bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in oscillatory potentials in the canine electroretinogram during dark adaptation
Authors: Sims Michael H. , Brooks Dennis E.
Published: January 2024

Oscillatory potentials (op) and electroretinograms (erg) were recorded from clinically normal dogs after 5, 10, 15, 20, 30, 40, 50, and 60 minutes of dark adaptation. At the end of the adaptation period, op were characterized by 5 distinct positive peaks, 01 through 05, with mean latencies of 14.46, 20.24, 27.38, 35.31, and 44.85 ms, respectively, and with mean amplitudes ranging from 7.20 to 34.84 μV. After 60 minutes of dark adaptation, the erg had a mean a-wave latency of 12.03 ms and a mean b-wave amplitude of 109.29 μV. Peaks 03 and 04, which partially mask the summit of the b-wave, had mean latencies of 28.66 and 36.83 ms, respectively. The mean amplitude of the b-wave measured to the peak of 03 was 240.06 μV and 230.73 (μV when measured to peak 04. Changes in the op during dark adaptation consisted of significant (P < 0.05) increases in the latencies of 01, 02, and 03, and significant increases in the amplitudes of 01, 03, 04, and 05. Concurrent erg changes consisted of significant increases in the amplitudes of the a-wave and b-wave measured from 03 and 04, and significant increases in the latencies of peaks 03 and 04 on the b-wave.
Absorption kinetics of regular insulin in dogs with alloxan-induced diabetes mellitus
Authors: Nelson R. W. , Brown S. Anthony , Jones R. J. , Smith P. , Bottoms G. D.
Published: January 2024

The absorption kinetics of porcine regular insulin following iv, im, and sc administration were evaluated in 10 dogs with alloxan-induced diabetes mellitus. Plasma immunoreactive insulin (iri) concentrations were evaluated immediately prior to and at 10, 20, 30, 45, 60, 90, 120, 180, and 240 minutes following iv administration; and immediately prior to and every 30 minutes for 2 hours and then every hour for 6 hours following im and sc administration of 0.55 U of porcine regular insulin/kg of body weight. Model-independent pharmacokinetic analysis was performed on each data set.

Plasma iri concentration declined rapidly after iv administration of regular insulin and then returned to baseline iri concentration by 3.2 ± 0.8 hours. The absorption kinetics following iv administration of regular insulin were similar to those found in earlier studies in healthy dogs and human beings.

The im and sc routes of regular insulin administration resulted in a pharmacologic concentration of iri at 30 minutes. The peak mean (± SD) plasma iri concentration was significantly (P < 0.05) greater following sc administratin than it was following im administration of regular insulin (263 ± 185 and 151 ± 71 IμU/ml, respectively). The time of the peak plasma iri concentration (68 ± 31 minutes and 60 ± 30 minutes) and the time to return to baseline plasma iri concentration (5.8 ± 1.2 hours and 5.8 ± 1.3 hours) were not significantly different following sc and im administration of regular insulin, respectively. The absorption kinetics following sc administration of regular insulin were similar to those found in earlier studies in healthy dogs and human beings. The absorption kinetics following im administration of regular insulin differed from those found in earlier studies and was similar to the absorption kinetics of regular insulin administered sc in this study. The reasons for this similarity were not readily apparent.
Evaluation of coagulation and fibrinolysis during the prodromal stages of carbohydrate-induced acute laminitis in horses
Authors: Prasse Keith W. , Allen Douglas , Moore James N. , Duncan Alexander
Published: January 2024

The balance of coagulation and fibrinolysis was studied in 15 horses during the prodromal stages of acute 1aminitis induced by carbohydrate overload. Progression of the disease was stopped 12 to 24 hours before the expected onset of lameness in trial 1 (8 horses) and at the onset of lameness in trial 2 (7 horses). The end points in each trial were identified by specific changes in blood pressures (trial 1) and by changes in pulse, rectal temperature, and arterial pressure (trial 2) that were anticipated on the basis of original description of the experimental model. Blood samples for hemostasis evaluation were collected before and after carbohydrate overload in trial 1 and after carbohydrate overload in trial 2.

Significant changes were not detected in platelet count, mean platelet volume, prothrombin time, activated partial thromboplastin time, fibrinogen concentration, plasminogen concentration, α-2-antiplasmin, antithrombin III, protein C, thromboxane B2, or fibrin(ogen) degradation product concentration. We concluded that an imbalance in coagulation and fibrinolysis is not pathogenic in the onset of experimentally induced equine acute laminitis. Because several test methods used to evaluate hemostasis in these horses were new, reference values for 34 healthy adult horses were established.
Composition and morphologic features of the interosseous muscle in Standardbreds and Thoroughbreds
Authors: Wilson David A. , Baker Gordon J. , Pijanowski Gerald J. , Boero Michael J. , Badertscher Robert R.
Published: January 2024

Suspensory ligaments (sl) from 32 Thoroughbreds and 32 Standardbreds were collected to evaluate the variation in muscle content with respect to age, breed, sex, limb, and use. Six transverse sections, each 3 to 5 mm thick, were obtained from each sl. Four sections were taken from the body of the sl and 1 from the midportion of each branch. Sections were stained with van Gieson picric acid-fuchsin solution, then photographed, and black-and-white slides were made from the processed negatives. The transverse-sectional area of the sl and tbe contained muscle were determined by use of a computer with a color monitor and a digitizing device with its associated software. The percentage of muscle was then calculated for each section, for the entire ligament, and for each horse. Results were analyzed by multiple-regression analysis and Duncan multiple-range test, using the General Linear Model of SAS. Standardbreds had 40% more muscle in their sl than did Thoroughbreds. There was no significant difference in the percentage of sl muscle among sex, age, use, individual limb, or forelimb vs hind limb. For Standardbred horses, females had significantly greater muscle area content than intact males. Also, hind limb muscle area content was significantly greater than forelimb muscle content. Thoroughbred horses between 2 and 10 years of age not in training had significantly more muscle content than horses of the same age not in training. The reasons for these differences remain unclear.
Application of renal microangiography to normal and diseased kidneys of cattle and mice
Authors: Sugimoto Koji , Sakurai Nobuo , Kaneko Masao , Shirasawa Haruyuki , Shibata Kiyoshi , Miyata Manabu , Noguchi Tsuneji , Uematsu Ken'ichi , Shimoda Kanzo , Sakata Jun
Published: January 2024

Use of microangiography is now essential for the study of microcirculation in various organs. Renal microangiographic studies have been reported in rats, rabbits, dogs, human beings, and mice. However, we could not find any report on use of the technique in cattle, despite high incidence of renal disease in that species.

The perfusion technique used in mice was improved over that of our previous report, and was applied to normal and diseased bovine kidneys. For the microangiographic technique, composition of the contrast medium, pressure of the injection, duration of perfusion, and washing of kidneys with heparinized saline solution before perfusion are important. In cattle, 1- to 2-mm-thick sections of the kidneys were generally necessary to observe renal vasculature: arcuate and interlobular arteries, afferent arterioles, and glomerular capillaries.

In normal bovine kidneys, the angiographic and microangiographic findings were easily recognized as normal, compared with those of normal mice. In affected bovine kidneys, which histologically represented glomerulonephritis and pyelonephritis, angiography and microangiography revealed corresponding findings.
Fungal flora of the coat of pet cats
Authors: Moriello Karen A. , DeBoer Douglas J.
Published: January 2024

The fungal flora of the coat of 172 healthy pet cats was examined qualitatively. Fungi were isolated from 136 (79%) of the 172 cats. Fifteen genera were isolated; 13 are commonly regarded as saprophytes, and 2 (Microsporum and Trichophyton) are commonly regarded as pathogens. Aspergillus, Alternaria, Penicillium, and Cladosporium spp were the most frequently isolated saprophytes. Dermatophytic fungi, including Microsporum gypseum (n = 1), M vanbreuseghemii (n = 1), and Trichophyton rubrum (n = 14), were recovered from 16 cats. Microsporum canis was not isolated from any cat during this study.
Retrograde flow of spermatozoa into the urinary bladder of cats during electroejaculation, collection of semen with an artificial vagina, and mating
Authors: Dooley M. P. , Pineda M. H. , Hopper J. G. , Hsu W. H.
Published: January 2024

The effect of methoxamine on retrograde flow of spermatozoa into the urinary bladder of domestic cats during electroejaculation and the incidence of retrograde flow during the collection of semen with an artificial vagina, or during mating was examined. In experiment 1, urine collected by cystocentesis prior to electroejaculation was azoospermic or contained few, nonmotile spermatozoa, whereas urine collected after electroejaculation contained more (P = 0.002) spermatozoa, and motile spermatozoa were evident in urine obtained from 6 of 8 cats. Administration of methoxamine hydrochloride (200 μg/kg of body weight, iv) did not affect spermatozoal output or percentage of retrograde flow. Percentage of retrograde flow for control cats ranged from 61.18 to 92.95% (mean ± sd, 80.00 ± 14.28%) and for methoxamine-treated cats, ranged from 15.25 to 92.49% (mean ± sd, 58.10 ± 32.28%), but the difference was not significant.

In experiment 2, an artificial vagina was used to collect semen from 5 of the 8 cats used in experiment 1. Urine collected by cystocentesis after ejaculation contained spermatozoa, and motile spermatozoa were evident in the urine from 4 of 5 cats. The mean (± sd) percentage of retrograde flow for these 5 cats was 46.82 ± 31.67% (range, 14.56 to 90.32%).

In experiment 3, each of the 5 cats that were used in experiments 1 and 2 were mated. Spermatozoa were recovered from the vagina of each mated female, and motile spermatozoa were also present in postejaculation urine obtained by cystocentesis from each of the 5 male cats. Mean total number of spermatozoa in the postmating urine was 29.42 ± 33.58 × 106 (range, 0.22 × 106 to 76.05 × 106 spermatozoa).

Anesthesia of cats with ketamine facilitated the obtention of urine by cystocentesis, but did not cause spermatozoal displacement into the urinary bladder. Results of this study confirm the fact that, in cats, appreciable numbers of spermatozoa are lost because of retrograde flow into the urinary bladder during electroejaculation. Recovery of spermatozoa from the urinary bladder after collection of semen with an artificial vagina or following natural mating, indicates that retrograde flow of spermatozoa is not an artifact derived from electrical stimulation, but is a component of the ejaculatory process in cats.
Secretion of interleukin-1 by bovine milk macrophages
Authors: Politis I. , McBride B. W. , Burton J. H. , Zhao Xin , Turner J. D.
Published: January 2024

The relative sensitivity of bovine blood monocytes and macrophages isolated from milk to lipopolysaccharide, with respect to interleukin 1 (il-1) production, was evaluated. Addition of lipopolysaccharide (0 to 30 μg/ml) to the culture medium resulted in increases in secreted and intracellular il-1 activity for monocytes and milk macrophages, with maximal stimulation achieved at 30 μg of lipopolysaccharide/ ml of medium. At this concentration of lipopolysaccharide, monocytes released 76% of the total il-1, whereas milk macrophages released only 26% of the total il-1 produced within the cell. Secretion of a small quantity of il-1 was a common property of macrophages isolated from healthy and mastitic quarters. We concluded that limited secretion of il-1 may render the milk macrophages less efficient in promoting lymphocyte activation.
Use of adult dog serum as a substitute for colostrum in the neonatal dog
Authors: Poffenbarger Ellen M. , Olson Patricia N. , Chandler Marjorie L. , Seim Howard B. , Varman Marian
Published: January 2024

Failure to obtain passive transfer of immunity via colostrum can be detrimental to the health and survival of a young pup. It has been stated that pups that do not receive colostrum in the first 2 days after birth, be given adult dog serum as a source of protective immunoglobulins. Twenty-five Beagle pups were obtained by cesarean section from 6 Beagle bitches. The pups were allotted to 3 groups at birth. Group 1 was a control group and was allowed to suckle colostrum. Group-2 pups received 22 ml of pooled adult dog serum/kg of body weight (10 ml/lb) sc at birth. Group-3 pups were given 22 ml of pooled adult dog serum/kg by stomach tube at birth. Pups from groups 2 and 3 were separated from the bitch for 48 hours to prevent colostral antibody absorption and were fed a commercially available milk replacer by stomach tube. After 48 hours, all pups were returned to the bitch until they were weaned at 6 weeks of age. Blood samples were collected from all of the pups at birth and on days 1, 2, 7, 14, 21, 28, and 35. The concentration of IgA, IgG, and IgM in serum was determined by radial immunodiffusion and compared by use of a one-way analysis of variance. The control pups had significantly higher serum concentrations of IgA and IgG, than the pups in groups 2 and 3 on days 1 and 2 and 2 and 7, respectively. Group-2 pups had significantly higher serum IgM concentrations on day 1 than either group 1- or group-3 pups.
Hemodynamic response of calves to tiletamine-zolazepam-xylazine anesthesia
Authors: Lin H. C. , Thurmon J. C. , Tranquilli W. J. , Benson G. J. , Olson W. A.
Published: January 2024

Six healthy Holstein calves were anesthetized with isoflurane in O2 and instrumented for hemodynamic studies. A saphenous artery was catheterized for measurement of blood pressure and withdrawal of blood for determination of the partial pressure of carbon dioxide (PaCO2), oxygen (PaO2), and arterial pH (pHa). Respiration was controlled throughout the study. The ecg and eeg were monitored continuously. A thermodilution catheter was passed via the right jugular vein into the pulmonary artery for determination of cardiac output and measurement of central venous pressure, pulmonary arterial pressure, and pulmonary capillary wedge pressure. Baseline values (time 0) were recorded following recovery from isoflurane. Tiletamine-zolazepam (4 mg/kg)-xylazine (0.1 mg/kg) were administered iv immediately after recording baseline values. Values were again recorded at 5, 10, 20, 30, 40, 50, and 60 minutes after injection. Changes in left ventricular stroke work index, Paco2, and pHa were insignificant. Arterial blood pressure and systemic vascular resistance increased above baseline at 5 minutes and then gradually decreased below baseline at 40 minutes, demonstrating a biphasic response. Values for pulmonary capillary wedge pressure, pulmonary arterial pressure, central venous pressure, and Pao2 were increased above baseline from 5 to 60 minutes. Stroke volume, stroke index, and right ventricular stroke work index were increased from 20 or 30 minutes to 60 minutes. Pulmonary vascular resistance increased at 10 minutes, returned to baseline at 20 minutes, and was increased again at 60 minutes. Heart rate, cardiac output, cardiac index, and rate pressure product were decreased at 5 minutes, and with the exception of cardiac output, remained so for 60 minutes. Cardiac output returned to the baseline value at 30 minutes. All calves recovered without complications. We concluded that tiletamine-zolazepam (4 mg/kg iv)-xylazine (0.1 mg/kg iv) is a safe and useful anesthetic regimen for use in calves.
Influence of polysulfated glycosaminoglycan on equine articular cartilage in explant culture
Authors: Caron J. P. , Eberhart S. W. , Nachreiner R.
Published: January 2024

Articular cartilage explants from 3 horses were maintained in tissue culture to test the effects of a polysulfated glycosaminoglycan on proteoglycan biosynthesis. Cultures were exposed to concentrations of 0, 50, or 200 μg of the drug/ml for either 2 days or 6 days, and labeled with 35S, before measuring the content of sulfated proteoglycan in the culture media and in extracts of cartilage. In a second experiment, the explants were incubated with the isotope and subsequently exposed to the same concentrations of the polysulfated glycosaminoglycan for 4 days. Subsequently, the amount of remaining labeled proteoglycan was determined. Gel filtration chromatography was used to compare the hydrodynamic size of proteoglycans from the cartilage explants in each experiment.

Polysulfated glycosaminoglycan caused a dose-dependent depression of sulfated proteoglycan synthesis, which was statistically significant after 6 days of exposure. Radioactive proteoglycan content in explants was similar in the experiment involving isotopic labeling prior to exposure to the drug. Proteoglycan monomer size was similar in all treatment groups. It was concluded that polysulfated glycosaminoglycan caused a modest depression in proteoglycan synthesis, had little effect on endogenous proteoglycan degradation, and did not influence the size of sulfated proteoglycans synthesized by normal equine chondrocytes in explant culture.
Prevalence of pigment gallstones in sheep
Authors: Cavallini Aldo , Messa Caterina , Mangini Vito , Linsalata Michele , Guerra Vito , Misciagna Giovanni , Di Leo Alfredo
Published: January 2024

In a survey of 666 sheep at a slaughterhouse, gallstones (concretions with a diameter ≥ 1 mm) were found in the gallbladder of 50 sheep (7.5%), sludge (concretions with a diameter <1 mm) was found in 9 sheep (1.4%), and sludge plus gallstones were found in 7 sheep (1.1%). Gallstones and sludge were associated, and were more frequent in lambs and females, compared with adults and males. Qualitative analysis of the stones revealed all to be pigment (bilirubin) stones. There was a statistically significant increase of biliary bilirubin (total and indirect quota) only in sheep with gallstones plus sludge, compared with control sheep without sludge or gallstones. Concentrations of bilirubin, cholesterol, phospholipids, total and single bile aids, and total and ionized calcium were similar in the bile of sheep with gallstones, sludge, or both and control sheep. Bacteriologic analysis of the bile in 10 sheep with gallstones and 10 controls revealed bacteria in 50% of the first group and in 75% of the second group (Escherichia coli in all sheep and Salmonella spp also in 1 sheep with gallstones). These findings confirm our earlier findings of a high prevalence of black pigment gallstones in sheep. On that basis, we suggest that gallstones are associated with high total bilirubin concentration in the bile, and deconjugating bacteria are common in the biliary tract of these animals.
Use of a direct enzyme-linked antiglobulin test for laboratory diagnosis of immune-mediated hemolytic anemia in dogs
Authors: Jones D. R. E. , Gruffydd-Jones T. J. , Stokes C. R. , Bourne F. J.
Published: January 2024

Detection of autoantibody, complement, or both bound to rbc is an essential requirement for unequivocal diagnosis of immune-mediated hemolytic anemia in dogs. An enzyme-linked antiglobulin test was adapted for laboratory diagnosis of this disease. The refinement and routine use of this assay have allowed further observation of the pathogenesis of the disease process. In particular, degree of hemolysis can be related to the degree of rbc sensitization associated with primary immune-mediated hemolytic anemia, and this correlation is highest for IgG autoantibody. Results indicate that autoantibody isotype might have an important role in the hemolytic process.
Abortion induced by cell-associated pseudorabies virus in vaccinated sows
Authors: Nauwynck Hans J. , Pensaert Maurice B.
Published: January 2024

Pregnant sows, immune against pseudorabies after vaccination, were inoculated at 70 days of gestation either with autologous blood mononuclear cells that had been infected in vitro with pseudorabies virus (prv) or with cell-free prv. The infected cells or cell-free prv were inoculated surgically into the arteria uterina.

Eight sows (A to H) had been vaccinated with an inactivated vaccine. The titer of seroneutralizing antibodies in their serum varied between 12 and 48. Five sows (A to E) were inoculated with autologous mononuclear cells, infected either with a Belgian prv field strain or with the Northern Ireland prv strain NIA3. These 5 sows aborted their fetuses: 2 of them (B and C) 3 days after inoculation, and the other 3 (A, D, and E) 10, 11, and 12 days after inoculation, respectively. Sows F, G, and H were inoculated with a cell-free prv field strain. They farrowed healthy litters after normal gestation. Neutralizing antibodies were absent against prv in the sera of the newborn pigs, which were obtained prior to the uptake of colostrum.

The 23 fetuses that were aborted in sows B and C 3 days after the inoculation were homogeneous in appearance and size. Foci of necrosis were not detected in the liver. Viral antigens were located by immunofluorescence in individual cells in lungs, liver, and spleen of 15 fetuses. Virus was isolated from the liver, lungs, or body fluids of 12 fetuses.

The 39 fetuses that were aborted in sows A, D, and E between 10 and 12 days after inoculation were of 2 types: 17 were mummified and 22 were normal-appearing. Foci of necrosis were found in the liver of all mummified fetuses and 13 of the normal-appearing fetuses. In fetuses with foci of necrosis in the liver, viral antigens were located in groups of cells in the liver, lungs, and spleen. Virus was isolated from 16 normal-appearing fetuses and from 11 mummified fetuses.

Pseudorabies virus was isolated from vaginal excretions of sows A and D until 1 and 2 days after abortion, respectively, and of sows B and C until 4 and 5 days after abortion, respectively. Virus was not isolated from sow E.

It was concluded that prv can reach the uterine and fetal tissues, via infected mononuclear cells, in the presence of circulating antibodies induced on vaccination. This cell-associated spread led to abortion. Cell-free virus did not induce abortion under similar circumstances.
Development of Anaplasma marginale in male Dermacentor andersoni transferred from parasitemic to susceptible cattle
Authors: Kocan Katherine M. , Stiller David , Goff Will L. , Claypool P. L. , Edwards Wanda , Ewing S. A. , McGuire Travis C. , Hair Jakie A. , Barron Selwyn J.
Published: January 2024

The development and transmission of Anaplasma marginale was studied in Dermacentor andersoni males. Laboratory-reared male D andersoni were allowed to feed for 7 days on a calf with ascending A marginale parasitemia. The ticks were then held in a humidity chamber for 7 days before being placed on 2 susceptible calves. Anaplasmosis developed in the calves after incubation periods of 24 and 26 days. Gut and salivary glands were collected from ticks on each day of the 23-day experiment and examined with light and electron microscopy. Colonies of A marginale were first observed in midgut epithelial cells on the sixth day of feeding on infected calves, with the highest density of colonies found in gut cells while ticks were between feeding periods. The first colonies contained 1 large dense organism that subsequently gave rise to many reticulated organisms. Initially, these smaller organisms were electron-lucent and then became electron-dense. On the fifth day after ticks were transferred to susceptible calves for feeding, A marginale colonies were found in muscle cells on the hemocoel side of the gut basement membrane. A final site for development of A marginale was the salivary glands. Colonies were first seen in acinar cells on the first day that ticks fed on susceptible calves, with the highest percentage of infected host cells observed on days 7 to 9 of that feeding. Organisms within these colonies were initially electron-lucent, but became electron-dense.
Effect of initial restraint, weaning, and transport stress on baseline and ACTH-stimulated cortisol responses in beef calves of different genotypes
Authors: Zavy Michael T. , Juniewicz Paul E. , Phillips William A. , VonTungeln David L.
Published: January 2024

The productivity and well-being of animals can be substantially affected by stress. This is particularly true in the case of beef calves that are subjected to a multitude of stressors over a short period during the first year of life. Perhaps the most often studied stress-responsive variable has been blood corticosteroid concentrations. Factors such as age, gender, genetics, and degree of prior experience, can influence how an animal perceives and responds to a given stressor. Few studies have tried to control these variables, and accordingly, many conflicting results have been published regarding the impact of various stressors on cortisol response.

We measured baseline plasma cortisol concentration over a 44-day study in Bos indicus and Bos taurus calves. Plasma cortisol values in Bos indicus calves were higher (32.60 ± 0.66 ng/ml) than values in calves of Bos taurus (25.81 ± 0.76) breeding. A precipitous decrease in cortisol concentration was observed 7 days after transport stress in all calves. Baseline cortisol concentration did not provide any indication of the intensity of the various stressors. However, significant differences were readily observed after acth administration. On the basis of cortisol secretion, stresses of transport and weaning were similar and were the most stressful to calves, regardless of genotype.
Effects of lactated Ringer solution and prednisolone sodium succinate on dogs with induced hemorrhagic shock
Authors: Hankes G. H. , Dillon A. R. , Ravis W. R.
Published: January 2024

Hemorrhagic shock was induced in nonsplenectomized dogs by removing 41% of their blood volume over a 15- minute period. Hemodynamic and metabolic variables were determined prior to and for 3 hours after completion of hemorrhage. One group of 5 dogs was not treated. After the 30-minute sample was collected, a second group of 5 dogs was given lactated Ringer solution (lrs) at 88 ml/ kg of body weight, iv. A third group of 5 dogs was given lrs (88 ml/kg, iv) and prednisolone sodium succinate (11 mg/kg, iv) 30 minutes after hemorrhage. The iv administration of lrs was completed within 15 minutes. The glucocorticoid was administered as an iv bolus after 500 ml of lrs had been given.

The large volume and administration of lrs significantly (P = 0.05) improved many of the hemodynamic and metabolic effects of acute hemorrhage and hemorrhagic shock. At one time or another during the 2.5-hour observation period after the initiation of treatment, mean arterial pressure, cardiac index, systemic vascular resistance, heart rate, respiratory rate, lactate, glucose, and arterial and venous blood gas values were significantly (P = 0.05) improved, compared with baseline values. The addition of prednisolone sodium succinate to the treatment regimen improved the effectiveness of lrs alone only some dogs at random sampling times. Significant trends were not observed except, possibly, the improvement of venous pH and A-V pH and Pco2 differences.
Hematologic alterations in adult cats fed 6 or 12% propylene glycol
Authors: Bauer Milton C. , Weiss Douglas J. , Perman Victor
Published: January 2024

Cat foods containing propylene glycol (pg) induce Heinz body formation in feline erythrocytes. To further study the hematologic importance of dietary pg, 21 adult cats were allotted to 3 groups of 7 each and fed diets containing 0,6, or 12% pg on a dry-weight basis. Cats fed pg had a dose-related increase in Heinz bodies within 2 weeks, and the increase persisted throughout the study. Although only slight changes occurred in pcv, hemoglobin concentration, and rbc count, punctate reticulocytes were significantly increased in the group fed 12% pg. Mean rbc survival was decreased in the groups fed 6 or 12% pg by 30 and 55%, respectively, compared with the control group. These data indicate that pg-containing diets cause a dose-dependent erythrocyte destruction, even when fed at concentrations as low as 6%.
Effects of dietary protein source on Basenjis with immunoproliferative enteropathy
Authors: Breitschwerdt Edward B. , Hirakawa Diane A. , Hurlbert Sue Ann , Gerig Thomas M. , Babineau Cynthia
Published: January 2024

The effects of 3 experimental diets that varied only in the source of dietary protein (ie, poultry, cereal, red meat) were compared in Basenjis (n = 8) with immunoproliferative enteropathy and healthy Beagles (n = 8). Significant differences in fecal character, serum IgA concentration, and intestinal digestive and absorptive function were not induced by the different sources of dietary protein. The results of this study do not support a causal role for dietary protein source in the pathogenesis of immunoproliferative enteropathy of Basenjis.
Bioelectrical impedance and zoometry for body composition analysis in domestic cats
Authors: Stanton Christine A. , Hamar Dwayne W. , Johnson Donald E. , Fettman Martin J.
Published: January 2024

Zoometric measurements and bioelectrical impedance analysis were evaluated as methods of body composition determination in healthy cats. Zoometric and impedance measurements were taken on 22 anesthetized adult cats of various ages, genders, breeds, and body weights. The cats were then euthanatized. The bodies were processed through a tissue homogenizer and free-catch specimens were taken, freeze-dried, and analyzed for total body water, protein, fat, potassium, and ash content. Stepwise regression analysis was implemented to identify statistically significant relationships between the chemically determined dependent variables (total body water, protein, potassium, fat-free mass, fat mass, and percent body fat) and the zoometric measurements, with or without bioelectrical impedance analysis. Statistical analysis revealed high correlations between the dependent variables and the corresponding predicted values of those variables. Body weight alone was a poor predictor of body composition in these cats. On the basis of these findings, we suggest that zoometric and bioelectrical impedance measurements may serve as practical, noninvasive, simple, and accurate methods for estimating body composition in domestic cats.
Duration of pituitary and adrenocortical suppression after long-term administration of anti-inflammatory doses of prednisone in dogs
Authors: Moore G. E. , Hoenig M.
Published: January 2024

Duration and magnitude of hypothalamic-pituitary-adrenal axis suppression caused by daily oral administration of a glucocorticoid was investigated, using an anti-inflammatory dose of prednisone. Twelve healthy adult male dogs were given prednisone orally for 35 days (0.55 mg/kg of body weight, q 12 h), and a control group of 6 dogs was given gelatin capsule vehicle. Plasma cortisol (baseline and 2-hour post-acth administration) and plasma acth and cortisol (baseline and 30-minutes post corticotropin-releasing hormone [crh] administration) concentrations were monitored biweekly during and after the 35-day treatment period.

Baseline plasma acth and cortisol and post-acth plasma cortisol concentrations were significantly (P < 0.05) reduced in treated vs control dogs after 14 days of oral prednisone administration. By day 28, baseline acth and cortisol concentrations remained significantly (P < 0.05) reduced and reserve function was markedly (P < 0.0001) reduced as evidenced by mean post-crh acth, post-crh cortisol, and post-acth cortisol concentrations in treated vs control dogs. Two weeks after termination of daily prednisone administration, significant difference between group means was not evident in baseline acth or cortisol values, post-crh acth or cortisol values, or post-acth cortisol values, compared with values in controls. Results indicate complete hypothalamic-pituitary-adrenal axis recovery 2 weeks after oral administration of an anti-inflammatory regimen of prednisone given daily for 5 weeks.
Effect of metoclopramide on luteinizing hormone secretion in postpartum anestrous cows
Authors: Thompson F. N. , Jones R. D. , Stuedemann J. A. , Mizinga K. M. , Smith C. K.
Published: January 2024

The effect of metoclopramide (mc), a dopamine antagonist on luteinizing hormone (lh), was examined in anestrous primaparous cows. Metoclopramide has been found to be beneficial in overcoming fescue toxicosis; increasing lh secretion stimulates return to ovulatory function after parturition. Consequently, if mc had negative effect on lh secretion, it would indicate that administration of mc to reproducing animals might be limited. Of 14 postpartum (47 to 66 days) cows, 7 were given mc (4 mg/kg of body weight, iv), and 7 served as controls. Blood was obtained via jugular cannulas at 15-minute intervals for 8 hours; mc was given at the end of the first hour, and gonadotropin-releasing hormone (GnRH, 7 mg/kg), was given iv at the end of hour 7 as a challenge stimulus for lh secretion. Prior to GnRH administration, mc did not have significant effect on lh secretion, as judged by mean serum lh concentration, lh pulse frequency, and lh pulse amplitude. Administration of mc resulted in greater (P < 0.05) lh response to GnRH, indicating enhanced secretory ability when the pituitary gland was challenged. Serum prolactin concentration was increased (P < 0.01) by mc administration. Therefore, mc did not have adverse effect on lh secretion in postpartum cows.
Effects of freezing on mechanical properties of rat skin
Authors: Foutz T. L. , Stone E. A. , Abrams C. F.
Published: January 2024

Two test specimens of skin were cut from the lateral aspect of each hind limb of 9 rats. Specimens were contiguous, thereby providing matched pairs. One specimen was immediately placed in liquid nitrogen for 5 minutes, then stored at −70 C and tested within 3 to 4 weeks. Within 5 minutes of harvest, the second specimen was used for immediate material testing. Basic engineering material tests were used to measure strength, loading response, and elastic and viscous properties. Each matched pair of tissues was used for the same procedure.

Quasistatic uniaxial tensile tests were used to apply deformations to the test specimens, and resulting loads were recorded. Stress and strain were calculated from the recorded data, providing information on yield strength, ultimate strength, fracture strength, and loading response. Each matched pair of specimens represented 1 repetition; 6 repetitions were made of each observation. Statistical analysis indicated that tissue freezing significantly (P < 0.05) increased fracture strength, but did not affect strength, ultimate strength, or loading response.

Dynamic vibration response tests were used to find mechanical mobility of the specimens, thereby providing information on elastic and viscous behaviors, which were quantified by calculation of spring and damping coefficients, respectively. As before, 6 repetitions were used. Statistical analysis indicated that tissue freezing did not affect these coefficients.
Cardiopulmonary, anesthetic, and postanesthetic effects of intravenous infusions of propofol in Greyhounds and non-Greyhounds
Authors: Robertson S. A. , Johnston S. , Beemsterboer J.
Published: January 2024

The cardiopulmonary, anesthetic, and postanesthetic effects of an iv infusion of the hypnotic agent propofol were assessed in 6 Greyhounds and 7 non-Greyhounds. After im injection of acetylpromazine and atropine, a bolus injection of propofol sufficient to allow endotracheal intubation (mean ± sem = 4.0 ± 0.3 mg/kg of body weight in Greyhounds; 3.2 ± 0.1 mg/kg in non-Greyhounds) was administered, followed by continuous infusion at a rate of 0.4 mg/kg/min for 60 minutes, during which time dogs breathed 100% oxygen.

In 23% of all dogs (3 of 13), apnea developed after initial bolus administration of propofol. Arterial blood pressure was well maintained in all dogs, but heart and respiratory rates were decreased significantly (P < 0.05) during the infusion in Greyhounds. In Greyhounds, mild respiratory acidosis developed after 45 minutes, whereas arterial carbon dioxide tension was increased at all times after propofol administration in non-Greyhounds. In all dogs, pcv and total plasma proteins were unaffected by propofol. Rectal temperature decreased during treatment. Muscle tremors were observed in approximately 50% of dogs (in 3 of 6 Greyhounds and 3 of 7 non-Greyhounds) during and after infusion of propofol.

Non-Greyhounds lifted their heads, assumed sternal recumbency, and stood 10 ± 1, 15 ± 3, and 28 ± 5 minutes, respectively, after the end of the infusion; in Greyhounds, the corresponding times were 36 ± 4, 43 ± 6, and 63 ± 7 minutes.
Inoculation of conventionally and specific-pathogen-free reared rabbits with Ostertagia ostertagi isolated from cattle
Authors: Boisvenue R. J. , Novilla M. N.
Published: January 2024

Eleven trials were conducted to collect helminthologic and pathologic data from 27 conventionally reared (cr) and 53 specific-pathogen-free (spf) 6- to 13-week-old male New Zealand White rabbits. These rabbits were given 2 to 100,000 ensheathed third-stage infective Ostertagia ostertagi larvae (L3) orally. The L3 had been isolated from the feces of cattle. Fecal egg counts were conducted and worm populations were determined after euthanasia 3 to 56 days after inoculation. At necropsy, nodules were observed in a confluent pattern in the mucosa of cardiac region of the stomach in all inoculated rabbits, except in cr rabbits inoculated at 6 weeks of age, which had no nodules or worm burdens 42 days after inoculation. Confluent areas were not observed in spf rabbits euthanatized 5 days or less after inoculation; however, small, transparent nodules were evident in the mucosa of the cardiac region of the stomach. Fourth-stage larvae (L4) were obtained from the mucosal nodules after digestion of stomach of both types of rabbits. There were more L4 in spf than cr rabbits. In addition, greater numbers of L4 were found in spf rabbits euthanatized 14 days or less after inoculation. Petechial hemorrhages were in the fundic area of the stomach mucosa in spf rabbits inoculated with 100,000 L3 and euthanatized 14 days later. Mature O ostertagi or worm eggs in feces were not found in inoculated cr or spf rabbits.

The pathologic changes had characteristics similar to those in cattle and goats infected with O ostertagi. Specific-pathogen-free rabbits inoculated orally with ≥ 50,000 L3 were determined to be a host/parasite laboratory test model for use in chemotherapeutic, immunogenic, or pathogenic studies.
Comparative virulence of Haemophilus parasuis serovars 1 to 7 in guinea pigs
Authors: Rapp-Gabrielson Vicki J. , Gabrielson David A. , Schamber George J.
Published: January 2024

Reference strains for Haemophilus parasuis serovars 1 to 7 were examined for virulence by inoculation of guinea pigs. Guinea pig response to intraperitoneal inoculation was similar for the 7 reference strains. However, apparent differences in virulence were detected after intratracheal inoculation. Cells of the reference strains for serovars 1 and 5 were most invasive, causing moribundity or death at higher doses and a persistent septicemia at lower doses. Haemophilus parasuis could be isolated from respiratory and systemic sites; purulent bronchopneumonia, pericarditis, and pleuritis were apparent in infected guinea pigs. Inoculation of cells of the reference strains for serovars 2 and 6 also resulted in bronchopneumonia and moribundity or death in some guinea pigs; however, reisolation of H parasuis and microscopic lesions at necropsy were less pronounced than those observed with serovars 1 and 5. Inoculation of cells of serovars 3, 4, and 7 induced only transient clinical signs and minimal evidence of H parasuis infection at necropsy. The data from intratracheal inoculation of guinea pigs are similar to data from other investigations in swine, indicating differences in the pathogenic potential of H parasuis strains. Thus, guinea pigs may be useful as a laboratory animal model for examining cellular factors associated with virulence and immunogenicity of H parasuis.
Age-related effects on motor nerve conduction velocity in chickens
Authors: Bagley Rodney S. , Wheeler Simon J. , James Robert L.
Published: January 2024

Compound motor-nerve action potentials evoked by supramaximal stimulation of the proximal and distal aspects of the tibial nerve were evaluated in chickens 1 to 15 weeks old. Motor-nerve conduction velocity increased from a mean of 22.6 m/s at week 1 to a mean of 52.7 m/s at week 15. The increase in conduction velocity was greatest for the first few weeks, and reached a plateau at 10 weeks Subcutaneous limb temperature, limb length, and proximal latency measurements also increased with age; however, distal latency measurements were not significantly influenced by age. A quadratic equation was calculated to predict mean motor-nerve conduction velocity for maturing chickens.
Isolation of Mycobacterium paratuberculosis after oral inoculation in uninfected cattle
Authors: Sweeney Raymond W. , Whitlock Robert H. , Hamir Amir N. , Rosenberger Anne E. , Herr Stephanie A.
Published: January 2024

Feces from cows naturally infected with Mycobacterium paratuberculosis was given to 6 uninfected heifers by orogastric intubation, to determine whether ingested organisms could be passively excreted and detected by bacteriologic culture of feces (ie, false-positive result). Heifers were paired, and each pair received a different dose of feces on days 1 and 2. Fecal samples were collected from the heifers 3 times daily. Mycobacterium paratuberculosis was detected in fecal samples of all heifers within 18 hours of being given the first dose of feces. The number of colony-forming units peaked on days 3 or 4, and organisms were no longer detected by day 7. The number of colony-forming units in fecal samples from the heifers was approximately proportional to the dose given. On days 15 and 16, the experiment was repeated with feces from a second infected cow. Results were similar to those in the first experiment. All heifers remained seronegative (agar-gel immunodiffusion test and elisa) and had negative results to the intradermal johnin test throughout the experiment.

Lymph node and intestinal tissues were obtained from all 6 heifers at slaughter on day 28. Mycobacterium paratuberculosis was not isolated from mesenteric lymph nodes from the ileocecal valve region, but was isolated from ileal mucosal samples from each heifer.
Radiographic/morphologic investigation of a radiolucent crescent within the flexor central eminence of the navicular bone in Thoroughbreds
Authors: Berry Clifford R. , Pool Roy R. , Stover Susan , O'Brien Timothy R. , Koblik Philip D.
Published: January 2024

The source of a previously described radiolucent crescent in the flexor cortex of the distal sesamoid (navicular) bone on the palmaro45°proximal-palmarodistal oblique (Pa45°Pr-PaDio) clinical radiographic projection was investigated in 48 forelimb navicular bones from 24 Thoroughbreds by use of high-detail radiography and x-ray computed tomography (ct). Twenty-five of these bones also were evaluated, using microradiography and histologic examinations. Of these 25 bones, 5 had been labeled in vivo with fluorochrome markers. Tetrachrome-stained 100-µm-thick nondecalcified sections of these 5 bones were examined, using epifluorescence microscopy.

A reinforcement line of compacted cancellous bone, parallel and several millimeters deep to the flexor cortex in the region of the flexor central eminence, was visualized by ct in 42 of 48 navicular bones and by microradiography in 23 of 25 navicular bones investigated. Variable degrees of compaction were observed in the cancellous bone between the flexor cortex and the reinforcement line. High-detail skyline radiographic projections and reconstructed ct images indicated a crescent-shaped lucency within the flexor central eminence of the flexor cortex in the bones in which the reinforcement line was identified, but the cancellous bone between the reinforcement line and the flexor cortex had not been compacted. The radiolucent crescent seen in the flexor central eminence of the navicular bone on the Pa45°Pr-PaDiO projection was not caused by the concave defect or synovial fossa of the flexor central eminence overlying the flexor cortex, as was described. The crescent-shaped lucency within the navicular bone flexor central eminence identified on clinical radiographs was associated with remodeling of cancellous bone within the medullary cavity of the navicular bone. It is hypothesized that remodeling of the cancellous bone is secondary to biomechanical stresses and strains placed on the navicular bone, although the clinical relevance of this finding was not determined during the study.
Evaluation of a one-hour saline diuresis protocol for administration of cisplatin to dogs
Authors: Ogilvie Gregory K. , Fettman Martin J. , Jameson Vicki J. , Walters Lisa M. , Lafferty Mary H. , Cooper Mary F. , Powers Barbara E. , Ciekot Phyllis A. , Atwater Stephen W. , Withrow Stephen J.
Published: January 2024

A study was undertaken to determine the toxic effects of cisplatin, an antineoplastic agent, when administered immediately after a 1-hour saline diuresis. Four treatments with cisplatin (70 mg/m2 of body surface, q 3 wk) were administered iv to 6 healthy dogs over a 20-minute period after 0.9% NaCl (saline) solution was administered iv for 1 hour at a volume of 132 ml (kg)0.75. Each dog vomited at least once within 8 hours after each treatment was administered. Clinical status, body weight, and food consumption were normal throughout the 12-week study for 5 of the 6 dogs. The sixth dog developed acute renal failure and became acutely blind and deaf within 3 days after the fourth treatment with cisplatin. Serum electrolyte, creatinine, and urea nitrogen values remained within established normal limits in all dogs immediately prior to each treatment, and in 5 of 6 dogs evaluated 3 weeks after the final treatment. The serum creatinine value (3.3 mg/dl) obtained from the Beagle euthanatized 2 weeks after the fourth treatment was above established normal values. Despite normalcy for all but 1 of the creatinine values, serum creatinine concentration obtained 3 weeks after the final treatment with cisplatin was significantly (P = 0.0001) higher than pretreatment values. When compared with data from all other evaluation periods, significant decreases in glomerular filtration rate, as determined by exogenous (P ≤ 0.0001) and endogenous (P ≤ 0.0001) creatinine clearance testing, were identified 3 weeks after the fourth treatment with cisplatin. Neutrophil counts decreased significantly below pretreatment values at the third (P = 0.009), fourth (P < 0.0001), and fifth (P < 0.0001) evaluation period. We concluded that cisplatin can be administered with biochemical evidence, but not necessarily clinical evidence, that renal dysfunction may develop after 4 treatments with cisplatin (70 mg/m2, iv) are administered to dogs, using a 1-hour diuresis protocol.