bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Pseudomonas aeruginosa ulcerative keratitis model in the dog
Authors: Wyman M. , Swanson C. , Kowalski J. J. , Powers Jean D. , Boraski E. A.
Published: February 2025

Primary Pseudomonas aeruginosa ulcerative keratitis and accompanying secondary ocular disease were induced bilaterally in 12 of 12 dogs subjected to corneal trephination and intrastromal inoculation. Successful experimental infection was based on recovery of viable Pseudomonas organisms from the lesions, as well as gross and biomicroscopic appearance of the corneas.
Furazolidone-induced congestive cardiomyopathy in ducklings: Lack of protection from selenium, vitamin E, and taurine supplements
Authors: Van Vleet John F. , Ferrans Victor J.
Published: February 2025

Newly hatched male White Pekin ducklings (n = 108) were allotted to 6 groups of 18 each and were fed for 4 weeks diets containing 750 mg of furazolidone (fz)/kg of feed either alone or with supplements of vitamin E (250 IU of dl-α-tocopheryl acetate/kg), selenium (2.5 mg as selenite/kg) or taurine (1%). Control groups were fed diets without fz and with or without added taurine (1%). Ducklings in the 4 fz-fed groups had retarded growth, mortality, ascites, and cardiac alterations of congestive cardiomyopathy. Supplements of vitamin E, selenium, or taurine did not protect against the development of the cardiac and extracardiac alterations of fz toxicosis. These findings could indicate that the development of fz-induced congestive cardiomyopathy is not mediated by low tissue concentrations of selenium, vitamin E, or taurine.
In vitro action of combinations of antimicrobial agents and EDTA-tromethamine on Escherichia coli
Authors: Wooley R. E. , Jones M. S. , Gilbert J. P. , Shotts E. B.
Published: February 2025

Combinations of EDTA-tromethamine and 7 antimicrobial agents [chloramphenicol, nalidixic acid, oxytetracycline, penicillin, polymyxin B, streptomycin, and triple sulfa (sulfamethazine, sulfapyridine, and sulfathiozole]) were tested for synergistic activities against Escherichia coli. Three in vitro tests were used including minimal inhibitory concentrations of the drugs, a 2-dimensional microtiter checkerboard technique, and bacterial inhibition studies. A strong synergistic inhibitory action was observed with combinations of EDTA-tromethamine plus penicillin and EDTA-tromethamine plus oxytetracycline. Combinations of EDTA-tromethamine plus chloramphenicol also had a synergistic action, but to a lesser extent than that with penicillin and oxytetracycline. When streptomycin or nalidixic acid was mixed with EDTA-tromethamine, a slight synergistic action was noticed. There was no synergistic effect recorded with combinations of EDTA-tromethamine and triple sulfa. Combinations of EDTA-tromethamine and polymyxin B had an antagonistic effect.
Induction of luteolysis in goats with prostaglandin F2α
Authors: Bretzlaff K. N. , Hill Andrea , Ott R. S.
Published: February 2025

On day 10 of each estrous cycle, 19 cycling does were given (im) 1 of 3 dosage levels of prostaglandin F2α (pgf2α) or saline solution. After injections, goats were observed twice daily for behavioral estrus, and serum concentrations of progesterone (P4) were determined from daily blood collections to measure response to treatment. Every dose of pgf2α (0.0165 mg/kg of body weight, 0.0275 mg/kg, and 0.0385 mg/kg) was administered during 20 estrous cycles, and 0.25 ml of saline solution was administered during 12 estrous cycles. Fourteen of 20, 15 of 20, 20 of 20, and 0 of 12 does exhibited signs of behavioral estrus within 96 hours of injections of 0.0165 mg of pgf2α/kg, 0.0275 mg of pgf2α/kg, 0.0385 mg of pgf2α/kg, and saline solution, respectively. A decline in mean concentrations of peripheral P4 from 3.6, 3.8, 4.4, and 4.3 ng/ml to < 1 ng/ml within 24 hours was observed in 15 of 20, 16 of 20, 20 of 20, and 0 of 10 does after injections of 0.0165 mg of pgf2α/kg, 0.0275 mg of pgf2α/kg, 0.0385 mg of pgf2α/kg, and saline solution, respectively. The dosage level of 0.0385 mg of pgf2α/kg (1.75 mg of pgf2α/45.36 kg) was effective for induction of estrus in 100% of the does.
Frequency of jowl abscesses in feeder and market swine exposed to group E streptococci as nursing pigs
Authors: Miller R. B. , Olson L. D.
Published: February 2025

Weaning and isolation were evaluated as management methods in controlling streptococcic lymphadenitis of swine. Nursing pigs in 3 experiments were exposed to group E streptococcus (ges) by contact with their ges-inoculated dams or other ges-inoculated pen mates. The exposed pigs were either weaned and isolated when 5, 6, or 8 weeks old or left in contact with the inoculated swine until 14 to 32 weeks old when all were necropsied. Abscesses were not recognized in 13 weaned or 7 unweaned pigs necropsied at 14 to 15 weeks of age, but ges was isolated from mandibular lymph nodes of 4 of the 7 unweaned pigs. Abscesses were recognized in 1 of 49 unweaned and 4 of 53 weaned swine when examined at market weight (24 or 32 weeks of age). In the 3rd experiment, 10 of 11 inoculated sows, one of 33 unweaned, and 11 of 25 weaned swine had serum titers > 4 to ges in a microtitration agglutination test.
Susceptibility of sows to experimentally induced Escherichia coli mastitis
Authors: Ross Richard F. , Harmon R. L. , Zimmermann Barbara J. , Young Theresa F.
Published: February 2025

A study was conducted to compare susceptibility of sows from 2 herds to experimentally induced Escherichia coli mastitis. Four sows each from herds R and S were inoculated intramammarily at postpartum hour 8 with a strain of E coli shown previously to be capable of producing mastitis. After inoculation with E coli, sows from herd S had higher temperatures, lower wbc counts, and lower plasma protein:fibrinogen ratios than did sows from herd R. Inoculated sows from herd S lost 83% of newborn pigs due to starvation by 14 days after inoculation, whereas sows from herd R lost none. Control, noninoculated sows from both herds had normal temperatures, normal hematologic values, and minimal mortality of piglets. Levels of antibodies (complement fixing, enzyme-linked immunosorbent assay, and agglutinating) to E coli in preinoculation sera from the 2 populations of sows did not differ. Assay of lactoferrin by radial immunoassay revealed comparable concentrations in milk of sows from both herds during the first 24 hours after sows had delivered, but significantly higher values were detected in milk from sows of herd S at postpartum days 2 and 3. The basis for the marked difference in susceptibility to E coli-induced mastitis was not determined except that “susceptible” sows (herd S) were from a conventional herd and “resistant” sows (herd R) were from a specific-pathogen-free herd.
Staphylococcal enterotoxin B and Escherichia coli endotoxin: Comparative observations in goats on fever and associated clinical hematologic and blood biochemical changes after intravenous and intramammary administration
Authors: van Miert A. S. J. P. A. M. , van Duin C. Th. M. , Verheijden J. H. M. , Schotman A. J. H.
Published: February 2025

Staphylococcal and coliform infections theoretically could lead to the circulation of potent toxins throughout the body. Moreover, staphylococcal enterotoxins are important causes of food poisoning. The present investigation was undertaken to examine the characteristics of purified staphylococcal enterotoxin B (seb) given to goats by iv (dose 0.02 to 2 μg/kg) and intramammary routes (1 mg). Rectal temperature, heart rate, rumen motility, plasma zinc and iron concentrations, and certain other blood biochemical and hematological values were studied and compared with the changes seen after Escherichia coli endotoxin is administered (dose: 0.1 μg/kg iv and 1 mg intramammarily). Similar changes such as fever, tachycardia, inhibition of rumen contractions, drop in plasma zinc and iron concentrations, lymphopenia, and neutropenia followed by neutrophilic leukocytosis and changes in serum enzymes activities were observed, although the patterns were different for the 2 toxins. In contrast to the effects of E coli lipopolysaccharide (lps), seb induced abdominal cramping pain, watery diarrhea with pseudomembranes, hemoconcentration, and increase in blood urea nitrogen. However, the latter effects were not present after intramammary seb administration. Fever, tachycardia, and decrease in plasma zinc and iron concentrations in the absence of a marked inhibitory effect upon rumen motility were seen after intramammary E coli lps infusion.

The results obtained demonstrate that the goat is a susceptible species and a useful model to study the gastrointestinal effects caused by seb. Moreover, the results obtained after intramammary administration indicate that endogenous inflammatory substances may be released from the udder instead of E coli lps absorption. However, absorption of seb from the udder could not be excluded. The present finding that no clear relationship could be found between the temperature response, and the alterations in plasma zinc and iron plasma values support the theory that the febrile reactions and the changes in plasma trace metals are mediated by different proteins released by activated macrophages.
Response to saline solution of normally fed horses and horses dehydrated by fasting
Authors: Carlson Gary P. , Rumbaugh Gary E.
Published: February 2025

Response to 4 hours' infusion of 20 L of saline solution was studied in healthy horses given the usual feed and water and in horses dehydrated by feed and water deprivation. Seven healthy horses in 8 trials urinated an average of 8.9 L during the infusion period. The mean 24-hour urinary production was 20.8 L, containing 3,310 mEq, 2,122 mEq, and 3,901 mEq of sodium, potassium, and chloride, respectively.

In contrast, only 1 of the 7 dehydrated horses urinated during the infusion. Mean 24-hour urine volume for the group was 9.1 L. Urinary sodium excretion (2,532 mEq) was not significantly different from that of the healthy horses, but potassium and chloride losses were significantly reduced (to 892 mEq and 2,918 mEq, respectively). Alterations in pcv, total plasma protein, and plasma sodium and chloride concentrations, and osmolality after the infusion were quantitatively similar in the 2 groups of horses. Significant reductions in pcv and total plasma protein persisted for 6 to 8 hours, and plasma potassium concentration was decreased for 4 to 6 hours. Plasma sodium concentration remained largely unchanged, and plasma chloride was significantly increased over preinfusion concentration for a period of 12 hours.

The results of the study confirmed reports that the relative water deficit produced by feed and water deprivation is not readily corrected by infusion of saline solution. Since sodium and chloride depletions were not the primary problems, there was a nearly quantitative urinary excretion of the infused saline solution. The elimination of the excess sodium chloride required major renal adjustments and increased urinary water loss. A close relationship between net fluid retention (as indicated by change in body weight) and urine output was demonstrated.
Warfarin pharmacokinetics in the horse
Authors: Thijssen H. H. W. , van den Bogaard A.E. J. M. , Wetzel J. M. , Maes J. H. J. , Muller A. P.
Published: February 2025

The pharmacokinetics of racemic warfarin were studied in 6 adult horses. After iv administration, the plasma concentration of warfarin showed a biphasic decline in time. Analysis of the data, according to 2-compartment kinetics, revealed the following constants: biological half-life was 13.3 hours, apparent volume of distribution was 0.46 L·kg-1, body clearance was 25.3 ml·hour-1·kg-1. Warfarin was bound (91.5%) to plasma proteins. Unchanged warfarin was not detected in the urine. Absorption from the gastrointestinal tract was almost complete.

Concentrations of warfarin in tissue were examined in 4 foals that were given 1 g of warfarin orally 14 hours before they were euthanatized. The concentrations in the kidney were higher than those in plasma (about 2 fold). The hypothrombogenic effect of the acute iv and oral administration of warfarin (0.75 mg/kg of body weight) was noticeable only after 60 hours and lasted for about 30 hours. The effect was weak; the maximum effect was a prolongation of 2.3 s (from 11.5 s to 13.8 s) in thromboplastin time.
Effects on cattle and their calves of tansy ragwort (Senecio jacobaea) fed in early gestation
Authors: Johnson A. Earl , Smart Ross A.
Published: February 2025

Tansy ragwort (Senecio jacobaea) fed to pregnant cows on gestation days 15 through 30 in lethal and near-lethal doses did not cause detectable damage to 100-day-old or to full-term fetuses as determined by gross examinations, serum enzyme tests chosen to detect hepatic changes, and by histopathologic examinations. Some cows that appeared normal during gestation expired soon after parturition from typical seneciosis apparently triggered by parturition stress.

Pregnant cows fed 12% smaller tansy ragwort doses on gestation days 30 through 45 had only minimal serum enzyme changes and gave birth to normal calves that had normal serum enzymes up to 64 days after parturition.
Assessment of thyroid functional reserve in the cat by the thyrotropin-stimulation test
Authors: Hoenig Margarethe , Ferguson Duncan C.
Published: February 2025

Serum thyroxine (T4) concentrations before and after various iv doses of bovine thyrotropin (tsh) were measured over a 48-hour period in 19 healthy cats. Base-line T4 values, as measured by radioimmunoassay, varied greatly. The peak T4 concentration occurred 6 hours after tsh injection, and there was an increase in post-tsh serum T4 concentration that was linearly related to the logarithm of the dose. Greatest stimulation was seen with the highest dose used (1 U of tsh/kg of body weight), and 6 hours after administration of this dose, the serum T4 concentration range was 4.1 to 8.4 μg/dl. The post-tsh serum T4 concentration and the absolute increase in serum T4 concentration after tsh administration correlated more closely with the tsh dose than did the ratio of post-tsh serum T4 concentration to base-line T4 concentration. Therefore, in cats with normal thyroid-binding protein concentrations, the former indices should represent the most reliable assessment of thyroid functional reserve.
Studies on the pathogenesis of epizootic bovine abortion
Authors: Kimsey P. B. , Kennedy P. C. , Bushnell R. B. , Casaro A. P. , BonDurant R. H. , Oliver M. N. , Kendrick J. W.
Published: February 2025

Ornithodoros coriaceus Koch ticks were fed on 37 pregnant cows. The fetuses were obtained from the cows at 23 to 126 days after maternal tick exposure. Characteristic lesions of epizootic bovine abortion were observed only in those fetuses recovered 100 days more or after maternal tick exposure. Fetuses collected between 50 and 100 days showed mild-to-moderate lymphoid and mono-nuclear cell hyperplasia. Reaction in fetuses studied < 50 days after maternal tick exposure were mild. Lesions could not be seen in 2 of the youngest fetuses.

Increases in serum immunoglobulin concentrations were present only in those fetuses examined 80 days or more after their dams had been exposed to ticks. The specificity of the immunoglobulins could not be determined. Sera from 12 fetuses tested failed to fix comple-ment in tests for group-specific chlamydial antibodies.

A wide variety of microbiological cultivation attempts were made to recover the causative agent of epizootic bovine abortion from these fetuses; however, no agent was recovered regularly, and chlamydial organisms were not recovered from any, The significance of 2 recovered agents, apparently viral, is still to be determined. Fetal tissues, both frozen and fresh, collected from fetuses of dams exposed to a feeding of ticks were capable of reproducing the disease after inoculation into pregnant cows or directly into fetuses.
Effect of feeding corn naturally contaminated with aflatoxin on feed efficiency, on physiologic, immunologic, and pathologic changes, and on tissue residues in steers
Authors: Richard J. L. , Pier A. C. , Stubblefield R. D. , Shotwell O. L. , Lyon R. L. , Cutlip R. C.
Published: February 2025

Two of 3 groups of Holstein-Friesian steers (groups II and III; n = 5 each) were fed a ration containing corn naturally contaminated with 800 ng of aflatoxin/g. The other group of steers (group I; n = 5) was fed a ration containing noncontaminated corn. The respective rations were fed for 17.5 weeks, except the ration given to group III; the latter's first diet (contaminated with aflatoxin) was changed to a noncontaminated diet after 15 weeks, continuing for the remaining 2.5 weeks. All steers were killed and tissues and fluids were obtained for aflatoxin analysis.

Although aflatoxin B1 and M1 could be detected in blood and urine at several sampling times during the experimental period in groups II and III steers (given the diets containing aflatoxin), there appeared to be no effects on body weight gains and immune phenomena, such as lymphoblastogenesis and antibody production, but there was a waning of the delayed cutaneous hypersensitivity in steers given aflatoxin-contaminated diets. In group III animals (diet was changed to noncontaminated ration at 15 weeks), aflatoxin B1 and M1 disappeared from urine before they were slaughtered. All tissues and fluids, except the rumen contents from these group III steers, were void of detectable aflatoxins B1 and M1 at necropsy. The concentrations of aflatoxin B1 in the rumen content of the latter steers were low. All tissues collected at necropsy from the group II steers fed the aflatoxin diet throughout the 17.5 weeks had detectable aflatoxins B1 or M1 present.
Scanning electron microscopic study of bovine leukemic cells
Authors: Yoshikawa Takashi , Oyamada Takashi , Yoshikawa Hiroyasu , Koyama Hiroyuki , Komoriya Yasunobu
Published: February 2025

Scanning electron microscopic observation of (i) leukemic cells in peripheral blood and tumor tissues of 11 cattle with bovine leukosis (adult form, n = 5; calf form, n = 2; and thymic form, n = 4) and (ii) peripheral lymphocytes from 2 cattle with persistent lymphocytosis and from 3 healthy cattle revealed morphologic differences of cell surface structures among various forms of bovine leukosis. These differences indicated an interrelationship of cell surface morphologic features between peripheral lymphocytes and tumor cells. Leukemic cells from cattle with the thymic and calf forms characteristically had a smooth surface. In cells from cattle with the adult form, the majority of abnormal cells in the peripheral blood, possessed numerous elongated microvilli on the cell surface, whereas tumor cells in the tissue were pleomorphic with a long villous, plicated surface or had stubby projections. Most of the peripheral lymphocytes from cattle with persistent lymphocytosis were characterized by a dense arrangement of elongated microvilli on the cell surface.
Influence of intramammary infusion of polymyxin B on the clinicopathologic course of endotoxin-induced mastitis
Authors: Ziv G. , Schultze W. D.
Published: February 2025

The influence of giving 1 dose of polymyxin B (l.6 × 106 U/quarter) by the intramammary route to dairy cows to modify the clinicopathologic course of mastitis induced by intramammary infusion of Escherichia coli endotoxin (1 mg/quarter) was examined. Pretreatment with polymyxin B or its simultaneous administration reduced and delayed the typical febrile and leukopenic responses to endotoxin infusion, prevented an increase in plasma lactate dehydrogenase activity and a reduction in plasma zinc concentration, but only marginally influenced the degree of udder inflammation and had no effect on leukocytosis in the milk. Intramammary infusion of polymyxin B at 30 or 60 minutes after endotoxin was infused prevented the increase in plasma lactate dehydrogenase activity and moderated the decrease in plasma zinc concentration, but otherwise failed to alter the clinicopathologic course of endotoxin-induced acute mastitis.
Cell culture-derived Babesia bovis vaccine: Sequential challenge exposure of protective immunity during a 6-month postvaccination period
Authors: Kuttler K. L. , Levy M. G. , Ristic M.
Published: February 2025

Cell culture-derived soluble Babesia bovis vaccine admixed with a saponin adjuvant was administered in 2 doses, 3 weeks between doses, to 18 yearling heifers. An additional 9 heifers served as nonvaccinated controls. Comparable groups of these animals were challenge exposed at 131 and 178 days after vaccination, using 1 × 108 B bovis organisms contained in freshly collected blood from a splenectomized calf with ascending parasitemia. Challenge exposure led to no deaths of vaccinated animals, whereas 4 of the control (nonvaccinated) animals died of disease. All clinical and hematologic variables examined indicated that the vaccinated animals had gained immunologic protection in comparison with the control group. An immune recognition as manifested by an anamnestic humoral response to challenge exposure was in evidence in the vaccinated animals.
Acute monensin toxicosis in swine: Effect of graded doses of monensin and protection of swine by pretreatment with selenium-vitamin E
Authors: Van Vleet John F. , Amstutz Harold E. , Weirich Walter E. , Rebar Alan H. , Ferrans Victor J.
Published: February 2025

Thirty-two weanling pigs (approx 20 kg each) were used for 2 studies of monensin toxicosis. In the 1st study, 5 groups (designated A through E) of 4 pigs each were given a single oral dose of monensin (10, 20, 30, 40, or 50 mg/kg of body weight) and were observed for 4 days to determine the clinical signs and pathologic alterations. The clinical signs of monensin toxicosis were dose related and included anorexia, diarrhea, lethargy, ataxia, dyspnea, and myoglobinuria; then, death. Clinical signs were not produced by the 10 mg/kg dose of monensin, but mortality resulted within 1 day among pigs given the 50 mg/kg dose. The frequency and severity of monensin-induced myonecrosis were dose-related. Affected pigs had bilaterally symmetrical pale areas of damage in the cranial and caudal thigh muscles, shoulder muscles, and loin muscles. Microscopically, the affected muscles had extensive hyaline necrosis with macrophagic invasion and early regeneration. In a few pigs, there was myocardial necrosis—most often involving the left atrial wall. Myoglobinuria was seen grossly in the pigs given the 50 mg/kg dose that died 1 day after dosing.

In the 2nd study, 6 pigs in 1 group (F) were orally given the 50 mg/kg dose of monensin a day after they were treated with selenium-vitamin E (Se as selenite at dosage of 0.25 mg/kg, and vitamin E as α-tocopherol acetate at dosage of 17 IU/kg); in the other group (G), 6 pigs were treated with placebo (saline solution) before dosing with monensin. Partial protection against monensin toxicosis was provided by Se-E pretreatment as demonstrated by (i) absence of mortality in group F pigs, (ii) smaller increases in serum aspartate aminotransferase and creatine kinase activities in group F pigs than in group G pigs, and (iii) less frequent and less severe clinical signs and lesions.
Bacteriophage typing of Staphylococcus hyicus subsp hyicus isolated from pigs
Authors: Kawano Junichi , Shimizu Akira , Kimura Shige
Published: February 2025

Four phages were isolated and used for typing Staphylococcus hyicus subsp hyicus isolated from pigs with or without exudative epidermatitis (ee) in Japan. Sixty-four (85.3%) of the 75 isolates examined were typeable at either routine test dilution (RTD) or 100 × RTD. Two or more kinds of phage patterns were present in the isolates from each pig with ee. All isolates from healthy pigs showed a single-phage pattern.

Fourteen (32.6%) of 43 isolates and 7 (87.5%) of 8 isolates from pigs with ee in Belgium and Czechoslovakia, respectively, were typeable with the 4 phages.

None of 180 isolates of S aureus, 7 (6.4%) of 110 isolates of S intermedius, and 2 (2.3%) of 86 isolates of S epidermidis were typeable.
Antibiotic-associated colitis due to Clostridium difficile in a Kodiak bear
Authors: Orchard John L. , Fekety Robert , Smith James R.
Published: February 2025

Clostridium difficile and its toxins usually are present in feces of laboratory animals and persons with antibiotic-associated colitis. We report antibiotic-associated colitis in a captive Kodiak bear (Alaskan brown bear, Ursus arctos) in which C difficile and its cytotoxin were found in feces. This indicates that the colitis associated with C difficile and its toxins can occur in nonlaboratory large animals and that this organism may be the causative agent in certain cases of idiopathic colitis in animals. This case also indicates that nonlaboratory animals may be a source of the organism.
Use of alpha-naphthyl acetate esterase staining to identify T lymphocytes in cattle
Authors: Kajikawa O. , Koyama H. , Yoshikawa T. , Tsubaki S. , Saito H.
Published: February 2025

Peripheral blood lymphocytes (pbl), lymph nodes, and/or spleens from clinically normal cattle were examined for cytochemical staining of α-naphthyl acetate esterase (anae). Two types of positive-staining patterns in anae staining resulted. By a combination of anae staining and latex-ingesting test, diffuse anae-positive cells were considered as mononuclear phagocytic cells. Using erythrocyte rosettes, erythrocyte antibody complement rosettes, nylon-wool column technique, surface immunoglobulin (SIg) staining, and the anae staining technique, granular anae-positive lymphocytes were shown to be T lymphocytes.

The frequency of T and B lymphocytes in pbl, spleens, and lymph nodes of clinically normal cattle was measured, using anae staining and SIg staining. In pbl, 47.7% were anae-positive and 26.9% were SIg-positive; in spleens, 22.4% were anae-positive and 53.7% were SIg-positive; and in lymph nodes, 38.5% were anae-positive and 28.3% were SIg-positive. The frequencies of T and B lymphocytes in pbl, spleens, and/or lymph nodes from cattle with enzootic bovine leukosis (ebl) and cattle with persistent lymphocytosis and in tumor cells from cattle with ebl were measured. When compared with those of clinically normal cattle, pbl, spleens, and lymph nodes of cattle with ebl and the pbl of cattle with persistent lymphocytosis contained numerous SIg-positive cells and few anae-positive cells. Tumor cells from cattle with ebl contained 7.3% anae-positive and 78.0% SIg-positive cells.
Bovine genital campylobacteriosis (vibriosis): Vaccination of experimentally infected bulls
Authors: Vasquez L. A. , Ball L. , Bennett B. W. , Rupp G. P. , Ellis R. , Olson J. D. , Huffman M. H.
Published: February 2025

The therapeutic efficacy of a Campylobacter fetus subsp venerealis bacterin was determined in experimentally infected bulls. Ten of twelve 5-year-old Angus bulls became infected after being infused intrapreputially with C fetus subsp venerealis. Of the 10 bulls, 6 were vaccinated with 5 ml of C fetus subsp venerealis vaccine on 2 occasions 4 weeks apart.

Preputial washings of the vaccinated bulls were culturally negative by the 8th week after primary vaccination. None of the 18 heifers exposed to the vaccinated bulls became infected. The 4 infected, nonvaccinated bulls remained culturally positive to C fetus (P < 0.002), and each bull infected at least 1 heifer (P < 0.001). Two noninfected, nonvaccinated bulls remained culturally negative and did not infect any heifer.

The 4 infected, nonvaccinated bulls were then vaccinated. Two bulls remained infected 9 weeks after primary vaccination, as determined by the virgin heifer test and cultural examination of preputial washings. Serologic data from 7 sampling periods were different (P < 0.001) for vaccinated vs nonvaccinated bulls at 4 (against K antigen) or 6 (against O antigen) weeks after primary vaccination.

Vaccination was effective in eliminating the infection in most of the infected bulls, but cannot be recommended as the sole measure of control in infected herds.
Protection against Pasteurella pneumotropica during infection with Angiostrongylus cantonensis
Authors: Laubach Harold E. , Kocan A. Alan
Published: February 2025

Lung infections of specific-pathogen-free rats were studied to determine cross-immunity between infections with Pasteurella pneumotropica and Angiostrongylus cantonensis. Rats were found to have differences in mortality due to pneumonic infections with P pneumotropica and A cantonensis and to coinfections of P pneumotropica and A cantonensis. Single infections of P pneumotropica were not dosage-dependent in their lethality for specific-pathogen-free rats. The mortality of coinfection with P pneumotropica and A cantonensis was significantly lower than that of a monoinfection with P pneumotropica, demonstrating a cross-protective phenomenon.
Preparation of biologically active components of Mycobacterium bovis, using Triton X-100 or potassium chloride
Authors: Hall Michael R. , Thoen Charles O.
Published: February 2025

Methods of producing antigen extracts of Mycobacterium bovis are described. Extraction of M bovis with a chaotropic salt, potassium chloride, or a nonionic detergent, Triton X-100, before autoclaving resulted in the production of soluble M bovis components. These antigens induced delayed-type hypersensitivity responses when injected intradermally in M bovis-sensitized guinea pigs. A comparison of the diameters of the hypersensitivity responses (on the basis of equal protein concentrations in the inoculums) revealed that the potassium chloride extract and the Triton extract of M bovis induced similar responses compared to the response induced with a purified protein derivative of M bovis. These findings indicate alternative methods may be used for the production of biologically active extracts of M bovis.
Ultrastructural myocardial alterations in monensin toxicosis of cattle
Authors: Van Vleet John F. , Ferrans Victor J.
Published: February 2025

The myocardial ultrastructural alterations induced in monensin toxicosis were studied in 20 beef calves weighing approximately 180 kg. Six of the calves were given (orally) 25 mg of monensin/kg of body weight, 7 calves were given 40 mg/kg and 5 calves were given 40 mg/kg on days 0 and 7; 2 calves were controls. The calves were euthanatized on days 1, 2, 4, 8, 9, and 11 to determine the sequential development of the cardiac lesions. The initial ultrastructural alterations seen in damaged myocytes from days 1 to 11 in all treated calves were extensive sarcoplasmic vacuolation from mitochondrial swelling and lipid droplet accumulation. By day 4, many degenerated myocytes also contained dense compact myelin figures. From day 4 to day 11, myocardial necrosis had developed in degenerated myocytes of the calves that were given the one or two 40 mg/kg doses of monensin. Necrotic myocytes appeared either as dense fibers with intact sarcomeres or disrupted fibers with hypercontraction bands. Lysing necrotic myocytes had disrupted masses of contractile material, pyknotic nuclei, swollen mitochondria with scattered dense matrical granules, and persisting “tubes” of external lamina. Areas of myocardial necrosis had extensive infiltration of macrophages into the inter-stitium and within the sarcolemmal “tubes” of necrotic myocytes. Macrophages engulfed and lysed fragments of necrotic myocytes. Occasionally, activated fibroblasts were present in the interstitium in areas of myocardial necrosis, but collagen deposition was not observed. Monensin cardiotoxicosis in cattle is characterized by initial myocyte degeneration and delayed onset of myocyte necrosis, and provides a useful model for studies of drug-related myocardial injury.
Respiratory syncytial virus pneumonia in young calves: Clinical and pathologic findings
Authors: Bryson D. G. , McNulty M. S. , Logan E. F. , Cush P. F.
Published: February 2025

Nine young calves given respiratory syncytial virus by a combined intranasal and intratracheal route developed a severe respiratory tract disease in which coughing, tachypnea, and hyperpnea were prominent clinical features. Calves were euthanatized on postinoculation (initial) days (pid) 1 to 13.

At necropsy, large areas of consolidation were present in the cranial, middle, accessory, and cranial parts of the caudal lung lobes of calves killed between pid 4 and 13. Histopathologic examination revealed widespread and severe lesions in small bronchi, bronchioli, and alveoli. Multinucleate epithelial syncytia on bronchiolar and alveolar walls, many containing eosinophilic intracytoplasmic inclusion bodies, were present in the lungs of calves killed on pid 4, 5, and 6. Necrosis and epithelial loss, hyperplasia, and metaplasia were also observed in the epithelium of small bronchi and bronchioli. The lumina of these airways were occluded to varying degrees with exudate. Exudate was present within alveoli, and interalveolar septa were markedly thickened. Collapse of the thickened septa produced large areas where alveolar air spaces were totally obliterated.

Repair was evident in the lungs of calves killed at pid 10 and 13 with reepithelialization of damaged bronchiolar mucosa, organization of bronchiolar exudate leading to bronchiolitis obliterans, and peribronchial and peribronchiolar fibrosis.

Inoculation of 3 calves by an intranasal route alone produced a less severe clinical disease with only minimal lesions present at necropsy.
Experimental respiratory syncytial virus pneumonia in young calves: Microbiologic and immunofluorescent findings
Authors: McNulty M. S. , Bryson D. G. , Allan G. M.
Published: February 2025

Young calves were inoculated with respiratory syncytial virus (rsv) intranasally or by a combined intranasal and intratracheal route and were killed between postinoculation (initial) days (pid) 1 and 14. Viral antigens were detected by immunofluorescence in nasopharyngeal cells from calves killed between pid 2 and 10. Evidence of infection of the trachea and lungs with rsv was obtained by immunofluorescence and virus isolation in calves inoculated by the combined route, but not in calves inoculated intranasally. Within the lungs, rsv antigens were observed in epithelial cells of bronchioli and alveoli.

The only virus detected in inoculated calves was rsv. With the exception of 1 calf, bacteria or mycoplasmas were not isolated from the lower respiratory tracts of inoculated calves. Antibody to rsv was not detected in calves killed up to pid 5, but 4 of 5 colostrum-deprived calves killed between pid 10 and 13 had antibodies to rsv. Preexisting, maternally derived antibody to rsv did not protect the calves from infection. Seemingly, the clinical signs of pneumonia and pathologic lesions observed in inoculated calves were caused by rsv infection.
A new analgesic drug combination in the horse
Authors: Robertson J. T. , Muir W. W.
Published: February 2025

A xylazine and butorphanol drug combination produced minimal and transient hemodynamic effects and no significant respiratory depression when administered to 6 healthy horses. Combining xylazine and butorphanol produced a synergistic analgesic effect and provided good chemical restraint for a standing surgical procedure.
Purification, characterization, and serologic characteristics of Bacteroides nodosus pili and use of a purified pili vaccine in sheep
Authors: Lee Simon W. , Alexander Barbara , McGowan Blaine
Published: February 2025

Hair-like appendages (pili) were isolated and purified from Bacteroides nodosus, the etiologic agent of foot rot disease in sheep.

Microscopic and biochemical analyses indicated that pili from organisms isolated in Australia, New Zealand, and the United States are morphologically and structurally similar. Pili are filamentous assemblies of identical protein subunits. Using specific antisera raised in rabbits against pili, 7 antigenic types were identified. A geographic pattern in the distribution of the pilus serotypes was not evident.

In a preliminary vaccine trial, sheep vaccinated with purified pili developed resistance to challenge exposure to B nodosus. Protection was correlated positively with the serum anti-pilus antibody titers.
Inoculation of neonatal gnotobiotic dogs with a canine rotavirus
Authors: Johnson Charles A. , Fulton Robert W. , Henk William G. , Snider Theron G.
Published: February 2025

Neonatal gnotobiotic dogs were inoculated orally with a rotavirus isolated from a pup with fatal diarrhea, and in the gnotobiotic dogs, diarrhea was observed between postinoculation hours (pih) 20 and 24. The diarrhea persisted through pih 154, and inoculated pups had clinical signs of dehydration after pih 24. Negative-contrast electron microscopy of the feces from inoculated pups revealed rotavirus particles from pih 12 through 154.

Using an indirect-fluorescent antibody test, serum rotavirus antibody was detected in inoculated pups by pih 96. In the duodenum, jejunum, and ileum of inoculated pups, group-specific rotaviral antigen was observed within absorptive villus epithelial cells and mononuclear cells in the villus lamina propria with an indirect-fluorescent antibody test. Fluorescence was seen in the small intestine of inoculated pups killed by pih 12 and was present in intestines of pups killed through pih 154. Rotaviral antigen was also seen in the mesenteric lymph nodes of a few inoculated pups killed at pih 48.
Influence of modified protein diets on the nutritional status of dogs with induced chronic renal failure
Authors: Polzin David J. , Osborne Carl A. , Stevens Jerry B. , Hayden David W.
Published: February 2025

The influence of a canine maintenance diet containing 44.4% protein (dry weight) and 2 reduced-protein renal-failure diets containing 8.2% or 17.2% protein (dry weight) on the nutritional status of dogs with induced chronic renal failure was evaluated for 40 weeks. Nutritional status was assessed by changes in serially determined body weights, hindlimb circumferences, serum protein concentrations, complete blood cell counts, serum cholesterol concentrations, glucose tolerance tests, and blood glucose concentrations. Evidence of suboptimum nutritional status was observed in dogs fed the 8.2% or 44.4% protein diets, but not in dogs fed the 17.2% protein diet. Only a small reduction in hindlimb circumference developed in dogs fed the 17.2% protein diet. Reduced body weight and hindlimb circumference and normocytic normochromic anemia developed in dogs fed the 44.4% protein diet. Reduced body weight and hindlimb circumference, hypoal-buminemia, hypoproteinemia, hypercholesterolemia, and normocytic normochromic anemia developed in dogs fed the 8.2% protein diet. A beneficial effect of moderate dietary protein restriction (17.2% protein) on the nutritional status of the dogs was observed. In contrast, excessive intake or restriction of dietary protein was associated with detrimental effects.
Detection of immune complexes in serum of dogs with neoplastic disease by solid-phase C1q binding, using an enzyme-linked immunosorbent assay
Authors: DeBoer Douglas J. , Madewell Bruce R.
Published: February 2025

A solid-phase C1q-binding assay for detection of serum immune complexes (ic) was modified for an enzyme-linked immunosorbent antibody method. The ic values were measured in sera from 25 clinically normal dogs and 74 dogs with histologically confirmed neoplastic disease. Serum ic values were expressed in micrograms of heat-aggregated canine immunoglobulin per milliliter that would produce equivalent binding under the same assay conditions. The ic concentrations in sera from normal dogs and dogs with neoplastic disease (mean ± sd) were 98 ± 45 and 701 ± 1,409 μg of aggregated canine immunoglobulin G equivalents/ml, respectively. Concentrations in the clinically normal group appeared to be distributed normally and clustered around the middle range of ic values. Dogs with neoplasms had ic values with an irregular distribution, and in general, more dogs had high and low concentrations of ic compared with those in the clinically normal group.
Sarcocystis infection in the white-tailed deer (Odocoileus virginianus) in Montana: Intensity and description of Sarcocystis odoi n sp
Authors: Dubey J. P. , Lozier Scott M.
Published: February 2025

Sarcocystis infection was diagnosed in 27 of 36 (75%) samples of meat from white-tailed deer (Odocoileus virginianus) in Montana. Two structurally distinct thin- and thick-walled sarcocysts were found in the white-tailed deer; the thin-walled sarcocysts were those of S odocoileocanis. A new name, S odoi, was proposed for the thick-walled sarcocysts. Sarcocysts of S odoi were up to 1,050 μm long and 260 μm wide and contained a 6.5- to 12-μm thick wall. The ultrastructure of sarcocysts of S odocoileocanis was compared with that of S odoi. A cat fed meat containing thin- and thick-walled sarcocysts shed oocysts and sporocysts 24 days later. The sporocysts in the cat's feces were 13.3 × 9.6 μm and probably belonged to S odoi.
Identification of canine T lymphocytes by membrane receptor to peanut agglutinin: T-lymphocyte identification in dogs with lupus-like syndrome
Authors: Rigal D. , Bendali-Ahcène S. , Monier J. C. , Mohana K. , Fournel C.
Published: February 2025

Canine T lymphocytes were detected, using fluorescent peanut agglutinin (pna) as a marker. Using a fluorescent technique and cytofluorometry, 70 ± 11% and 72.4%, respectively, of peripheral blood lymphocytes were bound to pna. Of thymocytes, 97 ± 4.5% were detected by fluorescent pna, but < 1% were detected for lymphocytes from bone marrow. The T-lymphocyte depletion and enrichment indicated that pna was bound to lymphocytes recognized by anti-T-lymphocyte heterologous serum. A T-lymphocyte deficiency was detected among 8 dogs with a lupus-like syndrome.
Development of Sarcocystis alceslatrans Dubey, 1980, in the small intestine of dogs
Authors: Colwell Douglas D. , Mahrt Jerome L.
Published: February 2025

Laboratory-reared dogs were fed moose musculature infected with Sarcocystis alceslatrans. These dogs shed sporocysts [15.6 × 11.4 µm (14.4 to 15.8 × 10.8 to 11.5)] 11 to 15 days after inoculation. The prepatent period was 10 to 14 days. Two cats and 1 coyote that also ate infected moose musculature did not pass sporocysts. Histologic examination of intestinal tissue from experimentally infected dogs revealed microgamonts, macrogametes, and oocysts. All stages were present in the lamina propria of the small intestine, usually in the luminal third of the villi. Infections were concentrated in the proximal half of the small intestine. Oocysts were first noticed in dogs killed 7 days after inoculation and a sequence of sporogonic development occurred in dogs killed on subsequent days. Ultrastructural observations were made on the oocyst and sporocyst walls during sporogony.
Hematologic and biochemical abnormalities associated with induced extrahepatic bile duct obstruction in the cat
Authors: Center S. A. , Baldwin B. H. , King J. M. , Tennant B. C.
Published: February 2025

Bile duct obstruction was induced in 6 cats by surgical ligation and transection of the common bile duct. Clinical and laboratory changes were monitored weekly for 25 to 54 days. Clinical signs of obstruction were similar in all cats and included anorexia, pyrexia, lethargy, intermittent vomiting, weight loss, palpable gallbladder, hepatomegaly, and bleeding tendencies. Tissue jaundice and acholic feces were evident grossly as early as postsurgical day (psd) 4 with a mean onset of jaundice at psd 5.3 ± 0.4.

Hematologic changes were initially characterized by a mild neutrophilic leukocytosis that increased with the chronicity of bile duct obstruction. Regenerative anemia developed in 4 cats associated with gastrointestinal blood loss. Acute serum biochemical changes were characterized by a marked increase in the mean values of aspartate aminotransferase, alanine aminotransferase, total cholesterol, and copper. Comparatively, only moderate increases in mean serum alkaline phosphatase activity were observed. Mean total bilirubin values increased remarkably at postsurgical week (psw) 1, reaching a maximal value of 23.1 ± 4.4 mg/dl at psw 3 with 71.6 ± 2.7% direct bilirubin.

With chronicity of bile duct obstruction ranging from psw 3 to psw 7, the mean serum values of aspartate aminotransferase, alanine aminotransferase, total cholesterol, serum alkaline phosphatase, and total and direct bilirubin stabilized and then declined, whereas the increased mean serum copper values persisted. At psd 25 to 54, hepatic copper values and serum bile acids were markedly increased. Seemingly, clinicopathologic changes of induced cholestatic hepatic injury depended largely on the duration of biliary obstruction. In addition to the conventionally used liver enzyme measurements, serum values of bile acids, total cholesterol, and copper may be of value in the assessment of clinical cholestatic hepatic injury in the cat.
Challenge exposure of cattle vaccinated with a chemically altered strain of Pasteurella haemolytica
Authors: Kucera C. J. , Wong J. C. S. , Feldner T. J.
Published: February 2025

Calves vaccinated with a chemically altered strain of Pasteurella haemolytica and their nonvaccinated controls were challenge exposed intranasally with the Cooper strain of infectious bovine rhinotracheitis virus. Five days later, the calves were challenge exposed intratracheally with the P haemolytica type A1.

Calves that had been vaccinated with large, medium, or small doses of the chemically altered vaccinal strain of P haemolytica had various degrees of resistance to the experimental challenge exposure. Nonvaccinated animals developed severe respiratory tract disease and pneumonia after challenge exposure.
Effect of the intramammary device on milk infection status, yield, and somatic cell count and on the morphological features of the lactiferous sinus of the bovine udder
Authors: Huston G. E. , Heald C. W.
Published: February 2025

Twenty primiparous heifers were fitted intramammarily with polyethylene coils in both quarters of one random right or left udder half at 5 days after parturition. Foremilk samples were collected and udder-half milk yields were measured at the afternoon milking on days −1, 3, 7, and 14 and on every 14th day for 8 months after the device was inserted. Three weeks after the heifers were fitted with the intramammary device, 6 were euthanatized for gross observation of devices and tissues and cytologic evaluation of the gland cistern epithelium.

There were significantly fewer bacterial isolations (P < 0.01) and less clinical mastitis (P < 0.05) in treated quarters than in the control quarters. Coagulase-negative staphylococci were isolated at frequencies of 0 and 15.2% for treated and control quarters. The reduction in isolation frequency for treated, compared with control, quarters was less marked with other organisms. Intramammary devices in no way interfered with the milking process. Milk yields per milking were 4.2 kg for treated udder halves compared with 4.4 kg for control halves; however, this 0.2 kg difference was not significant. Mean milk somatic cell counts, as determined by electronic counter, were 34 × 103 and 81 × 103 cells/ml for control and treated quarters (P < 0.05). Mean bovine serum albumin values were 0.160 and 0.175 mg/ml for control and treated udder halves (P < 0.05), indicating an increased capillary permeability due to the device. Quantitative morphologic analysis of gland cisterns showed a significant (P < 0.05) change toward a single layer of epithelial cells in treated quarters compared with a double layer in control quarters. Influence of intramammary devices on frequency of new infections probably is multifaceted, involving polymorphonuclear leukocyte migration, blood protein permeability, gland cistern epithelial modifications, and other undetermined mechanisms.