bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Four Serologic Tests for the Detection of Antibodies to Bovine Leukemia Virus
Authors: Miller J. M. , Schmerr M. J. F. , Van Der Maaten M. J.
Published: February 2025

Four tests for detection of antibodies to bovine leukemia virus (blv) were compared. The sera that were tested came from cattle in naturally infected commercial dairy herds, cattle that were infected under experimental conditions, and cattle in an isolated blv-free herd. The tests that were compared included a radioimmunoprecipitation assay (ria) with p24 antigen, a ria with glycoprotein (gp) antigen, an agar-gel immunodiffusion (agid) test with gp antigen, and a virus-neutralization (vn) test that was based on inhibition of blv-induced syncytia in cell culture.

Results of the 4 serologic tests agreed for 96.8% of the sera from cattle in commercial herds. The gp ria detected the greatest number of positive sera (188); it was followed in turn by the p24 ria (187), the vn test (183), and the agid test (176). The gp ria titers of the 12 sera that gave negative agid results were 175 or less.

In ria, the percentage of precipitation of labeled antigen by positive sera was almost always higher with gp antigen than with p24 antigen. Satisfactory sensitivity in the p24 ria required the acceptance of a low level of antigen precipitation, 15%, as a positive test. In the gp ria, however, almost all positive sera precipitated at least 50% of the labeled antigen. Nonspecific precipitation of antigen in the ria by sera from blv-free cattle ranged from 4% to 10%.

Examination of sequential serum samples from 17 experimentally infected cattle showed that blv antibody was first detected 2 to 8 weeks after inoculation. In 9 cattle, seroconversion was detected simultaneously by all of the tests. Results from the other 8 cattle indicated that seroconversion could be detected first by p24 ria, followed by the gp ria and the vn test. The longest interval between ria seroconversion and agid seroconversion was 10 days.

Monthly tests of sera from 10 laboratory cattle that were infected by contact exposure showed that 7 animals seroconverted in all tests at the same time. Two cattle were positive first in ria, but by the next month they were also positive in the vn and agid tests. One animal was positive in the ria and the vn test for 2 months before antibody was detected by agid.
Use of a Feline Cell Line in the Syncytia Infectivity Assay for the Detection of Bovine Leukemia Virus Infection in Cattle
Authors: Ferrer Jorge F. , Cabradilla C. , Gupta P.
Published: February 2025

This report describes a modified syncytia infectivity assay (sia) for the direct detection of bovine leukemia virus (blv) in blood lymphocytes of cattle, using transformed feline (CC81) cells as the indicator system. The data show that the syncytia present in cultures of CC81 cells inoculated with blv-infected cells are specific and arise through a mechanism similar to that responsible for the phenomenon of “late” polykaryocytosis described in other virus systems.

The susceptibility of the CC81 cells to the syncytia-inducing effect of blv-infected cells is comparable with that of early passages of bovine embryonic spleen cells, which were previously used as the indicator system in the sia. Unlike the bovine embryonic spleen cells, CC81 cells retain their susceptibility to syncytia induction for long periods of cultivation. Furthermore, the syncytia induced in the CC81 cultures are larger and easier to identify. Thus, the CC81 cells can be used advantageously as the indicator system when the sia is applied to the detection of blv-infected lymphocytes.

The results of the sia for the detection of infective blv agreed closely with those of the radioimmunoassay for the detection of blv antibodies in randomly examined cattle. On the other hand, many cattle in early stages of infection were positive in the radioimmunoassay several months before they reacted in the sia.

The detection of blv in blood lymphocytes provides a useful method for the diagnosis of blv infection in cattle when serologic tests cannot be used, eg, calves that may have passively acquired maternal antibodies and cattle given blv vaccines.
Therapeutic Effect of Phenylbutazone on Experimental Acute Escherichia coli Endotoxemia in Ponies
Authors: Burrows George E.
Published: February 2025

Phenylbutazone (pbz), a classic anti-inflammatory and prostaglandin-synthesis inhibitor drug, was used to determine the role of prostaglandins and other mediators on the development and perpetuation of the response to intraperitoneal Escherichia coli endotoxin administration. The pbz (15 mg/kg of body weight) was administered iv 30 minutes after endotoxin administration and was repeated later at 6 and 12 hours at a dose of 10 mg/kg. A variety of evaluation measurements (hematologic, blood glucose, pyruvate, lactate and fibrinogen, serum β-glucuronidase, prothrombin time, blood gases, hepatic glycogen, plasma esterase, capillary refill time, and rectal temperature) were utilized. Marked alterations were noted for all evaluators following endotoxin administration except for blood fibrinogen, prothrombin time, and plasma esterase activity. The pbz therapy blocked the hemoconcentration, hyperglycemia, increased blood lactate, decreased bicarbonate, decreased blood pH, pyrexia, and prolonged capillary refill time responses associated with endotoxin administration. Despite the significant blocking effects of pbz on endotoxin responses, the eventual survival rate was unaffected in these experiments.
Protection Against Enteric Colibacillosis in Pigs Suckling Orally Vaccinated Dams: Evidence for Pili as Protective Antigens
Authors: Moon H. W.
Published: February 2025

Pregnant gilts were vaccinated orally with Escherichia coli that produced pilus antigens K99 or 987P. The vaccines were live or dead enterotoxigenic E coli (etec) or a live rough non-etec strain which has little ability to colonize pig intestine. Pigs born to the gilts were challenge exposed orally with K99+ or 987P+ etec, which did not produce heat-labile enterotoxin or flagella and which produced somatic and capsular antigens different from those of the vaccine strains.

Control gilts had low titers of serum and colostral antibodies against pilus antigens, and their suckling pigs frequently had fatal diarrhea after challenge exposure. Serum antibody titers against pilus antigens of the vaccine strains increased in the gilts after vaccination with live etec, and the colostral antibody titers of these gilts were higher than those of controls. Pigs suckling such vaccinated gilts were more resistant than controls to challenge exposure by etec of the homologous pilus type. This resistance was not attained when vaccine and challenge strains were of different pilus types, and it could not be attributed to enterotoxin neutralization by colostrum. In contrast to the live etec vaccines given to the pregnant gilts, the live rough non-etec and dead etec vaccines stimulated little or no production of antibody against pili, and the pigs born of these vaccinated gilts remained highly susceptible to challenge exposure.

The results support the hypothesis that pili can be protective antigens in oral etec vaccines. It was indicated that in the system reported, protection depended on living bacteria for the production of pilus antigens in vivo or for the transport of pilus antigens across intestinal epithelium.
Toxicosis in Sows and Their Pigs Caused by Feeding Rations Containing Polybrominated Biphenyls to Sows During Pregnancy and Lactation
Authors: Werner Pedro R. , Sleight Stuart D.
Published: February 2025

The toxicity and the distribution of polybrominated biphenyls (pbb) were investigated by feeding rations containing different concentrations of pbb to sows during pregnancy and lactation. Sows and newborn pigs were clinically unaffected. Mortality was increased among pigs nursing sows fed rations containing pbb. Although transplacental passage of pbb resulted in an appreciable amount of pbb in tissues of newborn pigs, far more pbb were transferred to the pigs through the milk. On a body-weight basis, nursing pigs consumed pbb in concentrations similar to the concentrations given to the sows. The highest tissue concentrations of pbb (fat basis) were found in the liver, followed by the adipose tissue, kidney, and brain. Dietary concentrations of 10 mg of pbb/kg of feed increased serum concentrations of alkaline phosphatase, alanine aminotransferase, and thyroid hormones of pigs, whereas dietary concentrations of 100 or 200 mg of pbb/kg of feed caused those values to decrease. Gross pathologic changes consisted of increased weight of the thyroid gland of newborn pigs and increased weight of the liver of 4-week-old pigs. Histologically, thyroid glands of newborn pigs were slightly hyperplastic, and the colloid was scant and vacuolated. In the liver, lesions consisted of fatty change and centrolobular necrosis; changes were more severe in the sows than in the pigs nursing those sows. Measuring serum concentrations of ornithine carbamoyltransferase was the most effective clinical test in assessing the degree of liver damage in the pigs.
Immunosuppressive Effects of Cyclophosphamide in Pigs
Authors: Mackie Eleanor J.
Published: February 2025

Effects of cyclophosphamide (cy) on circulating leukocytes, lymphoid tissues, and antibody response of the pig were examined. Pigs (10 weeks old) were treated with intraperitoneal injections of 30 mg of cy/kg of body weight at 2-day intervals. Three cy injections depressed total leukocyte, neutrophil, and lymphocyte counts. Circulating B-lymphocyte percentages were depleted by 80% and absolute B-lymphocyte counts by 90%. Circulating T-lymphocyte percentages were not affected by cy treatment, but absolute T-cell counts were depressed by 50%. Lymphocytes were depleted from the cortex of the thymus gland and from the spleen and lymph nodes with a preferential effect on B-dependent areas. All these variables were depressed for the duration of cy treatment and had started to return to within normal values by 4 days after the final treatment. Formation of antibodies to sheep erythrocytes was suppressed in cy-treated pigs until 10 days after inoculation (6 days after final cy treatment); the response of control pigs was detectable 4 days after inoculation. The 6 cy treatments prolonged the depression of all the previously mentioned variables.
Acepromazine and Droperidol Inhibition of Halothane-Induced Malignant Hyperthermia (Porcine Stress Syndrome) in Swine
Authors: McGrath Charles J. , Rempel William E. , Addis Paul B. , Crimi Anthony J.
Published: February 2025

Pigs susceptible to malignant hyperthermia (mh; porcine stress syndrome) were treated with acepromazine or droperidol before studies with halothane were conducted. At lower dosages (0.55 mg/kg of body weight and 0.20 mg/kg, respectively), both drugs were capable of delaying the onset of mh. At dosages of 1.10 mg/kg of body weight and 1.65 mg/kg, acepromazine effectively prevented the occurrence of mh in 40.0% and 73.3% of mh-susceptible pigs, respectively
Anaplasma ovis in Idaho Sheep
Authors: Magonigle R. A. , Eckblad W. P. , Lincoln S. D. , Frank F. W.
Published: February 2025

Blood samples from 16 anaplasmosis complement-fixation (cf) positive sheep from a flock near Cambridge, Idaho, were inoculated into 3 intact sheep and 3 splenectomized calves. The 3 sheep became cf positive, and 2 developed parasitemia. None of the 3 calves had signs of anaplasmosis, but all became ill when they were subsequently challenge exposed with blood from known carriers of Anaplasma marginale.

After a 75-day observation period, blood from the recipient intact sheep was subinoculated into 3 splenectomized sheep. These splenectomized sheep developed clinical anaplasmosis and became cf positive. In only 1 sheep was there a positive rapid card agglutination test. Therefore, the rapid card agglutination test was not considered to be diagnostic for anaplasmosis carrier status in sheep.

Electron microscopic studies were performed on infected sheep erythrocytes to determine the morphologic structure of the organism involved. The causative organism was determined to be Anaplasma ovis.
Experimentally Induced Arthritis of the Equine Carpus: Histologic and Histochemical Changes in the Articular Cartilage
Authors: Mcilwraith C. Wayne , Van Sickle David C.
Published: February 2025

Arthritis was experimentally induced in the intercarpal joints of a series of mature ponies by the intraarticular injections of 400 μg of the polyene antibiotic filipin in 1 ml of dimethyl sulfoxide. Twelve consecutive weekly injections were administered and the ponies were euthanatized 4 weeks after the last injection of filipin was made. The ponies were exercised for 1 hour each day throughout the experiment. Articular cartilage specimens from 4 sites in each intercarpal joint were examined histologically and histochemically. For the histochemical examination, safranin O-fast green, Alcian blue in 0.4 M and 0.9 M MgCL2 and Alcian blue 0.9 M MgCL2-Van Gieson matrical staining techniques were used. Decalcified sagittal sections of selected carpi were also examined histologically.

There was superficial fibrillation with chondrocyte necrosis in the articular cartilage specimens of the joints. This was accompanied by loss of histochemical staining of the amorphous intercellular matrix, which was attributed to loss of glycosaminoglycans. There were hypertrophy of remaining chondrocytes and chondrone formation. On examination of decalcified sections of carpi, both exostoses and marginal osteophytosis were observed. There was evidence of both intramembranous and endochondral osteogeneses in the exostoses.

The pathologic changes seen in the experimental model were compared with those observed in the naturally occurring disease. It was concluded that the changes were comparable with the early changes of degenerative joint disease in the horse.
Detection of Bacteremia in Cattle Inoculated with Bovine Viral Diarrhea Virus
Authors: Reggiardo C. , Kaeberle M. L.
Published: February 2025

Bovine viral diarrhea virus infection of cattle interfered with normal blood clearance mechanisms, as evidenced by the detection of an endogenous bacteremia in up to 85% of infected calves during the first 5 days after infection. The occurrence of detectable bacteremia correlated with the period of leukopenia and depression of lymphocyte responses to mitogens. Noninoculated control animals, reinoculated immune calves, or calves inoculated with infectious bovine rhinotracheitis virus yielded consistently negative cultures. Bacillus spp were isolated in almost all calves. Similar organisms were isolated occasionally from the blood of normal calves when medium containing sodium polyanetholesulfonate was used for culture.

It was concluded that bovine viral diarrhea virus infection depressed the normal defense mechanisms, presumably humoral factors or phagocytic function, resulting in uninhibited blood circulation of bacteria during infection.
Antibody and Delayed Hypersensitivity Responses of Neonatal Calves Delivered from Protein-Restricted Dams
Authors: Woodard L. F. , Eckblad W. P. , Olson D. P.
Published: February 2025

The effects of moderate maternal protein restriction on in vivo humoral and cell-mediated immune responses of bovine neonates were studied. Hereford heifers were fed protein-adequate or protein-restricted rations for the last 150 days of gestation and for 6 months after parturition.

At birth, all calves from these heifers were allowed to remain with their dams and were inoculated with tetanus toxoid (tt) and an emulsion of tuberculoproteins and trehalose dimycolate (cord factor) of Mycobacterium bovis. One month later, blood samples were collected from all calves, and sera were examined for antibodies to tt. The calves were then given a 2nd inoculation of tt, and anamnestic antibody responses were measured 7 days later. Differences in primary or secondary antibody responses were not observed between principal and control groups of calves. Also, differences in tuberculin reactivity were not observed in calves from cows fed protein-adequate or protein-restricted diets.
Morphologic Characteristics of the Epithelial Surface of Aggregated Lymphoid Follicles (Peyer's Patches) in the Small Intestine of Newborn Gnotobiotic Calves and Pigs
Authors: Torres-Medina Alfonso
Published: February 2025

Scanning electron microscopic studies of the dome epithelium of aggregated lymphoid follicles (Peyer's patches) of gnotobiotic newborn calves and pigs revealed distinct characteristics. The dome epithelium in the calves was characterized by a uniform population of lymphoepithelial cells (M cells). These cells were columnar, with a luminal surface that bulged toward the intestinal lumen forming intercellular crevices. Bovine M cells were covered by densely packed blunt microvilli that were irregular, short and thick and that differed from microvilli of absorptive epithelial cells.

The dome epithelium in the pigs had 2 distinct cell populations. The majority had surface characteristics indistinguishable from those of ordinary absorptive epithelial cells. Interspersed among the absorptive-like epithelial cells were numerous M cells with distinctive surface morphologic characteristics. Porcine M cells were covered by densely packed, long microvilli that were irregular and thick and that projected above the microvilli of adjacent epithelial cells. The epithelium of aggregated lymphoid follicles in calves differed from that of primates and rodents. The organization of the dome epithelium in pigs resembled that of rodents. However, the surface morphologic features of porcine M cells were unlike that of rodents and human beings.
An Enzyme-Linked Immunosorbent Assay for Diagnosis of Fasciola hepatica Infection in Cattle
Authors: Farrell C. J. , Shen D. T. , Wescott R. B. , Lang B. Z.
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) was investigated for the diagnosis of Fasciola hepatica infection in cattle. Studies included examination of 4 antigen preparations: freshly collected fluke antigen (ffa), dead fluke antigen (dfa), lyophilized fluke antigen (lfa), and partially purified antigen (ppa) for activity and use of an elisa with ffa and lfa for diagnosis of experimentally and naturally occurring fascioliasis in cattle.

The elisa, using ffa, detected F hepatica antibody in calves as early as 4 weeks after exposure to this parasite. The dfa exhibited slightly less activity, and lfa did not have diagnostic value until 9 to 10 weeks after exposure. The ppa produced high background readings with noninfected control sera and was not considered sufficiently specific for further use. The long incubation and short incubation elisa procedures can be used for diagnostic work. Both were equally sensitive, with optical density readings of known positive sera routinely 2.5 times those of sera from normal controls. The repeatability of these tests was also excellent, and only slight variation in optical density was observed when elisa was performed on representative known positive and negative sera with similar reagents in replicate tests.
Canine Parainfluenza-Bordetella bronchiseptica Vaccine: Immunogenicity
Authors: Chladek Dan W. , Williams James M. , Gerber Don L. , Harris Louis L. , Murdock Fred M.
Published: February 2025

The immunogenicity and safety of 3 serials of a canine parainfluenza (cpi) virusBordetella bronchiseptica vaccine were evaluated. Each serial was used to vaccinate 10 dogs with single doses given intranasally. The 30 vaccinated and 10 nonvaccinated control dogs were challenge exposed with aerosols of virulent cpi virus and B bronchiseptica at 18 days and at 21 days, respectively, after vaccination. After challenge exposure, none of the 30 vaccinated dogs had clinical signs of disease; however, 9 of the 10 nonvaccinated dogs developed coughing problems. The cpi virus was isolated from nasal swab specimens obtained from nonvaccinated dogs on an average of 5.1 days after challenge exposure, but was not isolated from any of the specimens obtained from the vaccinated dogs. Bordetella bronchiseptica was isolated from nasal swab specimens obtained from both vaccinated and nonvaccinated dogs up to 18 days after challenge exposure. The erythrocyte sedimentation rates and total leukocyte counts for control dogs were generally increased, in contrast to those for the vaccinated groups. Dogs showed a primary serologic response to cpi virus and B bronchiseptica after vaccination and an anamnestic response to the bacterium after challenge exposure. Adverse local or systemic reactions attributable to the bivalent vaccine were not observed in the vaccinated dogs.
Computerized Tomography of Brain Tumors of the Rostral and Middle Fossas in the Dog
Authors: Fike John R. , LeCouteur Richard A. , Cann Christopher E. , Pflugfelder Christina M.
Published: February 2025

Computerized tomography (ct) was used to assess spontaneously occurring brain tumors of the rostral and middle fossas in the dog. Six dogs were used to illustrate the efficacy of ct as a noninvasive diagnostic procedure. Tumors were characterized on ct scans by density changes, presence of edema or calcification, displacement of normal anatomic landmarks, and contrast enhancement after injection of an iodinated contrast material. In terms of ct appearance, there were a number of morphologic similarities between human and canine brain tumors.
Influence of Norethindrone on Lipid Metabolism and Cholelithiasis in Rabbits
Authors: Borgman Robert F. , Lightsey Stephen F.
Published: February 2025

Rabbits were fed a purified ration containing 15% lard and were killed and examined at 0, 4, 8, 12, and 16 weeks. One group (group II) was given (treated) norethindrone in the ration (10 mg/kg of ration). There were no treatment effects noted on hepatic weight, percentages of dry matter and ether extract in liver, and hepatic cholesterol concentrations; however, there were some changes in the hepatic fatty acid percentages at some observation times. The occurrence and severity of cholelithiasis were not influenced by the treatment, but gallstone formation was pronounced in the 2 groups (ration alone, ration with added norethindrone) by the 4th week. The thoracic aorta did not reveal treatment effects as to weight and percentages of dry matter and ether extract, but the aortic cholesterol concentration was greater in the nontreated group than in the group fed the ration with the added norethindrone. Increased thoracic aortic weights were noted in both groups by the 4th week. Examinations and analyses of the adipose deposits forming the kidney pads did not reveal influences of time or treatment.
Heat- and Cold-Stress Suppresses in Vivo and in Vitro Cellular Immune Responses of Chickens
Authors: Regnier Jeffery A. , Kelley Keith W.
Published: February 2025

The influence of hot and cold ambient temperatures on cellular immune responses of chickens was assessed, utilizing dinitrofluorobenzene-induced contact sensitivity, phytohemagglutinin (pha) skin test, and pha-stimulated, whole blood lymphocyte transformation assays. Dinitrofluorobenzene- and pha-induced wattle swelling were reduced (P < 0.05) in birds exposed to air temperatures of 36 C or 1 C for 5 days when compared with wattle swelling in chickens maintained at 26 C. The pha-induced lymphocyte transformation, as measured by tritiated thymidine uptake, was also suppressed (P < 0.05) in chickens exposed to either heat or cold stress for 5 days. Some breed differences were observed. These data demonstrated that chronic heat and cold stress impaired expression of contact sensitivity in vivo and proliferation of T lymphocytes in vitro in the avian species.

Synthesis of antibodies to sheep rbc on day 5 after antigen injection was not altered (P > 0.05) when birds were vaccinated 24 hours before the start of thermal stress. This indicated that B cell and T-helper cell functions were not compromised by chronic thermal stress. However, New Hampshire birds that were heat-stressed had higher (P < 0.05) antibody titers than did control birds 10 days after vaccination.
Induction of Persistent Infection in Mice and Oncogenic Transformation of Mouse Macrophages with Infectious Bovine Rhinotracheitis Virus
Authors: Geder L. , Lee K. J. , Dawson M. S. , Engle R. , Maliniak R. M. , Lang C. M.
Published: February 2025

Infectious bovine rhinotracheitis virus (ibrv) established long-term persistent infection in intracerebrally inoculated athymic nude mice. After intraperitoneal injection into outbred mice, virus was isolated for only 3 days from spleens and livers. In vitro inoculation of outbred mouse spleen fragments with ibrv resulted in persistent infection and subsequent transformation of spleen macrophages. The ibrv-specific membrane and intracellular antigens were detected by indirect immunofluorescence techniques in transformed cells in early in vitro passages. The presence of ibrv genetic information was confirmed by in situ hybridization. The ibrv-transformed mouse macrophages induced fibrosarcomas and cystic tumors in athymic nude mice. Infective virus could not be rescued from transformed cells by cocultivation with rabbit kidney cells, treatment with iododeoxyuridine, or ultraviolet irradiation.
Experimental Intramammary Infection of Cows with Yersinia enterocolitica O9: Cellular and Immunologic Responses
Authors: Mittal K. R. , Barnum D. A. , Tizard I. R.
Published: February 2025

Three clinically normal cows were inoculated with viable Yersinia enterocolitica O9 by the intramammary route. This provoked an increase in the somatic cell count in milk from the inoculated quarter, but no obvious clinical response. Yersinia enterocolitica was isolated only sporadically from these cattle after inoculation. All cows showed a marked serologic response to Y enterocolitica and Brucella abortus. The anti-Brucella response provoked by inoculation of Yersinia was sufficient to render milk and serum Bracella-seropositive, as measured by the standard milk ring test, the quantitative milk ring test, and the serum agglutination test.
Clinical Chemistry of Anaplasmosis: Comparative Serum Protein Changes Elicited by Attenuated and Virulent Anaplasma marginale Isolates
Authors: Allen P. C. , Kuttler K. L. , Amerault T. E.
Published: February 2025

In a comparative study of the clinical chemical changes during Anaplasma marginale infection, 16 intact mature cows were infected with either of 2 virulent isolates. Eight others were treated with a live A marginale vaccine (sheep-attenuated) and 7 were maintained as controls. Before and during patency, samples of blood from the cows were analyzed for total wbc, parasitemia, card test titer (ctt), total protein, albumin, and globulin fractions.

In the cows inoculated with virulent isolates, albumin was significantly depressed throughout patency, whereas γ-globulins and wbc were increased after peak parasitemia, as well as during recovery. The ctt was highest immediately after peak parasitemia. A significant increase was not observed in β-globulin. Seven of the 16 infected cows died, but no consistent patterns of change in serum protein fractions or wbc coul be associated with mortality.

The 8 cows vaccinated with the attenuated isolate showed a significant mean decrease in albumin throughout patency, but no significant mean increase in α- or β-globulin. A mean increase in γ-globulin was observed only during the recovery period. The ctt increased gradually throughout patency, peaking during the recovery period. A significant mean increase over control in wbc count was observed only during rising parasitemia.
Cytogenetic Analysis of Preimplantation Blastocysts from Prepuberal Gilts Treated with Gonadotropins
Authors: Dolch Kathryn M. , Chrisman C. Larry
Published: February 2025

Metaphase chromosomes were examined in 10-day-old embryos collected from prepuberal gilts that had been induced to ovulate, using a combination of 200 IU of human chorionic gonadotropin (hcg) and 400, 600, or 800 IU of pregnant mare serum gonadotropin (pmsg) followed 72 hours later by 500 IU of hcg. A repeatable, reliable method was developed for the processing of early porcine embryos in the hatched spherical blastocyst stage for cytogenetic analysis.

Of 170 embryos recovered and processed from 21 gilts, 169 yielded analyzable metaphase cells for determination of somatic cell chromosome number for an overall success rate of 99.4%. All embryos were diploid (2n = 38) in chromosomal constitution, and although isolated tetrapioid (4n = 76) and octaploid (8n = 152) cells were found, true triploid or other polyploid embryos were not present. The absence of these aberrations indicated that at the dosage levels tested, the hormone pmsg did not cause an increase in occurrence of polyploidy in porcine blastocysts present at day 10 of gestation.

Analyses showed no significant (P < 0.05) increase in numbers of corpora lutea or embryos at day 10 of gestation in gilts treated with these pmsg dosage levels.
Seasonal Variations and the Effects of Age on Serum Copper and Zinc Values in the Dog
Authors: Keen Carl L. , Lonnerdal Bo , Fisher Gerald L.
Published: February 2025

Age-related changes in serum copper and zinc concentrations were evaluated in approximately 800 Beagle dogs. A 20% increase with age was established for both elements. Seasonal variation was also found to have a marked effect on serum zinc with the values positively correlated to ambient temperature. In contrast, serum copper was not affected by temperature. Hemolysis, but not lipemia, was found to affect analytical results.
Canine Axial Pattern Flaps, Using the Omocervical, Thoracodorsal, and Deep Circumflex Iliac Direct Cutaneous Arteries
Authors: Pavletic Michael M.
Published: February 2025

Development of skin flaps, incorporating a direct cutaneous artery and vein, enable the developing of flaps of considerable dimension without the necessity of a delay procedure.

Landmarks and guidelines for the development of axial pattern flaps are demonstrated, using the cervical cutaneous branch of the omocervical artery and vein, the thoracodorsal artery and vein, and the deep circumflex iliac artery and vein. These 3 axial pattern flaps have potential use for the rapid, safe restoration of extensive cutaneous defects involving the facial area, pinna, neck, shoulder, forelimb, axillary area, thorax, inguinal area, lateral thigh, and trochanteric areas in the dog.
Humoral Immunity in Experimental Thromboembolic Meningoencephalitis in Cattle Caused by Haemophilus somnus
Authors: Stephens L. R. , Little P. B. , Wilkie B. N. , Barnum D. A.
Published: February 2025

Of 23 cattle inoculated iv with Haemophilus somnus, 16 (70%) died of thromboembolic meningoencephalitis. The inoculum was prepared from a minimally subcultured isolate of H somnus that was passaged through a calf by intracisternal inoculation immediately before use. Serum antibody titers, as measured by 7 serologic tests, were not correlated with the animal's susceptibility to infection. All cattle that died had a mean 4-fold increase in agglutination titer during the acute phase of the disease, 2 to 4 days after inoculation. Similarly, high acute-phase titers were demonstrated in 15 cattle with naturally occurring disease. Haemophilus somnus was isolated more frequently and in greater numbers from the cns and urinary tract than from other organs of cattle that died.
Fractionation of Marek's Disease Virus-Induced Lymphoma by Velocity Sedimentation and Association of Infectivity with Cellular Fractions with and Without Tumor Antigen Expression
Authors: Sharma J. M.
Published: February 2025

Cell suspensions of lymphomas induced by Marek's disease (md) virus were fractionated by sedimentation at unit gravity on a continuous gradient of bovine fetal serum. Cells in various fractions were examined for md tumor-associated surface antigen (matsa) by indirect immunofluorescence, using specific antibody, and for viral infectivity by cocultivating fractionated cells with permissive monolayer cells of duck embryo fibroblasts. Most matsa-bearing cells in the lymphomas sedimented at a sedimentation velocity of greater than 3.0 mm/hour, whereas smaller, slow-sedimenting cells were generally devoid of matsa expression. Viral infectivity was associated with matsa-bearing and matsa-lacking fractions. Within the limits of the experimental procedures used, this observation provided evidence that presence of md virus genome in lymphocytes does not result in concurrent expression of detectable matsa and that matsa likely represents another stage of interaction between md virus and certain lymphocytes.
Turkey Respiratory Tract Adenoviruses: Oncogenic Potential in Neonatal Hamsters (Mesocricetus auratus)
Authors: Sutjipto S. , Simmons D. G. , Dillman R. C.
Published: February 2025

The tumorigenic properties of 3 turkey adenoviruses (CUA, NC-K, and MST) isolated from turkeys with respiratory tract disease and injected into neonatal hamsters (Mesocricetus auratus) have been determined. One of 3 adenovirus isolates (CUA) induced tumors at the site of inoculation (subcutaneously or intracranially) in neonatal hamsters. The tumors were identified as fibrosarcomas and undifferentiated sarcomas. The tumors were found to be free of infective virus, but hamsters which had tumors produced antibody to the virus-specific tumor antigen detectable by the complement-fixation test. The antibody titers for the tumor antigen were from 1:8 to 1:16. Abnormalities were not observed in the major organs collected from hamsters inoculated with the virus.

Inoculations of hamster embryo cells and of adult and baby hamster kidney cells with the 3 turkey adenoviruses at a high multiplicity of infection did not produce transformed cells in monolayers. Hamster cells were permissive for CUA virus, since cytopathic effect was observed in 3 to 5 days after inoculation.
Turkey Respiratory Tract Adenoviruses: In Vitro Infectivity of Purified DNA
Authors: Sutjipto S. , Simmons D. G.
Published: February 2025

Extracted purified turkey respiratory tract adenovirus DNA from 3 viruses was shown to be infective in turkey kidney cells. Cell monolayers inoculated with 5 to 25 μg of DNA developed cytopathic effect (cpe) 4 to 6 days later. The type of cpe (round cell formation) seen in the cell monolayers infected with DNA was similar to the cpe seen when the monolayers were inoculated with the intact adenoviruses. The infectivity of the DNA was demonstrated only when cell monolayers were pretreated with diethyl-aminoethyl-dextran. Treating the DNA solution with deoxyribonuclease 1 eliminated the infectious nature of the DNA.
Comparative Lymphocyte Stimulation Studies on Whole Blood from Vaccinated and Nonvaccinated Cattle with Paratuberculosis
Authors: Hintz A. M.
Published: February 2025

The lymphocyte stimulation test was evaluated in the diagnosis of bovine paratuberculosis, using whole blood samples from cattle. These samples were incubated with a purified protein derivative of Mycobacterium paratuberculosis. Samples from vaccinated and nonvaccinated cattle from paratuberculosis-free herds and from paratuberculous herds were used. Vaccinated and nonvaccinated groups from the paratuberculous herds each included fecal culture-positive cattle, fecal culture-negative cattle, and calves.

All groups included some cattle with a stimulation index (si) ≥ 2, and all groups except 2 of the 4 vaccinated groups had some cattle with a si ≤ 2. In paratuberculosis-free herds, 16% of the nonvaccinated cattle had a si ≥ 2, and 0.7% had a si ≥ 4. In paratuberculous herds, 42% of the nonvaccinated cattle that were negative on fecal culture had a si ≥ 2 and 24% had a si ≥ 4. Vaccinated cattle > 1 year old could not be distinguished from infected cattle by means of the lymphocyte stimulation test.

If a si of 2 or 4 had been used as a basis to cull individual animals, some paratuberculous cattle would have been identified incorrectly as noninfected, and some paratuberculosis-free cattle would have been identified incorrectly as infected.
Case-Control Study of Bovine Mycoplasmal Mastitis in California
Authors: Thomas C. B. , Willeberg P. , Jasper D. E.
Published: February 2025

A case-control study among California dairy herds of the presence of pathogenic mycoplasma in bulk tank milk samples revealed a strong association with large herd size and a lesser association with higher percentage of cows leaving the herd (culled). Estimates of the adjusted approximate relative risk of mycoplasma infection, as revealed by isolation of mycoplasma from bulk tank milk, are presented for several ranges of herd size and 2 levels of culling. The excess risk associated with herd size and importance of herd size as a proxy for factor(s) determining the prevalence of pathogenic mycoplasma in bulk tank milk are indicated by calculation of population attributable risk percentages.
Clinical Trials with Fenbendazole and Oxibendazole for Strongyloides westeri Infection in Foals
Authors: Drudge J. H. , Lyons E. T. , Tolliver S. C. , Kubis J. E.
Published: February 2025

In 2 trials, treatment with fenbendazole (50 mg/kg of body weight by stomach tube) resulted in reductions of Strongyloides westeri worm egg counts by averages of 86% and > 99%, respectively, and in complete clearance of eggs from feces of 9 of 12 foals that were positive before treatment.

In 6 trials, treatment with oxibendazole (10 mg/kg of body weight intraorally) resulted in 100% reduction of strongyloides worm egg counts in 5 trials and 81% in 1 trial; clearance of S westeri eggs from feces was recorded for 31 of 33 foals that were positive before treatment.
Effect of Method of Blood Sampling on Serum Creatine Kinase Concentrations in Swine
Authors: Bruss Michael L. , Becker H. Neil
Published: February 2025

Creatine kinase (ck) concentrations in serum obtained by 2 methods from the cranial vena cavae of swine were compared with ck concentrations in serum obtained from the lateral ear veins of the same animals. If the hypodermic needle was flushed with saline solution, ck concentrations in caval serum were equivalent to those obtained for serum from the ear vein. If the hypodermic needle was not flushed with saline solution, ck concentrations in caval serum were significantly higher than those obtained for serum from the ear vein.
Tissue Reaction to Suture Materials in Infected Surgical Wounds—A Histopathologic Evaluation
Authors: Varma S. , Johnson L. W. , Ferguson H. L. , Lumb W. V.
Published: February 2025

Suture materials are foreign bodies which induce and prolong tissue reaction in the wound area. Cellular responses to infected wounds containing 7 suture materials (braided polyglycolic acid [bpga, Dexon], multifilament stainless steel, monofilament nylon, black braided silk, braided Dacron [Mersilene], and plain and chromic catgut) were studied at 6, 10, 20, and 40 days.

Cellular reaction varied with different suture materials. In general, neutrophils were the predominant cells in acute infection, but later, macrophages and fibroblasts predominated. Occasionally, plasma cells, lymphocytes, eosinophils, and giant cells were present. In the infected wounds with implants of plain catgut, chromic catgut, silk, and braided Dacron, there were large numbers of neutrophils even in chronic implantation, indicating persistence of local infection. With nylon, steel, and bpga, the number of neutrophils rapidly decreased. Although bpga induced intense acute reaction, the response was mild in chronic implantation. It appeared to be absorbed more slowly than plain or chromic catgut, and tissue reaction was minimal in the absorption stages.

A reaction similar to the Splendore-Hoeppli phenomenon was seen around multifilament silk strands in chronic stages of implantation.
Enzyme Activities in the Dog: Tissue Analyses, Plasma Values, and Intracellular Distribution
Authors: Keller P.
Published: February 2025

Activities of 14 enzymes were determined in psoas muscle, smooth muscle, diaphragm, heart, brain, liver, kidney, spleen, pancreas, salivary glands, zygomatic gland, intestinal mucosa, subcellular fractions, and plasma of the dog.

In pups, plasma activity of most enzymes was high, except iditol dehydrogenase (id), glutamate dehydrogenase (gld), alanine aminotransferase (alt), aspartate aminotransferase (ast), and d-fructose-1,6-diphosphate aldolase (als).

Alkaline phosphatase (alp), als, cholinesterase (chs), creatine kinase (ck), α-hydroxybutyrate dehydrogenase (hbd), lactate dehydrogenase (ld), and malate dehydrogenase (md) decreased significantly (P < 0.01) with increasing age, but in dogs > 7 months, all enzymes except ck, hbd, and alt revealed reasonably constant plasma values.

Enzymes alt, gld, chs, and id are specific for liver, ck and als for muscle, hbd to some degree for myocardium, and α-amylase for pancreas.

The alp and γ-glutamyltransferase were located in microsomes, gld in mitochondria, md and ast in mitochondria and cytoplasm, and isocitric dehydrogenase, ld, and the other enzymes only in cytoplasm.
Endothelial Repair of the Canine Cornea
Authors: Befanis Paul J. , Peiffer Robert L. , Brown Doris
Published: February 2025

After transcorneal cryodestruction of 90% of the total corneal endothelium in the dog, the endothelial regenerative capacity was studied, using biomicroscopy, endothelial specular microscopy, pachometry, light microscopy, scanning electron microscopy, and autoradiography. Reestablishment of a continuous intact endothelial cell monolayer occurred at 6 weeks. Production of a thickened, multilaminar Descemet's membrane by endothelial and fibroblast-like cells was observed. Regenerating endothelial cells at the wound margin showed extensive formation of pseudopodia and incorporation of tritiated thymidine. Reendothelialization occurred by both mitotic division and enlargement and migration of remaining undamaged cells. The corneal endothelium of the young adult canine has marked regenerative potential, in contrast to that described for persons and cats.
Role of Salmonella arizonae and Other Infective Agents in Enteric Disease of Lambs
Authors: Harp J. A. , Myers L. L. , Rich J. E. , Gates N. L.
Published: February 2025

SUMMARY AND CONCLUSIONS

Fecal samples from 545 diarrheic lambs on 12 ranches in southern Idaho and western Montana were examined for potential enteric pathogens. On 3 of the 12 ranches, enterotoxigenic Escherichia coli, Salmonella typhimurium, or S dublin was implicated as the etiologic agent. Rotavirus and coronavirus were identified on 1 ranch and rotavirus alone on another. Salmonella arizonae serotype 26:30 was isolated from the feces of diarrheic lambs on 6 of the 12 ranches in this study.

Pregnant ewes from 1 of the 6 ranches in which S arizonae was enzootic were transported to the Montana Veterinary Research Laboratory and studies on S arizonae were conducted in lambs from these ewes. Salmonella arizonae was shown to elaborate an enterotoxin, the activity of which was reduced when assayed in the gut loop test, using lambs from ewes vaccinated with an S arizonae 26:30 bacterin.

Oral challenge inoculation of 22 young colostrum-fed lambs with S arizonae 26:30 failed to produce any significant enteric disease, in contrast to oral challenge inoculation with S Oranienburg which resulted in death, with severe diarrhea and dehydration, in 4 of 6 lambs tested.

Salmonella arizonae serotype 26:30 appears to be well adapted to the ovine host and may not be a significant cause of diarrheal disease on ranches where it is enzootic.
Immunogenicity of Bivalent Vaccine for Reproductive Failure of Swine Induced by Pseudorabies Virus and Porcine Parvovirus
Authors: Mengeling W. L. , Gutekunst D. E. , Pirtle E. C. , Paul P. S.
Published: February 2025

An inactivated, bivalent vaccine for pseudorabies virus (prv) and porcine parvovirus (ppv) was tested for its efficacy in preventing prv- and ppv-induced reproductive failure of swine. Sixteen gilts were vaccinated twice at a 2-week interval before conception and then exposed to either virulent prv at 9 weeks of gestation (8 gilts) or virulent ppv at 6 weeks of gestation (8 gilts). The gilts were killed at 13 weeks of gestation if exposed to prv and at 12 weeks of gestation if exposed to ppv. Their fetuses were examined and tested for both viruses and their homologous antibodies. Blood samples were obtained from gilts at selected times to determine their humoral antibody titer. Another 17 gilts from the same herd, kept in the same facilities and bred to the same boars, were treated similarly, except for vaccination. Of these, 8 were exposed to virulent prv and 9 were exposed to virulent ppv.

The vaccinated gilts developed humoral antibody for both viruses after vaccination. At 2 weeks after the 1st vaccination, the virus-neutralization titers for prv ranged from 4 to 64 and hemagglutination-inhibiting titers for ppv ranged from 80 to 640. By 2 weeks after the 2nd vaccination, the geometric mean titer of antibody had increased approximately 6-fold for prv, but was unchanged for ppv. The geometric mean titer decreased for both viruses by the time gilts were exposed to virulent virus (63 to 100 days after the 2nd vaccination) and then increased after exposure. Nonvaccinated gilts developed antibody only after they were exposed to virulent virus.

The gilts exposed to prv developed clinical illness that, in general, persisted longer and was more severe for nonvaccinated gilts than for vaccinated gilts. Fetuses of 2 of the 8 nonvaccinated gilts were transplacentally infected and were aborted 15 and 21 days after maternal exposure. The aborted litters consisted of 7 and 8 fetuses. At necropsy, 136 fetuses (7 to 14/litter) of the other 6 nonvaccinated gilts and of the 8 vaccinated gilts were clinically normal and free of infection. However, low levels of neutralizing activity for prv were detected in sera of several fetuses of 2 litters of nonvaccinated gilts. The nature of the neutralizing activity was not determined.

None of the gilts exposed to ppv became clinically ill. However, fetuses of 6 of the 9 nonvaccinated gilts were transplacentally infected and died in utero. These litters were comprised of 60 fetuses (7 to 13/litter); of these, 41 were dead and 19 were alive just before necropsy. All of the dead fetuses and 9 of the live fetuses were infected with ppv, and antibody for ppv was detected in sera of 8 of the 9 live infected fetuses. The fetuses (n = 131; 7 to 15/litter) of the other 3 nonvaccinated gilts and of the 8 vaccinated gilts were clinically normal and free of infection. None had antibody for either virus.
Effects of Xylazine and Ketamine Hydrochloride on the Electroencephalogram and the Electrocardiogram in the Horse
Authors: Purohit Ram C. , Mysinger Pat W. , Redding Richard W.
Published: February 2025

A continuous series of electroencephalograms (eeg) was obtained from each of 6 mature horses which had been given xylazine and ketamine hydrochloride iv. Electrocardiograms and respiratory rates were also obtained. The eeg of the unsedated standing adult horse displayed a dominant fast activity in the range of 25-35 Hz, 5-30 μV superimposed over slower 1-4 Hz, 10-50 μV activity with occasional 10-14 Hz, 10-40 μV spindle-type activity. The xylazine-sedated horse displayed hypersynchronous eeg patterns, with the dominant activity being 1-3 Hz, 10-70 μV with overlying mixed frequencies of 5-10 Hz, 10-40 μV and 10-14 Hz, 10-40 μV spindle-type activity. Some 25-35 Hz, 5-10 μV activity was present in 5 of the 6 horses. Ketamine administration 3 minutes after xylazine injection caused an increase in high-voltage slow activity. The dominant frequency was 1-3 Hz, 20-100 μV, with superimposed mixed irregular frequencies of 6-10 Hz, 10-50 μV and 10-14 Hz, 10-40 μV spindle-type activity.

All horses developed some degree of second-degree atrioventricular (av) heart block approximately 23 s after xylazine was injected. The second-degree av heart block disappeared approximately 1 minute and 30 s after ketamine was injected in 4 of the 6 horses. The remaining 2 had second-degree av heart block throughout the recording period (15 to 18 minutes). Respiration rates were depressed after xylazine was given and became irregular and apneustic after ketamine injection. The cyclic rate of respiration varied from 19 to 30 breaths/minute. Xylazine depressed heart rates from 13% to 41% (mean 29.3%). Heart rates became faster or remained unchanged after ketamine was administered.