bluuebunny/crossref_metadata_2025 huggingface dataset:
Somatosensory-evoked potential induced by stimulation of the caudal tibial nerve in awake and barbiturate-anesthetized sheep
Authors: Wilson Richard D. , Beerwinkle Kenneth R.
Published: February 2025

The somatosensory-evoked potential (sep) from caudal tibial nerve stimulation was recorded in sheep, using surgically implanted electrodes. Peak latencies of the sep remained stable throughout the 3- to 5-month recording period. Wave-form and peak latencies from awake sheep and concomitant changes during barbiturate anesthesia were compared with those reported for other animal species, including man. Wave form components representing activities from the primary somesthetic cortex, association cortex, and nonspecific diffuse projections were differentially susceptible to barbiturate anesthesia. The neural source of the initial positive peak (mean latency = 19 ms) was resistant to anesthesia and represented primary somesthetic activity of the cortex. Sheep with surgically implanted electrodes yielded stable latencies with sep wave-form features essentially homologous to those reported for other animal species.
Pasteurella haemolytica leukotoxin: Chemiluminescent responses of peripheral blood leukocytes from several different mammalian species to leukotoxin- and opsonin-treated living and killed Pasteurella haemolytica and Staphylococcus aureus
Authors: Chang Yung-Fu , Renshaw Harland W. , Martens Ronald J. , Livingston Charles W.
Published: February 2025

A luminol-dependent chemiluminescence (ldcl) assay was used to assess the response of polymorphonuclear leukocyte (pmn) preparations from 4 species of ruminants (ie, cattle, sheep, goats, and antelopes) and 6 species of nonruminants (ie, swine, dogs, cats, rabbits, horses, and persons) to both opsonized and nonopsonized preparations of living and heat-killed Pasteurella haemolytica and Staphylococcus aureus and to opsonized and nonopsonized heat-killed strains of each bacterium in the presence of sterile culture supernatant (leukotoxin) from Ρ haemolytica. The ldcl responses of pmn preparations from each of the species studied were greater for living than for heat-killed S aureus. The most efficient ldcl emission was observed with reaction mixtures containing opsonized living S aureus. Regardless whether they contained killed or living bacteria, the opsonized S aureus preparations elicited ldcl emissions more efficiently than did the corresponding nonopsonized preparations.

Living Ρ haemolytica cells and their sterile culture supernatant inhibited the ldcl emissions of phagocytically stimulated pmn preparations from ruminants, but not those from nonruminants. The ldcl response of ruminant pmn to nonopsonized living Ρ haemolytica was characterized by the development of a peak response at 10 minutes of incubation followed by a precipitous decrease and a subsequent complete cessation of chemiluminescence. The peak ldcl response was higher for opsonized living Ρ haemolytica than for nonopsonized living bacteria, and the increased response lasted longer. However, opsonization of living Ρ haemolytica with the serum samples tested only temporarily spared the ruminant pmn preparations from the detrimental effects of leukotoxin. Regardless whether Ρ haemolytica leukotoxin was presented with opsonized or nonopsonized heat-killed S aureus or Ρ haemolytica, it was able to inhibit the ldcl response of pmn of ruminant sources, but not of nonruminants. Leukotoxin acted as a powerful phagocytic stimulus for non-ruminant pmn yielding a marked increase in light emission over that observed in the same reaction mixtures without leukotoxin.

It is suggested that Ρ haemolytica leukotoxin is a virulence factor involved in determining the species-associated occurrence of Ρ haemolyitca-induced pneumonia and that its action on leukocytes may be a molecular pathogenetic mechanism of consequence in early stages of the disease. The potential value of adapting the ldcl assay as a tool to measure opsonizing antibody to Ρ haemolytica cells is considered.
Virus isolation from semen of bulls serologically positive for bluetongue virus
Authors: Phillips R. M. , Carnahan D. L. , Rademacher D. J.
Published: February 2025

Isolation of bluetongue virus was attempted from 85 semen samples taken from 3 long-term seropositive bulls and 9 short-term seropositive bulls in an artificial breeding service unit. Two types of cell cultures susceptible to bluetongue virus were used for virus isolation. Extended sonication, centrifugation of specimens, and treatment of cell cultures with dimethyl sulfoxide and diethyl-aminoethyl-dextran were used to enhance virus attachment and infection of cell cultures. Virus isolation results were negative on all specimens. These results indicate that at the limits of the methods used, bluetongue virus-seropositive bulls do not have long-term latent bluetongue virus in their semen.
Pharmacokinetics of cefotaxime in the domestic cat
Authors: McElroy Donita , Ravis W. R. , Clark Carl H.
Published: February 2025

Cefotaxime was administered as single iv or im dose for the purpose of examining its pharmacokinetics in healthy cats. The mean predicted plasma concentration of cefotaxime in 6 cats at 0 time after a single iv dosage of 10 mg/kg of body weight was 88.9 μg/ml. The mean plasma concentrations decreased to 10.8 μg/ml at 2 hours, 3.7 μg/ml at 3 hours, and 0.5 μg/ml at 6 hours. The half-life was 0.98 ± 0.25 hour (mean ± sd), and the total body clearance was determined to be 2.76 ± 1.25 ml/min/kg. After a single im injection of 10 mg/kg of body weight, the mean maximum observed plasma concentration was 36.2 μg/ml at 0.75 hour. The mean absorption half-life was 0.24 hour. In 2 animals, the bioavailability of an im injection was 98.2% and 93.0%.
Pharmacokinetics of probenecid and the effect of oral probenecid administration on the pharmacokinetics of cefazolin in mares
Authors: Donecker J. M. , Sams R. A. , Ashcraft S. M.
Published: February 2025

The pharmacokinetics and bioavailability of probenecid given iv and orally at the dosage level of 10 mg/kg of body weight to mares were investigated. Probenecid given iv was characterized by a rapid disposition phase with a mean half-life of 14.0 minutes and a subsequent slower elimination phase with a mean half-life of 87.8 minutes in 5 of 6 mares. In the remaining mare, a rapid disposition phase was not observed, and the half-life of the elimination phase was slower (172 minutes). The mean residence time of probenecid averaged 116 minutes for all 6 mares and 89.2 minutes for the 5 mares with biphasic disposition. The total plasma clearance of probenecid averaged 1.18 ± 0.49 ml/min/kg, whereas renal clearance accounted for 42.6 ± 9.3% of the total clearance. The steady-state volume of distribution of probenecid averaged 116 ± 28.2 ml/kg. Plasma protein binding of probenecid was extensive, with 99.9% of the drug bound at plasma probenecid concentrations of 10 μg/ml.

The maximum plasma probenecid concentration after 10 mg/kg orally averaged nearly 30 μg/ml. The half-life of probenecid after oral administration was approximately 120 minutes. Oral bioavailability was good with > 90% of the dose absorbed.

The effect of probenecid on tubular secretion of organic anions was evaluated by determining the pharmacokinetics of iv cefazolin (11 mg/kg) administered alone and 15 minutes after probenecid (10 mg/kg orally). Treatment with probenecid did not affect pharmacokinetic values of cefazolin. This failure of probenecid to alter the pharmacokinetics of cefazolin may be caused by insufficient plasma probenecid concentrations after the oral dose.
Bovine herpesvirus-1 and Pasteurella haemolytica aerobiology in experimentally infected calves
Authors: Jericho K. W. F. , Lejeune A. , Tiffin G. B.
Published: February 2025

Eight calves (2 calves in each of 4 groups) were exposed to an aerosol of bovine herpesvirus-1 (bhv-1) and 4 days later to an aerosol of Pasteurella haemolytica. Samples of tracheal and exhaled air were taken simultaneously beginning 1 day before viral exposure and once a day up to 3 to 4 days after the bacterial exposure. Samples were also taken during the period of aerosol exposure. Only 0.04% to 0.42% of P haemolytica-carrying droplets of the bacterial aerosol passed beyond the cranial part of the respiratory tract to the trachea. Nevertheless, numbers of bacteria as few as 1 bacterium/L of tracheal air were sufficient to produce fatal disease in the lungs of bhv-1-infected calves. In 1 of the 4 groups, bhv-1 was isolated from most daily samples of exhaled and tracheal air. Pasteurella haemolytica was isolated 7 times more frequently from air when calves were kept at 1 C than when calves were kept at 23 C. The number of P haemolytica-carrying droplets in exhaled air was low (< 1/L of air); however, samples obtained during the time that calves were coughing contained up to 10 P haemolytica-carrying droplets/L of air. It was learned that the cranial part of the respiratory tract serves as an efficient filter on inhalation and exhalation, but this filter is deficient in the animal when coughing occurs. This process expels infective droplets of size suitable for inhalation by other cattle in close proximity.
Comparative prevalence of four enterotoxin genes among Escherichia coli isolated from swine
Authors: Moon Harley W. , Schneider Robert A. , Moseley Steve L.
Published: February 2025

Presence of Escherichia coli enterotoxin genes LT (heat-labile enterotoxin), STaP (heat-stable enterotoxin a, porcine genotype), STaH (heat-stable enterotoxin a, human genotype), and STb (heat-stable enterotoxin b) among 874 swine isolates of E coli was determined, using DNA probes and the DNA colony hybridization technique. Of the 874 isolates evaluated, 45% hybridized with at least one of the enterotoxin gene probes and were designated as enterotoxigenic E coli (etec). Eighty-five percent of the etec were from pigs with enteric colibacillosis. The remaining 15% were from pigs with edema disease or various other diseases, and from healthy swine. Seventy-four percent of the etec hybridized with the STb probe, 52% with STaP, and 31% with LT; etec did not hybridize with the STaH probe. Most of the etec hybridized with more than one enterotoxin gene probe. Isolates that hybridized with the LT probe also hybridized with STb. The most prevalent gene combination was LT-STb. However, 35% of the etec from neonatal (≤ 1 week old) swine with enteric colibacillosis were of the STaP-only genotype, and 33% of the etec from older swine with enteric colibacillosis were of the STb-only genotype.
Growth inhibition of environmental mastitis pathogens during physiologic transitions of the bovine mammary gland
Authors: Breau W. C. , Oliver S. P.
Published: February 2025

Ten dairy cows were infused intramammarily near drying off with concanavalin A (conA) or phytohemagglutinin (pha). Mammary secretions were collected during physiologic transitions of the udder and were used in an in vitro microbiological assay to determine growth inhibition of mastitis pathogens. As mammary involution progressed, in vitro growth inhibition of Klebsiella pneumoniae, Escherichia coli, and Streptococcus uberis increased. Mammary secretions from conA- and pha-treated glands had significantly increased bacterial growth inhibition. Secretions contained significantly increased concentrations of lactoferrin and a decreased citrate:lactoferrin molar ratio earlier in the dry period than did control mammary secretions. Greatest bacterial growth inhibition was observed in mammary secretions obtained 7 days before parturition. However, differences in secretion composition or bacterial growth inhibition were not found between conA- or pha-treated and control udder halves during the prepartum period. Bacterial growth inhibition by mammary secretion decreased markedly during early lactation. A highly significant positive correlation was found between bacterial growth inhibition and concentrations of lactoferrin, serum albumin, and immunoglobulin G. A highly significant negative correlation was found in the citrate:lactoferrin molar ratio during early involution and the peripartum period.
Seroepizootiologic study of bovine respiratory syncytial virus in a dairy herd
Authors: Baker John C. , Ames Trevor R. , Markham R. J. F.
Published: February 2025

A 16-month seroepizootiologic study of bovine respiratory syncytial virus (brsv) infection was conducted in a dairy herd. Results indicated that antibodies to brsv present in serum from newborn calves were derived through the ingestion of colostrum. This passive immunity in calves became undetectable in an average of 99 days (sd = 36.5; range = 30 to 208 days). Two epizootics of respiratory tract disease occurred during the study period, and an association with brsv was demonstrated in both epizootics. In the 2 epizootics, clinical signs of respiratory tract disease were only mildly to moderately severe, with no mortality or evidence of chronic pneumonia occurring. Seemingly, the passive immunity failed to protect calves from infection and disease caused by brsv. Additionally, it was observed that if active immunity was induced by infection with brsv, this immunity protected from the development of clinical disease, but not from reinfection upon subsequent exposures to brsv.
Seroepizootiologic study of bovine respiratory syncytial virus in a beef herd
Authors: Baker John C. , Ames Trevor R. , Werdin Ronald E.
Published: February 2025

A seroepizootiologic study of bovine respiratory syncytial virus in a beef herd was conducted from February 1983 through March 1984. During the study period, 3 separate respiratory tract disease epizootics were recognized in calves after they had been split into 3 groups. Bovine respiratory syncytial virus infection was diagnosed in each epizootic on the basis of serologic evidence, postmortem findings, and immunofluorescent examination of lung tissue. Additionally, there was serologic evidence for involvement of bovine adenovirus type 3 in the epizootics in 2 of the groups of calves, but not in the 3rd. In 2 groups of calves, respiratory tract disease occurred in 2 stages, with the 1st stage being mild followed by apparent recovery. The 2nd stage, which was associated with a change to colder weather, was clinically more severe, with death loss occurring.
Epidemiologic study of campylobacteriosis in Iowa cattle and the possible role of unpasteurized milk as a vehicle of infection
Authors: Warner David P. , Bryner John H. , Beran George W.
Published: February 2025

Bile samples were collected from 477 Iowa dairy cows and were cultured for thermophilic campylobacters. The prevalence of thermophilic campylobacters in the bile was 15.5%. Campylobacter jejuni and C coli from dairy cattle, chickens, pigs, sheep, and human beings were serotyped to develop host-species profiles. Human and cattle serologic profiles were the most similar, and human and chicken profiles shared several similarities. Epidemiologic data from 168 human cases of campylobacteriosis indicated that 23% of the cases were associated with consumption of unpasteurized milk.
Baroreceptor control of heart rate in chickens (Gallus domesticus)
Authors: Bagshaw Roger J. , Cox Robert H.
Published: February 2025

The baroreceptor control of heart rate was examined in nonanesthetized, nonrestrained, White Leghorn chickens (n = 10) by measuring the heart period response to modest increases in systolic blood pressure induced by iv boluses of phenylephrine (0.04 μg/g). In each animal, a sciatic artery and a femoral vein were chronically instrumented for the measurement of blood pressure and heart rate, together with venous access.

Sustained and consistent cardiac slowing was seen in all chickens in response to small increases in systolic pressure. The mean slope of the regression equation between heart period and systolic pressure was 13.9 ± 0.8 s · 10−4/mm of Hg. This sensitivity was reduced to 2.1 ± 1.5 s · 10−4/mm of Hg by anesthetizing the chickens with isoflurane (inspired concentrations of 1%).
Echocardiographic assessment of left ventricular dimensions in clinically normal English Cocker Spaniels
Authors: Gooding Jean P. , Robinson Wayne F. , Mews Geoffrey C.
Published: February 2025

Seventeen clinically normal adult English Cocker Spaniels from a kennel population with a history of cardiomyopathy were assessed, using M-mode echocardiography, to establish reference values for left ventricular (lv) dimensions for this breed of dog. Echocardiographic measurements were compared with postmortem measurements in 10 of 17 dogs. The lv weight calculated from the echocardiographic measurements correlated significantly with lv weight at postmortem (P < 0.05). Echocardiographic measurements of end diastolic and end systolic diameters for the 17 dogs correlated significantly with body surface area (P < 0.01). Measurements of the interventricular septum were in close agreement with values in clinically normal dogs and were significantly correlated with postmortem measurements (r = 0.94, P < 0.01). However, 76% of the measurements for lv caudal wall thickness in this group of dogs were above the normal range.

Calculation of fractional shortening values identified a group of 5 dogs with reduced fractional shortening (mean ± sd, 20.97 ± 3.66%), which indicates that a depression in contractility may be present in some apparently healthy dogs of this kennel population. The remaining 12 dogs had fractional shortening values of mean ± sd, 34.26 ± 4.54%.
Pathologic changes in lambs with Ostertagia circumcincta infections associated with decreased infectivity of Haemonchus contortus
Authors: Blanchard J. L. , Gallina A. M. , Wescott R. B.
Published: February 2025

Two experiments were done to examine the severity and type of abomasal lesions induced by moderate infections of Ostertagia circumcincta in young lambs and to examine the differences in pathologic changes in lambs with monospecific and combined infections of O circumcincta and Haemonchus contortus. Observations included descriptions of gross and microscopic changes in the abomasums, as well as quantitative analysis of the thickness of the mucosa, numbers of mucus-containing cells, and inflammatory cell accumulations. Seemingly, the changes in the abomasal mucosa of lambs inoculated with O circumcincta were mild and included dilated glands, focal accumulations of lymphocytes, and significant (P < 0.05) numerical increases of mucus-containing cells, eosinophils, and globule leukocytes, and increase of mucosal thickness when compared with those in noninoculated controls. These differences were less pronounced in lambs given anthelmintic treatment to remove O circumcincta. When H contortus infections were superimposed upon O circumcincta infection, the changes were essentially the same as those described for O circumcincta plus a small, but significant (P < 0.05), numerical increase of globule leukocytes. Abomasal mucosa of lambs inoculated only with H contortus was more roughened and hyperemic than that of lambs with combined infections, but contained few dilated glands and globule leukocytes. Our conclusions were that moderate infection with O circumcincta did not cause severe or permanent damage to the abomasal mucosa and that such infection decreased the severity of the gross lesions produced by H contortus.
Eyeworms (Thelazia lacrymalis) in one- to four-year-old Thoroughbreds at necropsy in Kentucky (1984 to 1985)
Authors: Lyons E. T. , Tolliver S. C. , Drudge J. H. , Swerczek T. W. , Crowe M. W.
Published: February 2025

From Mar 1, 1984, to Feb 28, 1985, both eyes from 189 one- to four-year-old Thoroughbreds (88 males, 90 females, and 11 geldings) in Kentucky were examined at necropsy for eyeworms. Thelazia lacrymalis was recovered from 45% of 1-year-old horses, 26% of 2-year-old horses, 45% of 3-year-old horses, and 50% of 4-year-old horses; overall, 43% of 1- to 4-year-old horses were infected. Prevalence of eyeworms in horses in the present study was comparable with that in horses of similar ages examined at necropsy in Kentucky in 2 previous studies (1975 to 1976 and in 1979), except for the lower percentage of infected 2-year-old Thoroughbreds in the present study.
Interaction between canine platelets and adult heartworms: Platelet recognition of heartworm surfaces
Authors: Clemmons R. M. , Yamaguchi R. A. , Schaub R. G. , Fleming J. , Dorsey-Lee M. R. , McDonald T. L.
Published: February 2025

An interaction between blood platelets and adult heartworms was examined in vitro. Surfaces of glutaraldehyde-fixed heartworms, which were taken from infected dogs, washed, and incubated in platelet-rich plasma (prp), were evaluated by scanning electron microscopy. Adherence of platelets to heartworms occurred only with prp from infected dogs. Aggregation to epinephrine and adenosine diphosphate of prp incubated with heartworms was monitored. Seemingly, platelet activation to heartworm membranes occurs in dogs with heartworm disease. The increased platelet reactivity was also observed in dogs with occult heartworm disease, indicating that the presence of circulating microfilaria was not important for this process. The ability to transfer the reactivity to heartworm-negative platelets by suspending them in heartworm-positive plasma indicated that this reactivity resided in the plasma. The processes leading to platelet activation may be responsible for the platelet-associated vascular disorders of canine heartworm disease.
Efficacy of oxfendazole as administered by intraruminal injection to naturally infected calves
Authors: Yazwinski T. A. , Presson B. L. , Featherstone H.
Published: February 2025

Oxfendazole, formulated into a 22.5% suspension, was administered by intraruminal injection to cattle at the rates of 0, 1.125, 2.25, 4.50, and 6.75 mg/kg of body weight. In total, 50 naturally infected calves were used, with 10 animals being allocated to each of the 5 treatment groups on the basis of pretreatment counts of nematode eggs per gram of feces. All animals were necropsied 7 days after treatment. The trial was done between December 1983 and January 1984, with the animals kept on concrete for a minimum of 35 days immediately before necropsy. For all nematodes and stages combined, efficacies were 97.4%, 98.8%, 99.5%, and 99.8% for oxfendazole at dosages of 1.125, 2.25, 4.50, and 6.75 mg/kg of body weight, respectively. Early 4th-stage larvae of Ostertagia and Nematodirus helvetianus adults were eliminated at rates > 93% only at the dosages of 4.50 mg/kg and above. Local or systemic adverse reactions were not observed in any of the animals.
Hepatic morphology and effects of intravenous injection of sodium propionate on plasma propionate and glucose in fed and fasted dairy cattle
Authors: Bruss M. L. , Grùhn Y. , Huffman E. M. , Lindberg L.-A.
Published: February 2025

Sodium propionate (3 mmol/kg) was injected iv into 8 nonlactating dairy cows before and after 6 days (144 hours) of fasting. During fasting, long-chain fatty acids in plasma increased from 0.30 ± 0.05 (se) mM to 1.09 ± 0.15 mM (P < 0.05). Liver fat increased from 0.5 ± 0.3% to 9.3 ± 1.7% (P < 0.05). Half-life of injected sodium propionate increased significantly (P < 0.05) from 7.6 ± 0.5 minutes to 10.1 ± 1.0 minutes during fasting. Sulfobromophthalein half-life did not change significantly (3.8 ± 0.79 minutes to 5.3 ± 1.3 minutes). Increases in plasma glucose concentrations after propionate loading were significantly less during fasting than during feeding. Thus, the change in glucose concentration served as an indicator of hepatic conversion of propionate to glucose. Increases in glucose concentration of less than 2 mM at 30 minutes after propionate loading indicated that liver function was altered in nonlactating dairy cows.
Long-term biochemical and physiologic effects of surgically placed portacaval shunts in dogs
Authors: Schaeffer Monica C. , Rogers Quinton R. , Buffington C. A. , Wolfe Bruce M. , Strombeck Donald R.
Published: February 2025

After surgical placement of end-to-side portacaval shunts (pcs), 4 adult mongrel dogs (11.8 to 18.2 kg) were fed purified diets and monitored for approximately 50 weeks for changes in body weight, neurologic status, and an array of clinically important biochemical variables. Two healthy dogs, fed the same diets and maintained in the same environment, were also observed (controls). Body weights were relatively stable over the period of observation. The branched-chain ratio ([valine] + [leucine] + [isoleucine]/[phenylalanine] + [tyrosine]), an index of the degree of change in plasma amino acid concentrations, was significantly lower in dogs with pcs than in controls. Despite this depression in branched-chain ratio, the principals (dogs with pcs) were essentially free of neurologic symptoms. Statistically significant decreases due to portacaval shunting were seen in the serum concentrations of glucose, calcium, urea nitrogen, creatinine, cholesterol, and albumin. Total protein, globulin, and triglyceride concentrations tended to be lower in the serum of principals than in serum of controls, but the differences were not statistically significant. Statistically significant increases due to portacaval shunting were seen in plasma concentrations of total conjugated bile acids and sulfobromophthalein retention. Concentrations of the following compounds tended to be higher in serum of principals than in serum of controls: phosphorus, chloride, uric acid, total bilirubin, lactate dehydrogenase, aspartate transaminase, alanine transaminase, and alkaline phosphatase. Liver biopsy at 7 months after operation showed mild-to-extensive atrophy of hepatocytes, mild-to-extensive fibrosis, and collapsed portal veins in all principals examined.
Normal blood supply of the canine patella
Authors: Howard Paul E. , Wilson James W. , Robbins Teresa A. , Ribble Gail A.
Published: February 2025

The normal blood supply of the canine patella was evaluated, using microangiography and correlated histology. Arterioles entered the cortex of the patella at multiple sites along the medial, lateral, and dorsal aspects. The body of the patella was vascularized uniformly, with many arterioles that branched and anastomosed extensively throughout the patella. The patella was not dependent on a single nutrient artery for its afferent supply, but had an extensive interior vascular network. These factors should ensure rapid revascularization and healing of patellar fractures, provided appropriate fracture fixation is achieved.
Effects of urinary bladder distention on location of the urinary bladder and urethra of healthy dogs and cats
Authors: Johnston Gary R. , Osborne Carl A. , Jessen Carl R. , Feeney Daniel A.
Published: February 2025

Evaluation of the anatomic location of the distended and empty urinary bladders and urethras of healthy adult male and female dogs and cats by retrograde urethrocystography revealed substantial variations. In 15 dogs in lateral recumbency with empty bladder lumens, the caudal portion of the urinary bladder was within the pelvic canal in 5 of 7 male and 5 of 8 female dogs. In female dogs examined in ventrodorsal recumbency, only 4 of 8 had the empty urinary bladders in part within the pelvic canal. After luminal distention, 3 of 7 male and 3 of 8 female dogs, while in lateral recumbency, had the urinary bladders in part intrapelvically. However, when female dogs were placed in ventrodorsal recumbency, only 1 of 7 urinary bladders was in part within the pelvis. The urinary bladders of 14 cats were consistently within the abdominal cavity, irrespective of whether the bladder lumen was distended or empty.

Urethral flexures occurred in dogs with intrapelvic bladders that were distended or empty. Urethral flexures were not found in cats. The urethras of dogs and cats in lateral recumbency were generally closer to the floor of the pelvis after urinary bladder distention than when the bladder was empty. The urethra of the dogs and cats in ventrodorsal recumbency was to the left or right of or on the midsagittal plane, whether the urinary bladder was empty or distended. A greater degree of lateral displacement was encountered in ventrodorsal recumbency after urinary bladder distention.
Polymorphonuclear leukocyte function in cattle with left displaced abomasum with or without concurrent infections
Authors: Gyang E. O. , Markham R. J. F. , Usenik E. A. , Maheswaran S. K.
Published: February 2025

Cattle submitted to the University of Minnesota for surgical correction of left displaced abomasum (lda) were examined for the in vitro phagocytic and bactericidal activities of their polymorphonuclear leukocytes (pmn). The pmn from cattle with lda with or without concurrent infection had depressed phagocytic function when compared with pmn from healthy animals (controls). Those with concurrent infection had phagocytic activities lower than those in the group of cattle with lda without any concurrent infection, and the former group was also observed to have depressed intracellular killing. Cattle with lda complicated by infection were the only group in which phagocytic function was altered during surgical correction of lda (and recovery). Treatment of pmn from both groups of affected cattle with levamisole in vitro enhanced intracellular killing, but had no effect on phagocytosis.
In vitro bactericidal efficacy of equine polymorphonuclear leukocytes against Corynebacterium equi
Authors: Yager J. A. , Foster S. F. , Zink M. C. , Prescott J. F. , Lumsden J. H.
Published: February 2025

Polymorphonuclear leukocytes from adult horses were separated from whole blood, using a 2-step Percoll gradient, and were tested for bactericidal function against Corynebacterium equi. Staphylococcus aureus, an organism against which equine neutrophils have proved efficacy, was a positive control. The percentage of uptake after a 15-minute preincubation of the neutrophils and bacteria in the presence of normal horse serum was also calculated. The results indicated that equine neutrophils effectively phagocytosed and killed C equi and S aureus. The percentage of uptake for S aureus (95% ± 3%) was greater than that for C equi (85% ± 6%) (P < 0.001), but the bactericidal efficacy was equivalent. More than 90% of the ingested or attached bacteria were destroyed during the 3-hour incubation period (mean percentage of C equi killed = 96 ± 2%; mean percentage of S aureus killed = 91 ± 8%). These results indicated that a failure of bacterial killing by neutrophils is unlikely to be important in the pathogenesis of C equi pneumonia in the horse.
In vitro sulfoxidation of albendazole by ovine liver microsomes: Assay and frequency of various xenobiotics
Authors: Galtier P. , Alvinerie M. , Delatour P.
Published: February 2025

The in vitro biological oxidation of albendazole to its pharmacologically active sulfoxide and its sulfone by ovine liver microsomes has been studied. Sulfoxidation (maximal rate = 0.412 nmole/min/mg of protein, Michaelis constant = 185 × 10−6 M) was 107 times more potent than formation of albendazole sulfone. The sulfoxidation corresponds to a reduced nicotinamide-adenine dinucleotide phosphate-dependent enzymatic system characterized by a pH optima value around 8. Flavin adenine dinucleotide-containing monooxygenase could be responsible for this S-oxygenation because of the strong inhibitory effect of methimazole.

Albendazole sulfoxidase is inhibited competitively by the related anthelmintic drug fenbendazole (inhibitory constant = 243 × 10−6M) and noncompetitively by chlorpromazine (inhibitory constant = 135 × 10−6M). At high concentration, chloramphenicol, erythromycin, nalidixic acid, and hexobarbital are less active inhibitors, whereas dexamethasone acetate significantly enhances the reaction which is not inhibited by either carbon monoxide, griseofulvin, imidazole, phenylbutazone, or proadifen.
Anti-tumor evaluation of benzaldehyde in the dog and cat
Authors: MacEwen E. Gregory
Published: February 2025

Fourteen dogs and 11 cats with various malignant tumors were treated daily with benzaldehyde at a dosage rate of 10 mg/kg of body weight, orally, divided into 4 doses. Clinical signs of toxicosis were not observed. A partial response (> 50% regression) was observed in animals with an oral squamous cell carcinoma and an oral melanoma. A minimal response (< 50% regression) was observed in animals with a sweat gland adenocarcinoma and a mast cell sarcoma. One dog with an oral melanoma had stabilization of tumor growth for 8 weeks. Seemingly, benzaldehyde has only minimal anti-tumor activity at the dose studied.
Effect of flushing the vasa deferentiaa at the time of vasectomy on the rate of clearance of spermatozoa from the ejaculates of dogs and cats
Authors: Frenette M. D. , Dooley M. P. , Pineda M. H.
Published: February 2025

Flushing the vasa deferentia (ductus deferentes)a at the time of vasectomy reduced to zero the number of intact spermatozoa by postvasectomy day 6 in the dog and by postvasectomy day 7 in the cat and shortened the time from vasectomy to azoospermia in the dog, but not in the cat. The fluid used to flush the vasa deferentia was not eliminated through the penile urethra, but flowed into the urinary bladder, indicating that the least resistant pathway for the exit of vasal content in the anesthetized dog and cat is toward the urinary bladder. Both control and treated dogs and cats had spermatozoa in the urine obtained by cystocentesis immediately after ejaculation or ejaculation and flushing of the vasa deferentia.

Flushing the vasa deferentia at the time of vasectomy is easy to do, safe, and can be used in clinical practice to decrease the time from vasectomy to the safe utilization of dogs and cats as teasers. The procedure has potential application to males of other species.
Types of myofibers parasitized in experimentally induced infections with Sarcocystis cruzi and Sarcocystis capracanis
Authors: Powell E. C. , Pezeshkpour G. , Dubey J. P. , Fayer R.
Published: February 2025

Eighteen calves were orally inoculated with either 200,000 or 225,000 sporocysts of Sarcocystis cruzi. Eight goats were orally inoculated with 20,000 sporocysts of S capracanis. Calves and goats were euthanatized at various times after inoculation, and portions of their right and left biceps femoris, right and left longissimus dorsi, myocardium, and tongue were frozen at −150 C in pre-cooled isopentane and stored at −70 C. Frozen sections of these muscles were stained with hematoxylin and eosin, modified Gomori's trichrome, nonspecific esterase, diphosphopyridine nucleotide tetrazolium reductase, and adenosinetriphosphatase at pH 10.4 and 4.6. Muscle from the same locations was fixed in 10% neutral buffered formalin, processed for paraffin embedding, sectioned, and stained with hematoxylin and eosin. Microscopic examination of both calf and goat tissue indicated that both type I and type II muscle fibers were equally infected and that infected myofibers showed no apparent damage other than displacement by sarcocysts. Occasionally, muscle fibers within the muscle spindles contained sarcocysts.
Survival of Corynebacterium pseudotuberculosis in axenic purulent exudate on common barnyard fomites
Authors: Augustine John L. , Renshaw Harland W.
Published: February 2025

Several inanimate surfaces (eg, plastic, wood, and steel) and particulate fomites (eg, wood shavings, hay, straw, and feces), common to the environment of confined small ruminants, were inoculated with Corynebacterium pseudotuberculosis in axenic purulent exudate that had been surgically removed from a naturally occurring case of caprine caseous lymphadenitis. Each inoculated fomite was incubated at 37, 22, and 4 C, and the length of time that C pseudotuberculosis survived was determined by isolation of bacteria from the fomite. The organism remained viable longer when caseous lymphadenitis abscess contents were mixed with particulate fomites than when spread on surfaces. Incubation at lower temperatures generally extended the survival potential of C pseudotuberculosis. Depending on the particulate fomite and the incubation temperature, viable C pseudotuberculosis organisms were isolated for mean periods ranging from 7 to 55 days, whereas recovery of bacteria from surfaces varied from 1 to 8 days.
Pasteurella haemolytica leukotoxin: Physicochemical characteristics and susceptibility of leukotoxin to enzymatic treatment
Authors: Chang Yung-Fu , Renshaw Harland W. , Richards Alan B.
Published: February 2025

Sterile, concentrated culture supernatant from Pasteurella haemolytica (biotype A, serotype 1) strain 630 was subjected to physical, chemical, and immunologic treatments to determine their influence on leukotoxin (cytotoxin) activity contained in the supernatant. Each treated sample contained approximately 8 chemiluminescence inhibitory units of leukotoxin. Treatment effects were evaluated for their ability to inactivate leukotoxin activity. Leukotoxin activity in treated samples was determined by inhibition of the luminol-dependent chemiluminescence response of bovine neutrophils. Optimal leukotoxin synthesis by Ρ haemolytica occurred when the bacteria were at the logarithmic growth phase, whereas stationary phase cultures contained minimal amounts of leukotoxin activity in their culture supernatant. Leukotoxin activity was heat labile; activity was substantially decreased when concentrated culture supernatant samples containing leukotoxin activity were incubated at 37 C for several hours. When concentrated culture supernatant was incubated at progressively decreasing temperatures, there was a progressive increase in the length of time that the leukotoxin retained its biologic activity. Samples stored at − 70 C retained activity for at least 2 months. Leukotoxin activity was nondialyzable and was able to withstand considerable extremes in hydrogen ion concentration. Leukotoxin activity could not be pelleted when subjected to forces of 100,000 × g for 1 hour.

Chemical and enzymatic studies suggested that Ρ haemolytica leukotoxin contained carbohydrate and protein moieties. Chemical treatment with 0.2% sodium lauryl sulfate, 0.5% sodium deoxycholate, 7.5 mM EDTA and 8M urea with 8 mM 2-mercaptoethanol and enzymatic treatment with lipase, ribonuclease, and deoxyribonuclease had no discernible effect on leukotoxin activity. However, chemical treatment with appropriate concentrations of potassium metaperiodate and enzymatic treatment with chymotrypsin, trypsin, protease, and amylase completely inactivated leukotoxin activity. The leukotoxin preparation was without hemolytic activity against erythrocyte suspensions prepared from 12 different nonhuman animals and from human beings with each of the 4 ABO blood groups (A, B, O, and AB). Bovine fetal serum was without neutralizing activity against leukotoxin. Neutralizing activity was found in a serum pool from young cattle and in a convalescent phase serum collected from a cow that had recovered from spontaneously occurring pneumonia caused by Ρ haemolytica. Collectively, results from this study and previous studies suggest that metabolically active Ρ haemolytica synthesize and secrete into the culture supernatant a heat-labile, oxygen-stable, pH-stable, nondialyzable, nonhemolytic, and water-soluble antigenic glycoprotein that is toxic to ruminant leukocytes and that may be an important virulence factor of the microorganism.
Enterotoxin activity of a Salmonella typhimurium of equine origin in vivo in rabbits and the effect of Salmonella culture lysates and cholera toxin on equine colonic mucosa in vitro
Authors: Murray Michael J.
Published: February 2025

To determine whether a strain of Salmonella typhimurium (UCD 1755) of equine origin had enterotoxin activity, 2 ml of a cell-free culture lysate of strain UCD 1755 and approximately 109 viable strain UCD 1755 organisms were inoculated into ligated small intestinal segments of rabbits. Intestinal segments inoculated with viable strain UCD 1755 organisms and those inoculated with a cell-free culture lysate of strain UCD 1755 had significant (P < 0.05) accumulations of fluid 10 hours after inoculation when compared with ligated intestinal segments either inoculated with sterile brain-heart infusion broth or left empty. There was not a statistically significant difference between fluid accumulation of intestinal segments inoculated with viable strain UCD 1755 and that of segments inoculated with a cell-free culture lysate of strain UCD 1755.

The responses of equine colonic mucosa to culture filtrates of 2 strains of Salmonella typhimurium (UCD 1755 and SL 1027) and purified cholera toxin were studied in vitro. Isolated samples of colonic mucosa were incubated for 4 hours at 37 C in Krebs-Henseleit bicarbonate buffer (khb) alone, khb plus culture lysate of strain UCD 1755, khb plus culture lysate of strain SL 1027, and khb plus 1 μg of cholera toxin/ml. Cyclic adenosine monophosphate (cAMP) content of each sample was determined. Mucosa incubated in khb plus cholera toxin had a significantly (P < 0.01) greater cAMP content than did mucosa incubated in khb alone. Mucosa incubated in either khb plus strain UCD 1755 culture lysate or khb plus strain SL 1027 lysate had a greater cAMP content than did mucosa incubated in khb alone, but the difference was not significant.
Seroepizootiology of types 3 and 7 adenoviruses and bovine viral diarrhea virus infections of beef cattle from birth to first parturition
Authors: Stauber Ε. H. , Abinanti F. R. , Whitbeck G. D.
Published: February 2025

Twenty-nine female Angus cattle were monitored from birth until 24 months of age for infection with types 3 and 7 adenoviruses (AV3, AV7) and bovine viral diarrhea (bvd) virus by virus isolation and neutralization tests. Twenty-seven animals remained in the study for 450 days, whereas 16 animals remained at the conclusion of the tests. Viruses were not isolated from test animals. Seroepizootiologic examination indicated that there were 28 infections with AV3, 33 infections with AV7, and 13 infections with bvd virus. Of these infections, 5 with AV3, 6 with AV7, and 2 with bvd virus were reinfections. All but 1 primary AV3 infection had occurred between 180 and 360 days after parturition. Infection with AV7 occurred earlier than that with AV3, as shown by 6 seropositive animals by 180 days. Most adenovirus infections were documented after animals had left confinement and were turned out to pasture. Most bvd virus infections occurred within the first 90 days after parturition. At completion of the study, only 1 animal had not shown evidence of AV3 infection, 2 animals had not been infected with AV7, and 7 cows had remained free of bvd virus infection.
Concentrations of penicillin, streptomycin, and spiramycin in bovine udder tissue liquids
Authors: Franklin Anders , Horn af Rantzien Margareta , Obel Nils , Östensson Karin , Åström Göran
Published: February 2025

Concentrations of benzylpenicillin and spiramycin adipate were determined in bovine plasma and milk and in lymph draining the udder tissue after im or iv administration. Combined benzylpenicillin and dihydrostreptomycin sulfate concentrations were also determined in the same fluids after intramammary injection. A superficial parenchymal lymph vessel, afferrent to the supramammary lymph gland of the left quarters, was cannulated with a polythene catheter from which the lymph was allowed to drain freely. After injections of 9.5 mg of benzylpenicillin/kg of body weight im, a mean peak concentration (pc) in lymph (3.7 μg/ml), constituting 77% of the pc in plasma (4.8 μg/ml), was obtained 0.5 to 1 hour after pc in the plasma. The benzylpenicillin lymph concentration was close to that in plasma for about 7 hours after injection. Thereafter, the benzylpenicillin lymph concentration continued to exceed that in plasma, but not that in milk. After iv administration of spiramycin adipate, the lymph concentration was almost identical to that in plasma.

After intramammary injection of procaine benzylpenicillin (400 mg), in combination with the same amount of dihydrostreptomycin sulfate, into 2 udder quarters each, mean pc in the lymph of 3.5 μg/ml and 8.4 μg/ml, respectively, were obtained 6 hours after injection. In plasma, the mean pc of benzylpenicillin (0.07 μg/ml) and of dihydrostreptomycin sulfate (0.85 μg/ml) were obtained after 4 and 6 hours, respectively. In milk from the nontreated quarters, a mean concentration of 5 ng of benzylpenicillin/ml was obtained, whereas dihydrostreptomycin sulfate (≥ 0.3 μg/ml) was not detected. After administration of benzylpenicillin im or spiramycin adipate iv, concentrations of these drugs in the udder tissue extracellular fluid, the origin of the lymph of the cannulated vessels, were similar to the concentrations in plasma. After intramammary injection of procaine benzylpenicillin and dihydrostreptomycin sulfate, therapeutic concentrations of benzylpenicillin, but not of dihydrostreptomycin sulfate, were easily obtained in the udder tissue extracellular fluid.
Pharmacokinetics of single doses of gentamicin given by intravenous and intramuscular routes to lactating cows
Authors: Haddad Nadim S. , Ravis W. R. , Pedersoli W. M. , Carson R. L.
Published: February 2025

Healthy mature lactating cows (n = 6) were given gentamicin (5 mg/kg of body weight) by iv route and another dose 19 days later by im route. Serum gentamicin concentrations were determined over a period of 48 hours after each drug dosing, using radioimmunoassay. With the aid of a nonlinear least-square regression analysis program, the combined data of the iv and im treatments were best fitted by a 2-compartment open model, as indicated by residual trends and improvements in the sum of squares by F test and the sd of the estimated values. The distribution phase half-life was 0.25 ± 0.12 hour, and postdistribution half-life was 1.83 ± 0.18 hours. The volume of the central compartment was 0.10 ± 0.02 L/kg, volume of distribution at steady state was 0.16 ± 0.03 L/kg, and the total body clearance was 1.32 ± 0.17 ml/min/kg.

Intramuscular absorption was rapid, with a half-life for absorption of 0.63 ± 0.28 hour. The extent of im absorption was 92% ± 15%. The percentage of the im dose eliminated in the urine during the first 8 hours was 83 ± 8. Gentamicin was detected in milk for 48 hours. Kinetic calculations predicted that im injection of gentamicin at a dosage of 3.5 mg/kg of body weight every 8 hours would provide average steady-state serum drug concentrations of 5.08 μg/ml, with minimum and maximum steady-state concentrations of 1.03 and 12.05 μg/ml, respectively, whereas an im injection of a 5 mg/kg dosage every 8 hours would provide average steady-state serum concentrations of 7.26 μg/ml, with minimum and maximum steady-state serum concentrations of 1.47 and 17.21 μg/ml, respectively.
Evaluation of terminal deoxynucleotidyl transferase expression in bone marrow of clinically normal and feline leukemia virus-exposed cats
Authors: Lafrado Louis J. , Mathes Lawrence E. , Olsen Richard G.
Published: February 2025

Bone marrow cells from 8 specific-pathogen-free and 11 feline leukemia virus-exposed cats were examined for the expression of the nuclear antigen terminal deoxynucleotidyl transferase (TdT). Using a standard indirect immunofluorescence technique, feline leukemia-exposed cats had increased expression of TdT in bone marrow aspirates (2.0% to 29.0%) when compared with that in bone marrow cells from specific-pathogen-free cats (2.5% to 6.0%). Seemingly, TdT can be used as an antigenic marker in leukemogenesis of FeLV-infected cats.
Multielement assays of canine serum, liver, and kidney by inductively coupled argon plasma emission spectroscopy
Authors: Stowe Howard D. , Braselton W. Emmett , Slanker Michael , Kaneene John B.
Published: February 2025

Inductively coupled argon plasma emission spectroscopy was used to measure Al, As, Ca, Cd, Cr, Cu, Fe, Pb, Mg, Mn, Hg, Mo, Ρ, Κ, Se, Na, Tl, and Zn in canine specimens (70 serum, 270 liver, and 200 kidney). Mean concentrations of each of these elements in detectable amounts in these samples were established, and histograms of the concentration distributions of elements in the samples were developed.