bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacodynamic properties of succinylcholine in Greyhounds
Authors: Curtis Michael B. , Eicker Steven E.
Published: January 2024

Succinylcholine is a depolarizing neuromuscular blocking drug, which is rapidly hydrolyzed by the enzyme pseudocholinesterase. In Greyhounds, the metabolism of certain drugs is atypical relative to other breeds, and it has been suggested that Greyhounds may be an atypical population, with lower pseudocholinesterase activity, slower hydrolysis of the drug succinylcholine, and a prolonged duration of action of the drug, compared with a mixed-breed control population.

Six healthy adult Greyhounds and 6 healthy adult mixed-breed dogs were studied. Blood was drawn from each dog and analyzed for serum cholinesterase activity, and a biochemical profile was done to verify normal liver function. The dogs were anesthetized with methohexital (10 mg/kg) and isoflurane (1.25 minimal alveolar concentration) in 100% oxygen. Ventilation was controlled, fluids were administered iv (lactated Ringer solution, 10 ml/kg/ h), and blood gases, blood pressure, and heart rate were monitored. The right hind limb was immobilized and a force transducer was used to monitor twitch strength of the interosseous muscle with supramaximal stimulation of the tibial nerve. Succinylcholine was administered to each dog 3 times at a dosage of 0.3 mg/kg. After drug administration, the time to 50% recovery of twitch strength (single twitch, 1/s), and 50% recovery of train-of-4 was determined. Subsequent doses were administered after complete recovery. The time to 50% recovery after succinylcholine administration in Greyhounds (38 minutes, dose 1, single twitch) was not significantly different than the time to 50% recovery in mixed-breed dogs (29 minutes, dose 1, single twitch), using either monitoring technique. Pseudocholinesterase activity was also not significantly different between the Greyhounds (1,685 mU/ ml) and the mixed-breed dogs (1,588 mU/ml).

The Greyhounds in this study had pseudocholinesterase activity that was the same as that in group of mixedbreed dogs, and the dogs appeared to hydrolyze succinylcholine at the same rate as the mixed-breed dogs. Therefore, our results would indicate that succinylcholine can be used in Greyhounds with the same degree of confidence as in other breeds.
Exogenous creatinine clearance as a measure of glomerular filtration rate in dogs with reduced renal mass
Authors: Finco Delmar R. , Brown Scott A. , Crowell Wayne A. , Barsanti Jeanne A.
Published: January 2024

Renal mass was surgically reduced in 78 dogs by uninephrectomy or by combined renal infarction and uninephrectomy. Renal clearance of inulin and renal clearance of exogenous creatinine were determined simultaneously, and the creatinine to inulin clearance (c/i) ratio was calculated. Clearance procedures were performed 2 to 3 months after reduction of renal mass, and were repeated at intervals thereafter. Overall, the c/i ratio was 1.008 ± 0.007 for 192 determinations, with a highly significant correlation (R2 = 0.994, P < 0.0001) between creatinine clearance and inulin clearance. There was no significant effect of gender of dogs, time after partial renal ablation, or dietary protein intake on c/i ratios. Degree of renal ablation did not affect c/i ratios. The results indicated that exogenous creatinine clearance is a valid measure of glomerular filtration rate in both male and female dogs with reduced renal mass.
Respiratory, renal, hematologic, and serum biochemical effects of hypertonic saline solution in endotoxemic calves
Authors: Constable Peter D. , Schmall L. Michael , Muir William W. , Hoffsis Glen F.
Published: January 2024

The respiratory, renal, hematologic, and serum biochemical effects of hypertonic saline solution (hss) treatment were examined in 12 endotoxic, pentobarbitalanesthetized calves (8 to 20 days old). Escherichia coli endotoxin (055:B5) was infused iv at a rate of 0.1 μg/kg of body weight over 30 minutes. Endotoxin induced severe respiratory effects, with marked hypoxemia and increases in arterial-alveolar O2 gradient (P[A —a]O2), physiologic shunt fraction (Qs/Qt), and physiologic dead space to tidal volume ratio (Vd/Vt). Oxygen consumption was decreased, despite an increase in the systemic O2 extraction ratio. Peak effects were observed at the end of endotoxin infusion. The renal response to endotoxemia was characterized by a decrease in free-water reabsorption and osmotic clearance, as well as a decrease in sodium and phosphorus excretion. Endotoxemia induced leukopenia, thrombocytopenia, hyperphosphatemia, hypoglycemia, acidemia, and increased serum alkaline phosphatase concentrations.

Calves were treated with hss (2,400 mosm/L of NaCl, 4 ml/kg, n = 4) or an equivalent sodium load of isotonic saline solution (iss; 300 mosm/L of NaCl, 32 ml/kg, n = 4) 90 minutes after the end of endotoxin administration. Both solutions were infused over a 4- to 6-minute period. A control group (n = 4> was not treated. Infusion of hss or iss failed to induce a significant change in Pao2, P(A-a)o2, (Qs/Qt), (Vd/Vt), or oxygen consumption. Both solutions increased systemic oxygen delivery to above preendotoxin values. Hypertonic saline infusion induced significant (P < 0.05) increases in serum Na and Cl concentrations and osmolality, whereas iss induced a significant increase in serum Cl concentration and a significant decrease in serum phosphorus concentration. Both hss and iss reversed the endotoxin-induced changes in renal function, with increases in free water reabsorption and osmotic clearance, as well as increases in sodium and phosphorus excretion. Sodium retention was greater following hss administration. On the basis of these findings, hypertonic saline solutions can be rapidly and safely administered to endotoxic calves.
Flow cytometric study of oxidative burst activity in bovine neutrophils
Authors: Salgar Shashikumar K. , Paape Max J. , Alston-Mills Brenda , Miller Robert H.
Published: January 2024

A flow cytometric procedure was evaluated to measure the oxidative burst activity (hydrogen peroxide formation) of bovine neutrophils. The method involves measuring the oxidation of intracellular dichlorofluorescin to fluorescent dichlorofluorescein (dcf). Phorbol myristate acetate (pma) was used to perturb the neutrophil plasma membrane.

The sources of variation introduced into the dcf assay were also examined. The sources of variation were attributable to the isolation of neutrophils from blood, variation between duplicate assays and duplicate flow cytometric determinations of oxidative product formation, variation in neutrophil oxidative product formation among cows, and the variation (over repeated daily and weekly neutrophil isolations) in neutrophil oxidative product formation.

A final objective was to determine effects of dexamethasone on oxidative product formation, and whether differences existed between blood and mammary neutrophils in oxidative product formation.

There was an increasing trend in the formation of dcf with increasing time of incubation and with increasing pma concentration. Increasing the concentration of pma decreased lag time and increased the rate of oxidative product formation. The increase in dcf formation was statistically significant up to a pma concentration of 10 ng/ml. This concentration was considered optimal for bovine neutrophils.

Examination of the sources of variation indicated that (i) the neutrophil isolation technique was a major source of variation (17.2 to 28.4% of the total variation), and that more than one neutrophil isolation within a cow would be required to obtain an accurate estimation of dcf formation in neutrophils; (ii) duplicate assays and duplicate readings on the flow cytometer accounted for < 0.05% of the total variation and would not be necessary when performing the dcf assay; (iii) large variation (62.4 to 70.8%) existed among cows in neutrophil oxidative product formation, indicating that any treatment being compared should be done either within or preferably repeated across a large number of cows; and (iv) the variation over repeated daily (0.3%), but not weekly (19.6%) determinations of neutrophil oxidative product formation, were small enough to allow for the evaluation of major physiologic and environmental effects.

Intramuscular administration of dexamethasone (50 μg/kg of body weight) resulted in an approximate 80% decrease in neutrophil oxidative product formation. Oxidative product formation was 75% less for neutrophils isolated from mammary secretions when compared with neutrophils from blood. These results indicated that the dcf procedure was responsive to factors known to interfere with oxidative metabolism of bovine neutrophils.
Evaluation of Rhipicephalus sanguineus as a potential biologic vector of Ehrlichia platys
Authors: Simpson R. M. , Gaunt S. D. , Hair J. A. , Kocan K. M. , Henk W. G. , Casey H. W.
Published: January 2024

The brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae), transmits several diseases among dogs including Ehrlichia canis infection. The role of Rhipicephalus sanguineus as a biologic vector for E platys, the rickettsial agent of infectious canine cyclic thrombocytopenia, was studied in dogs. Laboratory-cultured, pathogen-free nymph ticks were fed to repletion on dogs acutely infected with E platys. Tick engorgement coincided with the development of initial parasitemia and thrombocytopenia in the infected dogs. Following repletion, nymph ticks were allowed to molt under controlled conditions. One-month-old E platys-exposed adult ticks failed to infect naive dogs in animal transmission studies. The presence of E platys was not detected in midguts or salivary glands of similarly exposed adult ticks by use of light and transmission electron microscopy. These studies indicate that R sanguineus may not transmit E platys infection.
Effects of nitroscanate on adult Taenia pisiformis in dogs with experimentally induced infections
Authors: Bowman Dwight D. , Lin Dah-Sheng , Johnson Robert C. , Lynn Randy C. , Hepler Douglas I. , Stansfield David G.
Published: January 2024

Twenty-four specific-pathogen-free Beagles were each given 50 cysticerci of Taenia pisiformis that had been harvested from experimentally infected rabbits. Quantitative fecal egg counts and fecal screening for recovery of passed segments were performed on postinoculation days 56 through 70. Twenty-three of 24 dogs fed cysticerci developed patent infections. The 23 dogs with patent infections were assigned to 1 of 2 groups and treated with nitroscanate or a placebo 60 days after inoculation. Egg counts in the treated dogs had markedly decreased by the second day after treatment, and by the sixth day after treatment, segments were not found in the feces of any of the treated animals. The control dogs continued to pass eggs and segments in their feces throughout the 9 days after treatment. The dogs were euthanatized and necropsied 70 days after being inoculated. At necropsy, the mean number of scolices recovered from control dogs was 24.6, the mean number of scolices recovered from treated dogs was 0.25. Worms recovered from the control dogs were intact, gravid cestodes. Efficacy of treatment with nitroscanate at a mean dosage of 56 mg/kg of body weight was 98.9%.
Canine corneal thickness measured by ultrasonic pachymetry
Authors: Gilger Brian C. , Whitley R. David , McLaughlin Susan A. , Wright James C. , Drane J. Wanzer
Published: January 2024

Ultrasonic pachymetry was used to measure central, superior peripheral, and temporal peripheral corneal thicknesses of 75 dogs (150 eyes) with normal corneas, anterior chambers, and intraocular pressure. Mean corneal thickness averaged over the 2 eyes, 3 locations, and 75 dogs was 562 ± 6.2 μm. The peripheral cornea was thicker on average than the central cornea by 49.43 ± 8.45 μm and this difference increased with age at 6.97 ± 1.3 μm/month of age. Mean corneal thickness changed with age (14.23 ± 2.26 μm/month), and weight (1.83 ± 0.38 μm/kg). Females had significantly thinner corneas (22.43 ± 11.03 μm than males) after adjusting for age and weight.
Evaluation of edetate and thiamine for treatment of experimentally induced environmental lead poisoning in cattle
Authors: Coppock R. W. , Wagner W. C. , Reynolds J. D. , Vogel R. S. , Gelberg H. B. , Florence L. Z. , Wolff W. A.
Published: January 2024

Twenty mature Holstein cows were randomized into 5 treatment groups. Cows of groups 2 to 5 were given 2 mg of elemental Pb/kg of body weight for 28 days. Clinical signs of plumbism were scored, and blood for Pb, progesterone, and hematologic analyses was collected weekly. Cows also were examined weekly for anomalous ovarian cycles. Starting on study day 28, cows in group 3 were treated once daily with 2 mg of thiamine HCl/kg (im) for 13 days, cows in group 4 were treated twice daily with 62 mg of Na2, Ca-edta/kg (iv) for 4 days, and cows in group 5 were given thiamine (dosage regimen the same as for group 3) plus Na2, Ca-edta (dosage regimen the same as for group 4). On study days 96 through 139, cows were slaughtered in a commercial abattoir and samples of blood, skeletal muscles, bones, liver, and kidneys were collected and assayed for Pb concentration.

Thiamine was not effective in reducing blood Pb concentration, and treatment with Na2, Ca-edta and thiamine plus Na2, Ca-edta was effective in reducing the concentration of Pb in blood. However, treatment with thiamine was more effective than treatment with Na2, Ca-edta or thiamine plus Na2, Ca-edta in inducing remission of clinical signs of plumbism. The concentration of Pb in blood was significantly (P < 0.05) correlated to the concentration of Pb in liver, kidneys, skeletal muscles, and bones. Significant (P < 0.05) relationship existed between number of days from Pb exposure to slaughter and concentration of Pb in blood, liver, and skeletal muscles. Exposure to Pb did not significantly alter cbc values. On the basis of progesterone analysis and ovarian examination, exposure to Pb and treatment for plumbism did not induce changes in the ovarian cycle.
Evaluation of use of progesterone to counteract zearalenone toxicosis during early pregnancy in gilts
Authors: Green M. L. , Stouffer D. K. , Scheidt A. B. , Long G. G. , Diekman M. A.
Published: January 2024

It has been shown that zearalenone disrupts early pregnancy in swine without altering intrauterine content of estradiol 17β or progesterone, embryo migration, or estradiol-17β synthesis by blastocysts. However, serum concentrations of progesterone were reduced 2 to 3 weeks after mating in gilts that ingested zearalenone. Therefore, progesterone was administered to gilts during early pregnancy to determine whether it could counteract the detrimental actions of zearalenone on embryonic development. Thirty-two crossbred gilts (Hampshire × Chester White × Yorkshire × Duroc) were assigned randomly to a 2 × 2 factorial arrangement of treatments: zearalenone (z); zearalenone plus progesterone (zp); progesterone (p); or control (c). From postmating days 4 to 15, z- and zp-treated gilts were fed 1 mg of z/kg of body weight, and p-treated and c gilts were fed ethanol as vehicle in a cornsoybean diet. On postmating days 3 to 15, p- and zp-treated gilts were injected im with 100 mg of progesterone, and c and z-treated gilts were injected with progesterone carrier (15% ethanol, 15% benzyl alcohol, 70% propylene glycol). Blood was collected from gilts by puncture of the jugular vein daily from days 3 to 15, on alternate days from days 17 to 31, and then twice weekly until the end of the experiment. Fetal development was assessed in z- and zp-treated gilts on postmating day 47.6 ± 2.9 by cesarean section and in p-treated and c gilts at slaughter on postmating days 51.2 ± 3.2. Serum concentrations of progesterone in p-treated gilts were greater on days 7 to 8, 10 to 15, 17, and 19 than in c gilts. Serum concentrations of progesterone were greater on days 8, 10, and 12 in zp-treated than in c gilts. However, serum concentrations of progesterone were lower in zp-treated gilts than in c gilts on postmating days 19 to 31. Serum concentrations of progesterone were lower in z-treated gilts than c gilts on postmating days 15, 17, and 19. At slaughter or cesarean section, viable fetuses were not found in z-treated gilts, but 80% of the c and p-treated gilts had viable fetuses. All z-treated gilts were classified as pseudopregnant because uteri were turgid and the ovaries had functional corpora lutea. Uteri of zp-treated gilts appeared normal. Corpora lutea of pregnancy had regressed by postmating day 35 in 7 of 8 zp-treated gilts. Crown-to-rump length was similar between p-treated and c gilts (94 vs 92 mm). Fetal weight was similar between p-treated and c gilts (70 vs 62 g). These data demonstrate that 100 mg of progesterone/d failed to counteract the adverse effects of 1 mg of z/kg of body weight on early pregnancy in primiparous gilts.
Electrocardiographic and echocardiographic features of trypanosomiasis in dogs inoculated with North American Trypanosoma cruzi isolates
Authors: Barr Stephen C. , Holmes Robert A. , Klei Thomas R.
Published: January 2024

Purebred Beagles were inoculated with Trypanosoma cruzi isolates from a North American opossum or armadillo (Tc-W), and dog (Tc-D). Although Tc-D established infection in dogs, the dogs did not develop cardiac abnormalities. Dogs inoculated with Tc-W developed acute myocarditis associated with increases in P-R interval, atrioventricular block, depression of R wave amplitude and shifts in mean electrical axis. Echocardiograms were normal during this stage. Three Tc-W-inoculated dogs died during the acute stage. Following the acute stage, 5 of 8 Tc-W-inoculated dogs entered an indeterminate stage in which ecg changes were minor and echocardiograms were normal. Progression to the chronic stage in 5 of the 8 Tc-W-inoculated dogs was indicated by development of ventricular-based arrhythmias, mainly ventricular premature contractions, between postinoculation days 60 and 170. In some dogs, ventricular premature contractions were multifocal. Electrocardiographic abnormalities progressively degenerated to various forms of ventricular tachycardia. Worsening ecg coincided with loss of left ventricular function as measured by echocardiography. Mean percent ejection fraction and percentage of fractional shortening decreased to 63% and 52% of control values, respectively. The left ventricular free wall (lvfw) thickness decreased and % septal: % lvfw thickening ratio increased, indicating a relative preservation of septal wall motion and lvfw hypokinesis.
Evaluation of accuracy of pulse oximetry in dogs
Authors: Jacobson John D. , Miller Matthew W. , Matthews Nora S. , Hartsfield Sandee M. , Knauer Kenneth W.
Published: January 2024

The accuracy of a pulse oximeter was evaluated over a wide range of arterial oxygen and carbon dioxide tensions, using 2 probes (finger probe and ear probe) and 2 monitoring sites (tongue and tail) in anesthetized dogs The arterial oxygen saturation of hemoglobin (SaO2) measured directly with a multiwavelength spectrophotometer was compared with saturation estimated by pulse oximetry (SpO2). Linear regression analysis of the pooled data from 399 simultaneous measurements of SpO2 and SaO2 indicated a highly significant correlation of SpO2 with SaO2 (r = 0.97; P ≤ 0.0001). Although the mean difference (± sd) between SpO2 and SaO2 for pooled data was small (- 0.06 ± 6.8%), SpO2 tended to underestimate high SaO2 values (≥ 70%) and to overestimate low SaO2 values (< 70%). When SaO2 values were ≥ 70%, the ear probe applied to the tail was less accurate (produced a significantly greater SpO2-SaO2 difference) than the ear probe on the tongue, or the finger probe at either site. When SaO2 values were ≤ 50%, the finger probe applied at the tail was more accurate (produced significantly smaller SpO2-SaO2 differences) than the ear probe at either site. When SaO2 values were ≤ 70%, high arterial carbon dioxide tension (≥ 60 mm of Hg) was associated with greater overestimation of SaO2.
Incidence of localized feline leukemia virus infection in cats
Authors: Hayes Kathleen A. , Rojko Jennifer L. , Mathes Lawrence E.
Published: January 2024

Anecdotal descriptions of atypical FeLV infections, wherein standard clinical elisa or immunofluorescence testing fails to detect active infections, suggest that an unknown proportion of FeLV-infected cats may go undetected. In this study, 127 viremic and nonviremic cats experimentally inoculated with FeLV were evaluated at necropsy for atypical expression of FeLV antigen. Results from viremic cats were in accordance with results of earlier studies on the pathogenesis of FeLV infection in cats, wherein antigen was found in lymphoid and epithelial tissues. Differences in time course or tissue distribution of viral antigen in some cats appeared to be attributable to the challenge virus preparations, consisting of cell-free tumor homogenate or infectious plasma. It was discovered that 5 of 19 of the FeLV challenge-exposed cats that were nonviremic had FeLV-specific antigens in select tissues (bone marrow, spleen, lymph node, and small intestine) 6 to 75 weeks after inoculation. These results indicated an additional category of possible outcomes for cats exposed to FeLV. Localized FeLV infection, as described here, may explain the discordance between clinical disease and laboratory testing for FeLV.
Effect of ivermectin on the control of ear mites (Psoroptes cuniculi) in naturally infested rabbits
Authors: Bowman Dwight D. , Fogelson Melissa L. , Carbone Lawrence G.
Published: January 2024

We examined the efficacy of ivermectin in the control of ear mites (Psoroptes cuniculi) in rabbits. The study involved 40 female and 35 male rabbits that were known to be naturally infested with ear mites. After a period of acclimation to the animal care facilities, the rabbits were ranked on the visual appearance of any ear lesion and the number of mites on glycerin-dipped ear swabs. The rabbits were then randomly assigned to 1 of 4 treatment groups; vehicle only (group 1), 50 µg of ivermectin/kg of body weight (group 2), 100 µg of ivermectin/kg (group 3) and 200 µg of ivermectin/kg (group 4). The rabbits were treated by SC injections on day 0 and day 14 of the trial; thus, the total dose of ivermectin given to groups 1 through 4, was 0, 100, 200, or 400 µg/kg, respectively. The study ended 2 weeks after the last treatment. Ear lesions of the treated rabbits improved significantly (P<0.001). By 28 days after the first treatment, the mean number of mites on the ear swabs (both ears) was 57.5 for untreated rabbits and 9.1, 0.5, and 2.5, respectively, for rabbits in groups 2, 3, and 4. The mean number of mites recovered from the ears of the untreated rabbits at necropsy was 24,297. For groups 2, 3, and 4, the mean number of mites recovered from the ears was 5,352, 96, and 96, respectively. The efficacy of treatment with a total dose of 100 µg/kg was 77.96%, with 200 µg/kg was 99.61%, and for 400 µg/ kg was 99.61%.
Synchronization of estrus in dairy goats treated with prostaglandin F at various stages of the estrous cycle
Authors: Nuti L. C. , Bretzlaff K. N. , Elmore R. G. , Meyers S. A. , Rugila J. N. , Brinsko S. P. , Blanchard T. L. , Weston P. G.
Published: January 2024

Dairy goats were given im injections of 125 μg of cloprostenol sodium on day 6 of the estrous cycle (prostaglandin F [pgf] 6, n = 22) or day 12 of the estrous cycle (pgf 12, n = 26). Mean ± se hours from injection to onset of behavioral estrus and proportion of goats responding were 46 ± 4.2 (range, 12 to 88 hours) and 95% and 48 ± 2.9 (range, 34 to 68 hours) and 100% for groups pgf 6 and pgf 12, respectively. There was no significant difference between the groups in mean time to onset of estrus, but variances about the means were different. Of the does in groups pgf 6 and pgf 12, 67 and 85%, respectively, had signs of onset of estrus between 36 and 60 hours after administration of pgf. Mean (± se) hours from injection to time of peak concentrations of luteinizing hormone (lh) were 62 ± 3.1 and 64 ± 2.1 for groups pgf 6 and pgf 12, respectively. Of the does in groups pgf 6 and pgf 12, 86 and 100%, respectively, had lh peaks. Of the does in groups pgf 6 and pgf 12, 68 and 77%, respectively, had peak concentrations of lh between 48 and 72 hours after administration of pgf. All does in groups pgf 6 and pgf 12 had concentrations of progesterone ≥ 1.0 ng/ml on the day of administration of pgf. Concentrations decreased to < 1.0 ng/ml by 48 hours after injection in all does except 1 in group pgf 6. Prostaglandin was equally effective for induction of estrus on day 6 or day 12 of the estrous cycle in dairy goats, but resulted in a more predictable time to estrus when injection was done on day 12.
In vivo isolation of Salmonella choleraesuis from porcine neutrophils
Authors: Roof Michael B. , Kramer Theodore T. , Kunesh Jerry P. , Roth James A.
Published: January 2024

Seventy-five pigs from 4 facilities were examined for Salmonella choleraesuis by use of bacteriologic culture of feces, blood, wbc (buffy coat), mononuclear leukocytes, and neutrophils. The organism was isolated from 0 of 75 fecal samples, compared with isolation from 39 of 75 purified neutrophil preparations. Of the pigs that did not have Salmonella isolated from feces or blood, but had S choleraesuis isolated from neutrophils, 6 were further examined. These pigs from 2 groups again had culture performed at least 3 successive times to test for repeatability and to determine optimal number of neutrophils required for Salmonella isolation. These same pigs were euthanatized and necropsied. Nineteen tissue specimens from each pig were obtained for culture, but S choleraesuis was isolated only from neutrophil samples. Results indicate that neutrophils may contribute to the carrier state in pigs and should be cultured when attempting to identify S choleraesuis carrier swine.
Analgesia and behavioral responses of dogs given oxymorphone-acepromazine and meperidine-acepromazine after methoxyflurane and halothane anesthesia
Authors: Sawyer Donald C. , Rech Richard H. , Adams Thomas , Durham Robert A. , Richter Marlee A. , Striler Elaine L.
Published: January 2024

This study was designed to test analgesia, duration, and cardiovascular changes induced by meperidine (mep) and oxymorphone (oxy) following methoxyflurane (mof) and halothane (hal) anesthesia. Eight healthy dogs were given atropine and acepromazine, and anesthesia was induced with thiamylal and maintained with 1.5 minimal alveolar concentration of mof or hal for 1 hour during controlled ventilation. Eight treatments were given with each anesthetic: 3 with mep (0.5, 1.0, and 2.0 mg/kg, iv), 3 with oxymorphone (oxy; 0.05, 0.1, and 0.2 mg/kg, iv), and 2 placebos with sterile water. Test drugs were given at the end of anesthesia when early signs of recovery were evident. Minimal threshold stimulus/response nociception was assessed by use of an inflatable soft plastic colonic balloon. Blood pressures and pulse rate were measured with a noninvasive monitor. Meperidine and oxy were found to be effective analgesics and could be reversed with naloxone. Intravenous administration of 2.0 mg of mep/kg provided analgesia for 36 ± 6 minutes and 39 ± 15 minutes after mof and hal, respectively. In contrast, oxy was effective at all 3 doses with effects of iv administration of 0.2 mg of oxy/kg lasting 154 ± 13 minutes and 152 ± 12 minutes, after mof and hal, respectively. Analgesia could not be demonstrated after anesthesia for acepromazine, mof, or hal. Blood pressure was not changed by either anesthetic nor was it influenced by mep or oxy. Pulse rate was significantly depressed by the higher doses of oxy following hal, but was not changed by mep following either anesthetic. This study demonstrated the longer duration of analgesia of oxy. In addition, we could not find that analgesia was provided by either mof or hal following recovery from anesthesia.
Managerial risk factors of intramammary infection with Streptococcus agalactiae in dairy herds in Ohio
Authors: Bartlett Paul C. , Miller Gay Y. , Lance Susan E. , Hancock Dale D. , Heider Lawrence E.
Published: January 2024

Dairy herds in Ohio were selected by stratified random sampling for participation in a disease-monitoring study to relate Streptococcus agalactiae intramammary prevalence to herd management and environmental conditions. Of 48 herds studied, 27 herds had at least 1 cow infected with this pathogen. Management and environmental conditions were assessed by direct observation as well as by an interview with the dairy producers. One-way anova or χ2 analysis, with presence or absence of Streptococcus agalactiae as the dependent variable, was used to test each of 70 independent variables. Variables found significant at P < 0.20 were further evaluated by use of logistic regression. Our sample size permitted only 4 independent variables to be simultaneously evaluated by logistic regression. The most predictive risk factors were identified as poor teat and udder hygiene, poor environmental sanitation, large herd population, and use of a shared washcloth for premilking cleaning of teats and udders.
Use of a biological extract of Serratia marcescens to decrease doxorubicin-induced myelosuppression in dogs
Authors: Ogilvie Gregory K. , Elmslie Robyn E. , Cecchini Marie , Walters Lisa M. , Pearson Frederick C.
Published: January 2024

Fifteen dogs were given doxorubicin, iv, at a dosage of 30 mg/m2 of body surface. A commercially available biological extract of Serratia marcescens (besm) was administered sc to 9 of these dogs (0.04 mg/kg of body weight every third day, n = 2; 0.08 mg/kg every other day, n = 2; and 0.08 mg/kg daily, n = 5), beginning the day after administration of doxorubicin, in an attempt to find an optimal dosage and schedule of administration of besm to reduce the duration and severity of chemotherapy-induced myelosuppression. Nine additional dogs were randomized into 3 groups of 3 dogs to receive 1 of the following dosages of besm sc: 0.08, 0.16, and 0.32 mg/kg. Serum was harvested immediately prior to treatment and at 2, 4, 6, 8, 12, 24, 48, and 72 hours from this latter group of dogs for subsequent analysis of canine granulocyte colony-stimulating factor (g-csf) by enzyme immunoassay. Increasing the dosage and schedule of administration of besm reduced the duration and severity of doxorubicin-induced myelosuppression. Neutrophil counts of the group of dogs given besmdaily at a dosage of 0.08 mg/kg and the controls were evaluated statistically. The neutrophil count increased significantly (P < 0.05) above pretreatment values in besm-treated dogs after day 7. Median neutrophil counts of the besm-treated dogs were never significantly lower than pretreatment values, whereas the median counts of the dogs treated with doxorubicin alone were significantly below normal for 6 days (days 7-12). The median counts decreased below normal (< 3,000 cells/μl) for 1 day in the dogs given besm and doxorubicin, and for 3 days in the dogs that were given only doxorubicin. Four of the 6 dogs not treated with besm and none of those given besm developed serious neutropenia (< 1,500/μl). There was an increase in canine g-csf 4 to 6 hours after besm was administered to dogs at dosages of 0.16 and 0.32 mg/kg. These findings demonstrate that besm is capable of reducing the duration and severity of doxorubicin-induced myelosuppression, and that this may be at least partially mediated by g-csf.
Evaluation of hemostatic analytes after use of hypertonic saline solution combined with colloids for resuscitation of dogs with hypovolemia
Authors: Zoran Debra L. , Jergens Albert E. , Riedesel Dean H. , Johnson Gary S. , Bailey Theodore B. , Martin Stephen D.
Published: January 2024

The effects of hypertonic saline solution (htss) combined with colloids on hemostatic analytes were studied in 15 dogs. The analytes evaluated included platelet counts, one-stage prothrombin time, activated partial thromboplastin time, von Willebrand's factor antigen (vWf:Ag), and buccal mucosa bleeding times. The dogs were anesthetized, and jugular phlebotomy was used to induce hypovolemia (mean arterial blood pressure = 50 mm of Hg). Treatment dogs (n = 12) were resuscitated by infusion (6 ml/kg of body weight) of 1 of 3 solutions: htss combined with 6% dextran 70, 6% hetastarch, or 10% pentastarch. The control dogs (n = 3) were autotransfused. Hemostatic analytes were evaluated prior to induction of hypovolemia (baseline) and then after resuscitation (after 30 minutes of sustained hypovolemia) at 0.25, 0.5, 1, 6 and 24 hours.

All treatment dogs responded rapidly and dramatically to resuscitation with hypertonic solutions. Clinically apparent hemostatic defects (epistaxis, petechiae, hematoma were not observed in any dog. All coagulation variables evaluated, with the exception of vWf:Ag, remained within reference ranges over the 24-hour period. The vWf:Ag values were not statistically different than values from control dogs, and actual values were only slightly lower than reference ranges. Significant (P ≤ 0.04) differences were detected for one-stage prothrombin time, but did not exceed reference ranges. The results of this study suggested that small volume htss/colloid solutions do not cause significant alterations in hemostatic analytes and should be considered for initial treatment of hypovolemic or hemorrhagic shock.
Potential use of simple manganese salts as antioxidant drugs in horses
Authors: Singh Raj K. , Kooreman Karin M. , Babbs Charles F. , Fessler John F. , Salaris Steven C. , Pham JoAnn
Published: January 2024

The scavenging of superoxide radicals by endogenous and therapeutically administered superoxide dismutases may prevent superoxide-mediated oxidative stress leading to lipid peroxidation, membrane lysis, and cell death in a wide variety of normal and pathologic states. Simple inorganic manganous salts such as MnCl2 also have superoxide dismutase-like activity and are extremely inexpensive, compared with enzymatic superoxide dismutase preparations. In this study, we explored the use of Mn salts as antioxidant drugs. We used the percentage of inhibition of nitroblue tetrazolium reduction by superoxide as a measure of the amount of superoxide dismutase-like activity. We found concentration-related increases in superoxide scavenging activity in simple buffer solutions upon addition of 1.25, 2.5, and 5.0 μM MnSO4. To determine whether Mn salts can inhibit oxidative damage in tissues, we used an in vitro model of lipid peroxidation in ischemic and reoxygenated rat liver slices. Concentrations of 10, 100, and 1000 μmoles MnCl2/L of buffer significantly decreased indicators of lipid peroxidation believed to be initiated by intracellular superoxide. We then determined the effectiveness of MnCl2 as a superoxide scavenger in conscious horses by measuring the superoxide scavenging ability of equine plasma before and during intravenous infusions of 1.0 L volumes of 0.9% slaine solution containing 0, 12.5, or 25 mM MnCl2. Plasma Mn concentrations, which were determined by atomic absorption spectrophotometry, increased as a function of time and dose. Intravenously administered MnCl2 concomitantly produced dose-related increases in superoxide scavenging ability of equine plasma at 15, 30, 45, and 60 minutes after the onset of infusion, compared with preinfusion control values. Heart rate and blood pressure of the treated horses, which were monitored to measure toxicity of MnCl2, gradually increased in both treatment groups. Clinical adverse effects of MnCl2 administration included defecation, pawing, hyperexcitability, flank watching, and sweating. The results of this study indicate that simple Mn salts may scavenge superoxide radicals in vivo with minimal adverse reactions and at a trivial cost.
Effect of dietary phosphoric acid supplementation on acid-base balance and mineral and bone metabolism in adult cats
Authors: Fettman Martin J. , Coble Jodi M. , Hamar Dwayne W. , Norrdin Robert W. , Seim Howard B. , Kealy Richard D. , Rogers Quinton R. , McCrea Karen , Moffat Kelly
Published: January 2024

Experimental evidence indicates that maintenance of urinary pH ≤ 6.4 is the single most effective means of preventing feline struvite crystalluria or urolithiasis of noninfectious causes. This may be accomplished by dietary acidification, but must be moderated to avoid potential adverse effects of excessive acidification, including bone demineralization, negative calcium balance, potassium depletion, and renal disease. Effects of chronic dietary phosphoric acid supplementation on acid-base balance and on mineral and bone metabolism were investigated in adult, domestic cats. One group of 6 cats was fed a basal, naturally acidifying diet without added acidifiers, and another group of 6 cats was fed 1.7% dietary phosphoric acid. Changes observed during 12 months of study included development of noncompensated metabolic acidosis, increased urinary calcium excretion, and lower but positive calcium balance in cats of both groups. Urinary pH decreased in cats of both groups, but was significantly (P < 0.05) and consistently maintained ≤ 6.4 in cats given dietary phosphoric acid. Urinary phosphorus excretion increased in cats of both groups, but was significantly (P < 0.05) greater in phosphoric acid-supplemented cats, leading to lower overall phosphorus balance as well. Potassium balance decreased in cats of both groups, but was only transiently negative in the phosphoric acid-supplemented cats midway through the study, and normalized at positive values thereafter. Plasma taurine concentration was not affected by dietary acidification, and remained well within the acceptable reference range for taurine metabolism. Double labeling of bone in vivo with fluorescent markers was followed by bone biopsy and histomorphometric measurement of several static and dynamic variables of bone formation. Overall indices of bone formation decreased in cats of both groups with age and confinement, but were not affected by dietary phosphoric acid supplementation. Dietary supplementation with phosphoric acid used as the principal inorganic P source to achieve moderate and stable degree of urinary acidification, did not appear over the course of 1 year, to have induced adverse effects on mineral, bone, or taurine balance in these adult domestic cats.
Anatomy of the prepubic tendon in the horse, cow, sheep, goat, and dog
Authors: Habel Robert E. , Budras Klaus-Dieter
Published: January 2024

Analyses of the fibers in the prepubic tendon of the horse and ruminants have shown that it is composed of the crossed and uncrossed tendons of origin of the pectineus muscles, the pelvic tendons of the rectus and obliquus abdominis muscles, and the tendons of origin of the cranial parts of the gracilis muscles. Pelvic attachments of the linea alba and the yellow abdominal tunic are incorporated in it. It is not a transverse ligament, and it is not homologous to the human superior (cramai) pubic ligament.

The dog differs in 4 respects: (1) the pectineus tendons do not cross, but each originates from the pubic bone of the same side; (2) an iliopubic cartilage is intercalated in the prepubic tendon on each side at the junction of the pectineus tendon and the abdominal and pelvic tendons of the external oblique at the caudal angle of the superficial inguinal ring; (3) in some dogs, the caudal border of the aponeurosis of the transversus abdominis joins the prepubic tendon; (4) the gracilis tendon does not extend to the prepubic tendon.

The clinical anatomy was described, illustrated, and compared between species. Conflicting descriptions in the literature were discussed and resolved by new approaches to the dissection. Studies of the inguinal region in the cat and pig were reviewed. A table of nomenclature is included.
Investigation of renal protein loss in dogs with acute experimentally induced Ehrlichia canis infection
Authors: Codner Ellen C. , Maslin William R.
Published: January 2024

Urinary protein-to-creatinine ratios and serum albumin concentrations were measured in 8 adult male dogs experimentally inoculated with Ehrlichia canis. Urinary protein concentration increased significantly, but transiently, during the acute phase of infection. Urinary protein-to-creatinine ratios were highest (mean, 8.6) during the third and fourth weeks after infection, and decreased to < 0.5 by 6 weeks after infection. Correspondingly, albumin concentration decreased significantly during the acute phase. Serum albumin concentrations were lowest (mean, 2.1 g/dl) the fourth week after infection and increased to > 3.0 g/dl by 11 weeks after infection.

There was an inverse linear correlation between urinary protein-to-creatinine ratio and serum albumin concentration. The magnitude of proteinuria and its inverse relationship with serum albumin concentration suggested that hypoalbuminemia associated with acute E canis infection may be attributable primarily to increased renal loss of protein, rather than decreased hepatic synthesis as previously suggested.

Another dog was subsequently inoculated with E canis from 1 of the experimentally infected dogs and a renal biopsy was performed during peak proteinuria (urinary protein-to-creatinine ratio = 22 and serum albumin = 1.1 g/dl). Immunofluorescent staining revealed mild to moderate deposits of anti-canine IgM, and to a lesser extent, anti-canine IgG and complement factor C3 in the glomerular tufts and mesangium. Ultrastructural evaluation revealed distortion and fusion of podocyte foot processes and increased microvilli on podocytes. These morphologic changes were consistent with transient glomerular leakage of protein of a magnitude that would significantly contribute to hypoalbuminemia during acute E canis infection. An underlying immunologic mechanism was suggested by positive glomerular immunofluorescence and previously described histologic findings.
Parasympathetic influence on the arrhythmogenicity of graded dobutamine infusions in halothane-anesthetized horses
Authors: Light Gwendolyn S. , Hellyer Peter W. , Swanson Clifford R.
Published: January 2024

We investigated the influence of parasympathetic tone on the arrhythmogenicity of graded dobutamine infusions in horses anesthetized under clinical conditions. Six horses were used in 9 trials. Two consecutive series of graded dobutamine infusions were given iv; each continuous graded dobutamine infusion was administered for 20 minutes. The dobutamine infusion dosage (5, 10, 15, and 20 μg/kg of body weight/min) was increased at 5-minute intervals. Isovolumetric saline solution vehicle (v) or atropine (a; 0.04 mg/kg) was administered iv, or bilateral vagotomy (vg) was performed as a treatment before the second series of dobutamine infusions. Treatment was not administered prior to the first dobutamine infusion. Significant interaction between treatment and dosage of dobutamine infusion existed for differences from baseline for mean arterial pressure, systolic arterial pressure, diastolic arterial pressure, heart rate, and cardiac index at dosages of 5 and 10 μg of dobutamine/kg/min, given iv and for heart rate at dosage of 15 μg of dobutamine/kg/ min, given iv. Results for group-v horses were different from those for group-A and group-VG horses, but were not different between group-A and group-VG horses in all aforementioned cases, except for heart rate and cardiac index at dosage of 5 p.g of dobutamine/kg/min, given iv. Normal sinus rhythm, second-degree atrioventricular block, and bradyarrhythmias predominated during low dobutamine infusion rates during the first infusion series (nontreated horses) and in group-v horses during the second infusion series. Only tachyarrhythmias were observed during the second infusion series in the horses of the A and VG groups. The modulating influence of parasympathetic nervous system activity on hemodynamics and development of arrhythmia was conspicuous during low dobutamine infusion rates. Significant differences were not observed in hemodynamic responses to dobutamine, with respect to parasympathetic influence at high dobutamine infusion rates.
Serum lipoprotein concentrations and hepatic lesions in obese cats undergoing weight loss
Authors: Dimski Donna S. , Buffington C. A. , Johnson Susan E. , Sherding Robert G. , Rosol Thomas J.
Published: January 2024

Serum lipoprotein concentrations, routine serum biochemical values, and morphologic changes of the liver were evaluated in cats undergoing weight loss. Food was witheld from 6 obese and 6 control cats for 3 days (days 0 to 2), followed by feeding 50% of previous food intake for 26 days (days 3 to 28). Percutaneous liver biopsy specimens were obtained from all cats on days 0, 7, 14, and 28. Blood samples for serum biochemical analysis and lipoprotein profiles were obtained on days 0, 3, 7, 14, and 28. All cats lost weight throughout the study, and none developed signs of clinical illness, including those of idiopathic hepatic lipidosis syndrome. Serum total cholesterol concentrations decreased initially in all cats, but rapidly returned to normal after day 3 in obese cats, suggesting altered cholesterol metabolism during dietary restriction. Low-density lipoprotein concentrations decreased throughout the study in control cats, but were unchanged in obese cats. Examination of liver biopsy specimens from each cat revealed minimal lipid accumulation in all specimens, although some specimens contained hydropic degeneration.
Fibrinogen-degrading proteins from Haemonchus contortus used to vaccinate sheep
Authors: Boisvenue R. J. , Stiff M. I. , Tonkinson L. V. , Cox G. N. , Hageman R.
Published: January 2024

Sixteen nonsibling sheep, approximately 12 months old, that were raised in a helminth-free environment, were used for 2 protection studies 6 months apart. Sheep were vaccinated weekly for 5 weeks by im injection of fibrinogen-degrading proteins derived from the intestinal tract of adult Haemonchus contortus. Ten days after the last vaccination, sheep were given 2,500 infective H contortus larvae by intraruminal injection. Vaccinated sheep produced specific antibodies, and were protected from the worm challenge. Significant differences in mean fecal worm egg counts for 56 days after worm challenge, in mean numbers of H contortus worms, and female fecundity ratios at necropsy were detected in vaccinated sheep, compared with those in control sheep. These data suggest that the fibrinogen-degrading proteins have a protective role in vaccination of sheep against H contortus.