bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on Canine Parvovirus Infections; Development of an Inactivated Vaccine
Authors: Eugster A. K.
Published: February 2025

Parvoviruses isolated from the intestines of dogs that died of an enteric infection were propagated in various parasynchronized canine and feline cell cultures. Viral antigen could be visualized in infected cell cultures with the aid of fluorescein-labeled feline, as well as porcine, parvovirus antisera, and in an indirect test with sera from dogs that had recovered from a parvovirus infection. The virus hemagglutinated porcine rbc at 4 C and 25 C but not at 37 C.

An inactivated canine parvovirus vaccine elicited an immune response, but no adverse reactions, when inoculated into dogs. Vaccinated dogs were immune and did not show any clinical signs when challenge exposed with virulent virus, whereas nonvaccinated, nonimmune dogs became clinically ill when inoculated with the same virus. Humoral hemagglutination-inhibiting parvovirus antibody values corresponded well with susceptibility and resistance to experimental inoculation of dogs with canine parvoviruses.
Optimization of the Suspension Culture Method for in Vitro Cultivation of Babesia bovis
Authors: Erp Elton E. , Smith Ronald D. , Ristic Miodrag , Osorno B. Miguel
Published: February 2025

An evaluation of some system variables for the suspension-culture method of in vitro Babesia bovis cultivation has identified some variables as critical and suggested optimum values for others. Growth of Babesia was not affected by siliconizing the culture vessels or including HEPES buffer in the culture medium. The culture pH, however, markedly influenced the growth rate. When supplemented with a large amount of serum, even Hanks's balanced salt solution was an adequate medium to support growth of B bovis, but growth improved with increasing medium complexity. A comparison of growth in the complex mammalian tissue culture mediums RPMI-1640, medium- 199, and NCTC-135 showed no significant differences. Heparinized plasma (plasma with added heparin) could not be substituted for serum. While serum could be stored by either freezing or refrigeration at 4 C for up to a week, rbc rapidly lost their ability to support growth of B bovis when stored at 4 C. Preliminary experiments with the gaseous environment indicated that CO2 is required and that the optimum oxygen tension was near the normal atmospheric level of about 20%.
Lymphocyte Immunostimulation in the Diagnosis of Corynebacterium equi Pneumonia of Foals
Authors: Prescott J. F. , Ogilvie T. H. , Markham R. J. F.
Published: February 2025

A lymphocyte stimulation test using antigens of Corynebacterium equi was used to compare the response of peripheral blood lymphocytes from foals with C equi pneumonia with ithose of clinically normal foals and adult horses. The test clearly distinguished infected foals from normal foals when tested in animals ≥ 2 months old. After the 2nd month, stimulation response from individual normal foals sometimes exceeded those from infected foals, but mean stimulation response to C equi antigens was significantly (P < 0.025) greater in 3- to 5-month-old infected foals when compared with mean values of 3- to 5-month-old normal foals. Mean stimulation responses in 5- to 7-month-old foals, which had recovered from C equi pneumonia, could not be distinguished from mean responses of normal foals. The test could still, however, be used diagnostically in foals > 2 months of age if stimulation responses were low. The test indicated the great extent of exposure to C equi in the normal horse population.
Enzyme-Linked Immunosorbent Assay for Detecting Antibodies to Brucella abortus in Bovine Milk and Serum
Authors: Heck F. C. , Williams J. D. , Pruett J. , Sanders R. , Zink D. L.
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) method was evaluated for the detection of antibodies to Brucella abortus in cows milk. Milk samples from seropositive or -negative cows were used to determine the distribution of absorbance values to classify milk as elisa positive or elisa negative. Brucella abortus was isolated from milk samples from 10 (45%) of the 22 cows whose milk and serum were elisa positive. The elisa was evaluated and determined to be an appropriate method for detecting antibodies to B abortus in bovine milk.
Anaplasma marginale in Bovine Erythrocyte Cultures
Authors: Mazzola V. , Kuttler K. L.
Published: February 2025

Bovine erythrocytes infected with Anaplasma marginale were standardized with normal bovine erythrocytes at 1.4% and 3.5% parasitemia and cultured under low oxygen pressure at 37 C. The number of erythrocytes infected by A marginale appeared to increase 3.3-fold by day 11 and 4.5-fold by day 3, as determined by microscopic examination of Giemsa-stained thin films of the culture suspension. Anaplasma parasites in experimental cultures were proven to be viable and pathogenic by calf inoculation for up to 16 days.
Relationship Among Particle Size Distribution, Dissolution Profile, Plasma Values, and Anthelmintic Efficacy of Oxfendazole
Authors: Shastri S. , Mroszczak E. , Prichard R. K. , Parekh P. , Nguyen T. H. , Hennessey D. R. , Schiltz R.
Published: February 2025

Three mean particle sizes of oxfendazole raw material (1.65 μm, lot A; 3.2 μm, lot B; 12,0 μm, lot C) were prepared and identically formulated as corresponding (A, B, and C) suspensions at 2.26% (w/v) concentration. Studies involving microscopic examination, scanning electron microscope analysis, particle size distribution, and surface area measurement were carried out on raw materials. In vitro dissolution profiles were obtained for the suspensions. A comparative bioavailability study of these 3 suspensions was performed in 12 sheep with each sheep given each formulation in a Latin square crossover study design; oxfendazole was dosed at a rate of 5 mg/kg of body weight. Plasma-value measurements were made followed by an analysis of various bioavailability studies. Plasma area values indicated that suspension C (dw = 12.0 μm) was significantly (P < 0.05) less bioavailable than was suspension A (dw = 1.65 μm); there was no difference between suspension A and suspension B. Significant differences were not seen in biological halflife and maximum plasma concentrations.

The term dw refers to that particle diameter (determined by Coulter counting) at which 50% of the oxfendazole mass was in the form of particles having a lesser diameter and 50% was in the form of particles having a greater diameter.

In a separate study involving 20 Merino weaner sheep infected with benzimidazole-resistant Haemonchus contortus larvae, oxfendazole's anthelmintic efficacy was demonstrated in the 2.26% suspension dosage form (90% particles < 10 μm) at a dosing rate of 5 mg/kg. A correlation was found between its anthelmintic activity and plasma area values when compared in individual sheep.

Data demonstrated that substantial differences in particle size distribution of oxfendazole could influence its dissolution rate, plasma concentrations, and absorption characteristics, thus indicating that oxfendazole's absorption could be dissolution-rate limited.
Purification and Properties of Haemophilus paragallinarum Hemagglutinin
Authors: Iritani Y. , Katagiri K. , Arita H.
Published: February 2025

Hemagglutinin (ha) of Haemophilus paragallinarum was purified, and its immunologic, chemical, and morphologic properties were studied. The ha was purified by gel filtration on Sepharose 6B and by subsequent ultracentrifugation of trypsinized cells after pretreatment with neuraminidase. After gel filtration, the ha component (fractionated ha) gave 1 precipitin line by gel diffusion, and after inoculation in chickens, hemagglutination-inhibition antibody to trypsin-sensitive ha antigen was found. Chickens inoculated with the fractionated ha were protected from challenge exposure with H paragallinarum. In a sample further purified by ultracentrifugation (purified ha), a single protein band was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; it had a molecular weight of approximately 39,000. A molecular weight of several hundred thousand to several million was observed by gel filtration. Seemingly, ha of H paragallinarum is an aggregate of more than 20 ha subunits. The purified ha included protein and some sugars, and according to electron microscopic observation, had a filamentous structure.
Development of a Migration Inhibitory Factor Assay Under Agarose of Bovine Mononuclear Leukocytes, Using an Antigen of Brucella abortus
Authors: Azadegan Aliakbar , Kaneene John M. B. , Muscoplat Charles C. , Johnson Donald W.
Published: February 2025

A study was conducted to develop a migration inhibitory factor assay under agarose of bovine mononuclear leukocytes, with an antigen of Brucella abortus. Different concentrations of mononuclear leukocytes were prepared by the Ficoll-Hypaque technique from the blood of nonvaccinated calves and from calves previously vaccinated with strain 19. Concentrations of 0.5, 1, 2, 3, 4, and 5 × 106 leukocytes were suspended in RPMI-1640 medium and various dilutions (20, 10, 1, and 0.1 μg) of B abortus-soluble antigen, dispensed in triplicate wells cut in 1% agarose containing minimal essential medium and 10% bovine fetal serum. These agarose plates were incubated for 4-, 8-, 12-, 16-, 20-, and 24-hour periods and then were fixed; leukocytes were stained with Wright’s stain. Migration distances were measured, and statistical analyses of the data revealed a concentration of 2 × 106 cells/well and an antigen concentration of 10 μg/well. An incubation period of 20 hours was optimal for the assay.
Congenital Tremor in Pigs Farrowed from Sows Given Hog Cholera Virus During Pregnancy
Authors: Vannier P. , Plateau E. , Tillon J. P.
Published: February 2025

At different stages of gestation, 3 groups of pregnant sows were inoculated with a strain of hog cholera virus (hcv). After the infection, clinical signs of hog cholera were not observed in the sows. Pigs from the sows infected on day 22 or 43 of gestation showed varying degrees of muscular tremor, ataxia, splayleg, and suckling inability. Of the pigs with tremor, 83% had cerebellar hypoplasia. Surviving pigs demonstrated persistent viral infection and continued to shed hcv, but did not have antibodies to hcv. Sows infected at 72 days of gestation farrowed numerous mummified and stillborn pigs. Signs of tremor were not seen in any pigs from these sows.
Revised Surgical Procedure for the Derivation of Gnotobiotic Dogs
Authors: Krakowka Steven , Austin Nancy J. , Long David J. , Helphrey Melvin
Published: February 2025

A revised surgical procedure for derivation of gnotobiotic pups was described. Pregnant bitches (n = 11) were sedated and anesthetized (epidural anesthesia). Fetal pups were removed from the uterine horns and then transferred to the isolation units where they were removed from the sacs and stimulated. The method compares favorably with the previously used hysterectomy procedure.
Endemicity of Dirofilaria immitis and Dipetalonema reconditum in Dogs of Pleasants Valley, Northern California
Authors: Walters L. L. , Lavoipierre M. M. J. , Timm K. I. , Jahn S. E.
Published: February 2025

A house-to-house survey of dogs in a 26-km2 area of Pleasants Valley (Northern California) was done to determine the prevalence of the filariids Dirofilaria immitis Leidy and Dipetalonema reconditum Grassi in the canine population. Blood samples were taken from the cephalic vein of 97 dogs (≥ 5 months of age) and were tested for the presence of microfilariae, using a modification of the Knott technique. Two dogs with autochthonous D immitis (2.1% of the dogs examined) were discovered. These dogs were outdoor-housed working or sporting dogs, 5 to 8 years old, 1 female and 1 male. Five male dogs, > 2 years of age (5.1%), were positive for Dip reconditum microfilariae. Mixed infections were not detected.
Neomycin Toxicosis in Calves
Authors: Crowell W. A. , Divers T. J. , Byars T. D. , Marshall A. E. , Nusbaum K. E. , Larsen L.
Published: February 2025

Calves (n = 4) were given neomycin (2.25 or 4.5 mg/kg) twice daily im and were compared with 2 calves given penicillin im. The 2 hallmarks of aminoglycoside toxicosis, nephrotoxicosis and ototoxicosis, were seen with both dosages of parenterally administered neomycin. Nephrotoxicosis was confirmed by abnormal findings in urinalysis (granular casts, proteinuria, low specific gravity), renal biopsy results (tubular degeneration and necrosis), and increased 24-hour amounts of urinary enzymes (alanine aminopeptidase and γ-glutamyltranspeptidase). Azotemia, decreased creatinine clearance, polyuria, and polydipsia also were documented in calves given neomycin. Clinically, deafness was suspected in 2 calves and was documented by electrical auditory-evoked response tests.

Abnormalities in partial thromboplastin times and renal residues of neomycin were seen in all 4 calves that were given neomycin, but not in calves that were given penicillin.
Vitamin E Deficiency Retinopathy in Dogs
Authors: Riis R. C. , Sheffy B. E. , Loew E. , Kern T. J. , Smith J. S.
Published: February 2025

Dogs fed purified diets developed retinopathy consistently when the nutrition was deficient in vitamin E. Deleting dl-methionine along with vitamin E and selenium (group 3 dogs) varied the development minimally. Supplementation of vitamin E to a selenium-deficient diet (group 1 dogs) protected the retina from changes. Ethoxyquin added to a diet deficient in vitamin E, but supplemented with National Research Council levels of selenium or 10 times the National Research Council levels, induced no beneficial recognizable changes in the retinopathy. The characteristic retinopathy was ophthalmoscopically visible as early as 3 months (group 2 to 9 dogs). Typical lesions developed first in the central, outer layers and progressed slowly toward the periphery. The tapetal retina was more extensively involved, showing a color change and mottling.

Microscopically, a yellow autofluorescent pigment accumulated in large amounts within the retinal epithelium. Later stages of retinopathy showed this pigment was present in migrating cells in all the retinal layers. The early disappearance of a recordable electroretinogram, night blindness, and eventual severe day visual impairment makes this retinopathy similar to some aspects of degenerations described for persons and pure breed dogs.
Systemic and Digital Vascular Effects of Intravenous Histamine in the Pony
Authors: Robinson N. E. , Scott J. B.
Published: February 2025

The effects of a 60-minute iv infusion of histamine (0.5 mg of histamine base/minute) on the systemic, pulmonary, and digital vasculature were investigated in mature ponies. Immediately after the start of histamine infusion, there were a transient decrease in systemic pressure lasting less than 1 minute and then a brief period of systemic hypertension. Systemic pressure then returned to preinfusion levels for the remainder of the infusion period. Pulmonary arterial pressure increased transiently coincident with systemic hypotension. Histamine increased cardiac output and decreased both total peripheral and pulmonary vascular resistances. In the digit, blood flow increased for the duration of the systemic hypertension, but was otherwise unchanged. Digital lymph flow and protein concentration were unchanged by histamine. Hematocrit increased significantly after 60 minutes of histamine infusion, but plasma and blood volumes were unchanged. Histamine caused cyanosis, hyperpnea, and sweating in all ponies. The effects of histamine given iv do not mimic the systemic and digital vascular effects of acute alimentary laminitis.
Experimental Intramammary Infection of the Dairy Cow with Escherichia coli During the Nonlactating Period
Authors: McDonald J. S. , Anderson A. J.
Published: February 2025

The nonlactating mammary gland was experimentally inoculated with Escherichia coli. During the first half of the nonlactating period, 32% of 34 inoculated glands were temporarily infected. All intramammary infections were eradicated by the cow without therapy and no signs of mastitis were observed.

During the 30 days before parturition occurred, 88% of 42 inoculated glands in the cows became infected. Twenty-three intramammary infections were eradicated by the cow and infection in 14 glands persisted after parturition occurred. Peracute toxic mastitis occurred in those cows with infected glands.
Refractoriness of Both Uterus and Mammary Gland of the Cow to Prostaglandin F2α Administration: Clinical Implication
Authors: Eiler H. , Oden J. , Schaub R. , Sims M.
Published: February 2025

Uterine and mammary pressure changes were simultaneously measured in lactating nonpregnant cows injected (iv) with different doses (0.1 to 32.0 mg) of prostaglandin F2α (pgf2α). The total work of the uterus increased up to 250% of base-line value as the dose of pgf2α was increased. But, a dose-response relationship was not seen in the uterus. Partial refractoriness was developed in the uterus, and total refractoriness was developed in the mammary gland. Further challenge with oxytocin (30 U) elicited significant responses in both the uterus and the mammary gland.

Because of the development of refractoriness and side effects, pgf2α is not recommended as a drug to be used when mechanical evacuation (free of endocrine effect) of the uterus or mammary gland (or both) is indicated.
Histochemical Differentiation of Fiber Types in Neonatal Canine Skeletal Muscle
Authors: Braund Kyle G. , Lincoln Clint E.
Published: February 2025

Differentiation of fiber types in developing canine skeletal muscle was studied, using morphologic, morphometric, and histochemical techniques. Sample collections were made from 6 muscles from the pectoral and pelvic limbs of 16 healthy pups between 1 day and 12 weeks of age. In newborn pups, 90% to 95% of the fibers in the 6 muscles were classified as undifferentiated or type IIC; the remaining fibers were classified either normal or large-size type I. Large-size type I fibers usually accounted for 2% to 4% of the total population and were considered analogous with the B fiber of Wohlfart. These fibers were larger than all other fiber types and disappeared after pups reached 4 to 5 weeks of age. After 2 to 4 weeks, the number of undifferentiated fibers decreased with the appearance of, and the concomitant numerical increases of, normal size type I and type IIA fibers. The percentages of type I and IIA fibers approached proportions of the adult dog by 12 weeks, at which time a type IIA fiber predominance was present in biceps femoris, lateral head of the gastrocnemius, cranial tibial, and long head of the triceps. Type I fibers predominated in medial head of the triceps and superficial digital flexor after 4 to 5 weeks.

The mean fiber diameters of type I and IIA fibers were similar in any given muscle throughout the postnatal development.

All fiber types stained uniformly with the oxidative stain nicotinamide adeninedinucleotide-tetrazolium reductase during the first 12 weeks of life, whereas a distinction between type I and II fibers was evident after 3 to 4 weeks with the periodic acid-Schiff stain reaction.
Lasalocid and Monensin in Finishing Diets for Early Weaned Lambs with Naturally Occurring Coccidiosis
Authors: Horton G. M. J. , Stockdale P. H. G.
Published: February 2025

Early weaned male crossbred lambs (n = 90) with an average weight of 14 kg were used in 6 groups to evaluate the efficacy of monensin (22 mg/kg of feed) and lasalocid (12.5, 25, 50, and 100 mg/kg of feed) on naturally occurring coccidiosis. Average 24-hour oocyst output at the start of the experiment ranged from 5.7 × 106 to 156.7 × 106 for monensin-treated and 100-mg lasalocid-treated groups, respectively. Monensin and lasalocid were effective against Eimeria ninakohlyakimovae and E ahsata.

To day 103, body weight gains were similar for the 4 groups fed lasalocid (336 g/day) and averaged 6% higher (P > 0.05) than did gains in control and monensin-treated lambs. Feed efficiency averaged 9% higher (P < 0.05) for lambs fed 25, 50, and 100 mg of lasalocid/kg of feed and 7% higher (P > 0.05) for lambs fed monensin and 12.5 mg of lasalocid/kg of feed. There were no treatment effects on digestibility, although lasalocid tended to increase (P > 0.05) crude protein digestibility (values were higher on day 76 than on day 28). Lasalocid and monensin were potent manipulators of rumen fermentation. Increasing the amount of lasalocid in the feed was associated with successive increases (P < 0.05) in molar proportions of propionic acid and decreases (P < 0.05) in acetic acid.

Lasalocid and monensin controlled naturally occurring coccidiosis and improved performance in early weaned lambs (45 days old) under feedlot conditions.
Serologic Response of Pigs to Experimental Infection with Yersinia enterocolitica Serotype O9 and Brucella abortus
Authors: Mittal K. R. , Tizard I. R.
Published: February 2025

Groups of young pigs were inoculated with either Brucella abortus or Yersinia enterocolitica O:9 and their serum was analyzed to identify techniques by which infections with these organisms could be distinguished. Yersinia enterocolitica was capable consistently of inducing a significant anti-Brucella agglutinin response. By means of microplate agglutination, it was shown that homologous titers usually exceeded or were equal to heterologous titers. This technique was also capable of detecting Yersinia flagellar agglutinins. When a group of serum samples from healthy pigs was surveyed, it was found that none of the techniques tested were capable of unequivocally distinguishing between the 2 infections.
In Vitro Properties of Low- and High-Passaged Strains of Transmissible Gastroenteritis Coronavirus of Swine
Authors: Laude H. , Gelfi J. , Aynaud J. M.
Published: February 2025

Low- and high-passaged cell culture strains of transmissible gastroenteritis virus were examined for stability toward digestive enzymes and at low pH. Correlation could not be made between the level of resistance and the cell passage status of the strains. Results of experiments on thermosensitivity of replication and thermolability did not permit separating the strains into 2 groups.
Toxic Effects of Lasalocid in Horses
Authors: Hanson L. J. , Eisenbeis H.G. , Givens S.V.
Published: February 2025

Lasalocid was given to horses in a series of sequentially increasing single oral doses ranging between 5 and 30 mg/kg of body weight, with an appropriate washout period between treatments. One of 5 horses died after a dosage of 15 mg/kg, 1 of 3 horses died after 21 mg/kg, 1 of 3 horses died after 22 mg/kg, and 1 of 2 horses died after 26 mg/kg. The ld50 of lasalocid for horses was estimated to be 21.5 mg/kg.

Monensin was given to horses in a similar manner at dosages of 1, 2, and 3 mg/kg of body weight. One of 2 horses died after a dosage of 2 mg/kg and 1 horse died after a dosage of 3 mg/kg.

The clinical signs of toxicosis observed in horses given either drug were progressive and included depression, ataxia, paresis, and paralysis with partial anorexia. Intermittent profuse sweating was observed before death in horses given monensin.
Influence of Parenteral Administration of Mineral Oil Adjuvant in Parturient Cattle on Immunoglobulin Secretion in Colostrum and Milk
Authors: De Cueninck Bernard J.
Published: February 2025

Pregnant heifers were sensitized to egg albumen by subcutaneous injection. Freund's incomplete adjuvant, as a water-in-oil emulsion containing aluminum hydroxide, was injected subcutaneously on the 4th day of the subsequent lactation. The treatment with adjuvant, without incorporated antigen, raised the serum egg-albumen antibody titers and resulted in a prolongation of specific antibody secretion in milk; the treatment did not affect the mammary secretion of exogenous radiolabeled IgG1, indicating that the phenomenon was based on stimulation of immunoglobulin synthesis.
Turkey Respiratory Tract Adenoviruses: Purification and Some Biochemical Properties
Authors: Sutjipto S. , Simmons D. G.
Published: February 2025

Equilibrium density gradient centrifugation of 3 purified turkey respiratory tract adenoviruses resulted in 3 distinct bands of identity for each virus. Complete virus particles were contained in the band with a buoyant density of 1.34 g/cm3. The complete virus particles had the morphology of adenoviruses, as determined by electron microscopy. The buoyant densities of extracted viral DNA from the 3 viruses were estimated to be 1.7089, 1.7154, and 1.7132 g/cm3, which corresponded to guanine + cytosine contents of 51%, 57%, and 55%, respectively.
Inhibition of Gastric Hydrochloric Acid Secretions in the Rat Given Ostertagia ostertagi (a Gastric Parasite of Cattle) Extract
Authors: Eiler H. , Baber W. , Lyke W. A. , Scholtens R.
Published: February 2025

The immersion of freshly collected Ostertagia ostertagi adults into saline solution (NaCl, 0.9%; pH 1.0) resulted in 100% mortality of worms within a 10-minute period. At pH 7.0, mortality was 58% after 270 minutes. At pH 2.2, which approximates the usual abomasal pH, 100% mortality resulted within 60 minutes.

In the stomach of rats injected with an extract of O ostertagi (from the abomasum of cattle), there were decreased total secretion of hydrogen ions and volume of secretion (P < 0.05) and increased mean pH of gastric secretion (P < 0.05). These effects were similar to those found in stomach of rats treated with cimetidine.

Results indicated that the pH of the abomasum was detrimental to parasitic survival and that hypochlorhydria found during ostertagiosis may be mediated partially by a chemical released from the parasite.
Decline in Assayable Progesterone in Bovine Plasma: Effect of Time, Temperature, Anticoagulant, and Presence of Blood Cells
Authors: Vahdat F. , Hurtgen J. P. , Whitmore H. L. , Seguin B. E. , Johnston S. D.
Published: February 2025

Jugular vein blood samples collected from 5 Holstein-Friesian cows during the luteal phase of the estrous cycle were incubated at 4 C, 22 C, and 37 C for 0, 0.5, 1, 2, 4, 6, 8, 12, and 24 hours. Blood samples were centrifuged after each incubation period, and plasma was frozen for later progesterone assay. Mean progesterone concentration in blood samples incubated at 4 C, 22 C, and 37 C decreased from 5.7 ng/ml at 0 hour to minimum concentrations of 3.5 ng/ml at 12 hours, 0.9 ng/ml at 12 hours, and 1.0 ng/ml at 8 hours, respectively. The first progesterone concentration which was significantly different from the initial value (0 hour) was at the 8-hour incubation period for blood samples incubated at 4 C and at the 1-hour incubation period for blood samples incubated at 22 C and 37 C.

Progesterone concentration decreased similarly when blood samples were collected into heparinized tubes or EDTA tubes and incubated at 22 C for 0, 6, and 12 hours.

Incubating harvested plasma or serum for 0 or 6 hours at 37 C had no effect on progesterone concentrations (7.9 and 8.2 ng/ml for plasma, and 6.9 and 6.6 ng/ml for serum).
Technique for Reversible Vagal Blockade in the Standing Conscious Pony
Authors: Derksen F. J. , Robinson N. E. , Stick J. A.
Published: February 2025

A surgical technique is described for preparation of chronic cervical vagal loops in ponies. Vagal blockade was induced by circulating methanol (—2 C) through coils which enclosed the loops. Vagal blockade increased tidal volume, heart rate, and systemic blood pressure and decreased respiratory rate. Atropine, given at a dose of 0.04 mg/kg iv, increased heart rate and systemic pressure but did not alter respiratory variables, indicating that vagal cooling caused both afferent and efferent blockade. The effects of vagal blockade were rapidly reversed when refrigerated coils were removed.
Transmission of Babesia bovis, Using Undifferentiated Embryonic Cells from Boophilus microplus Tick Eggs
Authors: Ronald N. C. , Cruz D.
Published: February 2025

An intact Hereford calf was inoculated with undifferentiated embryonic cells from Boophilus microplus tick eggs derived from Babesia bovis-infected Boophilus microplus. The eggs were incubated for 8 to 10 days at 26 C and for 80 hours at 37 C before inoculation into the calf. The calf subsequently developed typical signs of babesiosis and a maximum parasitemia of 5.0%.
Anemia of Inflammatory Disease in the Dog: Ferrokinetics of Adjuvant-Induced Anemia
Authors: Feldman Bernard F. , Kaneko J. J. , Farver T. B.
Published: February 2025

Anemia of inflammatory disease induced by injection of adjuvant was characterized by decreases in hematocrit (mean ± 1 sd, 37.5 ± 2.7%, as compared with base-line values of 49.8 ± 2.4%) and hemoglobin (12.54 ± 1.22 g/dl, as compared with base line of 16.87 ± 0.96 g/dl) and was classified as unresponsive, normocytic, and normochromic.

Disordered iron metabolism was manifest by decreases in serum iron (62.3 ± 13.6 g/dl, as compared with base line of 113.0 ± 8.2 g/dl) and shortened mean radioiron clearance half-times (50.0 ± 12.6 minutes, as compared with base line of 74.0 ± 13.6 minutes) in the presence of increased bone marrow reticuloendothelial iron. Shortened radioiron clearance half-times reflected maximal extraction of iron from the plasma by the erythroid marrow due to suboptimal iron supply, since extraction of iron by other tissues is minor.

Shortened mean marrow transit times (2.79 ± 0.46 days, as compared with base line of 5.4 ± 0.64 days) were indicative of adequate erythropoietin stimulation in the anemia of inflammatory disease. Increases in plasma iron turnover rate over base line (1.73 ± 0.33 mg/dl/day) to 1.51 ± 0.34 mg/dl/day), erythron iron turnover rate (1.50 ± 0.27 mg/ dl/day, as compared with base line of 0.99 ± 0.27 mg/dl/ day), and rbc iron utilization (86 ± 8.3%, as compared with base-line utilization of 65 ± 9.3%) indicated erythroid marrow proliferation was effective. The magnitude of erythroid response appeared to be limited mainly by iron supply.
Susceptibility of Vaccinated Swine and Mice to Generalized Infection with Specific Serotypes of Erysipelothrix rhusiopathiae
Authors: Wood R. L. , Booth G. D. , Cutlip R. C.
Published: February 2025

Swine were vaccinated with adsorbate bacterin made from Erysipelothrix rhusiopathiae of serotype 2 and were subsequently allotted to 4 exposure groups, each of which was exposed to 1 of the strains of E rhusiopathiae of serotypes 1, 2, 9, or 10. Mice were vaccinated with the same bacterin and were subsequently allotted to 60 exposure groups which were exposed to 60 strains of E rhusiopathiae, comprising 10 strains each of serotypes 1, 2, 4, 9, 10, and 11. Response to challenge of immunity in swine was determined by the presence of clinical signs of acute generalized erysipelas; response in mice was determined by the quantal (live-dead) method.

Vaccinated swine were as susceptible to the strain of serotype 10 as were nonvaccinated control swine, whereas vaccinated swine were immune and control swine were susceptible to the strains of serotypes 1 and 2. The strain of serotype 9 was not sufficiently virulent to induce acute generalized erysipelas, even in control swine. Arthritis was not prevented by vaccination, but its frequency and severity were less in vaccinated swine exposed to strains of serotype 1 or 2 than in those exposed to strains of serotype 9 or 10. Vaccinated mice were significantly (P < 0.05) more susceptible to the strains of serotype 10 than to those of any other serotype tested.
Potential Blood Supply to Muscles in Horses and Dogs and Its Relation to Athletic Ability
Authors: Gunn H. M.
Published: February 2025

A modification of the histochemical reaction to demonstrate myosin adenosine triphosphatase activity in skeletal (striated) muscle was used to define the density of capillaries in transverse sections of 3 muscles (semitendinosus, diaphragm, and pectoralis transversus) of horses and dogs. Thoroughbred horses and Greyhound dogs, breeds noted for their speed in running, were compared with other members of their respective species. Thoroughbred cross horses were grouped with non-Thoroughbreds for comparison with Thoroughbreds.

The area of muscle supplied by a capillary was remarkably similar in muscles of all groups of animals, except at early stages of growth. Adult Thoroughbreds had a greater capillary/fiber ratio in semitendinosus and pectoralis transversus than did other adult horses. Intermuscular differences in capillary/fiber ratio and the area per capillary within adults and young of each type of horse were negligible with one exception: the capillary/fiber ratio was less in the pectoralis transversus than in the semitendinosus of young non-Thoroughbreds.

There was little between-type difference in capillary density in adult dog muscles, although the capillary/fiber ratio was greater in the semitendinosus of Greyhounds. Although the capillary/fiber ratio increases with growth, the area per capillary did not alter markedly. Cessation of training increased the area per capillary in the pectoralis transversus of Greyhounds. In all adult dogs, capillary/fiber ratios in the diaphragm were less than they were in the semitendinosus and the pectoralis transversus. In adult Greyhounds, this was compensated by a smaller area per capillary in the diaphragm. Seemingly, the ability for high speed running by the Thoroughbred and Greyhound was not associated with an enhanced potential blood supply to skeletal muscle.
Reversible Detachment of Blood-Derived Bovine Macrophages by Replacement of Culture Medium with Phosphate-Buffered Saline Solution
Authors: Bendixen P. H.
Published: February 2025

Blood-derived bovine macrophages adhering to the surface of culture chambers were brought into suspension for enumeration and experimental use by replacement of culture medium with phosphate-buffered saline solution. Immediately after suspension in culture medium, cells were able to adhere to surfaces and to phagocytize particles.
Exercise-Induced Pulmonary Hemorrhage in Racing Thoroughbreds: A Preliminary Study
Authors: Pascoe John R. , Ferraro G. L. , Cannon J. H. , Arthur R. M. , Wheat J. D.
Published: February 2025

Of 235 Thoroughbred racehorses examined with a flexible fiberoptic endoscope within 2 hours of racing to determine the frequency of exercise-induced pulmonary hemorrhage (eiph), 103 (43.8%) had various degrees of hemorrhage in the tracheal lumen. Two of these horses (0.8%) subsequently had blood flow from the nostrils. Blood seemed to originate from the lung. Statistical analysis of frequency data for 191 horses which finished in 1st, 2nd, and 3rd places did not show any relationship between eiph and horse’s age, sex, or finishing position. However, a trend toward an increased frequency of eiph with age was shown, by a greater proportion of horses 5 years and older having eiph. This trend is thought to reflect the chronicity of the pulmonary lesions and an inability of the lung to repair damaged regions while training and racing continued. The efficacy of furosemide for the treatment of eiph was questioned, since 30 of 56 furosemide-treated horses which were examined had evidence of pulmonary hemorrhage. Nineteen (8%) horses had visible functional abnormalities of the upper respiratory tract.
Plasma Clot-Promoting Effect of Collagen in Relation to Collagen-Platelet Interaction
Authors: Gentry P. A. , Schneider M. D. , Miller J. K.
Published: February 2025

The hemostatic function of several acid-soluble collagen preparations and a fibrillar-form collagen preparation have been compared. Pepsin-treated acid-soluble collagen isolated from burro and horse aortic tissue and acid-soluble collagen isolated from human umbilical cord readily promoted platelet aggregation, but failed to activate the coagulation mechanism even after prolonged incubation with plasma at 37 C. By contrast, fibrillar-form collagen isolated from burro aorta was both an efficient stimulant for the induction of platelet aggregation and a potent clot-promoting agent. Similar results were found for all the collagen preparations irrespective of whether the studies were conducted with sheep or with burro plasma. Heat denaturation studies showed that the hemostatic function of the fibrillar-form collagen was dependent on an intact triple-helical structure.
Pharmacology of Narcotic Analgesics in the Horse: Selective Blockade of Narcotic-Induced Locomotor Activity
Authors: Combie Joan , Shults Theodore , Nugent Edith C. , Dougherty John , Tobin Thomas
Published: February 2025

The locomotor responses of horses given morphine and fentanyl were blocked or lessened by administration of naloxone or acepromazine. Naloxone given at the dosage of 0.015 mg/kg completely blocked the locomotor activity induced in horses given fentanyl (0.020 mg/kg of body weight).

The locomotor stimulation produced by morphine given at the dosage of 2.4 mg/kg was reduced by 75% by naloxone (0.020 mg/kg).

Acepromazine partially blocked the locomotor responses to fentanyl and morphine. This blockade activity reached its peak about 30 minutes after acepromazine was given (iv) and lasted more than 6 hours. Simultaneous administration of acepromazine and morphine was associated with substantial respiratory depression for more than 4 hours after administration of both drugs.

In other experiments, fentanyl did not add to the partial locomotor response observed after large doses of pentazocine were given—this being consistent with the concept that pentazocine possesses both antagonist and agonist actions at the narcotic receptor. Furosemide and phenylbutazone, given at usually used clinical doses, had no effect on the locomotor response to fentanyl, indicating that the usual clinical dosages of neither drug exerted stimulant or depressant actions.
Biochemical and Coagulation Changes in a Canine Model of Acute Necrotizing Pancreatitis
Authors: Feldman B. F. , Attix E. A. , Strombeck D. R. , O’Neill S.
Published: February 2025

Acute necrotizing (hemorrhagic) pancreatitis was induced in 12 dogs by infusing oleic acid into their pancreatic ducts. There were decreases in blood pH, complement, antithrombin III, blood platelets, 24- and 48-hour plasminogen, and 24-hour haptoglobin and modest decreases in serum albumin. There were increases in fibrinogen, 48- to 120-hour haptoglobin, and 96-hour and 120-hour plasminogen and prolongations of prothrombin and activated partial thromboplastin times. The latter 2 changes together with decreases in antithrombin III, platelet numbers, and complement were indicative of consumption coagulopathy. A clinically innocuous but statistically significant decrease in serum total and ionized calcium despite significant acidosis was noted. This indicates that serum total and ionized calcium is helpful in making the diagnosis of acute necrotizing pancreatitis. Methemalbuminemia of 6 mg/dl at 24 hours and 7 mg/dl at 48 hours indicates that methemalbuminemia is a valuable diagnostic and prognostic finding in association with acute necrotizing pancreatitis.
Effects of Ammonia Infusion on Plasma Glucagon, Insulin, and Amino Acids in Intact, Pancreatectomized, and Adrenalectomized Dogs
Authors: Strombeck Donald R. , Rogers Quinton R. , Stern Judith S.
Published: February 2025

Ammonium salts were infused in intact, pancreatectomized, and adrenalectomized dogs to produce coma-inducing amounts of plasma ammonia. Changes in intact dogs included hyperglycemia, hyperglucagonemia, hyperinsulinemia, and decreases in plasma concentrations of glutamine, alanine, threonine, glycine, lysine, valine, proline, serine, arginine, leucine, isoleucine, and methionine. Urinary excretion of catecholamines increased more than 20-fold, whereas plasma hydrocortisone concentrations were essentially unchanged. In pancreatectomized dogs, ammonia infusions caused hyperglycemia, a mild hyperglucagonemia, and no changes in plasma amino acid concentrations, other than a decrease in alanine and an increase in taurine. In adrenalectomized dogs, ammonia infusion resulted in normoglycemia, hyperglucagonemia (comparable with that seen in intact dogs), hyperinsulinemia (2 to 3 times that seen in intact dogs), and decreased plasma concentrations of alanine, isoleucine, leucine, and valine. Finally, propranolol administration did not affect ammonia-induced glucagon and insulin release.

The endocrine portion of the pancreas appears to mediate the major effects of ammonia on plasma amino acid values. The effect of ammonia in stimulating glucagon release may occur by an α-adrenergic pathway or by direct stimulation of pancreatic islet cells.
Complications of Bladder Distention During Retrograde Urethrography
Authors: Barsanti J. A. , Crowell W. , Losonsky J. , Talkington F. D.
Published: February 2025

A severe, ulcerative cystitis that resulted in macroscopic hematuria occurred in 8 of 20 healthy dogs undergoing a series of diagnostic tests. Four of the remaining 12 dogs had mild bladder lesions consisting of submucosal edema and hemorrhage. Nine of the 20 dogs developed urinary tract infection after the procedures. These complications seemed associated with the radiographic technique of retrograde urethrography performed when the urinary bladder was distended.

To test this hypothesis, retrograde urethrography was performed on 5 additional dogs. With the bladder undistended, no complications occurred. However, distention of these same dogs’ bladders for 1 minute or less with sterile lactated Ringer’s solution administered through a Foley catheter in the penile urethra resulted in a macroscopic hematuria in all 5 dogs which persisted for 24 hours. A microscopic hematuria continued for 5 days. One dog developed a bacterial urinary tract infection. A severe fibrinopurulent cystitis was present at necropsy of 2 dogs 2 days after distention. The morphologic changes in the bladder gradually diminished over 7 days, but mild submucosal edema and hemorrhage were still present when 2 dogs were necropsied, 7 days after distention.

These studies indicated that retrograde urethrography in dogs may be complicated by hemorrhagic cystitis and urinary tract infection if performed with urinary bladder distention.
Tissue Sources and Clinical Application of Four Enzymes in Phocid Seals
Authors: Austin Thomas , Geraci J. R.
Published: February 2025

Tissue distribution and plasma activity values of creatine kinase (ck), aldolase (als), γ-glutamyltransferase (ggt), and leucine aminopeptidase (lap) were determined in 6 ringed seals, Phoca hispida, and in 7 harp seals, P groenlandica. Muscle tissues had the highest activity of ck and als, though high activity of als was also in most other tissues. The lap and ggt were mostly concentrated in the kidneys; tissue lap activity was generally low. Reference plasma values were determined in 17 ringed and 15 harp seals. The ck and ggt, respectively, are recommended for monitoring exertional stress and hepatobiliary dysfunction in phocid seals.
Electrophysiologic Studies of a Combination of Secobarbital and Dibucaine for Euthanasia of Dogs
Authors: Wallach Marshall B. , Peterson Karen E. , Richards Richard K.
Published: February 2025

A combination of secobarbital and dibucaine was compared with secobarbital and with dibucaine, given iv, for euthanasia of dogs. The secobarbital-dibucaine combination was the most effective, as determined by latency to electrical silence of the eeg and ecg, as well as by visual observation of the behavior of the animal. The combination product produced a quiet and rapid death, according to all electrophysiologic changes that were monitored, whereas the barbiturate resulted in prolonged myocardial activity. Dibucaine alone is not desirable for use for euthanasia.
Specular Microscopic Observations of Clinically Normal Feline Corneal Endothelium
Authors: Peiffer Robert L. , DeVanzo Robert J. , Cohen Kenneth L.
Published: February 2025

Endothelial specular microscopy and pachometry were performed on right and left eyes of 11 anesthetized young adult American Shorthair cats with clinically normal eyes. Endothelial cells of the central cornea formed a mosaic-like pattern of hexagonal cells 15 to 20 µm in diameter; the average number of cells per millimeter2 was 2,668 ± 211 sd. Corneal thickness was 0.56 mm ± 0.06 sd.
Effect of Vaccinal Serum Antibodies on Bovine Respiratory Syncytial Viral Infection in Calves
Authors: Mohanty S. B. , Rockemann D. D. , Davidson J. P. , Sharabrin O. I. , Forst S. M.
Published: February 2025

A moderate level of serum antibodies elicited in calves by a killed bovine respiratory syncytial viral vaccine did not cause exacerbation of a mild respiratory tract disease after challenge infection of these calves. Control calves inoculated with the virus had clinical signs of disease and the noninoculated control calves remained normal.
Haloxon: Critical Tests of Antiparasitic Activity in Equids
Authors: Lyons E. T. , Drudge J. H. , Tolliver S. C.
Published: February 2025

Critical tests were conducted in 14 naturally infected equids (13 horses and 1 pony) to evaluate the antiparasitic activity of haloxon. Single doses were administered by stomach tube to 3 horses and 1 pony (60 mg/kg of body weight), by addition to the feed of 3 horses (60 mg/kg), and intraorally by powder gun to 7 horses (65 mg/kg).

Haloxon was efficacious (99% to 100%) against infections of Parascaris equorum, Oxyuris equi (mature and immature), and Strongylus vulgaris at both dosage levels. Probstmayria vivipara parasites were removed in 1 horse treated at 60 mg/kg by stomach tube and S equinus was removed (1 specimen) in 1 horse treated at 65 mg/kg with the powder gun. Removal activity against small strongyles varied from 67% to 92%, and averaged 88% in the aggregate. Removal of S edentatus fluctuated from 2% to 100%, and was 49% in the aggregate. Haloxon was generally ineffective against Gasterophilus intestinalis and G nasalis, except that it seemed active against 2nd instar G intestinalis when administered at the 60 mg/kg dosage rate in feed and at the 65 mg/kg dosage rate by powder gun.

The compound was inactive against Trichostrongylus axei, Habronema muscae, Draschia megastoma, Anoplocephala perfoliata, and A magna. Clinical signs of toxicosis were not observed after treatment.

Problems were not encountered in administration of haloxon directly into the back of the mouth with the powder gun.
Controlled Tests of Ivermectin Against Migrating Strongylus vulgaris in Ponies
Authors: Slocombe J. O. D. , McCraw B. M.
Published: February 2025

Twelve pony foals were reared worm-free and inoculated with Strongylus vulgaris. On day 7 after inoculation, 6 ponies were given ivermectin im at a dose of 200 μg/kg of body weight and on day 28 were necropsied. Ivermectin was effective in eliminating early 4th-stage S vulgaris larvae and reducing clinical signs associated with acute arteritis. After administration of the anthelmintic, signs of toxicosis were not observed.
Comparative Titration of Anaplasma marginale Antibodies by Card Agglutination and Complement-Fixation Tests
Authors: Amerault Thomas E. , Rose Joseph E. , Kuttler Kenneth L.
Published: February 2025

The card agglutination test for anaplasmosis was improved so that bovine serum could be titrated for Anaplasma antibodies. The modified test was validated when its results on 1 set of serum samples were compared with the results furnished by the complement-fixation test on the same set. The samples tested were from cows inoculated with an Anaplasma vaccine or with either 1 of 2 virulent strains of Anaplasma marginale. A correlation coefficient of 0.60 was calculated between the values of the titers furnished by the 2 tests, and regression equations were calculated and used to estimate the serum titer in 1 test from a titer measured in the other. The results indicate that the simple card agglutination test can yield titers comparable with those of the complement-fixation test.