0007). Hyperthyroidism induced a slight but significant decrease in protein binding (P = 0 002). However, the significant changes in the hypothyroid pigs and the hyperthyroid pigs were not of a magnitude sufficient to alter gentamicin elimination half-life. Gentamicin disposition was best described, with a 4-compartment open model.
Identification of Brucella abortus in formalin-fixed, paraffin-embedded tissues of cows, goats, and mice with an avidin-biotin-peroxidase complex immunoenzymatic staining technique
Authors: Meador Vincent P. , Tabatabai Louisa B. , Hagemoser Wayne A. , Deyoe Billy L.
Published: February 2025

An avidin-biotin-peroxidase complex immunoenzymatic staining technique was evaluated for light microscopic detection of Brucella organisms in formalin-fixed, paraffin-embedded tissues. Tissues from cows, goats, and mice inoculated with B abortus strain 2308 were examined, using rabbit antiserum to Brucella cell surface protein as primary antibody. Stained organisms were identified histologically in tissue sections containing B abortus, as detected by bacteriologic examination of duplicate nonprocessed tissue samples. Bacillus sp, Corynebacterium pyogenes, Escherichia coli, Listeria monocytogenes, Pasteurella haemolytica, P multocida. Salmonella typhimurium, Staphylococcus sp, and Streptococcus sp did not stain with this system, using anti-Brucella cell surface protein primary antibody, thus indicating specificity for Brucella organisms.
Physiologic aging of mature porcine erythrocytes: Effects of various metabolites, antimetabolites, and physical stressors
Authors: Kiel Johnathan L. , Erwin David N.
Published: February 2025

Red blood cells were collected from Landrace × Duroc pigs in pooled and single batches. The rbc were stored for 24 hours to 20 days and exposed to 1 or more chemical and physical stressors. The chemicals were pyruvate, lactate, inosine, concanavalin A-luminol-bovine serum albumin conjugate, hydrogen peroxide, l-mimosine, and 3-amino-l-tyrosine. Physical stressors included thermogenic microwave radiation (2,450 MHz, mean specific absorption rate of 91 W/kg) and conventional heating with hot air or hot-water bath. Heating erythrocytes to 43 C for 10 minutes with microwaves or hot air did not significantly (P > 0.05) increase hemolysis, compared with hemolysis of rbc at 4 C (controls). Pyruvate or lactate did not affect the rbc under these conditions. Hemolysis of cells coated with concanavalin A-luminol-bovine serum albumin and heated to 43 C for 10 minutes by use of microwaves or hot air was significantly (P < 0.05 by Student's t test) greater (48%) than that of rbc at 4 C (controls). The method of heating or the presence of pyruvate, lactate, or inosine did not have a significant (P > 0.05) effect on hemolysis. Lysis of rbc (14 days after collection) coated with concanavalin A-luminol-bovine serum albumin and stored at 4 C was not significantly different (P > 0.05) than that of noncoated cells (6 days after collection) stored at 4 C (control). When rbc were heated 20 days after collection to 48 C for 30 minutes, using a hot water bath, hemolysis was 60.6% greater than that of control cells (4 C). The l-mimosine (340 μM) did not affect thermal hemolysis. The 3-amino-l-tyrosine (74 μM) suppressed thermal hemolysis to that of the controls. When rbc were treated 19 days after collection with 44 mM H2O2 at 37 C for 15 minutes, their binding capacity for luminol-bovine serum albumin was 721% more than that of control cells at 37 C. In a second single batch of rbc, the increase in binding induced by H2O2 (11.7 mM) was inhibited 51% by 1.49 mM 3-amino-l-tyrosine. Red blood cells collected 72 hours before use and preincubated with pyruvate (1.33 mM) for 30 minutes at 37 C (hot air) had 2.66 times greater luminol-bovine serum albumin binding than did controls (37 C). Preincubation with 1.49 mM 3-amino-l-tyrosine totally inhibited the increase in binding with pyruvate. Therefore, the effectiveness of 3-amino-l-tyrosine for protecting natural membrane components from oxidation is related to its thermoprotective properties. The luminol-bovine serum albumin binding assay was a sensitive, simple technique for detecting oxidative physiologic aging of porcine rbc.
Pathogenicity and immunogenicity of piliated and nonpiliated phases of Moraxella bovis in calves
Authors: Jayappa Huchappa G. , Lehr Craig
Published: February 2025

Pathogenicity evaluations of Moraxella bovis strain EPP 63 grown in the piliated and nonpiliated phase indicated that the organism grown in the piliated phase induced clinical keratoconjunctivitis, whereas the organism grown in the nonpiliated phase did not induce disease under identical challenge conditions. Calves inoculated with culture grown in the piliated phase developed significantly (P < 0.01) higher lesion scores than did calves inoculated with culture grown in the nonpiliated phase. Vaccination/challenge exposure evaluations indicated that calves immunized with vaccine prepared from piliated culture had significantly lower lesion scores than did control calves (P < 0.001) or calves immunized with vaccine prepared from nonpiliated culture (P < 0.05). Similarly, calves immunized with piliated vaccine developed a significantly higher antibody titer against purified pili. Nonvaccinated controls and calves immunized with nonpiliated vaccine did not develop a significant increase in antibody titer. The results indicate that M bovis pili constitute an important factor in the pathogenicity of keratoconjunctivitis and may be used as a vaccine in the control of keratoconjunctivitis in cattle.
Genetic relatedness of disease-associated field isolates of bovid herpesvirus type 4
Authors: Henry Berch E. , Ota Ron , Evermann James F.
Published: February 2025

Eight field isolates of bovid herpesvirus type 4 (bhv-4) were examined by restriction analysis and Southern blot hybridization with respect to their relatedness to one another and to the bhv-4 prototype strain DN-599. Isolates were obtained from cattle exhibiting a range of disease states including abortion, pneumonia, enteritis, metritis, and vaginal blisters. Initial growth studies of all 9 viruses were performed and revealed that the overall rate of virus growth was slow when compared with that of other herpesviruses. Infection with each virus also resulted in the formation of large fused cells, which in addition to the slow growth rate, indicated that the isolates were of the cytomegalovirus type.

Further studies to characterize and compare the various bhv-4 isolates were undertaken by obtaining cell-free virus from infected cell populations. Viral isolates were purified and used as a source of bhv-4 DNA. Purified DNA, representing each of the 8 field isolates and the prototype strain DN-599, were each cleaved with 3 restriction enzymes and were separated by agarose-gel electrophoresis, and the resultant fragment patterns were compared. In general, genomic fragments of the field isolates corresponded to those generated by cleavage of DN-599 DNA, with the exception of the abortion-associated isolate 83-3572. Additional minor differences were also seen between DN-599 DNA and DNA from the other field isolates, but the overall restriction patterns were similar. To confirm that all isolates were members of the bhv-4 type, hybridization studies were performed using DN-599. Each DNA of the isolates was cleaved, separated, blotted to nitrocellulose, and hybridized to radiolabeled DN-599 DNA probe. Seemingly, all isolates were closely related to DN-599, although differences in restriction enzyme cleavage patterns were observed. Because an obvious difference was seen in relation to the abortion-associated isolate 83-3572 and DN-599, additional hybridization studies were done using other restriction enzymes. The 2nd abortion-associated isolate 79-1436 was also included. Isolate 83-3572 was markedly different in genomic organization when compared with those of DN-599 and 79-1436.
Quantitative studies of erythropoiesis in the clinically normal, phlebotomized, and feline leukemia virus-infected cat
Authors: Wardrop K. Jane , Kramer John W. , Abkowitz Janis L. , Clemons Gisela , Adamson John W.
Published: February 2025

Erythropoiesis was evaluated in 5 cats at base line with normal pcv and then in the same cats with anemia induced by phlebotomy and in 5 other cats with nonregenerative anemia from community-acquired feline leukemia virus (FeLV) infection. The hematologic evaluation included complete blood cell and reticulocyte counts, marrow morphologic features, determination of serum erythropoietin concentrations by radioimmunoassay, ferrokinetic studies, and in vitro marrow culture of early erythroid progenitors (erythroid burst-forming units; bfu-e) and late erythroid progenitors (erythroid colony-forming units; cfu-e).

Phlebotomized cats developed marrow erythroid hyperplasia and an increased reticulocyte count. Ferrokinetic studies revealed an increase in plasma iron turnover from 1.4 to 3.8 mg of Fe/dl of blood/day and rbc use from 50.4% to 78.5%. The mean cfu-e number and cfu-e/bfu-e ratio increased after phlebotomy, but the increase was not significant (P > 0.05). Serum erythropoietin values did increase significantly.

In FeLV-infected cats, a nonregenerative anemia was demonstrated by marrow erythroid hypoplasia and a low total reticulocyte count. An increased percentage of rubriblasts and prorubricytes was observed in 4 of the 5 cats. Although serum erythropoietin values were high (321 ± 123 mU/ml vs normal 14 ± 1 mU/ml), ferrokinetic data revealed decreased erythropoiesis. Marrow culture studies in the FeLV-infected cats also revealed low numbers of bfu-e and cfu-e, but normal numbers of granulocytemacrophage progenitors remained. Seemingly, the FeLV infection impaired the ability of feline marrow to respond physiologically to anemia.
Clinical biochemical values of llamas: Reference values
Authors: Lassen E. Duane , Pearson Erwin G. , Long Patrick , Schmotzer Wayne B. , Kaneps Andris J. , Riebold Thomas W.
Published: February 2025

Fifteen clinical biochemical measurements were done on serum from 64 clinically healthy adult llamas (26 males and 38 females). Values for several of these tests were different from those reported for llamas and from reference values for other domesticated ruminants. Comparison of values between males and females revealed significant differences for several tests. Clinical biochemical values reported in the present study can serve as reference values for adult llamas.
Effect of long-term administration of ketoconazole in cats
Authors: Willard M. D. , Nachreiner R. F. , Howard V. C. , Fooshee S. K.
Published: February 2025

Four cats given ketoconazole (30 mg/kg of body weight/day) for 30 days developed dry hair coats and weight loss. Plasma cortisol and serum cholesterol, testosterone, and progesterone did not change significantly (P > 0.01), and significant alterations in serum albumin, calcium, and alkaline phosphatase (P < 0.01) did not preclude use of the drug. Serum testosterone concentrations tended to decrease after 7 days of treatment, but in 2 cats returned to near-pretreatment values by day 30 of treatment, despite continued drug administration. These results were in contrast to those reported in the dog at similar and lesser dosages of ketoconazole.
Endotoxin-induced changes in the hemostatic system in neonatal calves: The effect of antiserum to a mutant Escherichia coli (J-5)
Authors: Morris Debra Deem , Whitlock Robert H. , Merryman Geralyn Schad , Bruce James , Corbeil Lynette B.
Published: February 2025

Changes in the hemostatic system were studied in 22 neonatal calves given a small dosage of Escherichia coli endotoxin (0.5 μg/kg) by slow (5-hour) iv infusion. The effect of pretreatment with an antiserum to mutant of E coli O111:B4 (J-5) was evaluated. The platelet count, plasma fibrinogen concentration, prothrombin time, and activated partial thromboplastin time changed significantly from base line during and after endotoxin infusions in all calves. The mean platelet count was significantly decreased from 1 through 24 hours after endotoxin infusion was started. Mean plasma fibrinogen was decreased 2 through 12 hours after endotoxin infusion was started. The mean prothrombin time and activated partial thromboplastin time were significantly greater than base line at 3 to 6 hours and 3 to 12 hours, respectively, after endotoxin infusion was started. Serum concentration of fibrinolytic degradation products remained < 10 μg/ml. Bovine J-5 antiserum did not prevent the endotoxin-induced changes in the hemostatic system of these neonatal calves.
Pharmacokinetics of rifampin given as a single oral dose in foals
Authors: Castro Luis A. , Brown Murray P. , Gronwall Ronald , Houston A. E. , Miles N.
Published: February 2025

Six foals from 6 to 8 weeks of age were given a single oral dose of rifampin at a dosage of 10 mg/kg of body weight. Serum rifampin concentrations were measured serially during a 24-hour period. The mean peak serum rifampin concentration was 6.7 μg/ml at 4 hours after treatment. The concentration decreased slowly, and at 24 hours the mean value was 2.7 μg/ml. The elimination half-life was 17.5 hours, and the elimination rate constant was 0.04/hr.
Body fluid concentrations and pharmacokinetics of chloramphenicol given to mares intravenously or by repeated gavage
Authors: Gronwall Ronald , Brown Murray P. , Merritt A. M. , Stone H. W.
Published: February 2025

Serum concentrations and the pharmacokinetics of chloramphenicol were determined in 6 healthy mares after a single iv administration (50 mg/kg of body weight) or after the 1st and 5th sequential intragastric (ig) administration (50 mg/kg/6 hours) of chloramphenicol. Synovial fluid, peritoneal fluid, csf, and urinary concentrations of chloramphenicol after the ig administrations also were determined. Mean (± sem) overall elimination rate constant (K) values for the iv, 1st ig, and 5th ig dosages were 0.42 ± 0.064/hr, 0.42 ± 0.049/hr, and 0.29 ± 0.074/hr, respectively, and were not significantly different from one another (P > 0.05). Bioavailability was 40 ± 8.6% after the 1st ig administration and was 21 ± 5.2% after the 5th ig administration. Values for the area under the curve (auc) for the 1st and 5th ig dosages were significantly different from the auc value for the iv dosage, and the auc value for the 5th ig dosage was significantly different from that for the 1st ig dosage. Chloramphenicol was administered to 2 mares in 6 consecutive doses; the first and last doses were given iv and the others were given ig. Mean K values after the 2 iv doses were 0.38 ± 0.112/hr and 0.56 ± 0.078/hr, which were not significantly different from each other or from the mean value for the iv dosage given to all 6 mares. Absorption of chloramphenicol decreased with repeated ig administrations, resulting in lower concentrations of chloramphenicol with subsequent administrations. Five consecutive ig doses of chloramphenicol were administered to 4 of the mares in a separate experiment and did not alter intestinal xylose absorption.
An in vivo model for the study of Bordetella avium adherence to tracheal mucosa in turkeys
Authors: Arp Lawrence H. , Brooks Emily E.
Published: February 2025

An in vivo model was developed for studies characterizing the adherence of Bordetella avium to the tracheal mucosa of turkeys. Three-week-old turkeys were anesthetized, and the cervical part of the trachea was isolated after tracheostomy was done. A hemostat was applied craniad to the tracheostomy site to occlude the tracheal lumen. Isolated tracheal segments were filled with an aqueous bacterial inoculum for 1 minute, and then excess inoculum and the hemostat were removed. After 1 hour, a 1-cm section was excised from each tracheal segment, and adherent viable bacteria were quantified. Modifications of the procedure were evaluated to produce a model that was technically simple to do, economical, and reproducible. To examine the validity of the model, adherence of B avium was compared with that of Escherichia coli and Staphylococcus aureus. Adherence of B avium to tracheal mucosa was 17 times greater than that with E coli and 1,550 times greater than that with S aureus. Colonization of the tracheal mucosa by B avium was demonstrated in tracheal sections obtained 6 hours after filling with bacterial inoculum. Because the ciliary clearance mechanism of the tracheal segments remained functional, washing of the tracheal lumen had no effect on numbers of associated bacteria. An important advantage of this model over in vitro models is the excellent preservation of the tracheal mucosal surface.
Antibody-mediated suppression of erythropoiesis in dogs with red blood cell aplasia
Authors: Weiss Douglas J.
Published: February 2025

Eight dogs with acquired rbc aplasia were studied. Unfractionated sera and serum immunoglobulin G fractions were examined for the presence of erythroid progenitor cell inhibitors. A serum immunoglobulin G inhibitor directed against precursors of erythroid colony-forming units was detected in 3 of 5 dogs that were direct Coombs' test-negative and in 1 of 3 dogs that were direct Coombs' test-positive. Sera from these dogs were treated with binary ethyleneimine to inactivate any viruses present. The inhibitory effects of the treated serum on erythroid colony-forming units was not ameliorated.
Comparative morphology of esophageal mucosa and submucosa in dogs from 1 to 337 days of age
Authors: Henk W. G. , Hoskins J. D. , Abdelbaki Y. Z.
Published: February 2025

Scanning electron microscopy, light microscopy, and morphometric analyses were used to examine the morphology of the tunica mucosa-tela submucosa of the cervical, thoracic, and abdominal parts of the esophagus of healthy dogs from birth to 337 days of age from 3 litters of dogs whelped and reared under controlled conditions. Apart from the absence of a lamina muscularis mucosae from the cervical part of the esophagus of all dogs examined, little regional variation was detected. However, morphologic variation associated with age was observed. The number and complexity of microplicae on surface epithelial cells, as observed with the scanning electron microscope, increased with age, particularly between 1-day-old and 21-day-old dogs. Although scanning electron microscopy revealed typical duct openings from the submucosal glands in 1-day-old dogs, light microscopy revealed few functional glands. These glands gradually developed into a complex strata of tubules and acini during the time that secretory activity and the volume fraction of the tunica mucosa-tela submucosa occupied by glands increased with age. The presence of ciliated cells in the esophagus of 1-day-old dogs was apparent with scanning electron and light microscopes. Ciliated cells were always most abundant in the abdominal part of the esophagus. Finally, morphometric analyses revealed a significant increase in epithelial and connective tissue compartment thicknesses, as well as a marked increase in the volume fraction occupied by glands between 1 day and 161 days after dogs were whelped. A smaller decrease in all 3 measures occurred between 161 and 337 days after the dogs were whelped.
Coagulation abnormalities associated with acute Angiostrongylus vasorum infection in dogs
Authors: Schelling Curtis G. , Greene Craig E. , Prestwood Annie K. , Tsang Victor C. W.
Published: February 2025

Ten dogs were experimentally infected with 150 3rd-stage larvae of the lungworm Angiostrongylus vasorum (Baillet, 1866). Blood samples obtained once a week for 5 weeks after infection was induced were examined for coagulation alterations. Thrombocytopenia developed in infected dogs before and after parasitic patency, which occurred 6 weeks after infection was induced. Prolongation of activated partial thromboplastin time and thrombocytopenia initially were associated with periods of larval migration and, later, at patency, with pulmonary egg embolism and hatching of 1st-stage larvae in the lung. Decreased factor-V activity, significantly shortened values for the prothrombin time, and increased factor-VIII activity were evident during postpatent periods of parasitic infection. Significant changes were not found in factors-XII and -IX activities throughout the course of infection. Coagulation abnormalities were attributed to excessive intravascular coagulation. Immature adults and first stages of the parasite seemed to have initiated the coagulopathy in the prepatent phase of infection, with subsequent coagulation abnormalities occurring at the time of patency.
Proteins specified by bovine herpesvirus-2
Authors: Adams Steven W. , Balachandran N. , Hutt-Fletcher Lindsey M.
Published: February 2025

Polypeptides synthesized in bovine testes cells infected with bovine herpesvirus type 2 were labeled with [35S] methionine and were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Thirty-eight virus-induced proteins, ranging in molecular weight from 32,000 to 149,000, were detectable by analysis of whole cell lysates between postinfection hours 2 and 36. A similar number was immunoprecipitated by rabbit antiserum to bovine herpesvirus type 2. Twelve proteins incorporated [3H]glucosamine. On the basis of their temporal characteristics and their pattern of synthesis in the presence of cycloheximide and dactinomycin, 3 proteins, including at least one that was nondetectable in the absence of drugs, were classified as a proteins, 4 as β proteins, 1 as a β/γ protein, and 27 as γ proteins. Host cell protein synthesis was not reduced substantially until postinfection hours 22 to 28.
Campylobacter jejuni infections in gnotobiotic pigs
Authors: Boosinger Timothy R. , Powe Thomas A.
Published: February 2025

At 3 days of age, 12 gnotobiotic pigs were inoculated orally with broth cultures of Campylobacter jejuni. One pig was euthanatized and evaluated each day for 12 days. In the cecum and colon, there was diffuse edema, neutrophilic infiltration, and sloughing of epithelial cells from the mucosa on postinoculation days (pid) 2 through 5. Dysplastic colonic crypt epithelial cells were observed in the submucosa of the colon on pid 5 through 12.

Curved, rod-shaped bacteria were detected on the surface of ileal, cecal, and colic absorptive and glandular epithelial cells. Bacteria also were found around small submucosal vessels on pid 3 and 4 and were associated with numerous perivascular neutrophils. The gnotobiotic pig appears to provide a simple, well-controlled in vivo model for the study of the pathogenesis of C jejuni infections in human beings, pigs, and other mammals.
Corynebacterium pseudotuberculosis infection in adult ewes by inoculation in the external ear
Authors: Pépin Michel , Pardon Pierre , Marly José , Lantier Frédéric
Published: February 2025

Caseous lymphadenitis, caused by Corynebacterium pseudotuberculosis, was studied in ewes to devise a reliable method of induced infection that would help to understand mechanisms by which abscesses develop in lymph nodes or internal organs, especially the lungs. Fifteen adult ewes, from a flock where the occurrence of caseous lymphadenitis was unknown, were inoculated sc in the auricle with various doses of a virulent strain of C pseudotuberculosis. Ewes inoculated with at least 108 viable corynebacteria develop a strong local reaction that was apparent 4 hours after challenge exposure and lasted 7 to 14 days. Of these ewes, all developed at least 1 abscess and 3 developed multiple abscesses in lymph nodes draining the inoculated auricle and in the lungs. All infected ewes developed a strong antibody response against C pseudotuberculosis exotoxin, which persisted for 3 months. Of 9 ewes infected with 1.2 × 108 corynebacteria, 3 developed lesions because of field strains of C pseudotuberculosis and had an increased capacity to limit the dissemination of challenge-inoculum bacteria by developing only one abscess in the draining lymph node (parotid or prescapular lymph node). Seemingly, inoculation in the external ear was a suitable method for obtaining a reproducible infection and indicated that a primary infection might protect against reinfection by limiting dissemination of C pseudotuberculosis.
Clinical, clinicopathologic, pathologic, and toxicologic alterations associated with gossypol toxicosis in feeder lambs
Authors: Morgan Sandra , Stair E. L. , Martin Terry , Edwards W. C. , Morgan Gregor L.
Published: February 2025

The toxicity of gossypol was studied in 20, 8-week-old feeder lambs that weighed approximately 16 kg. The lambs were allotted to 4 groups (A, B, C, D) and given (orally for 30 days) a daily dosage of gossypol (0, 45, 136, or 409 mg, respectively). Lambs were observed twice daily until they died or were euthanatized on the day the last dose was given. Clinical, electrocardiographic, clinicopathologic, pathologic, and toxicologic findings were recorded.

All lambs given 409 mg of gossypol (group D) died before the end of the 30-day study. In this group, clinical signs included sudden death and/or chronic dyspnea syndromes. One group-B lamb had chronic dyspnea, but did not die. Electrocardiographic abnormalities observed in gossypol-treated lambs included increased amplitude of the T wave and decreased duration of the st segment. Clinicopathologic alterations in group-D lambs included high serum total lactate dehydrogenase and lactate de-hydrogenase liver-specific isoenzyme activities. Serum total creatine kinase activity decreased markedly in lambs of all groups treated with gossypol. Hemoglobinuria was detected in 2 group-D lambs.

The average daily weight gain was remarkably consistent in lambs of all groups, except in 1 lamb each of groups D and B.

Lambs were necropsied when they died or on day 30 of the study. The heart of gossypol-treated lambs weighed more than did that of untreated (control group A) lambs. In many of the treated lambs, macroscopic lesions included excessive, often red-tinged, pericardial and thoracic fluid volumes, white streaks on the epicardium extending into the myocardium, pale mottled cardiac musculature, generalized icterus, and edematous lungs with wide interlobular septa. Sections of heart, kidneys, liver, spleen, lungs, brain, skeletal muscle (diaphragm and serratus ventralis muscle), bladder, rumen, abomasum, small intestine, and large intestine were stained with hematoxylin and eosin and were examined microscopically. All gossypol-treated lambs had various degrees of cardiomyopathy, characterized by vacuolation and degeneration of myocardial fibers, separation of fibers by edema, influx of lymphoreticular cells, and necrosis of myocardial fibers. Pulmonary and hepatic lesions reflected progressive cardiomyopathy.

Liver, kidney, and semimembranosus muscle specimens were obtained immediately after death or euthanasia, and free and bound gossypol concentrations in such tissues were determined. The liver and kidneys of treated lambs had consistently higher free gossypol concentration than did those of control lambs.