bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutritional and pathophysiologic effects of clinically apparent and subclinical infections of Ostertagia ostertagi in calves
Authors: Xiao L. , Gibbs H.C.
Published: January 2024

Nutritional and physiologic effects of clinically apparent and subclinical Ostertagia ostertagi infections were studied in 3 groups of 5 calves each. Group-1 calves were inoculated with 100,000 Ostertagia ostertagi third-stage larvae (L3)/calf/wk for 14 weeks. Group-2 calves were inoculated with 10,000 L3/calf/wk for 14 weeks, and group-3 calves were not inoculated. Calves in group 1 had decreased dry matter intake and feed utilization from 4 weeks after initial inoculation. Group-2 calves had no changes in dry matter intake, but had decreased feed utilization at 12 and 14 weeks. Calves with clinically apparent infections (group 1) lost a mean weight of 11.8 kg, whereas calves with subclinical infections (group 2) lost a mean of 46.6 kg, and control calves lost a mean of 60.7 kg. Calves with O ostertagi infections (groups 1 and 2) also had decreased carcass quality at slaughtering, which was reflected in decreased dressing weights and increased water-holding capacity of the rib-eye muscle. Calves in groups 1 and 2 also had lower carcass yield and rib-eye muscle weight, and group-1 calves had decreased protein content. Results of hematologic, pathologic, parasitologic, and clinical examinations mirrored nutritional changes.
Clinical evaluation of the efficacy of inoculating cattle with a vaccine containing Tritrichomonas foetus
Authors: Kvasnicka William G. , Hanks Donald , Huang Juch-Chin , Hall Mark R. , Sandblom David , Chu Hsien-Jue , Chavez Lloyd , Acree William M.
Published: January 2024

To test the efficacy of a polyvalent Tritrichomonas foetus vaccine, 130 nulliparous heifers were randomly assigned to either receive the test T foetus vaccine or to serve as nonvaccinated controls. The polyvalent test vaccine consisted of a Campylobacter fetus/Leptospira canicola-grippotyphosa-hardjo-icterohaemorrhagiae-pamona bacterine containing 5 × 107 killed T foetus/dose. The polyvalent control vaccine consisted of the aforementioned formulation without T foetus. Heifers were administered 2 doses of control or experimental vaccine at 3-week intervals. Heifers were bred to T foetus-infected bulls and their conception and pregnancy rates were determined throughout gestation. In addition, serum samples were analyzed to determine induced concentrations of antitrichomonal antibodies and vaginal secretions were sampled to determine T foetus infection rates in control and vaccinated animals. One week after each of the 15-day breeding periods, 60% (6 of 10) of tested vaccinates and 80% (8 of 10) of tested control animals were T foetus culture-positive. The mean duration of infection of vaccinates was 3.8 weeks (± 7.5 days), compared with 5.4 weeks (± 7.5 days) of infection for control heifers. All vaccinates developed increased immunofluorescence and serum neutralizing antibody titers following the first immunization, and had additional increases of at least fourfold in response to the second injection. In contrast, no consistent increase in immunofluorescence or serum neutralizing antibodies was observed in control animals.

Conception rates were 89.2% for vaccinates and 85.9% for control animals 30 days after breeding and 80 to 90% of these remained pregnant 60 days after breeding. However, within the next 4 months, the pregnancy rate of control heifers decreased to 30% for those that had conceived. During the same 4-month period, more than 60% of vaccinated heifers remained pregnant. Significantly, 62.5% of heifers vaccinated against T foetus produced calves, whereas only 31.5% of control heifers produced calves. These findings indicate that the polyvalent test vaccine induced an immune response that was effective in lowering the rate of T foetus infection, decreasing the duration of infection, and reducing losses in calf production attributable to early fetal death and abortion caused by T foetus infection.
Pharmacokinetics of enrofloxacin after intravenous and intramuscular injection in rabbits
Authors: Cabanes Ana , Arboix Margarita , Garcia Anton Jose M. , Reig Francisca
Published: January 2024

The pharmacokinetics and bioavailability of enrofloxacin were determined after iv and im administration of 5 mg/kg of body weight to 6 healthy adult rabbits. Using nonlinear least-squares regression methods, data obtained were best described by a 2-compartment open model. After iv administration, a rapid distribution phase was followed by a slower elimination phase, with a half-life of 131.5 ± 17.6 minutes. The mean body clearance rate was 22.8 ± 6.8 ml/min/kg, and the mean volume of distribution was 3.4 ± 0.9 L/kg. This large volume of distribution and the K12/K21 ratio close to 1, indicated that enrofloxacin was widely distributed in the body, but not retained in tissues. After a brief lag period (6.2 ± 2.86 min), im absorption was rapid (4.1 ± 1.3 min) and almost complete. The mean extent of im absorption was 92 ± 11%, and maximal plasma concentration of 3.04 ± 0.34 μg/ml was detected approximately 10 minutes after administration.
Effects of dietary phosphorus and protein in dogs with chronic renal failure
Authors: Finco Delmar R. , Brown Scott A. , Crowell Wayne A. , Duncan Robert J. , Barsanti Jeanne A. , Bennett Samuel E.
Published: January 2024

Four diets were formulated to contain: 16% protein and 0.4% phosphorus–diet 1; 16% protein and 1.4% phosphorus– diet 2; 32% protein and 0.4% phosphorus–diet 3; and 32% protein and 1.4% phosphorus–diet 4. Forty-eight dogs were fed diet 1 for 3 months after surgical reduction of renal mass, then were allotted to 4 groups of 12 dogs each, with equal mean values for glomerular filtration rate (gfr). Dog of groups 1–4 were fed diets 1–4, respectively, for 24 months. Data collected from the dogs during and at termination of the study were analyzed statistically for effects of dietary protein, phosphorus (P), time, and interactions between these factors.

During the 24 months of study, 24 dogs developed uremia and were euthanatized for necropsy. Necropsy also was performed on the remaining 24 dogs after they were euthanatized at the end of the study. Dog survival was significantly enhanced by 0.4% P diets (vs 1.4% P diets), but survival was not significantly influenced by amount of dietary protein. The 0.4% P diets (vs 1.4% P diets) significantly increased the period that gfr remained stable before it decreased, but dietary protein did not have significant effect.

Significant blood biochemical changes attributed to P, protein, and time were identified during the study. Terminally, plasma parathyroid hormone concentration was significantly increased from prediet values in all groups of dogs.

Urine protein excretion was not significantly affected by dietary amount of either protein or P, when measured by either timed urine collection or urine protein-to-creatinine ratio. A tendency was seen for increased protein excretion with passage of time.

Histologic and mineral analyses of kidneys removed at necropsy revealed some significant difference attributable to diet, but differences were more marked when diet was ignored, and the 24 surviving dogs were compared with the 24 that developed uremia.

Overall, amount of dietary P was more important than amount of dietary protein for preventing adverse responses. However, because renal damage specifically attributable to either dietary component was not obvious, it is possible that the effects of P were manifested by extrarenal mechanisms.
Efficacy of a drug combination of praziquantel, pyrantel embonate, and febantel against helminth infections in dogs
Authors: Lloyd S. , Gemmell M. A.
Published: January 2024

Tablets containing praziquantel, pyrantel embonate, and febantel were tested for efficacy against helminths in dogs. A single treatment with this drug combination gave 100% reductions in Toxocara canis and Taenia hydatigena in experimentally induced infections in dogs. In dogs with naturally acquired infections, treatment gave > 97 to 98% reductions in fecal egg counts attributable to Toxascaris leonina, T canis, and Uncinaria stenocephala. Efficacy against Trichuris vulpis was > 92%.
Efficacy of milbemycin oxime in chemoprophylaxis of dirofilariasis in cats
Authors: Stewart V. Ann , Hepler Douglas I. , Grieve Robert B.
Published: January 2024

Although cats are less susceptible to infection with Dirofilaria immitis than are dogs, the possibility of severe consequences from infection or adulticidal treatment renders preventive treatment a desirable alternative in endemic areas. To evaluate the efficacy of milbemycin oxime as a chemoprophylactic agent in cats, 48 cats were inoculated with infective D immitis larvae. Single oral treatment with 2.3 mg of milbemycin oxime (0.5 to 0.9 mg/kg of body weight) at 30 or 60 days after inoculation with infective larvae gave strong but incomplete protection. Treatment at 60, as well as 90, days after inoculation with infective larvae was completely effective in preventing development of infection. A control group of inoculated, but untreated, cats was monitored biweekly for hematologic changes and for changes in parasite-specific serum antigen and antibody concentrations. Pronounced increases in total leukocyte counts and eosinophil numbers were associated with the estimated time of in vivo molting from fourth- to fifth-stage larvae. Antibody reactivity correlated with infection status, but serum antigen concentrations through 161 days after inoculation were undetectable.
Median effective dosage of propofol for induction of anesthesia in dogs
Authors: Watney G. C. G. , Pablo L. S.
Published: January 2024

The median effective dosage (ed50) of propofol for induction of anesthesia was determined in 25 dogs premedicated with acepromazine, 0.05 mg/kg of body weight, and in 35 unpremedicated dogs. The ed50 was found to be 2.2 mg/kg in premedicated dogs and was 3.8 mg/kg in unpremedicated dogs. The mean ± sd total dosage of propofol required to induce anesthesia in premedicated animals was 2.8 ± 0.5 mg/kg and was 4.7 ± 1.3 mg/kg in unpremedicated animals. Signs of excitement were observed in 5 of the unpremedicated dogs, but in none of those that were premedicated.
Metabolic response of horses to a high soluble carbohydrate diet: Effects of low-intensity submaximal exercise and sodium bicarbonate supplementation
Authors: Ferrante Pamela L. , Menninger Jacqueline H. , Spencer Pamela A. , Kronfeld David S.
Published: January 2024

Four mares fed a low fiber, high soluble carbohydrate diet were used in a crossover design to evaluate the effects of dietary sodium bicarbonate (NaHCO3) supplementation during daily low-intensity submaximal working conditions. Mares were fed the diet at 1.7 times the maintenance energy requirement for mature horses at work. The horses tolerated the diet well and had no clinical abnormalities. Resting venous blood bicarbonate (HCO3), standard HCO3, and base excess (be) concentrations significantly (P < 0.05) increased with NaHCO3 supplementation, but no significant changes in resting venous blood pH or carbon dioxide tension (Pco2) were recorded.

Venous blood HCO3, standard HCO3, be, hemoglobin, and heart rate were significantly (P < 0.05) increased and plasma lactate concentration was significantly (P < 0.05) decreased in the control horses and in the horses given the NaHCO3 supplement during low-intensity submaximal exercise. There were no significant changes in venous blood pH, Pco2, or plasma protein concentration with exercise. Venous blood HCO3, standard HCO3, and be concentrations were significantly (P < 0 05) greater during submaximal exercise in horses given the NaHCO3 supplement. There were no significant differences in plasma lactate or total protein concentrations, blood pH, Pco2, or hemoglobin concentration between the 2 groups during exercise.
Inoculation of pigs with Streptococcus suis type 2 alone or in combination with pseudorabies virus
Authors: Iglesias J. Gerardo , Trujano M. , Xu J.
Published: January 2024

Pigs (9 [± 1] weeks old) were inoculated with Streptococcus suis type 2, pseudorabies virus (prv), or both. For each pig of groups A, B, and C the inoculum of S suis was 109 colony-forming units. For each pig of groups A, B, and D the inoculum of prv was 5 × 103 tcid50 of either prv strain 4892 (group A, n = 9) or prv isolate B (group B, n = 9). The prv strain 4892 is a highly virulent strain; isolate B causes mild clinical signs of infection in inoculated pigs. Group-C pigs (n = 9) were given S suis alone, and group-D pigs (n = 3) were inoculated only with prv isolate B. Clinical signs of infection and development of lesions were readily seen in pigs of groups A, B, and C. Duration and severity of clinical signs of disease and lesions were reduced m pigs of group C, compared with those of the other 2 groups. Lesions, such as polyarthritis and fibrinous pericarditis, were more abundant and acute in the groups of pigs given mixed challenge exposure, compared with pigs inoculated exclusively with S suis type 2 (group C). The group of pigs inoculated with prv isolate В alone did not manifest clinical signs of disease or lesions. Average daily gain for group-C pigs was higher, compared with that of other groups; the difference was statistically significant at P < 0.02 and P < 0.05 for groups B and D, respectively. Spread of S suis within the tissues of infected pigs was higher in pigs of groups A and B, compared with pigs of group C. Total number of isolations was 8, 15, and 7 for groups A, B, and C, respectively; S suis was isolated from more than 1 tissue specimen from some pigs. The rate of pigs carrying S suis was 4 of 4 in group-A, 7 of 9 in group-B, and 5 of 9 in group-C pigs. It was concluded that clinical disease associated with S suis type 2 was enhanced by concomitant infection with prv and such effect was common to both prv strains tested, the highly virulent strain and the strain with low virulence.
Indocyanine green disposition in healthy dogs and dogs with mild, moderate, or severe dimethylnitrosamine-induced hepatic disease
Authors: Boothe D. M. , Brown S. A. , Jenkins W. L. , Green R. A. , Cullen J. M. , Corrier D. E.
Published: January 2024

Disposition kinetics of indocyanine green (icg) were used to evaluate hepatic function in healthy Beagles (group 1; n = 6) and Beagles with progressive hepatic disease induced by oral administration of dimethylnitrosamine, a hepatospecific toxin. Three classes of hepatic disease were defined by histologic features: mild (group 2; n = 5), moderate (group 3; n = 6), and severe (group 4; n = 5). Disposition of icg was studied 3 weeks following the last dose of toxin. A rapid iv injection of 0.5 mg of icg/kg was administered and serum samples were obtained at certain intervals during 60-minute periods. Serum icg was analyzed by use of visible spectrophotometry. Disposition kinetics were determined from serum icg concentrations vs 15- and 60-minute time curves and compared between one another and among groups. Data based on 60-minute time curves were not significantly different from those based on 15-minute curves. Area under the curve for icg was greatest in group 3. Clearance of icg was decreased and mean resident time was increased in groups 3 and 4, compared with those in groups 1 and 2. When disposition data (60 minutes) were normalized for differences in hepatic weight among dogs, group-3 mean resident time was significantly greater than that of group 4. This study supports the diagnostic benefits of using icg disposition kinetics as a method of evaluating hepatic function in dogs with progressive liver disease.
Effects of synthetic ovine corticotropin-releasing hormone on plasma concentrations of immunoreactive adrenocorticotropin, alpha-melanocyte-stimulating hormone, and cortisol in dogs with naturally acquired adrenocortical insufficiency
Authors: Peterson Mark E. , Kemppainen Robert J. , Orth David N.
Published: January 2024

We evaluated the effect of ovine corticotropin-releasing hormone (crh) on plasma immunoreactive (ir) concentrations of acth, α-melanocyte-stimulating hormone, and cortisol in 8 dogs with naturally acquired adrenocortical insufficiency. Of the 7 dogs with primary adrenal insufficiency, 6 had markedly high basal plasma ir-acth concentrations and exaggerated acth responses to crh administration, whereas 1 dog that was receiving replacement doses of prednisone at the time of testing had normal basal ir-acth concentrations and a nearly normal response to crh. In contrast, the 1 dog with secondary adrenocortical insufficiency had undetectable basal plasma ir-acth concentrations, which failed to increase after administration of crh. Basal plasma α-melanocyte-stimulating hormone concentrations in the dogs with adrenal insufficiency were within normal range and were unaffected by crh administration. In all 8 dogs with adrenal insufficiency, plasma cortisol concentrations were low and did not increase after administration of crh. Therefore, stimulation with crh produced 2 patterns of plasma ir-acth response when administered to dogs with naturally acquired adrenal insufficiency. Dogs with primary adrenal insufficiency had high basal plasma ir-acth concentrations and exaggerated responses to crh, whereas the dog with secondary adrenal insufficiency had undetectable basal plasma concentrations of ir-acth that did not increase after stimulation with crh.
Morphologic features and hydrophobicity of the cell surface of Mycoplasma hyopneumoniae
Authors: Zielinski Gustavo C. , Ross Richard F.
Published: January 2024

Cell surface hydrophobicity of Mycoplasma hyopneumoniae was evaluated by phase partitioning in a hydro-carbon-aqueous mixture, by hydrophobic interaction chromatography, and by salting out with ammonium sulfate. Results obtained by use of these techniques gave evidence that the cell surface of M hyopneumoniae is weakly hydrophobic, compared with strongly hydrophobic Staphylococcus aureus Cowan I and hydrophilic Klebsiella pneumoniae. After treatment of the organisms with trypsin, M hyopneumoniae became less hydrophobic as measured by hydrophobic interaction chromatography. Significant changes in hydrophobicity were not seen after periodate treatment. Electron microscopy of M hyopneumoniae treated with polycationic ferritin revealed an intermediate, compact, unlabeled layer between the cytoplasmic membrane and an external, heavily labeled layer. Electron microscopy of ferritin-labeled M hyopneu-moniae after treatment with trypsin or periodate revealed the intermediate layer to be composed of a trypsin-sensitive protein(s). The outer layer was made of periodate-sensitive carbohydrate(s). Therefore, it appears that proteins in the intermediate layer confer at least part of the total hydrophobicity of the mycoplasmal cell and may contribute to adherence of M hyopneumoniae to target respiratory cells by hydrophobic interactions.
Development of Anaplasmamarginale in salivary glands of male Dermacentor andersoni
Authors: Kocan Katherine M. , Goff Will L. , Stiller David , Edwards Wanda , Ewing S. A. , Claypool P. L. , McGuire Travis C. , Hair Jakie A. , Barron Selwyn J.
Published: January 2024

Development of the rickettsia, Anaplasmamarginale, in salivary glands of male Dermacentor andersoni exposed as nymphs or adult ticks, was studied indirectly by inoculation of susceptible calves with homogenates and directly by examination, using light microscopy and a DNA probe; some unfed ticks were incubated before tissues were collected. Salivary gland homogenates made from ticks in every treatment group caused anaplasmosis when injected into susceptible calves; prepatent periods decreased as the time that ticks had fed increased. Colonies of A marginale were seen only in salivary glands of ticks exposed as adults and not in those exposed as nymphs; the percentage of salivary gland acini infected in these ticks increased linearly with feeding time. However, the probe detected A marginale DNA in salivary glands of ticks from both groups; the amount of DNA detected increased as feeding time was extended. The amount of A marginaleDNA appeared to remain constant in gut tissues, but to increase in salivary glands. Salivary glands of adult-infected male ticks that were incubated, but did not feed a second time, became infected with A marginale, and the pattern of infection of acini varied with incubation temperature. Development of A marginale in salivary glands appears to be coordinated with the tick feeding cycle; highest infection rate was observed in ticks exposed as adults.
α2-Adrenergic receptor agonist effects on supraventricular and ventricular automaticity in dogs with complete atrioventricular block
Authors: Day Thomas K. , Muir William W.
Published: January 2024

Complete atrioventricular block was induced in 26 pentobarbital-anesthetized dogs to determine the effects of the α2-adrenergic receptor agonists, xylazine and medetomidine, on supraventricular and ventricular automaticity. Prazosin and atipamezole, α- adrenoceptor antagonists, were administered to isolate α1- or α2-adrenoceptor effects. Six dogs served as controls and were given glycopyrrolate (0.1 mg/ kg of body weight, iv) and esmolol (50 to 75 μg/kg/ min, iv) to induce parasympathetic and β1-adrenergic blockade, respectively. Eight dogs were given sequentially increasing doses of xylazine (n = 5), 0.000257 mg (10−9M) to 25.7 mg (10−4M) and medetomidine (n = 3), 0.000237 mg (10−9M) to 2.37 mg (10−5M) after parasympathetic and β1-adrenergic blockade. Twelve dogs were given xylazine (n = 6, 1.1 mg/kg, iv) or medetomidine (n = 6, 0.05 mg/kg, iv) after parasympathetic and β1-adrenergic blockade. Three dogs given xylazine and 3 dogs given medetomidine were administered prazosin (0.1 mg/kg, iv) followed by atipamezole (0.3 mg/kg, iv). The order of prazosin and atipamezole was reversed in the remaining 3 dogs given either xylazine or medetomidine.

Complete atrioventricular block and administration of glycopyrrolate and esmolol resulted in stable supraventricular and ventricular rates over a 4-hour period. Increasing concentration of xylazine or medetomidine did not cause signficant changes in supraventricular or ventricular rate. Xylazine and medetomidine, in the presence of the α-adrenoceptor antagonists, prazosin (α1) and atipamezole (α2), did not cause significant changes in supraventricular or ventricular rate. α2-Adrenoceptor agonists do not induce direct α1- or α2-adrenoceptor-mediated depression of supraventricular or ventricular rate in dogs with complete atrioventricular block.
Effects of intra-articularly administered endotoxin on clinical signs of disease and synovial fluid tumor necrosis factor, interleukin 6, and prostaglandin E2 values in horses
Authors: Hawkins Dan L. , MacKay Robert J. , Gum Glen G. , Colahan Patrick T. , Meyer James C.
Published: January 2024

In each of 4 horses, sterile synovitis was induced by intra-articular injection of 3 μg of Escherichia coli endotoxin (lipopolysaccharide, LPS) into one antebrachiocarpal joint; an equal volume (2 ml) of phosphate-buffered saline solution (PBSS) was injected into the opposite, control carpus. Blood and 1.5 ml of synovial fluid were obtained at postinjection hours (pih) 0, 2, 4, 8, 12, 18, 42, 66, and 144. Synovial fluid sample collection was accomplished by use of an indwelling, intra-articular catheter through pih 12, and by arthrocentesis subsequently. Joint fluid samples were analyzed for cell counts, protein concentration, cytologic variables, and tumor necrosis factor (tnf), interleukin 6 (IL-6), and prostaglandin E2 (PGE2) values. Tumor necrosis factor and 1L-6 activities and WBC count were also measured in blood. To monitor local inflammation, skin temperature of each carpus was imaged, using a thermographic scanner prior to each sample collection time.

Horses had minimal systemic effects. Mean (± SEM) rectal temperature increased significantly to 39 02 ± 0.15 C only at pih 18 after intra-articular injection of LPS. One horse had signs of mild depression from pih 7 to 18, but its vital signs did not change appreciably. Each horse had mild signs of discomfort in the LPS-injected limb from pih 1 to 3 until pih 8 to 10. Mean peak surface temperature of the LPS-injected carpi was significantly higher than that of control carpi from pih 8 to 144 (P < 0.05).

Mean synovial fluid WBC count in the LPS-injected and control carpi increased after injection and peaked by pih 8 (193,125 ± 8,528 cells/μl, LPS-treated; 16,425 ± 8,336 cells/μl, controls). Mean values for LPS-treated (principal) joints were significantly greater than values for control joints from pih 2 until after pih 66 (P < 0.05). Mean synovial fluid protein concentration increased in the principal and control joints, with values for the principal joints remaining significantly greater than values for control joints from pih 4 to 144 (P < 0.05). Mean TNF activity in synovial fluid was maximal at pih 2 (10,573 ± 5,924 U/ml). Interleukin-6 activity increased more gradually and peaked at pih 8 (1.78 ± 0.71 × 106 U/ml). Tumor necrosis factor activity did not increase above the minimal detectable value of 6 U/ml in the control joints. Mean PGE2 concentration in the principal joints peaked by pih 2 (3.6 ± 0.37 ng/ml) and remained significantly (P < 0.05) greater than the value for control joints from pih 2 through 66. These results indicate that a humane model of synovitis was created by intra-articular injection of LPS and can be used to establish the basic responses of synovial TNF, IL-6, and PGE2 in horses with early inflammatory joint disease.
Effects of acute physical stress on immune competence in pigs
Authors: Waern Marianne Jensen , Fossum Caroline
Published: January 2024

Some interrelations between physical stress and immune competence were studied in pigs. One group of pigs underwent 2 intense short-term treadmill exercise tests, separated by an interval of 1 week, and another group served as controls. In vitro production of interferon α by blood mononuclear cells and the ability of lymphocytes to proliferate and produce interleukin 2 were chosen as markers of immune competence, plasma concentrations of cortisol, lactate, and purines were used as markers of physical stress. Blood samples were drawn from a catheter in situ 60 minutes before, immediately after, and at 10, 30, and 60 minutes, and 7, 24, and 72 hours after exercise. Physical stress resulted in immediate increase in the plasma concentrations of cortisol, lactate, and hypoxanthine, but had no effect on the blastogenic capability of lymphocytes or on their interleukin-2 production on either of the test occasions. Ability of blood mononuclear cells to produce interferon α in vitro was not affected by exercise stress.
Effects of lead on glucose metabolism, ion flux, and collagen synthesis in cerebral capillaries of calves
Authors: Abrens Franklin A.
Published: January 2024

Brain capillary function was assessed in 4- to 6- week-old calves given lead acetate (15 mg/kg of body weight) orally for 7 to 8 days. Neurologic signs of lead poisoning included cns depression, blindness, and hyperesthesia. Brain capillaries were isolated from cerebral cortex of control and lead-treated calves and evaluated for metabolic indicators, ion transport, and prolyl hydroxylase activity. In lead-treated calves, the rate of glucose metabolism was less than half that in controls. Ion efflux of 45Ca or 36CI from endothelial cell suspensions was not affected by lead treatment. Prolyl hydroxylase activity in endothelium and proline- to-hydroxyproline ratio in endothelial basement membranes were similar in control and lead-poisoned calves. Results indicate that lead may inhibit energy metabolism, but not ion transport or collagen biosynthesis in brain capillaries of calves and, compared with suckling rats, damage to the blood-brain barrier is less important. In calves, neuronal tissue may be the primary target for the cns effects of lead.
Linkage of serum resistance, aerobactin production, and resistance to antimicrobial agents on conjugal plasmids in some strains of Escherichia coli isolated from septic foals
Authors: Hirsh Dwight C. , Kirkham Caroline , Wilson W. David
Published: January 2024

Fifteen isolates of Escherichia coli obtained from the blood and tissues of septic foals had plasmid dna of size ranging from 2.5 to 93 megadaltons. These isolates grew in normal equine serum (serum resistant), a trait previously documented to be expressed by isolates obtained from blood and tissues of septic foals, but not by isolates obtained from the feces of clinically normal horses. Of these isolates, 3 contained conjugal plasmids that encoded resistance to multiple antimicrobial agents linked to serum resistance and, in 1 isolate, to production of aerobactin as well. Serum resistance and production of aerobactin are related to virulence of septicemic E coli from non-equine sources.
Intrauterine transmission of Borrelia burgdorferi in dogs
Authors: Gustafson John M. , Burgess Elizabeth C. , Wachal Michael D. , Steinberg Howard
Published: January 2024

To determine whether intrauterine transmission of Borrelia burgdorferi could exist in dogs, 10 female Beagles were inoculated intradermally with approximately 1,000 B burgdorferi on day 1 of proestrus; inoculation was repeated every 2 weeks during the gestation period. Ten female control Beagles were similarly inoculated with phosphate-buffered saline solution. Prior to the start of the study, all females and 3 males used for breeding were seronegative for B burgdorferi on the basis of results of the indirect fluorescent antibody test and immunoblot (western blot) analysis. Similarly, results of culture of blood for B burgdorferi were negative. All 20 of the females were bred naturally. Blood samples were collected weekly for serologic testing and culture. Blood samples were obtained from live pups on day 1 of life, then weekly until pups were 6 weeks old when they were euthanatized. Tissues were obtained for culture and testing by use of polymerase chain reaction (pcr). Of 10 spirochete-inoculated (si) females, 8 became infected with B burgdorferi as evidenced by spirochete culture results and/or pcr-detected B burgdorferi dna in the tissues of females or their pups. Of the 10 si females, 8 delivered litters (3 to 7 pups) that had at least 1 neonatal or 6-week-old pup with B burgdorferi dna-positive tissues (by pcr), and spirochetes were cultured from tissues from pups of 2 litters. Four pups of 3 separate litters (a stillborn, a neonate that survived to 30 minutes of age, a 20- hour-old, and a 48-hour-old) had B burgdorferi-positive tissues (by pcr), and the 20-hour-old pup was also culture-positive, indicating intrauterine infection. Further evidence of intrauterine exposure was the presence of IgM antibodies to B burgdorferi detectable by western blot in 3 of 7 one-day-old pups that did not receive colostrum, indicating a primary immune response. Eight of 10 si females and 10 of 10 control females carried litters to term. Differences between si and control Beagles were seen in the duration of gestation, number of resorptions, and number of dystocias. All control females and pups remained seronegative, culture-negative, and B burgdorfer-inegative throughout the study.

Intrauterine infection by B burgdorferi does occur in dogs and is a potential means by which the spirochete can be transmitted in a breeding population in the absence of a tick vector.
Semiquantitative test for Dirofilaria immitis as a predictor of thromboembolic complications associated with heartworm treatment in dogs
Authors: Rawlings Clarence A. , Tonelli Quentin , Lewis Robert E. , Duncan J. Robert
Published: January 2024

A semiquantitative heartworm test of antigen concentration was evaluated as a predictor of thromboembolism after adulticide treatment. Seventeen dogs with naturally acquired infections of Dirofilaria immitis (heartworms) were studied before and after thiacetarsamide treatment, using physical examinations, arterial blood gas analyses, thoracic radiography, and pulmonary hemodynamic and arteriographic tests. Eight dogs were considered to have a low burden of heartworms and 9 had a high burden. Dogs with a high worm burden had more severe pulmonary thromboembolism with pulmonary hypertension, dilated pulmonary arteries, flow obstruction of the caudal pulmonary arteries, and parenchymal lesions in the caudal lung lobes. Dogs with a low worm burden had minimal changes. Within each group of dogs, the severity of thromboembolism was less in some dogs in which all heartworms were not killed. Six of the 9 dogs with a high burden of heartworms had surviving heartworms, and 1 of these dogs had 38 live heartworms. Only 4 of the 8 dogs with a low worm burden had complete heartworm mortality, but only 1 dog had more than 3 surviving heartworms. We concluded that dogs with a high worm burden were more likely to have pulmonary thromboembolism after thiacetarsamide treatment and that dogs with a low worm burden were more likely to have minimal changes. A semiquantitative heartworm test of antigen concentration is recommended as part of the pretreatment evaluation of dogs infected with heartworms.
Efficacy of albendazole against giardiasis in dogs
Authors: Barr Stephen C. , Bowman Dwight D. , Heller Ruth L. , Erb Hollis N.
Published: January 2024

Efficacy of albendazole for treating giardiasis in dogs was assessed in 3 experiments. In experiment 1, Giardia cysts were cleared from feces of 5 of 7 dogs (as determined by the zinc-sulfate concentration technique) after the dogs received a single dose of albendazole (25 mg/kg of body weight, po), whereas feces of 3 of 7 dogs became clear of cysts without treatment. In experiment 2, feces of 5 of 5 dogs became clear of cysts after albendazole treatment (25 mg/kg, po, q 12 h for 4 doses); feces of 1 of 5 untreated control dogs became clear. In experiment 3, feces of 18 of 20 dogs became clear of cysts after albendazole (25 mg/kg, po, q 12 h for 4 doses) was given; none of the 20 control dogs had feces clear of cysts. Signs of toxicosis were not observed in any dog. These results indicate that a single dose of albendazole (25 mg/kg, po) is not effective for treating giardiasis in dogs. However, 4 doses of albendazole (25 mg/kg, po, q 12 h) are highly effective and nontoxic for treatment of giardiasis in dogs.
Use of indirect enzyme-linked immunosorbent assay with hot saline solution extracts of a variant (M—) strain of Brucella canis for diagnosis of brucellosis in dogs
Authors: Mateu-de-Antonio E. M. , Martin M. , Soler M.
Published: January 2024

An elisa, using hot saline solution extracts (hss) of a less-mucoid variant (M—) strain of Brucella canis as antigen, was developed for detection of antibodies against B canis in dogs. The test was applied to 177 field serum samples previously tested by use of the 2-mercaptoethanol rapid slide agglutination test, 2-mercaptoethanol-tube agglutination test, and agar gel immunodiffusion containing hss and cytoplasmic antigens of B canis. Results indicated that this elisa seems to be highly specific (95.6%) and slightly less sensitive (93.8%). The hss obtained from B canis wild-type RM 6/66 also have been used, but in our study, it seemed to be unsuitable for use in elisa because of the high background values observed for sera with negative test results.
Prevalence of atretic corpora lutea in ovaries of bovine fetuses
Authors: Weber Alvin Francis , Cox Victor Stuart , Shope Richard Edwin , Fletcher Thomas Francis , Lee Debra Marie
Published: January 2024

Both ovaries from 88 bovine fetuses in the fifth month or later of gestation were studied histologically to determine the prevalence, origin, and time of appearance of atretic corpora lutea (acl). Ovaries from 36 (41%) fetuses had acl; fetuses < 6 months of gestation did not have acl. Six fetuses had more than 25 acl, but there was no apparent relationship between fetal age and number of acl.

Formation of acl involved disintegration of the stratum granulosum of secondary follicles, concomitant with proliferation and invasion by vascularized elements of the theca. Fully developed acl consisted of a large primary oocyte surrounded by a prominent zona pellucida and encased in a well-vascularized, largely thecal, fibrocellular wall. They measured approximately 0.5 to 1.0 mm in diameter. Empty, collapsed zona pellucidas were seen in many of the degenerating acl.
Comparison of the chemiluminescence responses of bovine neutrophils to differently opsonized zymosan particles
Authors: Leino Lasse , Paape Max J.
Published: January 2024

Stimulatory effects of 6 zymosan preparations on luminol-dependent chemiluminescence (cl) responses of isolated bovine neutrophils were compared. Unopsonized zymosan particles and zymosan particles opsonized with bovine IgG1, IgG2, fresh serum, or serum from which zymosan-specific antibodies, but not complement, had been removed (C3-serum) induced strong cl responses, with nearly equal maximal peaks in the presence of extracellular Ca2+ and Mg2+, whereas the response to fetal bovine serum-opsonized zymosan particles was markedly low. Removal of extracellular divalent cations almost completely blocked the cl reaction triggered by unopsonized, IgG1-opsonized, C3-opsonized, and fetal bovine serum-opsonized zymosan particles. By contrast, no change in the respiratory burst activity induced by serum-opsonized zymosan and only partial reduction in the response to IgG2-opsonized zymosan were seen under these conditions. Further experiments were performed with 4 zymosan preparations on neutrophils isolated from 2 calves with a genetic deficiency of CD11/CD18 membrane antigens. The unopsonized zymosan-induced cl reaction was absent in these cells. A reduced, but clear, response was observed with C3-opsonized zymosan. Unexpectedly, in the absence of extracellular Ca2+ and Mg2+, serum-opsonized zymosan failed to generate the respiratory burst, whereas response to IgG2-opsonized zymosan was normal in the CD11/CD18-deficient neutrophils. These findings indicate that unopsonized zymosan may act in a divalent cation-dependent manner at the receptor for C3bi in bovine neutrophils, as it has been shown to do in the human system. In addition, it seems that IgG2-Fc receptors capable of signaling the respiratory burst in the absence of extracellular Ca2+ and Mg2+ exist on bovine neutrophils.
Use of scintimetry to assess effects of exercise and polysulfated glycosaminoglycan on equine carpal joints with osteochondral defects
Authors: Todhunter Rory J. , Altman Naomi S. , Kallfelz Francis A. , Nersesian Pamela , Lust George
Published: January 2024

Combined blood pool and delayed images produced by use of 99MTc-methylene diphosphonate (99MTcMDP) were evaluated as an objective measurement of the response of equine joints with osteochondral defects to postoperative exercise and intra-articularly administered polysulfated glycosaminoglycan (PSGAG).

Osteochondral defects (approx 2.4 × 0.9 cm) were induced arthroscopically in the dorsodistal radial carpal bones of 18 ponies. These ponies were randomized (while balancing for age [range 2 to 15, median, 5.0; mean, 5.1 years]) to 2 treatment groups. Nine ponies were assigned to be exercised, and 9 were stall-rested. Six ponies in each group were administered PSGAG (250 mg) in 1 joint (medicated) and lactated Ringer's solution (LRS) in the contralateral joint. The 3 remaining ponies in each group were administered LRS in both joints (nonmedicated). Medication was given at surgery, then weekly for 4 weeks. The exercise protocol (begun at postoperative day 6 and conducted twice daily) started with 30 minutes walking (approx 0.7 m/s), and, by postoperative month 3, the ponies were being walked for 15 minutes and trotted (approx 1.6 m/s) for 25 minutes. Simultaneous dorsal images of both carpi were made 2 to 3 minutes after IV administration of 99MTcMDP (blood pool image) and 90 to 120 minutes later (delayed image). Scintimetry, in counts per minute per pixel per millicurie, was done before, and at 1, 2, 4, 8, 10, 13, and 17 weeks after surgery, prior to euthanasia.

Radionuclide uptake on blood pool images decreased faster than that on delayed images, in which uptake remained high for 17 weeks. This indicated that bone was metabolically active for at least 17 weeks after surgery. Exercise significantly (P < 0.05) decreased uptake on the blood pool images of medicated joints up to 1 month after surgery. Thus, exercise (in the presence of PSGAG) probably had a transient, beneficial effect on soft tissues of the joint. Exercise, without PSGAG, promoted increased bone remodeling, because the highest uptake on delayed images was observed in exercised, nonmedicated ponies up to 3 months after surgery. This was consistent with development of osteoarthritis in these ponies. Medication alone stimulated bone remodeling, and data indicated that an identical effect may take place in contralateral LRS-injected joints, because of systemic circulation of the drug. However, the combination of exercise and medication appeared to moderate the independent effects of each. The combination of exercise and medication in individual joints resulted in notably (P < 0.05) decreased bone remodeling. Medication caused a decrease in bone remodeling in exercised ponies, indicating a protective effect against development of osteoarthritis.
Serum osteocalcin concentration in horses treated with triamcinolone acetonide
Authors: Lepage Olivier M. , Laverty Sheila , Marcoux Marcel , Dumas Ghislain
Published: January 2024

The effect of triamcinolone acetonide (0.09 mg/kg of body weight, im) on serum osteocalcin concentration was studied. Two groups of horses were investigated and included clinically normal horses (group 1, n = 5) and horses with chronic obstructive pulmonary disease (group 2, n = 5). Before treatment, results of a t-test did not reveal any significant difference in serum osteocalcin concentration between the 2 groups. After treatment, a significant (P < 0.05) decrease in serum osteocalcin concentration was observed for both groups. Osteocalcin concentration in individual horses reached a minimum by 24 to 48 hours after treatment. In both groups of horses, serum osteocalcin response to glucocorticoid administration was similar. In 7 of 10 horses, return to pretreatment values was observed after 28 days. Pretreatment values for the other 3 horses were reached between 62 and 150 days.
Seroepidemiologic survey for adenovirus infection in lambs
Authors: Lehmkuhl Howard D. , Cutlip Randall C. , Brogden Kim A.
Published: January 2024

A serologic survey was conducted to determine the prevalence and seroconversion rates for ovine adenovirus (oav) serotypes 1–4 and bovine adenovirus (bav) serotypes 2, 3, and 7 in sheep in Iowa and in surrounding states. For 2 consecutive years, paired serum samples were obtained from 1- to 2-month-old lambs as they entered a ram test station and, again, 2 months later. Sera were tested for adenovirus antibodies by use of a microtitration serum virus-neutralization test. At the time of entry, high prevalence of antibody (titer ≥ 2) was detected to all tested adenoviruses except bav-3. All adenoviruses were active in the ram test station both years, as indicated by ≥ fourfold increase in adenovirus antibody titer (seroconversion) in some of the lambs. The prevalence and seroconversion rate for oav-1 was 94.0 and 7.2%, respectively; for oav-2, 98.6 and 15.1%; for oav-3, 86.5 and 11.0%; for oav-4, 98.4 and 13.2%; for bav-2, 97.6 and 22.4%; for bav-3, 11.4 and 3.8%; and for bav-7, 81.6 and 4.5%. The results indicate that adenovirus infections were widespread in the sheep population and that the prevalence of active infection based on seroconversion rates was approximately 45%.
Reproducibility of urethral pressure profiles in clinically normal sexually intact female dogs by use of microtransducer catheters
Authors: Arnold Susi , Chew Dennis J. , Hubler Madeleine , Casal Margret , Wiestner Thomas , Hogg Hermann , Heckmann Rudolf , Powers Jean , Ruesch Peter
Published: January 2024

Urethral pressures profiles (upp) obtained by use of microtransducer catheters were determined in 8 anestrous sexually intact female Beagles during general anesthesia. A upp study consisted of 3 consecutive recordings, and 4 upp studies were repeated at an interval of 5 days in each dog. Maximal urethral pressure (cm of H2O), bladder pressure (cm of H2O), and anatomic urethral length (cm) were recorded. Maximal urethral closure pressure (cm of H2O) was calculated.

Mean ± sd (for all measurements) maximal urethral closure pressure was 12.8 ± 5.6 cm of H2O (range, 2.4 to 25.2 cm of H2O). Maximal urethral closure pressure was significantly (P < 0.05) decreased during the first recording period (11.4 ± 5.8 cm of H2O), compared with the second (13.0 ± 5.2 cm of H2O) or third (14.1 ± 5.7 cm of H2O) recording periods within a upp study (3 consecutive recordings). Mean maximal difference in urethral closure pressure during a single upp study was 4.8 ± 2.4 cm of H2O. Significant difference in maximal urethral closure pressure was not observed between studies.

Mean (for all measurements) anatomic urethral length was 6.2 ± 0.9 cm (4.1 to 7.8 cm). Anatomic urethral length was significantly (P < 0.05) less during the first recording period (6.1 ± 0.9 cm), compared with values for the second and third periods (6.3 ± 0.9cm, 6.4 ± 0.9 cm respectively). Anatomic urethral length for time 3 was significantly (P < 0.05) less than the value for time 1 (5.8 ± 0.7 cm vs 6.6 ± 0.8 cm).

We conclude that the microtransducer catheter technique for measurement of upp was reproducible during a single study and between successive studies.

This method is useful in documenting maximal urethral pressure, maximal urethral closure pressure, and anatomic urethral length in clinically normal sexually intact female dogs.
Interspecific conjugal transfer of antibiotic resistance among staphylococci isolated from the bovine mammary gland
Authors: Muhammad Ghulam , Hoblet Kent H. , Jackwood Daral J. , Bech-Nielsen Steen , Smith K. Larry
Published: January 2024

In vitro transferability of pemcillm. strepiomycin, tetracycline, and erythromycin resistance from coagulase-negative staphylococci to Staphylococcus aureus and among the former species of bovine mammary gland origin was examined by bacterial mating on filters and by mixed-culture matings in broth and in skim milk. One hundred twenty-six (42 each on filter, in broth, and in skim milk) matings were performed among 37 isolates of different Staphylococcus species. Transfer of resistance to penicillin, tetracycline, or erythromycin was not detected. Of 51 matings performed to determine streptomycin-resistance transfer, 9 (3 each on filters, in broth, and skim milk) were successful. Nine strains representing 3 species of coagulase-negative staphylococci were tested as prospective donors of streptomycin resistance. Of these, 2 strains could transfer streptomycin resistance. A double-resistant donor, Shominis, not only transferred its streptomycin resistance to an S chromogenes strain lacking resistance, but also to an S aureus strain already carrying penicillin and tetracycline resistance. The transfer of streptomycin resistance from the donor S hominis, harboring 2 plasmids, to a plasmidless S chromogenes recipient strain was associated with apparent acquisition of the smaller plasmid of the donor by the recipient. The single-resistant donor, S epidermidis 681A, transferred streptomycin resistance to a tetracycline-resistant. S aureus recipient. This strain however failed to transfer its streptomycin resistance to another S aureus, 2 S hyicus, and 1 S xylosus recipient. Frequency of transfer of streptomycin resistance ranged from 1.1 × 10−5 to 1 × 10−4. When transfer of resistance was successful, attempts were made to characterize the transfer process. Conjugation appeared to be the mode of streptomycin-resistance transfer. Transfer of resistance between staphylococci of bovine mammary gland origin appears to be fairly uncommon. However, in view of the limitations of the procedures used, additional in vitro and in vivo work is needed to further assess the role of coagulase-negative staphylococci in dissemination of antibiotic resistance.