bluuebunny/crossref_metadata_2025 huggingface dataset:
Myometrial activity during natural and dexamethasone-induced parturition in the cow
Authors: Burton M. J. , Dziuk H. E. , Fahning M. L. , Zemjanis R.
Published: February 2025

Myometrial activity was monitored during natural and dexamethasone-induced parturition in 8 Holstein dairy cattle, using strain gauge transducers. Four gauges were attached to the serosal surface of the gravid uterine horn, dividing it into thirds. Parturition was induced in 2 of 4 heifers and 2 of 4 cows (group 1); the remaining animals were allowed to calve spontaneously (group 2). Chains of low-amplitude contractions (repeated small deviations from base line) were detected before parturition was induced, and these were more common at distended parts of the uterus. Uncharacteristically sharp peaks followed by small rhythmic contractions, during preinduction recording, indicated that the myometrium was responsive to fetal movement even several days before parturition. By 18 hours before parturition, discrete single contractions appeared independently of contraction chains, and the first tubocervical peristaltic contraction waves were detected. The mean area under recorded contraction curves (uterine work) increased quadratically and the frequency of contractions decreased linearly from 12 hours before parturition to 2 hours after parturition. There was also an increase in the proportion of tubocervical waves over this period, and contraction chains were no longer present. During the second stage of labor, distended and undistended parts of the uterus were equally active, and forceful maternal straining was associated with larger sustained contractions. Fetal membrane rupture was accompanied by a doubling in the rate of passage of contraction waves along the length of the uterus. After the calf was expelled, contractions became extremely regular, and the majority progressed in a tubocervical direction. Although contraction waves were propagated more slowly after calving was completed, the area under recorded contraction curves continued to increase. Therefore, at 2 hours after parturition, uterine work was approximately 150% of that at calf expulsion. From 12 hours before to 2 hours after parturition, there were no significant differences in uterine activity between heifers and cows. Although all animals in group 1 retained their placenta, this was not the result of abnormal uterine activity during the immediate peri-partum period, because differences were not detected between the animals in groups 1 and 2.
Heparin-induced agglutination of erythrocytes in horses
Authors: Moore James N. , Mahaffey Edward A. , Zboran Michael
Published: February 2025

Heparin was administered subcutaneously 2 times a day for 4 days to 5 horses. An additional group of 5 horses was used as time-matched controls. Significant decreases in pcv, erythrocyte count, and hemoglobin concentration were observed during heparin therapy. The mean corpuscular volume (mcv) of the heparin-treated horses increased to a peak value of 66.1 fl on the last day of treatment. Erythrocyte creatine concentration and glucose 6-phosphate dehydrogenase activity increased moderately during the treatment. These data indicated that the rapid, profound increase in mcv during heparin therapy was not primarily a result of release of large immature erythrocytes from the bone marrow.

A second experiment was subsequently performed, using 3 horses. These horses were given heparin 2 times a day, as was done in the first experiment. Saline wet mounts of erythrocyte suspensions were examined once a day for the presence of agglutination. Cell suspensions were examined with or without exposure to a dilute trypsin solution, and erythrocyte counts were done on each suspension, using an electronic cell counter. Agglutination of erythrocytes was evident on the first day of treatment and became more pronounced as treatment progressed. Exposure to trypsin solution reversed the agglutination. The apparent erythrocyte count decreased and mcv increased sharply in the samples processed normally, but there was little change in those suspensions exposed to trypsin. These data indicate that heparin treatment induces erythrocyte agglutination in horses, that this agglutinating factor(s) is proteinic, that alterations in erythrocyte count and mcv are largely artifac-tual, and that evidence indicating that heparin induces augmentation of reticuloendothelial system function may require reconsideration.
Effects of feline leukemia virus infection on neutrophil chemotaxis in vitro
Authors: Kiehl A. R. , Fettman M. J. , Quackenbush S. L. , Hoover E. A.
Published: February 2025

A procedure for measuring in vitro feline neutrophil chemotaxis was developd, using a modified Boyden chamber apparatus and 3-μm-pore polycarbonate filters. A pooled feline serum sample was used as the chemoattractant. Chemotaxis was evaluated in 5 groups of cats: group 1—specific-pathogen-free cats that had not been exposed to feline leukemia virus (FeLV); group 2—previremic, FeLV-infected, specific-pathogen-free cats; group 3—FeLV-viremic, subclinically affected cats; group 4— FeLV-viremic, clinically affected cats; and group 5—sick cats that were not infected with FeLV.

Neutrophils from the viremic, clinically affected cats had significantly lower (P < 0.025) chemotactic responses than did those from subclinically affected, viremic cats. Conversely, neutrophils from cats that were ill due to causes other than FeLV had the highest mean chemotactic values. Among the viremic, subclinically affected cats, a linear relationship was found between age and chemotaxis, indicating that impairment of neutrophil function may be greater in younger viremic cats. However, FeLV-infected cats can not be identified on the basis of neutrophil chemotaxis.
Immunologie response to Pasteurella haemolytica and resistance against experimental bovine pneumonic pasteurellosis, induced by bacterins in oil adjuvants
Authors: Confer A. W. , Panciera R. J. , Gentry M. J. , Fulton R. W.
Published: February 2025

Immunogenicity of and protection afforded by Pasteurella haemolytica bacterins were studied in calves. Bacterins contained an aluminum hydroxide in gel (alh) adjuvant or one of the following oil-in-water adjuvants: Freund's complete adjuvant (fca), Freund's incomplete adjuvant (fia), and trehalose dimycolate (tdm). On days 0 and 7, calves were vaccinated with phosphate-buffered saline solution (pbss), a bacterin, or live P haemolytica. Transthoracic intrapulmonic challenge exposure was done on day 21. In 3 experiments, there were no significant (P > 0.05) differences between lung lesions induced in pbss-or alh bacterin-vaccinated calves. Both fca and fia bacterins significantly (P < 0.05) enhanced resistance against challenge exposure. Resistance induced by fca and fia bacterins was comparable with that induced by vaccination with live P haemolytica. Calves vaccinated with fia bacterin and challenge-exposed to P haemolytica at a concentration of 4.5 × 109 colony-forming units (4.5 times greater than used in the first 3 experiments) resisted challenge exposure similar to calves given live organisms. The tdm bacterin failed to enhance resistance.

All bacterins caused a significant increase (P < 0.05) in serum antibody to P haemolytica somatic antigens, as measured by a quantitative fluorometric immunoassay.

Pasteurella haemolytica leukotoxin neutralizing antibody titers did not increase significantly (P > 0.05) in sera after vaccination with any bacterin. Vaccination with fca and fia bacterins resulted in a significant increase (P < 0.001) in serum antibody to a carbohydrate-protein sub-unit of P haemolytica, as measured by an enzyme-linked immunosorbent assay. The tdm-bacterin vaccinates had antibody responses similar to those of the alh bacterin-or pbss-vaccinated calves. High antibody responses to the glycoprotein subunit correlated significantly (P < 0.05) with resistance to challenge exposure.

Seemingly, P haemolytica bacterins adjuvanted with fca or fia enhance resistance to induced pneumonic pasteurellosis, whereas alh-adjuvanted bacterins do not. The mechanism of induced resistance was not associated with leukotoxin neutralizing antibody, but may have been caused by antibody to antigens in a carbohydrate-protein subunit of P haemolytica.
Absolute and relative concentrations of immunoglobulins G, M, and A, and albumin in the lacteal secretion of sows of different lactation numbers
Authors: Klobasa F. , Butler J. E.
Published: February 2025

The concentrations of immunoglobulin (Ig)G, IgM, IgA, and albumin in the lacteal secretion of 80 sows were measured not more than 14 times during lactation to determine whether the age of the sow, the anatomic location of the mammae, or the farrowing barn housing of the sow influenced Ig concentrations. The combined data indicated that there were lactation stage-dependent changes in the total Ig concentration, as well as changes in the relative importance of the 3 classes of Ig studied. Mean values of any one time point showed enormous variation in absolute values, with coefficients of variation ranging up to 70%. The largest variations were observed between colostral samples obtained on the first day. The IgM showed the least variation on day 1. Such variations hindered attempts to statistically identify their source. Normalization of Ig concentrations in relation to albumin concentrations decreased some of the apparent variation. Normalized data accentuated the changeover from colostrum to milk which occurred after the first 3 days. There was also a 3-fold increase in IgA concentrations which occurred during the last 4 weeks of lactation. Data showed that older sows tended to have higher concentrations of all Ig. Lactation number-dependent increases in IgM and IgG were restricted to colostrum in lactation numbers higher than 4. Immunoglobulin A increased in a similar pattern and, in addition, increased in mature milk in sows with more than 2 lactations. The enormous variations observed seemed to be individual animal variations. This allowed only trends, rather than statistically significant differences, to be recognized. Several such trends were apparent. First, variations among individual mammae were not greater than overall variations, supporting the view that variations were individual animal variations. Secondly, caudally located glands showed a tendency to have higher Ig concentrations and lower albumin concentrations than other mammae. Thirdly, IgG, IgM, and albumin concentrations seemed to be highest in sows of 1 to 2 lactations, whereas IgA concentrations were higher in older sows. Finally, sows housed in different farrowing barns had different relative concentrations of IgG:IgA:IgM in colostrum, which was maintained into early lactation. It was concluded that variation in the amount of lacteal Ig in sows, other than those which are associated with differences in the stage of lactation, cannot be ascribed to a single physiologic factor. Individual animal variation seems to have the largest influence.
Cross-reactivity between human and feline la antigens, using a monoclonal antibody HLA-D.m1
Authors: Kuramochi T. , Takeishi M. , Ishida T. , Kato K. , Ishida M.
Published: February 2025

A murine monoclonal antibody HLA-D.m1 produced against human la antigens which react with 10% to 30% of human peripheral-blood mononuclear cells was found to react with > 90% of feline mononuclear cells. The antigen was not expressed on granulocytes. By direct immunofluorescence, 7% to 41% of feline lymphocytes expressed surface immunoglobulins. In mixed-lymphocyte reaction, the addition of antibody HLA-D.ml to cultures abolished proliferation. These studies indicate that most feline peripheral-blood mononuclear cells express la-like antigens.
Arterial hypotention and the development of postanesthetic myopathy in halothane-anesthetized horses
Authors: Grandy J. L. , Steffey E. P. , Hodgson D. S. , Woliner M. J.
Published: February 2025

The effect of halothane-induced hypotension on the development of postanesthetic myopathy was studied, using 6 healthy adult horses. Horses were anesthetized with halothane in oxygen for 3.5 hours on each of 2 occasions. Intermittent positive-pressure ventilation was used to maintain Paco2 of 45 to 55 mm of Hg throughout both anesthetic exposures. By regulating the inspired halothane concentration, a mean arterial blood pressure of 85 to 95 mm of Hg (normotension) was maintained throughout the 1st anesthetic exposure, and a mean arterial blood pressure of 55 to 65 mm of Hg (hypotension) was maintained during the 2nd anesthetic exposure. All horses recovered uneventfully from normotensive anesthesia, but all had some muscle dysfunction after prolonged hypotensive anesthesia. Because of apparent animal discomfort and lameness involving more than 1 limb, 3 horses were euthanatized soon after they recovered from hypotensive anesthesia. The 3 other horses showed a degree of lameness. In addition, 1 horse had raised, swollen plaques over the hip, rib, and facial areas which were in contact with the surgical table, and another had evidence of facial nerve paralysis. One hour after the 6 horses stood after hypotensive anesthesia was completed, values obtained for aspartate transaminase and creatinine were significantly (P < 0.05) greater than those obtained after normotensive anesthesia was completed. Aspartate transaminase, total bilirubin, and creatinine values were significantly (P < 0.05) increased when compared with those obtained before horses were anesthetized. A large increase was measured in creatine kinase. Twenty-four hours after hypotensive anesthesia was completed, creatine kinase and lactate dehydrogenase in the 3 surviving horses were significantly (P < 0.05) greater than those values after normotensive anesthesia was completed.
Anesthetic interaction in cardiovascular research models: Effects of xylazine and pentobarbital in cats
Authors: Fosse Richard T. , Grong Ketil , Stangeland Lodve , Lekven Jon
Published: February 2025

The effects of xylazine given to cats before anesthetization was induced with pentobarbital were determined. Cardiac hemodynamic variables and regional blood flow rates in the heart and other organs were measured, using radiolabeled microspheres. Two groups, each of 10 cats, were included in the study: one group (group 1) was anesthetized with pentobarbital given intraperitoneally and subsequently given xylazine; the other group (group 2) was first given 1 mg of xylazine/kg, im, and then anesthetized with pentobarbital given iv. Anesthesia was maintained in both groups with nitrous oxide.

The preanesthetic administration of xylazine decreased the amount of pentobarbital used for surgical anesthesia by approximately 50%. It also resulted in decreased heart rate, cardiac contractility, and cardiac output and increased left ventricular end-diastolic pressure, compared with those values in cats given pentobarbital (group 1). After the latter cats (anesthetized with pentobarbital) were given xylazine, heart rate, cardiac contractility, and cardiac output decreased and left ventricular end-diastolic pressure increased to values similar to those found in group 2 (given xylazine before anesthetization). Myocardial tissue blood flow rates in the left and right ventricles were lower in the cats of group 2. In group 1 cats, myocardial blood flow rates decreased when xylazine was subsequently added. Blood flow rates in the kidneys and gastrointestinal tract were generally decreased by xylazine.

Xylazine profoundly changed cardiac hemodynamic function and perfusion in the heart, as well as several other organ systems, because of marked cardiodepression.
Canine distemper virus: In vivo virulence of in vitro-passaged persistent virus strains
Authors: Axthelm Michael K. , Krakowka Steven , Gorham John R.
Published: February 2025

Groups of ferrets were inoculated intraperitoneally with cell lysates or equivalent doses of whole cells from 9 different cell lines persistently infected with canine distemper virus. Viral persistence in these cell lines was characterized by noncytolytic infection and restricted release of cell-free infectious virus. In vivo replication competency of the various viruses in ferrets ranged from nil to virulent and did not correlate with in vitro titers of inocula. Ferret virulence (cell lysates only) for one cell line (CCL64-RCDV) was associated with morphologic absence of virion assembly, failure to interfere with lytic virus replication after superinfection, and in vitro infectivity restricted to canine macrophage-like tumor cells. Virion protein production in the CCL64-RCDV virulent inoculum and in the CCL64-Ly avirulent inoculum was evaluated by use of the immunoblot technique. All major virion proteins were produced by infected cells. Virulence was not associated with obvious changes in electrophoretic mobility of virion proteins when profiles of ferret-virulent CCL64-RCDV were compared with those of avirulent CCL64-Ly.
Changes in basal lamina of seminiferous tubules associated with deranged spermatogenesis in the bull
Authors: Veeramachaneni D. N. Rao , Heath E. H. , Ott R. S. , McEntee K. , Hixon J. E.
Published: February 2025

The basal lamina of seminiferous tubules of 16 beef bulls, with scrotal circumferences (sc) from 40.5 to 28 cm, was characterized. The mean thickness of basal laminae was from 0.55 to 0.94 μm in normospermic bulls with sc > 30 cm. Of 3 bulls that had a sc < 30 cm, 1 had hypoplastic testes and was azoospermic, whereas 2 bulls had atrophic changes in their testes and were Oligospermie. The latter 2 bulls had thick basal laminae, with a mean of 1.35 μm and 1.68 μm, respectively, whereas basal laminae of the bull with hypoplastic testes had a mean thickness of 0.96 μm, comparable with that of bulls with normal testes (sc, > 30 cm). Thickness of the basal lamina of seminiferous tubules might be a useful criterion in differentiating atrophy from hypoplasia.
Total protein, albumin quota, and electrophoretic patterns in cerebrospinal fluid of dogs with central nervous system disorders
Authors: Sorjonen D. C.
Published: February 2025

Cerebrospinal fluid was analyzed for total protein, albumin quota, and electrophoretic patterns of albumin and α-, β-, and γ-globulins in 10 healthy dogs and 35 dogs with cns disorders. Values obtained in healthy dogs were used to establish control data. Samples also were collected from dogs with neurologic diseases that were classified according to clinical and pathologic diagnosis as inflammation, neoplasm, and spinal cord compression. The albumin quota and total csf albumin values were used as indicators of blood-brain barrier disturbance. Four patterns were observed on agarose electrophoresis that included intrathecal immunoglobulin production, intrathecal immunoglobulin production combined with blood-brain barrier disturbance, blood-brain barrier disturbance, and unaltered csf. These patterns correlated with the observed clinical and pathologic conditions. Seemingly, agarose electrophoresis of csf is a simple and reliable technique that aids in the diagnosis of cns disorders of dogs.
Blood antioxidant status and plasma pyruvate kinase activity of halothane-reacting pigs
Authors: Duthie Garry G. , Arthur John R.
Published: February 2025

Samples of blood were collected (by jugular venipuncture) from 10 homozygote halothane-reacting pigs and 7 homozygote nonreactors. Antioxidant status was assessed by measurement of blood glutathione peroxidase, glucose-6-phosphate dehydrogenase, and superoxide dismutase activities and plasma concentrations of vitamin E. Significant differences in these values were not apparent between halothane-reacting pigs and nonreactors. Halothane-reacting pigs had tissue damage as indicated by significantly increased plasma activities of the enzymes creatine kinase and pyruvate kinase. The latter showed better discrimination between the 2 populations than did creatine kinase and could prove to be a more effective marker for identification of stress-susceptible pigs.
Effect of topical phenylephrine on the equine pupil
Authors: Hacker Dennis V. , Buyukmihci Nedim C. , Franti Charles E. , Bellhorn Roy W.
Published: February 2025

The mydriatic effect of 10% phenylephrine was evaluated in 9 horses. Base-line pupillary size in mesopic conditions and during light stimulation was ascertained before application of pharmacologic agents. In study 1, 10% phenylephrine was applied to each eye (n = 5 horses). After 15 minutes, the pupillary size was determined in both lighting conditions. Phenylephrine was again applied to each eye, and after an additional 15 minutes, the pupillary size was determined. In study 2, 1% tropicamide was applied to each eye (n = 4 horses), and after 30 minutes, the pupillary size was determined in both lighting conditions. Tropicamide and phenylephrine were applied to each eye immediately after determination of pupillary size, and after an additional 30 minutes, the pupillary size was determined. There was no significant change (P > 0.9) in pupillary size when phenylephrine was used alone or when phenylephrine was used in an eye that had been dilated with tropicamide.
Antibody activity to Babesia canis in dogs in North Carolina
Authors: Levy M. G. , Breitschwerdt E. B. , Moncol D. J.
Published: February 2025

Sera from 600 dogs from 6 geographic regions of North Carolina were analyzed for antibody activity to Babesia canis, using an indirect fluorescent antibody test. Overall, 3.8% of the dogs had an antibody titer ≥ 1:80, which was considered to be indicative of infection. Dogs were more likely to be seropositive if they were housed at humane facilities and were located within areas of the state with a milder climate than were pet animals living within colder regions of North Carolina.
Demonstration of colonies of Cowdria ruminantium in midgut epithelial cells of Amblyomma variegatum
Authors: Kocan Katherine M. , Morzaria Subhash P. , Voigt Wolf P. , Kiarie Jim , Irvin Anthony D.
Published: February 2025

The development of colonies of Cowdria ruminantium was studied in midgut epithelial cells of adult Amblyomma variegatum that had become infected by feeding as nymphs on cattle with experimentally induced heart-water disease. Colonies were not observed in gut tissues obtained from nymphs during the feeding period, but were present in midgut epithelial cells of ticks obtained at 15 days after they were replete through molting to the adult stage. Colonies were small (1 to 10 µm) initially, but as tick development progressed, their diameter increased to as much as 60 μm. With electron microscopy, colonies were observed to be membrane bound and contained pleomorphic organisms that were reticulated. The organisms seemed to be dividing by binary fission. Many colonies contained a large, electron-dense inclusion that was morphologically similar to hemoglobin deposits found in the cytoplasm of midgut epithelial cells of recently fed ticks. Cowdria ruminantium was often observed adhered to these inclusions.
Effect of clenbuterol on histamine-induced airway obstruction in ponies
Authors: Derksen F. J. , Scott J. S. , Slocombe R. F. , Robinson N. E.
Published: February 2025

We determined the effect of iv administered β2-adrenergic receptor agonist clenbuterol on pulmonary function and on the response to histamine in 12 healthy ponies. Measurements were made at base line and after saline solution or clenbuterol was administered iv at a dosage of 0.2, 0.8, or 1.6 µg/kg. The dosage of clenbuterol used in each study was unknown to the investigators until all the data had been analyzed. Intravenous administration of saline solution or clenbuterol did not alter base-line pulmonary function significantly. Aerosol histamine administration significantly decreased arterial oxygen tension and dynamic compliance and increased pulmonary resistance, respiratory frequency, and minute ventilation, but had no effect on arterial carbon dioxide tension and tidal volume. The magnitude of change in these variables was unaffected by previous administration of clenbuterol at any of the dosages tested. We conclude that clenbuterol at the dosages tested is not a bronchodilator in healthy ponies and does not exert a significant protective effect against aerosol histamine-induced airway narrowing.
BW755C modifies endotoxin-induced respiratory failure in pigs
Authors: Olson Neil C.
Published: February 2025

The porcine pulmonary response to endotoxemia was evaluated before and after 3-amino-1-(3-trifluoromethyl-phenyl)-2-pyrazoline hydrochloride (BW755C), a dual inhibitor of the cyclooxygenase and lipoxygenase pathways of arachidonic acid metabolism. Escherichia coli endotoxin (055-B5) was infused iv into anesthetized 10- to 14-week-old pigs at 5 µg/kg the first hour, followed by 2 µg/ kg/hr for 3.5 hours. The BW755C was infused at 20 mg/ kg before endotoxin was administered and at 2.2 mg/kg during endotoxemia. During phase 1 (ie, 0 to 2 hours), the endotoxin-induced pulmonary hypertension, increased pulmonary vascular resistance and alveolar-arterial oxygen gradient, and decreased cardiac index and lung dynamic compliance were blocked or modified by BW755C. During phase 2 endotoxemia (ie, 2 to 4.5 hours), BW755C modified or blocked the increases in pulmonary vascular pressures, pulmonary vascular resistance, alveolar dead space ventilation, alveolar-arterial oxygen gradient, lung water, and bronchoalveolar lavage albumin concentration. The BW755C also modified the phase 2 decreases in cardiac index, lung dynamic compliance, and aortic platelet count. With regard to the endotoxin-induced pulmonary vasoconstriction, bronchoconstriction, and impairment of gas exchange, the data do not support a role for lipoxygenase metabolites, because the modified blockade (provided by BW755C) was of no greater magnitude than that reported for indomethacin (cyclooxygenase blocker). However, the data supports a possible role for lipoxygenase metabolites with regard to altering vascular permeability, cardiac index, and aortic platelet count.
Evaluation of creatine kinase and lactate dehydrogenase activities in clinically normal and abnormal equine joints
Authors: Yancik S. A. , McIlwraith C. W. , Wagner A. E. , Trotter G. W.
Published: February 2025

Creatine kinase (ck) and lactate dehydrogenase (ld) enzyme activities and isoenzymes were determined for synovial fluid, synovial membrane, and articular cartilage from 24 clinically normal equine tarsocrural (tibiotarsal) and femoropatellar joints. All 3 tissues contained ld isoenzymes ld1 to ld5, and ck isoenzymes bb and mm. The ck isoenzyme mb was not found. The similarities in isoenzyme composition of these 3 tissues made differentiation of the source of ld and ck impossible by isoenzyme pattern alone. Reference values for the total enzyme activities of specific joint tissues also had wide variations. The wide variation in activities, as determined by the enzymatic analysis of synovial fluid and a lack of tissue specificity in clinically normal equine joint tissue, indicated that those values were not predictive for the extent and type of tissue damage in equine joint disease. This hypothesis was confirmed when synovial fluids from 22 abnormal joints were analyzed for ld isoenzymes and total enzyme activity. The various causes of the joint problems were not distinguishable.
Chemical analysis of bovine and porcine vitreous humors: Correlation of normal values with serum chemical values and changes with time and temperature
Authors: McLaughlin P. S. , McLaughlin B. G.
Published: February 2025

Vitreous humors collected from cattle and swine at time of death were compared with serum samples collected before these animals were slaughtered to determine whether vitreous chemical constituents were stable after death occurred. Vitreous humor from 1 eye and serum were obtained from each of 120 cattle and 120 swine at slaughter. The second eye from each animal was enucleated and incubated at 4 C, 20 C, and 37 C for 6, 12, 24, and 48 hours, and then vitreous humor was obtained from the incubated eye. Serum and the fresh and incubated vitreous samples were analyzed for urea nitrogen, creatinine, sodium, potassium, calcium, magnesium, chloride, and phosphorus concentrations. In the incubated vitreous sample, stability varied for urea nitrogen, creatinine, sodium, calcium, magnesium, and chloride concentrations, but the values were generally more stable with samples incubated at lower temperatures and for shorter incubation periods. Potassium and phosphorus concentrations increased with time and temperature of incubation of the samples.
Placental transfer of specific antibodies during ovine congenital toxoplasmosis
Authors: Dubey J. P. , Hughes H. P. A. , Lillehoj H. S. , Gamble H. R. , Munday B. L.
Published: February 2025

The passage of non-Toxoplasma antibodies from dam to fetus through damaged placenta was studied in sheep inoculated with Toxoplasma gondii. Six ewes were inoculated with chicken globulins and Leptospira bacterins 2 months before oral inoculation with Toxoplasma gondii oocysts. Ewes were euthanatized between 42 and 62 days after T gondii inoculation. Antibody titers against chicken globulins, Leptospira spp, Haemonchus contortus, Sarcocystis spp, and T gondii were measured in the maternal and fetal sera. All ewes became infected with T gondii and had grossly visible necrotic foci in the placentas, and T gondii antibodies were found in the fetuses and the ewes. Appreciable amounts of antibodies to Haemonchus contortus, Sarcocystis sp, Leptospira spp, and chicken globulins did not cross the placental barrier. Seemingly, serologic examination of the fetus was reliable for the diagnosis of ovine congential toxoplasmosis.
Complement immunofluorescence in sera of dogs with pemphigus foliaceus
Authors: Medleau Linda , Dawe Donald L. , Scott Danny W.
Published: February 2025

Sera from 14 dogs with active pemphigus foliaceus were tested for the presence of circulating antiepithelial antibodies. These antibodies could not be detected in the dogs with indirect immunofluorescent staining or in vitro complement-staining methods.
Pharmacokinetics of selenium administered parenterally at toxic doses in sheep
Authors: Blodgett D. J. , Bevill R. F.
Published: February 2025

Pharmacokinetics of Se were evaluated in 24 female crossbred sheep, 8 to 14 months of age, after toxic doses of Se were administered. Five groups of 4 sheep each were given 0.4, 0.6, 0.7, 0.8, or 1 mg of Se/kg of body weight, im. Nine of these sheep died within 36 hours after Se administration. Blood Se disappearance curves were triphasic for the 11 sheep that lived for at least 36 hours after Se administration and were biphasic for the 9 sheep that died within 36 hours. The λ2 rate constants of Se disposition after im administration indicated a dose dependency. Sheep given 0.4, 0.6, 0.7, or 0.8 mg of Se/kg had λ2 rate constants of 0.110, 0.079, 0.046, and 0.034 hour−1, respectively (r2 = 0.97). The respective half-lives of the 2nd distributive phase after im administration were 6.3, 8.8, 15.1, and 20.4 hours. In the 11 sheep that had triphasic pharmacokinetics, the mean λ3 elimination rate was 0.0011 hour−1.

Four additional sheep were given 0.7 mg of Se/kg, iv. These sheep survived and had blood Se disappearance curves that were triphasic. In the 4 sheep given Se iv, the mean λ3 elimination rate was 0.0020 hour-1, which represented a biological half-life of 354 hours or 14.7 days.
Effect of jejunal loop location on the activity of Escherichia coli heat-stable enterotoxin in 4- to 5-week-old pigs
Authors: Dove Charles R. , Zinn Gene M. , Veum Trygve L. , Ellersieck Mark R. , Parker Charlotte D. , White Arnold A.
Published: February 2025

Heat-stable enterotoxin (STa) from Escherichia coli strain 431 was injected into the jejunum of 4 pigs from each of 3 litters, using a ligated intestinal loop assay (with loops beginning 1 m caudad to the pylorus). The jejunum was divided into 4 contiguous areas, with 4 loops in each area. Doses of 0, 10, 100, or 1,000 ng of purified toxin (10 ng/ mouse unit) were injected into the loops within an area, using a 4 × 4 Latin square design. Fluid accumulation in the loops increased (P < 0.05) with increasing concentrations of STa in pigs in all litters, but the magnitude of the response varied across litters. Fluid responses to the STa varied in the different areas of the jejunum, with pigs in 2 litters having a decrease (P < 0.05) in the response to STa in the caudal areas. These data quantitate the variability within the different areas of the jejunum of the young pig.
Retrograde flow of spermatozoa into the urinary bladder of rams
Authors: Pineda M. H. , Dooley M. P. , Hembrough F. B. , Hsu W. H.
Published: February 2025

Retrograde flow of spermatozoa into the urinary bladder of rams during electroejaculation (ee) was examined. In experiment 1, semen and 4 consecutive samples of the urine released during the first post-ee micturition were collected once a week from 6 rams for 5 weeks during the nonbreeding season. The overall mean concentration per milliliter and the mean total number of spermatozoa in the urine ranged from 3.06 to 4.32 × 106 and from 80 to 2,865 × 106, respectively. The spermatozoal concentration in sequential urine samples was not different between samples, indicating that these spermatozoa had mixed with the urine before micturition. The percentage of the total number of spermatozoa displaced during ee, which flowed into the urinary bladder (retrograde flow), varied among rams (range 3.9% to 80%). The overall mean percentage of retrograde flow during the nonbreeding season was 28.3%.

In experiment 2, a catheter was implanted into the urinary bladder of 6 rams (4 rams were from experiment 1), and semen was collected over 4 weeks during the subsequent breeding season. A urine sample was collected from the implanted catheter before ee. Immediately after semen collection, urine was collected by evacuating the bladder. The spermatozoal concentration in the pre-ee urine ranged from 0 to 1.3 × 106 (mean ± sd, 0.17 ± 0.38 × 106) and was significantly (P < 0.0001) lower than the spermatozoal concentration in the post-ee urine, which ranged from 1.10 to 22.55 × 106 (mean ± sd, 9.46 ± 11.30 × 106). The overall mean percentage of retrograde flow during the breeding season was 20.1%. Considerable losses of spermatozoa occurred during ee as a result of retrograde flow of spermatozoa into the urinary bladder. The magnitude of retrograde flow can be estimated by determining the number of spermatozoa contained in the ejaculate and those recovered in the urine released during the first post-ee micturition.
Antimicrobial alternatives for calf diarrhea: Enteric responses to Escherichia coli, deferoxamine, or gallium in neonatal calves
Authors: Fettman Martin J. , Brooks Patricia A. , Jones Robert L. , Mero Kendall N. , Phillips Robert W.
Published: February 2025

Intestinal malabsorption or transferable resistance in enteric bacteria are potentially serious complications of routine oral administrations of antibiotics. On the basis of reports on antimicrobial effects of host iron sequestration and on synthetic iron chelators or competitors in vitro, 2 iron antagonists were studied for their potential as alternative antimicrobials for Escherichia coli diarrhea. Deferoxamine, a fungal iron chelator used to treat acute iron intoxication, and elemental gallium, a competitive inhibitor of iron activity in metabolic enzyme systems, were examined for their effects on enteric morphology and function in neonatal calves.

Twelve male calves were allotted to 4 groups: (1) given nonpathogenic E coli (control); (2) given enterotoxigenic B44 E coli; (3) given deferoxamine (50 mg/kg, twice a day); and (4) given gallium (4 mg/kg, twice a day). Calves were studied for 8 days, including the conduct of oral glucose and lactose tolerance tests on days 1, 3, and 7. By day 7, according to oral glucose and lactose tolerance tests, peak plasma glucose concentrations in all calves of groups 2, 3, and 4 were lower than those values in controls. The frequency of diarrhea was significant in all treated calves, and disease was most severe in the deferoxamine-treated calves. Quantitative cultural examination on day 8 showed significant numerical increases of jejunal and ileal E coli and ileal lactobacilli in deferoxamine-treated calves (group 3) and of ileal streptococci in gallium-treated calves (group 4) and showed jejunal and ileal overgrowths of Saccharornyces yeast in deferoxamine-treated calves. Histopathologic ranking of intestinal sections obtained on day 8 revealed more severe lesions in treated (groups 2, 3, and 4) vs control (group 1) calves and in gallium-treated (group 4) vs E coli-inoculated (group 2) calves. Alterations in enteric flora, morphology, and function indicated that, at the doses used in the present study, the 2 iron antagonists would not provide an efficacious alternative therapeutic approach.
Serum triiodothyronine and thyroxine concentrations in weanling horses fed carbohydrate by direct gastric infusion
Authors: Glade Michael J. , Luba Norman K.
Published: February 2025

Plasma glucose and serum insulin, thyroxine, and triiodothyronine concentrations were monitored in 6 weanling Thoroughbreds after direct gastric infusion of solutions containing sucrose or casein. Neither plasma glucose nor serum hormone concentrations were affected by infusions of water or by infusions of 326 or 424 g of casein/250 kg of body weight. However, glucose and hormone concentrations increased significantly (P < 0.001) after infusions of 649 or 844 g of sucrose/250 kg. Initial rates of increase were more rapid and increases were subsequently reversed more rapidly when 844 g of sucrose/250 kg was infused than when 649 g of sucrose/250 kg was infused. Soluble carbohydrate in the digestive tract triggered specific responses in the serum thyroid hormone concentrations of weanling horses. Magnitudes and durations of these responses appeared to depend on the amount of carbohydrate present.
Radioimmunoassay for parathyroid hormone in equids
Authors: Roussel Allen J. , Lin Y. C. , Strait John R. , Modransky Paula D.
Published: February 2025

Radioimmunoassay for parathyroid hormone (pth) in equids was performed on blood samples from healthy equids and equids with hypercalcemia and hypophosphatemia. The assay was validated for equine carboxy-terminal pth. Manipulation of serum ionized Ca in healthy equids by infusing Na2 EDTA and CaCl2 produced an expected increase and decrease, respectively, in measurable immunoreactive pth. Intra-assay and interassay coefficients of variation were 2.6% and 11.7%, respectively. The range of pth valves for healthy mature horse mares and geldings maintained on pasture was < 0.27 ng/ml to 0.92 ng/ml and for horse colts fed grain was 0.61 to 1.25 ng/ml. Serum pth values were measured on 2 equine patients with hypercalcemia, 1 pony with primary hyperparathyroidism and 1 horse with pseudohyperparathyroidism. Both patients had increased serum pth values.
Feline renal ultrasonography: Quantitative analyses of imaged anatomy
Authors: Walter P. A. , Feeney D. A. , Johnston G. R. , Fletcher T. F.
Published: February 2025

Maximal kidney dimensions from serial ultrasonograms were measured in 10 healthy cats. Because clinical ultrasonographic examination is often performed in conjunction with excretory urography, the effect of radiographic contrast medium-induced diuresis on dimensional change also was evaluated. Although a slight, statistically significant increase in size was observed (compared with kidneys scanned without contrast medium), this increase could not be detected on the basis of visual image evaluation alone.
Technique for measuring the area of canine articular surfaces
Authors: Probst Curtis W. , Eyster George E. , DeCamp Charles E.
Published: February 2025

A method for measuring the surface area of canine articular cartilage was developed. Ten pairs of humeri were harvested from fresh canine cadavers. The articular cartilage of each humeral head was covered with liquid rubber latex applied with a brush to the margins of the articular surface. The latex cast was removed from the cartilage after the latex dried. Radial cuts were made in the cast so it could be flattened into a 2-dimensional plane. The surface area of each cast was then measured, using a compensating polar planimeter.
Renal functional relationships in dogs with glomerulopathies
Authors: Allen Timothy A. , Fettman Martin J. , Jaenke Roger S. , Wilke W. Lee
Published: February 2025

Glomerular filtration rate, effective renal plasma flow, and nitration fraction were determined by measuring plasma disappearance of [14C] inulin and [3H]tetraethylammonium bromide after a single iv bolus injection was given to 8 dogs with membranous nephropathy, renal glomerulosclerosis, or renal amyloidosis. Glomerular filtration rate was decreased in the 8 dogs. Effective renal plasma flow was within reference values in 1 dog, increased in 1 dog, and decreased in 6 dogs. Filtration fraction was within reference values in 2 dogs and decreased in 6 dogs. The glomerular filtration rate also was estimated by the endogenous creatinine clearance technique and was decreased in the 8 dogs with glomerulopathies.
Efficacy of a streptomycin-dependent, live Pasteurella haemolytica vaccine against challenge exposure to Pasteurella haemolytica in cattle
Authors: Blanchard-Channell M. T. , Ashfaq M. K. , Kadel W. L.
Published: February 2025

A streptomycin-dependent, live Pasteurella haemolytica vaccine was given in 1 or 2 doses to 2 groups of weaned calves; 2 other groups of calves were not vaccinated. All calves in the vaccinated groups and calves in 1 of the nonvaccinated groups were stressed by transport, intratracheally inoculated with bovine herpesvirus type-1 (Cooper strain), and then intratracheally inoculated with P haemolytica type Al. The 4th group of calves (nonvaccinated controls) was not stressed and were not intratracheally inoculated with virus or bacteria. Mean daily weight gains, total clinical sign scores, lung lesion scores, plasma fibrinogen concentrations, and antibody titers against P haemolytica were determined at various intervals. Calves that had been vaccinated twice had greater mean daily weight gains and lower total clinical sign scores and lung lesion scores than did nonvaccinated, challenge-exposed calves, but the difference was not significant (P > 0.05). Calves vaccinated once had the greatest mean daily weight gains, the lowest total clinical sign scores, and the lowest lung lesion scores when compared with the other 2 challenge-exposed groups of calves. Mean daily weight gains and total clinical sign scores of calves vaccinated once were significantly different (P < 0.05) than those of calves vaccinated twice. Nonvaccinated, non-challenge-exposed control calves did not develop clinical signs of disease, did not develop lung lesions, and had consistently positive daily weight gains, and had scores in these areas that were significantly different (P < 0.05) from those of all challenge-exposed groups of calves. Increases in plasma fibrinogen concentrations corresponded to infection with P haemolytica. Antibody titers against P haemolytica were not consistent among animals in any group, and a significant correlation was not found between antibody titers and the severity of illness.
Persistence of colonies of Anaplasma marginale in overwintering Dermacentor variabilis
Authors: Logan Thomas M. , Kocan Katherine M. , Edwards Wanda , Hair Jakie A. , Claypool P. L. , Ewing S.A.
Published: February 2025

Dermacentor variabilis were infected as nymphs with Anaplasma marginale by allowing the ticks to feed on a single infected donor calf. Two weeks after molting to the adult stage, the ticks were allotted into 1 of 3 groups and were allowed to overwinter at room temperature (25 C) in the laboratory (group 1), cold storage (4.5 C) in the laboratory (group 2), or outdoors in leaf litter (group 3). Persistence of A marginale was assessed by determining density of colonies (number of colonies/0.1 mm2 of gut tissue examined) in tick gut specimens at 3, 5, 7, 9, and 12 months after molting to the adult stage. Colonies of A marginale were found in all groups at every density evaluation period. Highest colony densities were observed uniformly in specimens collected at month 7 (May); densities decreased at month 9 and were lowest at month 12. Statistical analysis indicated that ticks subjected to cold storage and to outdoor conditions had similar colony densities of A marginale; the density curve in these 2 groups indicated significant quadratic effects over time, with peak densities in May. Mean colony density in ticks kept at room temperature fit a different quadratic equation. The morphologic data indicated that A marginale overwinters in Dermacentor variabilis, and that increasing numbers of organisms are found from January to May.
Anthelmintic efficacy of ivermectin in naturally parasitized cats
Authors: Blagburn Byron L. , Hendrix Charles M. , Lindsay David S. , Vaughan Joy L.
Published: February 2025

Ivermectin was administered per os ([po]; n = 15) or subcutaneously ([sc]; n = 3) to naturally parasitized cats at 10 (n = 6), 100 (n = 6), or 300 (n = 6) μg/kg of body weight. Nontreated control cats were given sterile isotonic saline solution po (n = 5) or sc (n = 1). Qualitative fecal examinations were performed on each cat 1 day before treatment and 14 days after treatment. Cats were euthanatized 14 days after treatment, at which time parasites from the gastrointestinal tracts were recovered, identified, and enumerated. Lungs and urinary bladders were examined histologically or by digestion (lungs only) for Capillaria spp and/or Aelurostrongylus abstrusus. Ivermectin was effective in removing Ancylostoma spp at all doses, but removal of Toxocara cati required 300 μg of ivermectin/kg. Efficacies against A abstrusus, Capillaria spp, and Physaloptera spp could not be determined definitively. Ivermectin had no effect on Dipylidium caninum, Hydatigera taeniaeformis, Spirometra mansonoides, or Isospora spp. Adverse reactions were not observed in cats given ivermectin po; however, 3 cats given ivermectin sc reacted as though they experienced pain at the injection site.
Ultrasonographic imaging to monitor fetal and placental developments in ewes fed locoweed (Astragalus lentiginosus)
Authors: Panter K. E. , Bunch T. D. , James L. F. , Sisson D. V.
Published: February 2025

Ultrasonographic imaging was used to monitor the effects of locoweed (Astragalus lentiginosus) on fetal, placental, and cotyledonary developments in pregnant ewes and proved to be a useful noninvasive method of monitoring the effects of locoweed poisoning on fetal and placental development. Ultrasonographic imaging may be a good research technique to observe the effects of toxicants on fetal movement, fetal heart action, and growth and development of the fetus and placenta.

Known effects of locoweed poisoning in pregnant ewes, such as fluid accumulation in the placenta (hydrops allanfeois, hydrops amnii), altered cotyledonary development, and fetal death were observed with ultrasonographic imaging. A previously unknown effect of locoweed on fetal heart action also was observed. Locoweed decreased fetal heart rates, caused cardiac irregularity, and decreased the strength of heart contractions. All ewes, except No. 3525, fed locoweed aborted. At necropsy, aborted fetuses had hypertrophy of the heart, right ventricular dilatation, rounded at the apex of the heart, and generalized edema.