bluuebunny/crossref_metadata_2025 huggingface dataset:
Altered Metabolism, Acute Shock, and Therapeutic Response in a Calf with Severe Coronavirus-Induced Diarrhea
Authors: Phillips R. W. , Case G. L.
Published: February 2025

Acute shock and metabolic failure appeared in a diarrheic calf being studied intensively to determine kinetics of glucose and lactate metabolism. Intravenous therapy significantly improved its condition. During metabolic failure, the rapid increase in blood lactate and concomitant decrease in glucose were due to inhibited gluconeogenesis, as glucose entry and lactate oxidation were not modified. Therapy restored metabolic activity and decreased the severe hyperkalemia.
Chemotherapeutic Value of 2-Deoxy-d-Glucose in Infectious Bovine Rhinotracheitis Viral Infection in Calves
Authors: Mohanty S. B. , Rockemann D. D. , Tripathy R. Ν.
Published: February 2025

Daily injection of 2-deoxy-d-glucose (2-dG) had no protective effect against respiratory tract infection in calves caused by infectious bovine rhinotracheitis virus. It also did not reduce the severity of this infection. Ocular instillation of the drug, however, markedly reduced the severity of viral-induced conjunctivitis and keratoconjunctivitis. The drug was effective when given at the time of ocular infection or after clinical conjunctivitis developed.
Plasma Glucocorticoid and Circulating Blood Leukocyte Responses in Cattle After Sequential Intramuscular Injections of ACTH
Authors: Gwazdauskas F. C. , Paape M. J. , Peery D. A. , McGilliard M. L.
Published: February 2025

Nine Holstein-Friesian cows in the same stage of lactation were randomly given im injections of saline solution, 100 IU of ACTH, or 200 IU of ACTH for a period of 3 days at 0800 and 1600 hours on one day and at 0100 hours the next day. A dose of 100 IU of ACTH represented the amount of ACTH released during physiologic stress and 200 IU of ACTH represented a therapeutic dose. Blood samples were obtained from indwelling jugular catheters for total circulating leukocyte and total plasma corticosteroid determinations at −1, 0, 0.25, 0.50, 1, 1.50, 2, 4, 6, and 8 hours after the 0800-hour ACTH injections. Concentrations of blood leukocytes and total plasma corticosteroids were affected significantly (P < 0.05) by treatment, cow within treatment, day of injection, treatment by day interaction, time, treatment by time interaction, and day by time interaction. Total plasma corticosteroids were 5.6 ng/ml (saline), 38.9 ng/ml (100 IU of ACTH), and 59.8 ng/ml (200 IU of ACTH). Mean corticosteroid concentrations from 0.5 to 8 hours were 29.2 ng/ml on day 1, 42.5 ng/ml on day 2, and 32.7 ng/ml on day 3.

Blood leukocytes were 8,545 cells/mm3 (saline), 11,241 cells/mm3 (100 IU of ACTH) and 9,777 cells/mm3 (200 IU of ACTH). When compared with basal circulating leukocyte concentrations (within cow), this represented increases of 20.7% for 100 IU of ACTH and 24.5% for 200 IU. Mean circulating leukocyte concentrations from 0.5 to 8 hours were 8,900 cells/mm3 on day 1, 10,500 cells/mm3 on day 2, and 10,000 cells/mm3 on day 3.

These data indicate that the adrenal gland responded less on day 3 and that continuous stimulation of bovine adrenal glands by ACTH at physiologic and therapeutic concentration could lead to reduced synthesis or release of adrenal corticosteroids (or both) with concomitant reduction in the concentration of total circulating leukocytes.
Intimai Lesions of the Pulmonary Artery in Dogs with Experimental Dirofilariasis
Authors: Munnell John F. , Weldon John S. , Lewis Robert E. , Thrall Donald Ε. , McCall John W.
Published: February 2025

Microscopic examination, particularly by scanning electron microscopy, of the tunica intima of the pulmonary arteries of dogs experimentally infected with a known number of larvae of Dirofilaria immitis revealed various numbers and shapes of intimal thickenings. The number and morphology of these thickenings were related to the degree of infection. At 11 months after infection, dogs having adult worm populations of 8 to 21 worms had scattered discrete intimal lesions, whereas in dogs with 41 to 68 adult worms, the intima was diffusely affected. Discrete lesions took the form of rugous or verrucous protrusions, and in severely affected animals, the intima was extensively covered with anatomosing ridges. Light microscopy and transmission electron microscopy confirmed earlier reports that the thickenings were mainly confined to the tunica intima, that the surface was covered by endothelium, and that many of the cells in the intimal swellings were derived from smooth muscle.
Escherichia coli Heat-Stable Enterotoxin in Feces and Intestines of Calves with Diarrhea
Authors: Acosta-Martinez F. , Gyles C. L. , Butler D. G.
Published: February 2025

Two experiments were conducted to evaluate detection of Escherichia coli heat-stable enterotoxin (st) in the feces of calves as a method for implicating Ε coli in neonatal calf diarrhea.

The first experiment evaluated the use of the infant mouse test for detection of st in the feces of calves with naturally occurring diarrhea. Simultaneous identification of bovine enteropathogenic strains of Ε coli (eec) and of other infective agents implicated in neonatal calf diarrhea was attempted in these samples. The st was detected with certainty in only 7 of 41 samples from calves ≤ 3 weeks old. Enteropathogenic Ε coli, however, was detected in 27 samples. In 23 of these 27 samples, eec was the only recognizable diarrheagenic agent. In a small percentage of the samples, Salmonella, rotavirus, coronavirus, and cryptosporidium were recognized alone, in combination with each other, or with eec.

In the second experiment, 6 calves were fed colostrum from cows inoculated with the bovine eec strain B44; 6 were given colostrum from cows vaccinated with non-eec strain 28F, and 4 were given milk from nonvaccinated heifers. Two of the calves that were given colostrum from cows inoculated with strain B44 were challenge exposed with the non-eec strain 28F.

The remaining calves were challenge exposed with the eec strain B44. Fecal samples were taken from these calves at intervals and were examined for the presence of st and of the challenge-exposure organism. The st was detected in approximately one half of the fecal samples obtained, and it was most often detected in the early stages of the induced diarrhea. Calves were observed to shed the challenge-exposure eec strain for long periods in the absence of diarrhea or detectable amounts of st in the feces. The st was detectable in fecal samples when the diarrhea was severe and when the dry matter content of the fecal samples was low.
Immunologic Aspects of Combined Immunodeficiency Disease in Arabian Foals
Authors: Lew A. M. , Hosking C. S. , Studdert M. J.
Published: February 2025

Tests for T- and B-cell quantitation and immune function were developed, and their application in the diagnosis of primary severe combined immunodeficiency disease (cid) in Arabian foals was investigated. Foals with cid had severe lymphopenia and had small or zero numbers of B cells, as shown by immunofluorescence of surface immunoglobulin (Ig), erythrocyte-antibody-complement rosetting, and staphylococcal protein A rosetting. Serum IgM was undetectable in four cid foals 25 to 71 days old. Demonstrable antibody responses were not elicited in cid foals by phage φX-174, a potent antigen in normal foals. Nonspecific esterase (nse) staining in the pattern of a single vesicle was investigated as a possible marker for equine T cells. For normal foals, 64.0% of peripheral blood lymphocytes stained nse positive. The cid foal 1 had only 4.0% nse-positive lymphocytes, whereas cid foals 2, 3, and 4 had 75%, 68%, and 77.5%, respectively.

In an in vitro T-cell function test, lymphocytes from 12 normal foals showed a marked response, whereas cells from four cid foals did not show a response. In normal foals, intradermal injection of 50 μg of phytohemagglutinin induced visible reactions, and skin grafting induced a pronounced mononuclear cell response at the base of the graft.

In contrast, there was little or no response in the foals with cid.
Thermography in the Diagnosis of Inflammatory Processes in the Horse
Authors: Purohit Ram C. , McCoy Michael D.
Published: February 2025

To evaluate the use of thermography in equine medicine, a three-phase study was conducted. In the first phase, six horses were examined thermographically, before and after exercise, to determine a normal thermal pattern, In the second phase, nine horses with acute and chronic inflammatory processes were examined thermographically. In the third phase, thermography was used to evaluate the effectiveness of anti-inflammatory drugs on chemically induced inflammatory reactions.

All normal horses tested had similar infrared emission patterns. There was a high degree of symmetry between right and left and between front (dorsal) to rear (palmar, plantar) in the legs distal to the carpus and the tarsus. The warmer areas of the thermogram tended to follow major vascular structures. The coronary band was the warmest area of the leg, Heat increase due to exercise did not substantially alter the normal thermographic pattern.

Use of thermography in clinical cases successfully detected a subluxation of the third lumbar vertebra, a subsolar abscess, alveolar periostitis and abscess, laminitis, serous arthritis of the femoropatellar joint, and tendonitis.

Thermography was effective in quantitative and qualitative evaluation of anti-inflammatory compounds in the treatment of chemically induced inflammation.
Thermography: A Technique for Subclinical Diagnosis of Osteoarthritis
Authors: Vaden Mary F. , Purohit Ram C. , McCoy Michael D. , Vaughan J. T.
Published: February 2025

Thermographic and radiographic evaluations of the tarsus (hock) were done on 20 Standardbred racehorses before and after exercise at three consecutive 6-week intervals. All horses were from the same stable and given the same care and training under identical schedules and conditions.

Normal thermographic patterns were established before and after exercise. These patterns corresponded to the underlying tarsal vasculature. Postexercise thermal patterns indicated a warming trend, and the increases were uniform. Abnormal thermal patterns were more localized and did not conform to the normal underlying vascular distribution.

Five of the 20 horses trained successfully and competed professionally, with 1 of the 5 showing abnormal thermographic changes. Four horses were too slow to race, and all of these had abnormal thermographic changes of their tarsi. The medial aspect of the right tarsus was more commonly involved than the lateral in these horses. Only one horse was clinically lame and exhibited thermal increases, as well as radiographic changes in the right tarsus. The remaining horses were removed from training due to miscellaneous causes.

It was believed that the four horses that failed to make minimum track times (for racing) suffered discomfort in their tarsi sufficient to impair performance. This problem was attributed to early subclinical inflammatory changes within the joints. Though difficult to recognize radiographically, these early changes were conspicuous as abnormal thermographic patterns typical of inflammation.
Effects of Furosemide on Cardiovascular Function and Performance When Given Prior to Simulated Races: A Double-Blind Study
Authors: Milne D. W. , Gabel A. A. , Muir W. W. , Skarda R. T. , Hamlin R. L. , Pipers F. S.
Published: February 2025

In a double-blind study under simulated racing conditions, six Standardbred horses, which had been trained for 12 weeks, were given 1 mg of furosemide/kg of body weight or saline solution iv 15 minutes before the first of two warm-up workouts (1.6 km at 60-minute intervals). Sixty minutes later, 135 minutes after drug or placebo injection, these horses were driven 1.6 km at maximum speed.

Heart rate, respiratory rate, cardiac output, pulmonary trunk pressure, body temperature, pcv, arterial oxygen, and plasma lactic acid were recorded during and after the first warm-up workout and after a simulated race (1.6 km). Values increased compared with values determined at rest whether saline solution or furosemide was given. There were decreases in arterial CO2 and pH.

When furosemide was given, the pulmonary trunk pressure was significantly lower (P < 0.05) during the first warm-up workout (1.6 km). There were no significant differences in the other values. The average times of the simulated races were not significantly (P < 0.05) different after the use of furosemide compared with average times after use of saline solution.
Ontogeny of Lymphocyte Function in the Equine Fetus
Authors: Perryman Lance E. , McGuire Travis C. , Torbeck Richard L.
Published: February 2025

The capacity of cells from thymus, liver, spleen, mesenteric lymph nodes, peripheral blood, and bone marrow to respond to in vitro phytolectin and allogeneic lymphocyte-stimulation was determined in 16 pony fetuses 61 to 200 days old (gestational age). Phytolectin-responsive cells were detected in the thymus at the 80th gestational day, peripheral blood at 120 days, lymph node at 160 days, and spleen at 200 days. Mixed lymphocyte culture-responsive cells were detected in thymus at 100 days and in the spleen at 200 days (gestational age).

Immunoglobulins (Ig) M and IgG were quantitated by radioimmunoassay. They were detected in fetuses prior to 200 days of age. All of 50 normal newborn foals had detectable quantities of IgM (165 ± 56 μg/ml of serum). Quantities of IgG in normal newborn foal serum were lower and more variable. The minimal-maximal concentrations of IgG were 2 to 170 μg/ml of serum with a mean and sd of 51 ± 49 μg/ml. The results indicate that (1) functional T lymphocytes are present in the fetus by 100 days (gestational age), (2) functional B lymphocytes are present by 200 days, and (3) that foals are immunocompetent before birth.
Experimentally Induced Bovine Sarcocystosis: Correlation of In Vitro Lymphocyte Function with Structural Changes in Lymphoid Tissue
Authors: Frelier P. F.
Published: February 2025

The effect of acute bovine sarcocystosis was studied by correlating in vitro lymphocyte blast transformation studies with morphologic and hematologic changes. Yearling calves inoculated with 900,000 sporocysts (large dose) had decreased responses to phytohemagglutinin and pokeweed mitogen and corresponding morphologic evidence of depletion of both T and B lymphocytes in all lymphoid organs examined during the first 4 weeks. The T-cell depletion was characterized by marked thymic atrophy. In lymph nodes denoting B-cell depletion, there were lymphoid follicular exhaustion and various degrees of follicular loss. Significant change in total circulating lymphocytes was not observed. All animals given this large dose died or were killed (in a moribund state) by 5 weeks after they were inoculated.

Changes in mitogen responsiveness were not significant during the 4 weeks after yearling calves were inoculated with 90,000 sporocysts (small dose). The mitogenic effect of phytohemagglutinin was significantly greater than that of the control group during weeks 4 to 18. During this period, morphologic evidence of thymic cortical regeneration occurred.

The results indicate that acute sarcocystosis is accompanied by a lymphoid abnormality which could result in immunosuppression, adding to the severity of natural infection.
Isolation of Bovine Herpesvirus-1 from Trigeminal Ganglia of Clinically Normal Cattle
Authors: Homan E. J. , Easterday B. C.
Published: February 2025

Trigeminal ganglia collected from 56 adult dairy cattle at slaughter were maintained in explant culture. Bovine herpesvirus-1 was isolated from six ganglia after periods of 7 to 24 days’ maintenance in vitro. Antibody against bovine herpesvirus-1, indicating exposure to that virus, was found in 45.4% of the sample population from which ganglia were collected.
Secretory Immune Response in Intestinal Mucosa and Salivary Gland After Experimental Infection of Pigs with Transmissible Gastroenteritis Virus
Authors: DeBuysscher Eduard V. , Berman David T.
Published: February 2025

Pigs 8 to 10 weeks of age were orally infected with transmissible gastroenteritis (tge) virus or infected by inoculation of the virus into Thiry-Vella loops of jejunum. Concentrations of immunoglobulin (Ig) A, IgM, and IgG in serum, saliva, jejunal secretions, loop secretions, and bile were determined by solid-phase radioimmunoassay for tge virus-infected and control pigs. A multiple-staining fluorescent antibody technique was used to determine the relative numbers of IgA-, IgM-, and IgG-producing plasma cells in intestinal mucosa, mesenteric lymph node, spleen, iliac lymph node, and submandibular salivary gland. The numbers of IgA- and IgM-producing plasma cells were greater in the jejunal mucosa of pigs infected and reinfected orally with tge virus than in that of the control pigs. There was also an increase of IgA- and probably of IgM-cells in the submandibular salivary glands. Similar numerical increases of IgA- and IgM-cells were observed in jejunal mucosa and salivary glands of all pigs with intestinal loops whether exposed to tge virus or not. Increases in plasma cells in mucosa or salivary gland were not associated with increases in concentrations of IgA or IgM in the respective secretions or serum. The data support the hypothesis that after stimulation, IgA- and IgM-producing cells leave the intestinal mucosa and are trapped by distant secretory epithelia. The absence of a simultaneous increased concentration of IgA and IgM in saliva and intestinal secretions indicates that in an intact epithelium, the transport of IgA and IgM mediated by secretory component is probably saturable.
Coyote as a Final Host for Sarcocystis Species of Goats, Sheep, Cattle, Elk, Bison, and Moose in Montana
Authors: Dubey J. P.
Published: February 2025

Tissues (1 kg) from sheep, goats, cattle, moose, bison, or elk naturally infected with Sarcocystis species were fed to one to four Sarcocystis-free coyotes and the number of sporocysts in feces and intestines were counted. All 12 coyotes fed naturally infected tissues shed Sarcocystis in feces, with a prepatent period of 9 to 15 days. The four coyotes fed infected beef had 15, 25, 113, and 201 million sporocysts in their feces and intestines. The coyotes fed elk, moose, or bison had 2.5, 15, and 2.5 million sporocysts in their intestines, respectively. Sporocysts in feces of coyotes fed musculature of cattle, sheep, goats, and elk were structurally similar to those described previously from the feces of dogs. This is evidently the first report of the completion of life cycle of Sarcocystis species in moose and bison. Cross-transmission experiments indicated that one species of goat Sarcocystis completes its life cycle in both dog and coyote and that the ovine Sarcocystis is not transmissible to goats.
Application of Individualized Digoxin Dosage Regimens to Canine Therapeutic Digitalization
Authors: Button C. , Gross D. R. , Allert J. A.
Published: February 2025

Congestive right heart failure was established in three dogs subjected to surgical tricuspid valvectomy and pulmonic stenosis. The eliminative dispositions of digoxin in serum and ascitic fluid were determined after administration of 30 μg of digoxin/kg of body weight by iv injection and radioimmunoassay of multiple serum and ascitic fluid samples.

Individualized digoxin dosage regimens for the three dogs were calculated from data collected in the present experiment and data from the literature. The regimens were tested on the three dogs after their body weight had been corrected for the volume of ascitic fluid present. An iv maintenance therapy resulted in serum digoxin concentrations slightly lower than anticipated. The administration of digoxin tablets with no food restriction resulted in serum digoxin concentrations mostly in the expected range. The same doses of digoxin in tablet form were given to the three dogs after fasting. Fasting resulted in slight, but significant, increases in serum digoxin concentrations. Serum digoxin concentrations after administration of digoxin elixir were close to anticipated values.

These experiments indicate that individualized digoxin dosage regimens may be useful to set serum digoxin concentrations within the therapeutic, nontoxic range.
Natural Transmission of Dirofilaria immitis by Aedes vexans
Authors: Hendrix Charles M. , Bemrick William J. , Schlotthauer John C.
Published: February 2025

Aedes vexans mosquitoes were reared in the laboratory from field-collected fourth instar larvae. Mosquitoes were allowed to feed on dogs which were infected with Dirofilaria immitis and then the mosquitoes were housed in an environmental chamber with an ambient air temperature of approximately 26 C and a relative humidity of approximately 80%. Incandescent lighting was used to simulate daylight. On the 17th, 19th, 21st, and 28th day after their infected blood meal, the mosquitoes were allowed to feed on five microfilaria-negative dogs which had been reared in mosquito-free environments. Blood from four of the five exposed dogs became positive for microfilariae of D immitis in an average of 272 days after the feeding.

The local strain of A vexans was established as a vector of canine heartworm disease in the Minneapolis-St. Paul metropolitan area.
Cultural and Histopathologic Confirmation of Canine Blastomycosis Diagnosed by an Agar-Gel Immunodiffusion Test
Authors: Phillips Walter E. , Kaufman Leo
Published: February 2025

Sixteen sera from 17 dogs with blastomycosis produced a precipitin band identical with the diagnostically significant precipitin A band formed by a Blastomyces dermatitidis reference antiserum and a soluble B dermatitidis yeast-form antigen in the agar-gel immunodiffusion test (94% sensitivity). The other serum from a dog with histopathologic demonstration of B dermatitidis in pulmonic tissues produced an unrelated precipitin band.

Sixteen of the 17 diagnoses made by the detection of precipitin A were confirmed by isolation and culture of B dermatitidis or by histopathologic demonstration of the pathogen. Three cases were confirmed by cultural isolation only, 10 by histopathologic demonstration only, and 3 by both. In three other dogs given amphotericin B, there were demonstrable changes in serum precipitin A reactions.
Serum Complement and Blood Platelet Adhesiveness in Acute Canine Ehrlichiosis
Authors: Lovering Sandra L. , Pierce Kenneth R. , Adams L. Garry
Published: February 2025

Three dogs inoculated with Ehrlichia canis served as infected controls (group I), 3 dogs treated with cobra venom factor (cvf) after inoculation with Ε canis were the principals (group II), 3 noninfected dogs were the noninfected controls (group III), and 1 noninfected dog given cvf was the noninfected, decomplemented control (group IV).

Thrombocytopenia occurred in all Ε canis-inoculated dogs (groups I and II) within 3 weeks after they were inoculated. However, the severity of the thrombocytopenia was moderated in the group II dogs (decomplemented Ε canis-inoculated). Hypocomplementemia occurred in the cvf-treated dogs (groups II and IV) immediately and persisted for up to 5 days after administration of cvf. Hypocomplementemia also occurred in all Ε canis-infected dogs (groups I and II) during the period of maximal thrombocytopenia.

The mean platelet retention was significantly decreased in all E canis-inoculated dogs and in the cvf-control dog (groups I, II, and IV). There was no correlation between platelet retention and the number of platelets in group III (nontreated, noninoculated) controls. The correlation between the decrease in platelet retention and the number of platelets was significant in the complement-intact infected dogs, yet was not significant in the decomplemented infected dogs.

Data indicated that complement consumption occurred in acute canine ehrlichiosis and coincided, to a degree, with the development of thrombocytopenia. Decomplementation of inoculated dogs moderated the severity of the thrombocytopenia. Platelet function is also altered in acute stages of the disease.
Inactivated Vaccine for Parrot Herpesvirus Infection (Pacheco's Disease)
Authors: Hitchner S. B. , Calnek B. W.
Published: February 2025

Four tests of an inactivated emulsified vaccine against a herpesvirus infection (Pacheco's disease) in budgerigars demonstrated that an effective vaccine could be produced with concentrated virus. Virus was propagated in chicken kidney cells, and cells and fluid were harvested 3 to 5 days after inoculation and sonicated. The virus was concentrated 100 × by centrifugation to produce a multiple emulsion vaccine that was protective against im challenge exposure with live virus. The serologic response after vaccination was negligible, and many survivors to virus challenge exposure did not show a positive titer.
Involvement of Calcium in Mitogenic and Immunoglobulin Responses in Bovine Lymphocytes
Authors: Atluru D. , Sloane E. D. , Johnson D. W. , Muscoplat C. C.
Published: February 2025

Removal of calcium from cultures of bovine splenic lymphoid cells with ethyleneglycol-bis-(2-aminoethylether)-N,N′-tetraacetic acid (egta) caused significant suppression of pokeweed mitogen-induced immunoglobulin (Ig) biosynthesis. It was found that removal of calcium for 48 hours of a 5-day culture significantly altered Ig biosynthesis. Re-addition of calcium after 48 hours did not restore Ig synthesis. The egta caused significant (P < 0.05) suppression of DNA synthesis when calcium was removed from concanavalin A- and purified protein derivative-stimulated peripheral blood lymphocyte cultures. Further, removal of calcium for 48 hours of 4-day cultures significantly altered the DNA synthesis in mitogen- and antigen-stimulated cultures.
Efficacy of Avermectin B1a for Treatment of Experimentally Induced Nematode Infections in Cattle
Authors: Wescott R. B. , Farrell C. J. , Gallina A. M. , Foreyt W. J.
Published: February 2025

Two formulations of avermectin B1a, C-076 and MK-933, were examined for anthelmintic activity in two trials, each using 20 calves with experimentally produced nematode infections. In one trial, C-076 was given orally, and in the other trial, MK-933 was given by injection at dosages of 50, 100, and 200 μg/kg of body weight. Treated calves were held for 7 to 8 days and then, together with non-treated controls, were euthanatized and were examined for nematodes in their gastrointestinal tracts and lungs. Efficacy of C-076 approached 100% for Dictyocaulus viviparus, Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, and Oesophagostomum radiatum at 50 μg/kg. A dosage level of 100 μg/kg was required to achieve 97% efficacy against Cooperia punctata. Efficacy of MK-933 at 50 μg/kg was variable, but at 100 μg/kg, it approached 100% for D viviparus, Ο ostertagi, Haemonchus placet, T axei, and T longispicularis. Activity against C oncophora was less, reaching 80% efficacy at 200 μg/kg.
Comparison of the Enzyme-Linked Immunosorbent Assay with Other Tests for Brucellosis, Using Sera from Experimentally Infected Heifers
Authors: Ruppanner R. , Meyer M. E. , Willeberg P. , Behymer D. E.
Published: February 2025

During an evaluation of H-38 Brucella melitensin vaccine, serum samples were collected from 24 Hereford-Angus heifers (nonvaccinated controls) before exposure and then 11 times between 12 and 102 days after exposure to Brucella abortus strain 2308. Antibody concentrations were determined by the enzyme-linked immunosorbent assay (elisa) and by standard tube agglutination (sta), 2-mercaptoethanol agglutination (me), microtitration complement-fixation (mcf), and automated complement-fixation (acf) tests.

The results were compared in terms of concordance, sensitivity, and specificity. Concordance between the elisa and other tests was 100% (sta), 75.7% (me), 97.8% (mcf), and 95.2% (acf). On the 12th day after heifers were exposed, antibodies were detected in 18.2% of the infected heifers by the elisa and in 11.1% with the sta test, in 0% with the me test, in 33.3% with the mcf test, and in 44.4% with the acf test. On the 25th day, elisa and all serotests (except me) detected antibodies in all infected heifers. All serum samples from the heifers before exposure were negative.
Influence of Exercise on Serum Selenium and Peroxide Reduction System of Racing Standardbreds
Authors: Gallagher Kenneth , Stowe Howard D.
Published: February 2025

Blood samples were obtained from 45 racing Standardbred horses immediately before and immediately after a training jog at a commercial race track to establish reference values for serum selenium and related values of the peroxide reduction system of racing horses.

Hemoglobin, hematocrit, and serum selenium increased significantly (P < 0.001), whereas rbc-reduced glutathione decreased significantly (P < 0.01) immediately after exercise. Glutathione peroxidase and glutathione reductase were not altered by exercise. Serum copper and magnesium were significantly increased (P < 0.01) after exercise.
Replication of African Swine Fever Virus in Cell Cultures
Authors: Pan I. C. , Shimizu Μ. , Hess W. R.
Published: February 2025

Infection-specific, nonstructural, African swine fever virus antigens, as visualized by the immunofluorescence technique, appeared as fine stipplings, evenly distributed in the cytoplasm and nucleus of Vero cells and in monocytes by postinoculation hour (pih) 3. Cytoplasmic inclusion bodies (ib) appeared at pih 4 and continued to increase in size up to pih 8. The viral DNA was solely synthesized within the ib of infected monocytes, as evidenced by an autoradiographic chase experiment; maximum synthesis occurred at pih 5. The 2,300-S and 2,500-S (sedimentation coefficient) structural viral antigens were visualized in the ib at pih 5 and 6, respectively. The infective new progeny of African swine fever virus were formed between pih 7 and 8, and the cell surface viral antigens were produced between pih 8 and 9. Free virus was released between pih 10 and 11. Infected cells detached from the glass surface from pih 13. The 5-iodo-2′-deoxyuridine interfered with the formation of infective virus, but did not interfere with the production of viral antigens.
Immunofluorescence Studies on the Pathogenesis of Hemagglutinating Encephalomyelitis Virus Infection in Pigs After Oronasal Inoculation
Authors: Andries K. , Pensaert Μ. B.
Published: February 2025

Hemagglutinating encephalomyelitis virus (hev; also designated vomiting and wasting disease virus) was inoculated oronasally in 14 colostrum-deprived pigs at the day of birth. Anorexia and vomition were seen after 4 days. Pigs were killed at different times after inoculation, and the results of the examination by immunofluorescent antibody technique revealed that the epithelial cells of nasal mucosa, tonsils, lungs, and small intestine served as sites of primary viral replication. After the local replication near the sites of entry, the virus spread via peripheral nervous system to the cns. During the incubation period, viral antigens were detected in the trigeminal ganglion, the inferior vagal ganglion, the superior cervical ganglion, the intestinal nervous plexuses, the solar ganglion, and the dorsal root ganglia of the lower thoracic region. In the brain stem, the infection started in the trigeminal and vagal sensory nuclei and spread to other nuclei and to the rostral part of the brain stem. In later stages of the infection, viral spread into the cerebrum, cerebellum, and spinal cord was sometimes also observed. Viral replication in nervous plexuses of the stomach was not present during the incubation period, but was detected in all except 1 of the pigs that were ill when killed. The question whether the vomition is induced centrally by viral replication in the brain stem or is due to viral replication in peripheral nervous tissues remains unanswered.
Digoxin Pharmacokinetics, Bioavailability, Efficacy, and Dosage Regimens in the Horse
Authors: Button C. , Gross D. R. , Johnston J. T. , Yakatan G. J.
Published: February 2025

The pharmacokinetics of iv administered digoxin and the bioavailability of intragastrically administered powdered digoxin tablets suspended in water were investigated in 6 clinically normal adult horses by 125I radioimmunoassay. The effect of 3 to 5 sequential iv doses of 5 μg of digoxin/kg of body weight at 2-hour intervals on a left ventricular index of contractility (Vmax) was assessed in 5 clinically normal horses. Standard pharmacokinetic equations and mean pharmacokinetic variables were used to derive parenteral and oral (loading and maintenance) doses for digoxin in horses. The calculated dosage regimens were administered and resulting plasma digoxin concentrations were monitored in 5 horses and 1 pony.

Digoxin disposition after iv injection was triexponential. A rapid distributive phase with a half life (t1/2 of 15 minutes was followed by a slow distributive phase with a t1/2 of 4.1 hours. The biological disposition t1/2 was 23.1 hours. The volume of distribution by extrapolation was 6.79 L/kg of body weight and 4.89 L/kg by the area method. The average bioavailability estimate for intragastrically administered digoxin was 19.2%. The Vmax increased significantly (P < 0.01) after iv digoxin administration. Greatest changes in Vmax were recorded after the first 2 injections (5 μg of digoxin/kg) corresponding to plasma digoxin concentrations of 0.83 and 1.68 ng/ml. Doses of digoxin were calculated as follows: iv loading 14, iv maintenance 7, oral loading 70, and oral maintenance 35 μg/kg/24 hours.

When these doses were given to a group of horses, plasma digoxin concentrations measured 12 and 24 hours after administration were mostly in the proposed therapeutic, nontoxic range of 0.5 to 2.0 ng/ml.
Antibody-Producing Cells in Bovine Lacteal Secretions After Local Immunization
Authors: Chang C. C. , Winter A. J. , Norcross N. L.
Published: February 2025

The indirect Jerne plaque assay was used to determine the presence of antibody-forming cells in lacteal secretions of 2 cows inoculated in the mammary gland with T4 phage. Two adjacent mammary glands of 2 nonlactating 7-months pregnant cows were inoculated by intramammary injection 4 times at 3- to 5-day intervals. The presence of plaque-forming cells (pfc) was assessed in each quarter beginning on postinoculation day 8 and at 4- to 14-day intervals thereafter. Amounts of antibodies in serum and secretions were measured by an indirect hemagglutination test.

The pfc were detected in secretions from all quarters of both cows between postinoculation days 8 and 32. Concentrations of pfc fluctuated within quarters during the course of the experiment but no relationship was evident between numbers of pfc in a quarter and its inoculation status. The use of monospecific antiglobulin sera at 1 sample-collection period revealed that cells synthesizing immunoglobulin (Ig)G and IgA antibodies were predominant in lacteal secretions. Antibody amounts in serum and secretions rose after inoculation, and titers in secretions were markedly higher in most instances.

Antibody-forming cells were thus demonstrated to accumulate in the mammary gland after intramammary inoculation. The presence of antibody-forming cells in noninoculated glands may have been the result of antigen transfer among quarters, but was considered more likely to have resulted from systemic migration of antigen-stimulated cells with migration into all quarters, regardless of inoculation status. Antibodies in lacteal secretions may have accumulated through a combination of local synthesis and selective transport from the bloodstream.
Effect of Local Immunization of the Mammary Gland on Phagocytosis and Intracellular Kill of Staphylococcus aureus by Polymorphonuclear Neutrophils
Authors: Guidry A. J. , Paape Μ. J. , Pearson R. E. , Williams W. F.
Published: February 2025

Four cows in the latter part of their 2nd, 3rd, or 4th lactations were immunized by multiple intramammary infusions of heat-killed Staphylococcus aureus in 2 quarters. The direct bactericidal effects of milk whey from the immunized and control quarters, before and after immunization, and the ability of these whey to support phagocytosis and intracellular kill were determined by incubating live S aureus with polymorphonuclear neutrophils isolated from milk. Immunoglobulins (Ig) were determined by single radial immunodiffusion. One immunized and 1 control quarter in each cow were challenge exposed with live S aureus and the courses of the infections were determined for 2 weeks.

There were significant cow differences in all Ig classes and in percentage of phagocytosis. Immunization resulted in a significant increase in IgA, IgG2, and IgM in the immunized quarters. Whey collected from immunized quarters supported phagocytosis of S aureus by isolated milk polymorphonuclear neutrophils significantly greater than did whey from control quarters. Extracellular live S aureus in the incubation medium was decreased by 59% in whey collected after immunization from immunized quarters. This decrease in extracellular S aureus was associated with a concomitant increase in total intracellular S aureus. However, intracellular live organisms showed no change. This lack of change indicated that the additional S aureus that were phagocytosed were killed. Direct bactericidal effects of whey were not observed. Intracellular live S aureus was not significantly correlated with any of the variables measured.
Scanning Electron Microscopy of Canine Pulmonary Arteries and Veins
Authors: Schaub Robert G. , Rawlings Clarence A. , Stewart Gwendolyn J.
Published: February 2025

In this communication we describe (1) a method for preparing pulmonary arteries and veins for examination by scanning electron microscopy and (2) the topographic characteristics of the luminal surface of these vessels. Seven healthy adult dogs were used in this study. The pulmonary vasculature was washed free of blood by perfusion with Tyrode's solution. Blood vessels were partially fixed in situ under physiologic pressure in 3 dogs (15 mm of Hg) or 2 times physiologic pressure in 4 dogs (30 mm of Hg) by perfusion with 1% glutaraldehyde. The pulmonary artery and aorta were tied off and the lungs were removed and immersed in 1% glutaraldehyde for 4 hours for additional fixation under pressure. Blood vessels were dissected free of surrounding tissue, further fixed in 2.5% glutaraldehyde, postfixed in osmium tetroxide, dehydrated, and critical point dried. The luminal surfaces were sufficiently flat to allow visualization of most of the topographic features of the luminal surface. Even 1 missing endothelial cell would have been obvious. Contrary to previous reports, we did not find a dense population of finger-like projections on the surface of arterial endothelium. Rather, we found a modest number of small rounded blebs. The venous endothelial sheet was similar in appearance. These observations demonstrate that scanning electron microscopy may be used to study vascular lesions in pulmonary vessels, as well as in more accessible peripheral vessels.
Effects of Ketamine HCl-Xylazine HCl Combination on Cardiovascular and Pulmonary Values of the Rhesus Macaque (Macaca mulatta)
Authors: Reutlinger Richard A. , Karl Alva A. , Vinal Steven I. , Nieser Mary Jo
Published: February 2025

Rhesus monkeys (Macaca mulatta) were anesthetized with 4% thiamylal sodium and then surgically prepared (instrumented) to record mean arterial blood pressure, heart rate, arterial Po2 and Pco2, venous Po2 and Pco2 and rectal temperature. Arterial blood pH and respiratory rate were manually recorded. Monkeys were placed in a restraint chair and allowed to regain full consciousness. A 30-minute base-line period was recorded and this was followed by an im injection of ketamine (7 mg/kg), xylazine (0.6 mg/kg), or ketamine-xylazine combination; the physiologic values were recorded for 255 minutes. Similar experiments conducted substituting saline solution for the drugs served as controls (saline control), with values recorded for 180 minutes.

When compared with one another, there was no significant difference of the 3 anesthetic regimens and saline control values with regard to (1) mean respiratory rate, (2) mean arterial pH, (3) mean arterial Po2, (4) mean arterial Pco2, or (5) mean venous Pco2. Statistically significant effects were expressed by the ketamine-xylazine combination and xylazine alone with regard to mean arterial blood pressure and heart rate. Both regimens exhibited an approximate 46% decrease (P < 0.05) in mean blood pressure and a 32% decrease (P < 0.01) in mean heart rate when compared with saline control and ketamine alone. These effects occurred within 30 minutes of injections being made and gradually returned toward but did not reach base-line values during the experimental period. When compared with control or ketamine values, ketamine-xylazine combination and xylazine significantly decreased mean rectal temperature. Statistically significant effects of the anesthetic agents on blood gases included a 28% maximum increase in venous Po2 at 30 minutes with ketamine, which gradually returned to normal over the 225-minute experimental period (P < 0.05 compared with saline control), and a 26% maximum decrease in venous Po2 at 30 minutes following ketamine-xylazine injection, which value remained depressed throughout the 225-minute experimental period (P < 0.05 compared with saline control).

The results indicate that although, clinically, the ketamine-xylazine combination appears to have offsetting pharmacologic effects, vital physiologic factors are being compromised for a long time.
An Age-Related Coagulation Disorder Associated with Experimental Infection with Infectious Bursal Disease Virus
Authors: Skeeles J. K. , Slavik Μ. , Beasley J. N. , Brown A. H. , Meinecke C. F. , Maruca S. , Welch S.
Published: February 2025

Specific-pathogen-free White Leghorn chickens were inoculated with a field strain of infectious bursal disease virus. One group (A) was inoculated at 17 days after the chicks were hatched, and the other groups (C and E) were inoculated at posthatch day 42. Blood samples were obtained for determination of clotting times (whole blood recalcification, prothrombin, and activated partial thromboplastin times), virus-neutralizing antibody, and total hemolytic complement. There were significant increases in clotting times for groups C and E at 3 and 5 days after they were inoculated. There were no significant increases in clotting times at 3 days after inoculation in the group A chickens (inoculated at 17 days after hatching). There were no significant decreases in total complement activity in any of these chickens (groups A, C, and E).

This study indicates that the mortality and clinical symptoms observed in chickens experimentally infected with infectious bursal disease virus may be associated with a clotting abnormality because it was noted only in chickens that developed severe clinical disease (inoculated at 42 days after hatching) and was not noted in chickens that remained clinically normal (inoculated at 17 days).
Collection and Processing of Blood Samples Dried on Paper for Microassay of Newcastle Disease Virus and Avian Influenza Virus Antibodies
Authors: Brugh Max , Beard C. W.
Published: February 2025

A practical method for collection and processing of dried whole blood samples on filter paper was developed to facilitate large-scale testing programs for Newcastle disease virus and avian influenza virus antibodies. A modified paper punch was used to cut and place dried blood samples simultaneously in a standard 96-well microplate for elution of antibody. Twelve eluted samples were simultaneously transferred to another microplate for the hemagglutination-inhibition (hi) microtest.

Similar hi titers were obtained with simultaneously collected serum and dried blood samples. Minor differences were not considered of practical importance in diagnostic serologic studies. Dried blood titers were not markedly affected by method of drying (37 C for 2 hours or 26 C for 4 hours), by storage for 24 hours before drying, or by storage of dried samples at 4 C for 28 days or 30 C for 14 days. Blood dried on paper was a satisfactory sample for assay of hi antibodies to Newcastle disease virus and avian influenza virus.
Serum Hydrocortisone (Cortisol) Values in Glaucomatous and Normotensive Beagles
Authors: Chen C. L. , Gelatt K. N. , Gum G. G.
Published: February 2025

Serum hydrocortisone (cortisol) values were measured by radioimmunoassay in 5 normotensive and 20 glaucomatous Beagles at 1 am, 7 am, 1 pm, and 7 pm. Significant differences (P < 0.01) in mean serum values of cortisol occurred between glaucomatous (20.9 ng/ml) and normotensive (9.5 ng/ml) Beagles. The slightly increased serum cortisol values in glaucomatous Beagles at 1 am and 7 am coincided with increases in intraocular pressure of glaucomatous Beagles. However, neither the normotensive nor glaucomatous Beagles exhibited any diurnal variations in serum cortisol values.
Collateral Arterial Blood Supply to the Normal and Ischemic Canine Kidney
Authors: Christie B. A.
Published: February 2025

Latex rubber was perfused into the abdominal aorta of 10 healthy dogs. Each kidney was found to have 4 to 6 vascular extensions of interlobar or arcuate arteries which communicated with an extrarenal artery. Renal collateral arterial connections were made with the phrenicoabdominal, spermatic, deep circumflex iliac, ureteral, caudal mesenteric, lumbar, and adrenal arteries.

The renal collateral circulation was stimulated in 4 dogs by gradual compression of the renal artery and the presence of hypertrophied vessels confirmed by angiography.

In 1 of these 4 dogs, the right renal artery was gradually compressed and finally occluded. Subsequently, contralateral nephrectomy was performed. Nine weeks later, the dog was still active, alert, and eating well.
Excretion of Mycobacterium avium from Lesions in the Intestine and Tonsils of Infected Swine
Authors: Ellsworth Steven , Kirkbride Clyde A. , Johnson Darrell D.
Published: February 2025

Five 8-week-old pigs were given an oral dose of approximately 108 viable units of Mycobacterium avium and confined in such a way as to prevent ingestion of fecal material. At necropsy 70 to 79 days later, there were granulomatous lesions, some containing acid-fast organisms, in the tonsils, aggregated lymphatic follicles (Peyer's patches) of the jejunum and ileum, mucosa of the caudal portion of the ileum, ileocecal valve, and cecum. The organism was isolated from tonsils, intestine, and swabs from the surface of some of these tissues. Mycobacterium avium that apparently originated from lesions in the pigs was first detected in the feces 20 to 23 days after the animals were inoculated. The number of organisms excreted began to decrease at 55 days, and none was isolated from feces at 69 days. It was concluded that lesions in the intestine and possibly the tonsils were the sources of the organisms in the feces. The role of tonsil and intestine lesions of swine as sources of perpetual herd infections is discussed.
Serum Complement Activity of Protein-Energy Malnourished Beef Cows
Authors: Woodard L. F. , Eckblad W. P. , Olson D. P. , Bull R. C. , Everson D. O.
Published: February 2025

Beef heifers were fed protein- or energy-deficient rations (or both) for approximately the last 5 months of pregnancy. Serum samples were periodically collected and were analyzed for amounts of total complement (C) hemolytic activity. After being fed the rations for approximately 2 months, heifers given low-energy rations had significantly lower (P < 0.01) amounts of C than did those fed adequate energy rations. This decrease in C was observed regardless of the amount of dietary protein, although low protein intake seemed to exaggerate the effect of low energy consumption. Reduced protein in the rations had no effect on C titers when caloric intake was adequate. Also, the depressive effect of low dietary energy on C values was no longer apparent after approximately 4 months of feeding the rations. Amounts of C dropped by 20 to 40 U for all groups at or near the time of parturition. The C values averaged over all test dates were significantly lower (P < 0.05) for those heifers given low energy in their rations as compared with values for heifers fed adequate energy rations (146.9 vs 160.8 U).