bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenesis of naturally acquired bovine respiratory syncytial virus infection in calves: Morphologic and serologic findings
Authors: Kimman T. G. , Straver P. J. , Zimmer G. M.
Published: February 2025

Lesions in 32 calves that died or were euthanatized during the course of severe natural infection with bovine respiratory syncytial virus (brsv) are described. All calves had been dyspneic for 1 to 2 days. At necropsy, lesions that could be related to dyspnea included congested and cyanotic mucosae and widespread petechiae. The lungs had various lesions in the cranioventral (cv) and caudodorsal (cd) portions. The cv portion of the lungs was consolidated, firm, and edematous. Histologically, the main characteristic was degenerative, necrotic bronchiolitis, with few syncytial cells. Signs of repair, such as epithelial hyperplasia, fibrosis, and bronchiolitis obliterans, often were observed. The cd portion of the lungs was markedly distended, owing to severe edema and emphysema. Bronchiolar lesions were lacking in the cd portion. In 14 calves, hyaline membranes were seen in the cv and cd portions. Results of immunofluorescence for brsv were positive in 24 calves, but only in the cv portion of the lungs. The calves had variable concentrations of brsv-specific IgG1 and IgM in serum, lung lavage fluid, or both. The brsv-specific IgA, on the contrary, was seldom detected.

Thus, 2 discrepancies existed. Although the clinical picture appeared to be acute, bronchiolar lesions and serotest results suggested infection of longer duration. Also, although virus and viral cytopathologic features were detected only in the cv portion of the lungs, the cd portion had extensive lesions that consisted of emphysema and edema.
Pathogenesis of naturally acquired bovine respiratory syncytial virus infection in calves: Evidence for the involvement of complement and mast cell mediators
Authors: Kimman T. G. , Terpstra G. K. , Daha M. R. , Westenbrink F.
Published: February 2025

Indicators of immune-mediated disease were studied in calves with severe natural bovine respiratory syncytial virus infection. Although antigen and antibody were detected concurrently in most calves, immune complexes were not detected by use of immunofluorescence, elisa, and binding of the 1q component of complement. Complement component C3, however, was observed by immunofluorescence in the cranioventral, virus-infected portion of the lungs of 19 of 25 calves. Reductions in the amount of histamine and in the numbers of mast cells and mast cell granules in the virus-positive cranioventral and virus-negative caudodorsal portions of the lungs, indicated activation of mast cells and liberation of their granule contents. On the basis of these and previous findings, a model for the pathogenesis of bovine respiratory syncytial virus-induced disease was proposed.
Forces loading the tarsal joint in the hind limb of the horse, determined from in vivo strain measurements of the third metatarsal bone
Authors: Schamhardt H. C. , Hartman W. , Lammertink J. L. M. A
Published: February 2025

Strain gauge rosettes were bonded to the dorsal, lateral, medial, and plantar aspects of the third metatarsal bone in the hind limbs of 6 ponies. The maximal compressive principal strain was approximately −600 × 10−6 m/m, and exceeded the amplitudes of the tensile strains at all aspects of the bone. After transformation, the shear strain and the principal strains parallel and perpendicular to the bone were obtained. The first peak in the bending strain was higher in the dorsal and lateral aspects, and the second peak was higher in the medial and plantar aspects. Young modulus of elasticity was determined in a 4-point bending test at the dorsal and plantar sides; it averaged 19.5 GPa in tension and compression. Applying linear bending theory, the eccentricity of an axial force parallel or a bending force perpendicular to the bone were calculated. The position where the total force penetrated the tarsometatarsal joint surface was largely within the joint surface, indicating that the joint is merely loaded in (eccentric) compression.
Phagocytic and nitroblue tetrazolium reductive properties of mature and immature neutrophils and eosinophils from blood and bone marrow from cows
Authors: Silva Indira D. , Jain Nemi C. , George Lisle W.
Published: February 2025

Functional capabilities of morphologically mature (segmented) and immature granulocytes (neutrophils and eosinophils) from bone marrow from cows were studied and compared with similar activities of segmented granulocytes from blood. Phagocytosis of Escherichia coli and postphagocytic oxidative metabolic stimulation, measured by nitroblue tetrazolium (nbt) reduction, were evaluated simultaneously. Phagocytosis was observed readily in segmented neutrophils, neutrophilic bands, and metamyelocytes and rarely in myelocytes. Phagocytosis was not seen in promyelocytes and myeloblasts. Neutrophilic bands and metamyelocytes were phagocytically less active than were segmented neutrophils. Washed segmented bone marrow neutrophils possessed phagocytic activity similar to that of blood neutrophils, whereas the activity of unwashed segmented bone marrow neutrophils was markedly less than that of blood neutrophils. Reduction of nbt was observed only in blood segmented neutrophils and bone marrow segmented neutrophils; the magnitude of nbt reduction was significantly (P = < 0.005) less in bone marrow neutrophils than in blood neutrophils. Eosinophils were phagocytically less competent than were neutrophils. The nbt reduction was observed only in eosinophils from blood, but not in eosinophils from bone marrow.
Survival analysis for evaluation of corneal ulcer healing times in calves with naturally acquired infectious bovine keratoconjunctivitis
Authors: Edmondson A. J. , George L. W. , Faruer T. B.
Published: February 2025

A clinical trial examining the efficacy of 2 drugs for treatment of a natural epizootic of infectious bovine keratoconjunctivitis was performed. The study was conducted in 103 grazing Hereford calves during the summer of 1985. The calves were prospectively and randomly assigned to 1 of 3 groups at the beginning of the study on June 17, and were examined 3 times weekly thereafter until the final observation on August 6. Calves in group 1 (n = 34) were not treated and were used as controls. Calves of group 2 (n = 34) with corneal ulcers were treated with a long-acting Oxytetracycline formulation (otc group). The parenteral treatment was repeated in 72 hours. Affected calves of group 3 (n = 35) were treated topically with furazolidone spray when they developed new corneal ulcers, or when existing lesions worsened during subsequent examination periods (nfz group). Healing times of the corneal ulcers were reported in 3 ways: the combined times for ulcers present in both eyes of a calf simultaneously (method A), independent times of each ulcer on a calf (method B), and time of the first ulcer for each calf (method C). Censored healing times were examined as left censored (ulcer present at the beginning of the study), right censored (ulcer not healed at the end of the study), or uncensored (true) healing times. The effect that the treatments had on healing times were investigated by use of notched box and whisker plots, life tables, and Cox regression models. The analysis indicated that treatment of calves with either antimicrobial reduced the healing time of corneal ulcers, compared with untreated controls. Calves treated with otc had shorter periods with ulcers present on both eyes than did nfz-treated calves. The healing time of the first ulcer on a calf was faster when treated with either antimicrobial than when not treated, but no significant difference between periods for otc and nfz treatments was found. Censored healing times were consistently longer than uncensored healing times. Box and whisker plots indicated that both treatments shortened healing times more than those for controls, and otc shortened healing times more than did nfz for responses A and B (but not C). Life tables showed that otc healing times were shorter than those for controls, and nfz shorter than controls for response B and C (but not A). Cox regression model (for response A) showed a borderline significant difference between times for otc group and controls, and no significant difference between times for nfz group and controls.
Uterine clearance mechanisms during the early postovulatory period in mares
Authors: LeBlanc Michelle M. , Asbury Atwood C. , Lyle Sara K.
Published: February 2025

Uterine response to inoculation with Streptococcus zooepidemicus organisms, 51Cr-labeled 15-μm microspheres, and charcoal was evaluated in 9 mares (4 resistant and 5 susceptible to endometritis) to determine mechanical and cellular clearance rates during the early postovulatory period. Mares were inoculated at estrus prior to ovulation during estrous cycles 1, 3, and 5. Uterine swab specimens for aerobic and anaerobic bacteriologic culture and serum for progesterone determination were obtained on postovulation day 3 during estrous cycle 1, on the day of ovulation during estrous cycle 3, and on postovulation day 5 during estrous cycle 5. Immediately thereafter, the uterus was irrigated with 50 ml of sterile physiologic saline solution containing tracer amounts of 125I-labeled human serum albumin.

Streptococcus zooepidemicus was isolated from 10 of 15 (67%) uterine specimens collected from susceptible mares and incubated aerobically. Escherichia coli also was isolated from 2 of the 10 specimens incubated aerobically. Anaerobic bacteriologic culture of specimens from all mares yielded no growth. Chromium-labeled microspheres were recovered twice from 2 susceptible mares, on day 0 and day 5. Charcoal was retained in 5 specimens collected from 3 susceptible mares. Bacteriologic culture of specimens from resistant mares did not yield growth. On day 0, chromium-labeled microspheres and charcoal were recovered once from 1 resistant mare. Mares susceptible to endometritis accumulated more fluid within the uterine lumen after ovulation than did resistant mares (mean ± sem, 52.73 ± 15.22 ml and 7.41 ± 1.96 ml, respectively; P < 0.01). From this study, it appeared that uterine cellular and bactericidal mechanisms are dysfunctional during the early postovulatory period. However, there appeared to be no disruption of the mechanisms responsible for mechanical clearance of materials inoculated in the uterus.
Immunodeficiency in young pigs
Authors: Hammerberg C. , Schurig G. G. , Ochs D. L.
Published: February 2025

Immunodeficiency in neonatal and young pigs was studied in terms of T-cell function. Generalized T-cell deficiency did not exist in young pigs on the basis of the in vitro response of blood mononuclear cells to a polyclonal T-cell mitogen, phytohemagglutinin. However, immunodeficiency that extended from birth up to 4 weeks, was observed in serum antibody concentration and in vitro proliferative responses of blood mononuclear cells from young pigs exposed to a low antigen dose of a T-cell dependent antigen, egg white lysozyme. The low in vitro proliferative response to lysozyme was not attributable simply to a lack of interleukin-2 production, because supplementation with human interleukin-2 did not enhance the in vitro cellular response. Also, pokeweed mitogen-stimulated B cells from young pigs up to the age of 5 to 6 weeks produced immunoglobulin concentration, which also was not affected by the addition of human interleukin-2 to the in vitro cultures. The blood mononuclear cells obtained from pigs within the first 5 to 6 weeks after birth and incubated with monoclonal antibodies reactive to all T cells (MSA4), helper T cells (74-12-4) or suppressor/ cytotoxic T cells (76-2-11) did not yield consistent excess of suppressor/cytotoxic T cells. This observed immunodeficiency cannot be attributed to a simple lack of functional T cells or to an excessive number of suppressor/ cytotoxic T cells, but may be a property of the ability of specific T-cell clones to respond to low concentration of T cell-dependent antigens or may be attributable to the induction of a suppressor T-cell population in response to in vitro stimulation with the polyclonal T-cell-dependent pokeweed mitogen system.
Immunohistochemical staining and radionuclide imaging of canine tumors, using a monoclonal antibody recognizing a synthetic carbohydrate antigen
Authors: Haines Deborah M. , Matte Gilbert , Wilkinson A. A. , Noujaim A. A. , Turner C. , Longenecker B. M.
Published: February 2025

The in vitro and in vivo binding of a monoclonal antibody (mab) that recognizes a tumor-associated carbohydrate antigen was studied in dogs. Monoclonal antibody 155H.7 was raised in response to innoculation of mice with β-galactose(l-3)βN-acetylgalactosamine conjugated to human serum albumin. Avidin-biotin-complex immunohistochemical staining of cryostat sections of normal and neoplastic canine tissue specimens revealed heterogenous binding of mab 155H.7 to the cells of many canine mammary and lung carcinomas and homogenous staining of many sarcomas, including osteogenic sarcoma. In addition, there was variable staining of a variety of normal tissues including some ductual epithelium, peripheral nerve fibers, and some endothelial cells and fibroblasts. Immunoscintigraphy with 131I-labeled mab 155H.7 was used to study the in vivo distribution of the antibody. The 131I-labeled mab 155H.7 was administered to 1 clinically normal dog, 7 dogs with osteogenic sarcoma, 1 dog with undifferentiated sarcoma, and 2 dogs with mammary tumor. Scintigraphy revealed concentration of radioactivity in 8 of 10 tumor sites within 24 hours after mab administration. The ratio of 131I in tumor sites to 131I in the surrounding normal tissues, compared with the similar ratio of 99mTc-labeled erythrocytes ranged from 1.1 to 4.3, in tumor vs normal tissue with a mean value of 2, confirming tumor localization of the radiolabeled mab in excess of that associated with enhanced tumor vascularization.
Vascular anatomy of the equine small colon
Authors: Archer R. M. , Lindsay W. A. , Smith D. F. , Wilson J. W.
Published: February 2025

The vasculature of 22 small colons from dead adult ponies was perfused with latex or barium sulphate solution. The vascular anatomy was studied by use of dissection and alkali digestion of the latex specimens and microangiography of the barium sulphate-perfused specimens. The small colon is supplied by the caudal mesenteric artery. The left colic artery arises from the caudal mesenteric artery, which then becomes the cranial rectal artery. Branches from the left colic and cranial rectal arteries form anastomosing arcades that become narrower distally along the length of the small colon. From these arcades arise terminal arteries, which enter the small colon wall and give rise to a subserosal, an intermuscular, and a large submucosal plexus, with frequent anastomoses between them. The venous drainage closely parallels the arterial supply, except near to its origin from the portal vein, when the left colic vein and caudal mesenteric vein are separate from the corresponding arteries.
Failure of aspirin to impair bovine platelet function
Authors: Gentry P. A. , Tremblay R. R. M. , Ross M. L.
Published: February 2025

The effect of aspirin on bovine platelet function and thromboxane A2 (txa2) production in stimulated platelets was evaluated. A single dose of aspirin (100 mg/kg of body weight) was administered orally to Holstein cows, and blood samples were obtained before and at regular intervals for 7 days after treatment. The production of txa2 was assessed by measuring the stable metabolite thromboxane B2, using a specific radioimmunoassay. Within 4 hours of aspirin administration, the production of txa2 was significantly (P < 0.05) decreased, irrespective of whether collagen, adenosine diphosphate, or platelet activating factor was used to initiate platelet aggregation. Despite the inhibition of txa2 release from the stimulated platelets, platelet function, assessed by initial rate of aggregate formation and extent of aggregation, was unaffected by aspirin administration. The extent of aggregate formation in response to collagen, adenosine diphosphate, or platelet activating factor was independent of the amount of txa2 released from platelets before and after aspirin treatment. The results suggested that txa2 formation is not the primary biochemical pathway involved in the aggregation of stimulated bovine platelets.
Tissue sulfonamide concentration and correlation in turkeys
Authors: Epstein R. L. , Ashworth R. B.
Published: February 2025

Nineteen hen turkeys (10 to 12 kg each) were used in a feeding study to determine sulfadimethoxine and sulfaquinoxaline concentrations in blood serum, liver, and skeletal muscle, as well as the respective ratios at selected withdrawal intervals. Two feeds were prepared by use of premixes to achieve 60 mg of sulfadimethoxine/kg and 100 mg of sulfaquinoxaline/kg, respectively. Each of the medicated feeds was given to 9 turkeys for 7 days. The turkeys were then fed nonmedicated feed at intervals from 24 to 56 hours and were slaughtered. One turkey was used as control. The serum/liver and serum/muscle ratios for sulfaquinoxaline were 60 to 70% higher than for sulfadimethoxine. However, the liver/muscle ratio for both sulfonamides was equivalent, approximately 3. Disposition of both sulfonamides approximated first-order pharmacokinetics. The calculated half-life of sulfadimethoxine was half that of sulfaquinoxaline, approximately 16 vs 30 hours. The coefficients of variation in the serum/tissue ratios for both sulfonamides were between 13% and 25% for serum/liver and < 15% for serum/muscle, indicating excellent potential for using serum as a predictor of actionable concentrations of sulfonamide residues.
Effects of testosterone on the prevention of T-2 toxin-induced adrenocortical necrosis in mice
Authors: Thurman J. D. , Creasia D. A. , Trotter R. W.
Published: February 2025

To evaluate the effect of exogenous testosterone on the development of T-2 toxin-induced necrosis of adrenal glands, mice were allotted to 3 treatment groups. Each treatment group contained castrated male, and castrated and sexually intact female mice. Each mouse in group 1 was given 0.16 mg testosterone propionate at 48-hour intervals for a total of 12 injections, group-2 mice were given similar injections of only the vehicle, and group-3 mice were given no treatment. Twenty-four hours after the last injection, the mice in all 3 groups were exposed for 10 minutes to an aerosol of T-2 toxin. All mice alive at 24 hours after exposure were euthanatized and the adrenal glands and thymuses were examined histologically. Necrosis of the adrenal cortex was not found in any of the mice given preexposure treatment with exogenous testosterone, whereas all mice given vehicle only or no treatment had T-2 toxin-induced necrosis of the inner portion of the adrenal cortex. Lymphocytosis in the cortex of the thymus confirmed that each mouse of all 3 treatment groups had experienced systemic mycotoxicosis. The uniform severity of the lesion in all mice suggests that the thymus was not protected by exogenous testosterone administration or by the castration status of the mice. We propose that T-2 toxin-induced adrenal necrosis in mice is prevented by the presence of testosterone.
Effect of xylazine treatment on equine proximal gastrointestinal tract myoelectrical activity
Authors: Merritt A. M. , Campbell-Thompson M. L. , Lowrey S.
Published: February 2025

Five 5 to 6 month old horses were surgically prepared with silver electrodes sutured to the serosa of gastric antrum, duodenum and proximal portions of the jejunum. Normal migrating motility complex (mmc) periodicity was determined during daytime hours in horses that were fed and horses from which food was withheld for 24 hours. Periodicity was defined as time span from the end of one period of regular spike activity (rsa) to the end of the next rsa in the mmc. The periodicity was 120.5 ± 9.5 (sem) minutes in horses from which food was withheld, and was 125.7 ± 20.3 minutes in horses fed hay free choice. Coincident with each duodenal rsa, antral spike activity ceased. Xylazine (0.25 and 0.5 mg/kg), given IV during the period of intermittent spike activity of the mmc to either fed or unfed horses induced, within 2 minutes, a rsa complex in the duodenum that migrated to the proximal portion of the jejunum. This was followed by a period of no spike activity of normal duration, which proceeded on to a period of intermittent spike activity of varying duration to complete the mmc cycle. Pretreatment iv administration of an α2-adrenergic antagonist, tolazoline (1 mg/kg) also provoked a rsa complex, but blocked the xylazine effect. The results indicated that xylazine resets the duodenal mmc in the horse, but does not seriously disrupt proximal gastrointestinal tract motility, and that control of mmc periodicity in this region probably involves more than α2-adrenergic receptors.
Electromyographic activity of cubital joint muscles in horses during locomotion
Authors: Tokuriki Mikihiko , Aoki Osamu , Niki Yoko , Kurakawa Yoshiyuki , Hataya Masa-aki , Kita Takashi
Published: February 2025

Electromyographic (emg) activity of 4 muscles of the cubital joint and the strain of forelimb hooves were recorded telemetrically in 4 Thoroughbreds (with and without a rider) standing, walking, trotting, and cantering. Bipolar fine wire electrodes were inserted into the muscles, and strain gauges were attached to the hoof wall. Motion pictures (16 mm), synchronized with emg tracings, were taken to obtain kinematic data.

When horses were standing, the biceps brachii had tonic activity, but the brachialis and the caput longum and the caput laterale of the triceps brachii had no emg activity. The biceps brachii had emg activity during the stance phase. The brachialis had emg activity from the end of the stance phase to the middle of the swing phase. Unlike the biceps brachii, the brachialis acted as a flexor muscle of the cubital joint during locomotion. The emg activity of the caput longum of the triceps brachii was detected from midswing phase to early stance phase. The emg activity of the caput laterale of the triceps brachii began in midswing or late-swing phase and ceased in early stance or midstance phase. During locomotion, caput longum emg activity always preceded caput laterale activity.

When horses were cantering, the brachialis and the caput longum (acting mainly in the swing phase) had an emg activity phase different from those in leading and trailing forelimbs. These 4 muscles had similar emg activity patterns during locomotion in horses with and without a rider.
Effect of dry, soft moist, and canned dog foods on postprandial blood glucose and insulin concentrations in healthy dogs
Authors: Holste L. C. , Nelson R. W. , Feldman E. C. , Bottoms G. D.
Published: February 2025

The effect of dry, soft moist, and canned dog foods on immediate postprandial plasma glucose and insulin concentrations was evaluated in clinically normal dogs. Dogs were fed either dry (10 dogs; group I), soft moist (10 dogs; group II), or canned (8 dogs; group III) dog food for 5 consecutive days. On the fifth day, plasma glucose and insulin concentrations were determined in each dog prior to, during, and at 5, 10, 15, 30, 45, 60, 90, 120, 180, and 240 minutes after ingestion of the food.

The alterations in plasma glucose concentrations were not significantly different from prefeeding values until 240 and 180 minutes after feeding for groups I and III, respectively. In contrast, the increments in plasma glucose were significantly (P < 0.01) increased from basal concentrations at 30 and 45 minutes after feeding in group-II dogs. The maximal mean postprandial plasma glucose concentration was significantly (P < 0.0001) less for group III, compared with concentrations for groups I and II, but there was no significant difference between concentrations for groups I and II.

Although a biphasic insulin secretory response was found in all 3 groups of dogs, the patterns of phase-2 insulin secretion and the total amount of insulin secreted during the study were significantly different. There was a rapid increase in the plasma insulin concentration immediately after phase 1 in group II, with maximal plasma insulin concentrations occurring 30 minutes after feeding, followed by a gradual decrease in concentrations throughout the remainder of the study. In contrast, plasma insulin concentrations increased steadily in groups I and III after phase-1 insulin secretion, with maximal values occurring at 240 minutes after feeding. The maximal mean increase from basal insulin concentrations during phase-2 secretion was significantly (P < 0.005) greater for group II (80 ± 15 μIU/ml) than for groups I and III (23 ± 3 and 24 ± 6 μIU/ml, respectively). Whereas the integrated areas under the glucose response curves were not significantly different between groups, total insulin secretion and total insulin secreted during phases 1 and 2 were significantly (P < 0.01) greater in group II than in groups I and III.

Differences in dietary composition may offer the best explanation for differences in postprandial glucose concentrations and insulin secretory responses between groups. These findings emphasize the importance of dietary formulations when designing hormonal studies or interpreting research data when dogs are the animal model.
Effect of vaccination with a bacterin containing Leptospira interrogans serovar bratislava on the breeding performance of swine herds
Authors: Frantz Joseph C. , Hanson Lyle E. , Brown Albert L.
Published: February 2025

Swine herds suspected to be infected with Leptospira interrogans serovar bratislava were vaccinated with bacterins containing 5 or 6 leptospiral serovars in which serovar bratislava was the unique component. The principal diagnostic feature indicating an infection by this organism was demonstration of antibody against serovar bratislava in sera from stillborn pigs. For 1 breeding cycle after vaccination of herds on 3 farms, 255 of 266 (95.9%) sows and gilts given the 6-serovar bacterin farrowed. In contrast, 233 of 311 (74.9%) sows and gilts given the 5-serovar bacterin farrowed. These results, as evaluated by analysis of variance techniques, showed a significant improvement (P < 0.01) in reproductive performance for groups vaccinated against serovar bratislava.
Evaluation of lasalocid and decoquinate against coccidiosis resulting from natural exposure in weaned dairy calves
Authors: Hoblet K. H. , Charles T. P. , Howard R. R.
Published: February 2025

Eighteen female Holstein calves, raised as natural herd additions under conditions typical of a well-managed midwestern United States dairy farm, were used in a natural-exposure study to determine the anticoccidial efficacies of lasalocid and decoquinate. Calves were allotted to 6 treatment blocks of 3 calves each as they were weaned. Within each block, calves were randomly assigned to be given either lasalocid or decoquinate or to remain as a nonmedicated control. Calves were given medication for 90 days and remained separated from other calves for 120 days. Adjusted weight gains were consistently greater in calves that were given medication; however, differences were not statistically significant. Fecal specimens were obtained from calves at weekly intervals during the study. Overall, oocyst shedding was low. During the medication period, quantitative mean fecal shedding of oocysts was reduced eightfold in calves given decoquinate and fourfold in calves given lasalocid, as compared with nonmedicated control calves. During the period following the medication period, calves that had been controls shed fewer oocysts than did calves that had previously been given medication. A pairwise comparison of the proportion of specimens that were oocyst-positive was made to assess qualitative oocyst shedding among treatment groups. During the medication period, qualitative oocyst shedding (all species, Eimeria bovis, E zuernii, species other than E bovis and E zuernii) was greater in controls than in either lasalocid-or decoquinate-treated groups. Likewise, lasalocid-medicated calves shed oocysts more frequently than did the decoquinate-medicated group. After medication, qualitative findings were reversed. Little diarrhea was noticed in treatment or control calves during the study. However, calves given either lasalocid or decoquinate had glossier coats and a healthier appearance by the end of the medication period than did nonmedicated controls. It was concluded that, under the exposure conditions of the study, trends in weight gain and oocyst shedding patterns approximated those resulting from previous studies that used experimental inoculation of oocysts.
Effects of dopamine administration on cecal mechanical activity and cecal blood flow in conscious healthy horses
Authors: Clark E. Susan , Moore James N.
Published: February 2025

Lateral cecal arterial blood flow, carotid arterial pressure, heart rate, and mechanical activity of the circular and longitudinal muscle layers of the cecal body were measured in 7 conscious healthy horses during iv infusion of physiologic saline solution for 60 minutes (control), during a 60-minute iv infusion of dopamine (at dosages of 1, 2.5, and 5 μg/kg/min), and for 60 minutes after iv infusion of dopamine. The mean values for lateral cecal arterial blood flow during iv infusion of dopamine at a dosage of either 1 or 2.5 μg/kg/min were not significantly different from the mean values for lateral cecal arterial blood flow during iv infusion of saline solution. The mean values for lateral cecal arterial blood flow, however, were significantly greater during iv infusion of dopamine at a dosage of 5 μg/kg/min than the mean values for lateral cecal arterial blood flow during iv infusion of saline solution. Intravenous infusion of dopamine at 1 and 2.5 μg/kg/min did not significantly change the mean values for carotid arterial pressure. In contrast, the mean values for carotid arterial pressure were significantly less during iv infusion of dopamine at dosages of 2.5 and 5 μg/kg/min than during infusion of saline solution. The mean values for heart rate were not significantly altered by infusion of dopamine at a dosage of either 1 or 2.5 μg/kg/min, but infusion of dopamine at a dosage of 5 μg/kg/min significantly increased heart rate.

Intravenous infusion of dopamine at dosages of either 1 or 5 μg/kg/min did not significantly change the mechanical activity of the circular muscle layer of the cecal body, as measured by the area under the strain gauge deflection curve. Conversely, the mechanical activity of the circular muscle layer of the cecal body was significantly reduced by iv infusion of dopamine at a dosage of 2.5 μg/kg/min. This reduction of circular muscle mechanical activity by dopamine infusion was attributable to a significant decrease in the total duration of contractions. The mechanical activity of the longitudinal muscle layer was not significantly altered by infusion of dopamine at any dose.

These results suggest that iv infusion of dopamine at a dosage of 5 μg/kg/min increased lateral cecal arterial blood flow by either increasing cardiac output or dilating the lateral cecal artery, an effect most likely mediated by dopaminergic or β-adrenergic receptors. In addition, dopamine had a biphasic effect on contractile activity of the equine cecum.
Comparison of two methods for isolation of Mycobacterium paratuberculosis from bovine fecal samples
Authors: Kim Y. G. , Bech-Nielsen S. , Gordon J. C. , Slemons R. D. , Spangler E.
Published: February 2025

Fecal samples from 131 cattle clinically suspect for paratuberculosis were cultured bacteriologically, using the traditional sedimentation processing method and a processing method that included a centrifugation step. Of 16 samples that were contaminated, 6 were culture-positive on at least 1 medium and by 1 processing method. Ten of 131 (7.6%) fecal samples processed by both methods were lost because of contamination.

The number of culture-positive samples (using both processing methods) were 65 of 121 (53.7%) on media without miconazole and 60 of 121 (49.6%) on media with miconazole. Seven of the 121 (5.8%) samples were culture-positive, using centrifugation, after 16 weeks’ incubation at 37 C. Thirteen of 60 (21.7%) isolates were obtained only with centrifugation, and 10 of these had low colony counts, suggesting that a centrifugation step may have concentrated microorganisms that would have gone undetected without centrifugation. Six of 60 (10%) isolates positive for M paratuberculosis on the sedimentation method were negative on the centrifugation method. Contamination rates were significantly (P < 0.001) increased when centrifugation was used. The miconazole significantly (P < 0.001) decreased contamination rates when centrifugation was used.
Ontogeny of the third component of complement in neonatal swine
Authors: Tyler Jeff W. , Cullor James S. , Douglas Vicki L. , Parker Kent M. , Smith Wayne L.
Published: February 2025

Ontogeny of the third component of complement (C3) was monitored in 10 neonatal swine, using a radial immunodiffusion technique. Significant differences in mean serum C3 concentrations, expressed as percentage of C3 concentration in a pooled standard drawn from 15 adult swine, were not observed between serum samples collected before pigs suckled and at 2 days of age (P = 0.2583). Serum C3 concentrations increased significantly between 2 and 7 days of age (P < 0.0001) and 7 and 14 days of age (P < 0.0001). Concentrations comparable with those in adults were observed at 14 days of age and significant changes were not observed thereafter. Acquisition of adult concentrations of C3 appeared to be a function of endogenous production by the neonate, rather than by passive colostral transfer.
Production and characterization of monoclonal antibodies to Ehrlichia risticii
Authors: Shankarappa Basavaraju , Dutta Sukanta K.
Published: February 2025

Hybridomas producing monoclonal antibodies to Ehrlichia risticii were developed to provide a means of molecular investigation of the biochemical and immunopathologic characteristics of the organism. All of 6 stable monoclonal antibodies obtained were IgG isotypes. The ascitic fluid titers induced by the hybridomas ranged from 102 to 107. Competitive binding experiments conducted by elisa and binding of labeled protein A to antigen-antibody complexes indicated competition among monoclonal antibodies. Two monoclonal antibodies (HybI and 14D4) were reactive in an indirect fluorescent antibody test; these antibodies also bound a maximum of labeled protein A, indicating recognition of epitopes on the surface of the ehrlichiae. Protein specificity of monoclonal antibodies could not be demonstrated with western blot procedure. HybI monoclonal antibody, however, did precipitate the 28 kD protein from 125I-surface-labeled ehrlichiae and was shown to be specific to E risticii on the basis of nonreactivity with E sennetsu, using the indirect fluorescent antibody test. By use of the different monoclonal antibodies as probes, more definitive molecular studies now will be feasible.
Ultrastructure of cultured canine oral keratinocytes
Authors: Wilkinson J. Erby , Lee C. S. , Lillie John H. , Suter Maja M. , Lewis Robert M.
Published: February 2025

Keratinocytes from explants of the oral mucosa of dogs were grown in culture for five passages. The ultrastructure of primary cultures and fully developed subcultures passaged 1, 3, and 5 times was examined. At every stage, the cells had the morphologic characteristics of epithelial cells and formed a multilayered squamous epithelium. The basal cells had the characteristics of metabolically active cells, whereas the suprabasal cells and the cells at the media interface expressed many, but not all, of the organelles and cell surface characteristics associated with keratinocyte differentiation. Keratohyalin granules were located in the suprabasal and superficial cells. Cell size and shape and the relationship between cells in the layers also reflected the morphologic characteristics of the parent tissue. Cells maintained this typical structure through all passages and the cultures changed minimally for up to a week after development.
Effectiveness of two benzathine cloxacillin formulations for treatment of naturally occurring infectious bovine keratoconjunctivits
Authors: George Lisle W. , Keefe Thomas , Daigneault Josee
Published: February 2025

A field study was performed to determine the effectiveness of benzathine cloxacillin for the treatment of infectious bovine keratoconjunctivits in cattle from 2 farms located in northern California. The study was performed between June and September of 1987. Affected calves ranging from 2 to 9 months of age were selected from the main herd when signs of corneal ulceration were observed. The study was conducted in 2 phases. For phase I, the affected calves of herd 1 (n = 21; Holsteins) and herd 2 (n = 43 Angus crossbred), were randomly assigned to 1 of 3 groups, and were either treated with 250 (n = 23) or 375 mg (n = 21) of benzathine cloxacillin, or mineral oil (n = 20) on days 1 and 4. For phase II, affected calves (n = 16; Angus crossbred, 3 to 9 months of age) from herd 2 were treated with benzathine cloxacillin (250 mg). Eight of these calves were retreated on day 4.

After treatment, all calves were examined every 72 hours for 16 days. For examinations, a clinical score was assigned to each eye, and the surface areas of photographed corneal ulcers were measured. The ocular secretions were collected and examined culturally for Moraxella bovis.

On days 7, 10, and 13, the calves treated with benzathine cloxacillin had significantly (P < 0.05) lower lesion scores, compared with the controls. The percentage of day-1 area measurements on posttreatment days 4, 7, and 10 were significantly larger in the controls than in the treated calves. The mean healing times of corneal lesions in the 2 antibiotic treatment groups were significantly (P < 0.05) shorter than in the controls. In the treated calves, the healing times of corneal ulcers ≤ 0.5 cm in diameter on day 1 were significantly (P < 0.05) shorter than the healing times of larger lesions. The healing times of the corneal ulcers in the Angus crossbred calves were significantly (P < 0.05) longer than the healing times of the Holsteins. The controls had the greatest number of nonhealed corneal ulcers on day 16. The number of calves that remained infected with M bovis on days 4, 7,10, and 13 was significantly less in both groups of treated calves than in the controls. The scores, surface area measurements, healing times, and the M bovis isolation frequency in the calves of the 250-mg and 375-mg and 1- and 2-dose treatment groups were not significantly different.

The minimal inhibitory concentrations (mic) of penicillin, cloxacillin, and ampicillin in the day-16 isolates from benzathine cloxacillin-treated herd-2 calves were greater than in isolates from corresponding calves on observation day 1; however, twofold increases of the respective mic of pretreatment and day-16 specimens were not observed. The highest mic of ampicillin, cloxacillin, gentamicin, oxytetracycline, and penicillin were 0.5, 8.0, 0.5, 2, and 1 μg/ml, respectively, for isolates collected during the final study week.
Gas conductance during high-frequency oscillatory ventilation in large animals
Authors: Dodman N. H. , Lehr J. L. , Spaulding G. L. , Gavriely N.
Published: February 2025

Three sheep, a foal, a pony, and a calf were anesthetized and ventilated for short periods, using a high-frequency oscillatory ventilator. The efficiency of CO2 elimination was characterized at various oscillatory frequencies (50 to 30 Hz) and various tidal volumes, although the tidal volume used was always less than the measured dead space of the animal. In general, increasing either the oscillatory frequency or tidal volume increased CO2 elimination, but increasing the tidal volume had more effect. The relationship between these 3 variables was best described by a power law equation. Ventilatory frequencies and tidal volumes required to maintain eucapnia in the species studied were extrapolated from the results and, when technically possible, the potential of the technique to maintain eucapnia was tested in extended runs. The animals were supported successfully over this period, with normal blood gas tensions and no detrimental effects to heart rate and rhythm or arterial blood pressure.
Bovine serum and nasal secretion immunoglobulins against Pasteurella haemolytica serotype 1 antigens
Authors: Nelson Sandra L. , Frank Glynn H.
Published: February 2025

Experimental intranasal inoculation of cattle with Pasteurella haemolytica serotype 1 resulted in a group that shed the bacteria in their nasal secretions (colonized) and a group that did not shed (uncolonized). After inoculation, antibody titers in serum and nasal secretions against the total P haemolytica increased significantly, and the proportions of total antibody against specific P haemolytica antigens changed so that the proportion directed against the 94- and 62-kD antigens increased. Prior to inoculation, the proportion of total antibody in the serum against 94- and 62-kD antigens of P haemolytica was higher in calves that remained uncolonized than in those that became colonized with P haemolytica after exposure. Antibody specificity of serum and nasal secretions differed in the relative amounts directed against each P haemolytica antigen. The specificity against P haemolytica antigens differed between IgG and IgA isotypes of serum and nasal secretions, with IgA being directed against fewer antigens than was IgG.
Separation of bovine lymphocytes and granulocytes from blood by use of elutriation
Authors: Khansari Nemat , Beauclair Kim , Gustad Thomas
Published: February 2025

Bovine blood mononuclear cells were separated into 2 fractions by use of centrifugal elutriation. Total recovery, as well as recovery of each fraction, was greater than that obtained by use of Ficoll-sodium diatrizoate separation. The lymphocyte fraction contained < 1% granulocytes, and the granulocyte fraction contained only 7% lymphocyte contamination. The technique was reproducible and results proved to be comparable with those of Ficoll-sodium diatrizoate density-gradient centrifugation; furthermore, the method is considerably cheaper and less time-consuming for processing large volumes of blood. Viability of cells separated by elutriation always was > 98%, wheras viability of cells separated by Ficoll-sodium dia-trizaote was > 95%. Also, mitogen activation of lymphocytes separated by elutriation was superior to that of lymphocytes separated by Ficoll-sodium diatrizoate centrifugation.
Concanavalin A-induced suppressor cell activity in intestinal mucosal leukocytes obtained from healthy cows
Authors: Nagi Abdelbagi M. , Babiuk Lorne A.
Published: February 2025

Leukocytes isolated from the intraepithelium, lamina propria, and aggregated lymphoid follicles (alf) of the bovine small intestinal mucosa were activated by concanavalin A (conA) to generate suppressor activity against the proliferative response of autologous and allogeneic leukocytes to conA, phytohemagglutinin, and pokeweed mitogen. Freshly obtained intraepithelium, lamina propria, and alf leukocytes, preincubated with 25 to 50 μg/ml of conA for 24 to 48 hours, were able to inhibit the mitogenic responses of autologous and allogeneic lymphocytes when cocultured at a ratio ≥ 1:1 (suppressor cells to responder cells). Depletion of adherent cells (monocytes/macrophages) by sequential plastic and gel adherence completely abrogated the conA-induced suppressor activity of all 3 leukocytes populations. However, reconstitution with autologous or allogeneic monocytes/ macrophages during the induction phase restored the inducible suppressor activity. Addition of recombinant human interleukin-2 at a concentration as low as 5 U/ml during the responder phase enabled the responder population to recover the response apparently impaired by the conA-treated alf leukocytes. At a concentration of 10 U/ ml, human interleukin-2 was not only able to restore the responder population's response to phytohemagglutinin stimulation, but highly enhanced its proliferative ability. Although quantitative variations were observed between different cell populations and cells obtained from individual cows, the extent and general pattern of the inducible suppressor activity were similar in cells from cows studied.
Antibody response of pseudorabies virus subunit-vaccinated pigs to viral nucleocapsid proteins following low-dose virus challenge of immunity
Authors: McGinley M. J. , Platt K. B.
Published: February 2025

The antibody response to pseudorabies virus nucleocapsid proteins (ncp) was evaluated by the western immunoblot analysis before and after challenge of immunity by nasal inoculation of 102.3 plaque-forming units of virus in 10 pigs that had been vaccinated with pseudorabies virus envelope glycoproteins. Antibody to 5 ncp with molecular mass of 140, 63, 41, 34, and 23 kD was first detected in vaccinated and nonvaccinated pigs on day 14 after challenge of immunity. Antibody to 2 of the 5 ncp continued to be detected through day 113 in 9 of 10 vaccinated pigs. Beyond day 32, antibody to ncp was not detected in 1 vaccinated pig. The 23-, 34-, and 41-kD proteins were the most immunogenic. Antibody to each of these proteins was first detected on day 14 in 10, 10, and 8 pigs, respectively. Seven, 6, and 8 pigs, respectively, were antibody-positive for these proteins on day 113. The 140- and 63-kD proteins were the least immunogenic. Antibody to these proteins was detected in 8 and 9 pigs, respectively, on day 14, and in 4 and 5 pigs, respectively, on day 113. Chi-square analysis for dependency indicated that the antibody response to the 140- and 63-kD proteins was interdependent. These results suggested that combinations of ncp may be useful as nonvaccine diagnostic antigens.
Uptake and excretion of Brucella abortus in tissues of the face fly (Musca autumnalis)
Authors: Cheville Norman F. , Rogers Douglas G. , Deyoe William L. , Krafsur Elliot S. , Cheville John C.
Published: February 2025

To determine their capacity to host Brucella abortus, face flies were examined 1 to 120 hours after feeding on broth containing bacteria and bovine erythrocytes. Brucella abortus was cultured in large numbers from whole flies for 12 hours after feeding, but not after 72 hours. Histologic analysis showed that brucellae were rapidly taken into the midgut, sequestered from erythrocytes, transiently stored, and shed in the feces; there was no evidence of bacterial replication within epithelial cells. Immunoperoxidase and immunogold techniques revealed that most brucellae in the gut were confined to the lumen by the peritrophic membrane, that brucellae were degraded in secondary lysosomes of midgut epithelial cells, and that intact brucellae passed into connective tissues surrounding the midgut. Bacterial excretion without midgut replication is consistent with transient, but not long-term, insect transmission in nature.
Detection of infectious hematopoietic necrosis virus in an invertebrate (Callibaetis sp)
Authors: Shors Scott T. , Winston Vern
Published: February 2025

Infectious hematopoietic necrosis virus (ihnv) was detected in the common Mayfly (Callibaetis sp) by western immunoblot assay and was propagated in fish cells (CHSE-214) in culture. When propagated in cell culture, cytopathic effect characteristic of ihnv infection was observed. Antibody specific for ihnv was used to detect all of the major proteins of ihnv in the western immunoblot assay. When the crude lysate was subjected to electron microscopy, bullet-shaped particles (84 nm × 194 nm) characteristic of ihnv were observed. The data suggested that the Mayfly may be a factor in the dissemination of ihnv.