bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of monensin and supplemental hay on ruminal 3-methylindole formation in adult cows after abrupt change to lush pasture
Authors: Potchoiba Michael J. , Carlson James R. , Nocerini Mark R. , Breeze Roger G.
Published: January 2024

The effect of feeding monensin, with or without dry hay plus wilted forage, on ruminal formation of 3-methylindole (3MI) was investigated in pastured cattle. Eighty-two cows were allotted to 3 groups. Cows of group-1 served as controls and were given a daily energy supplement (1 kg/head) without monensin for 1 day before and for 7 days after being allowed access to lush pasture. Cows of groups 2 and 3 were given the same daily energy supplement, which also contained monensin (200 mg/kg of supplement). Cows of group 3 also were fed dry hay for 5 days before the start of the study and continued to be given supplemental hay for 4 days after being allowed access to lush pasture containing a layer of wilted forage. Ruminal 3MI and indole concentrations increased on day 1 after all groups were allowed access to lush pasture. By day 7, 3MI concentration in all cows had decreased to pregrazing concentration. Indole concentration did not reach pregrazing concentration until day 10 for cows of groups 1 and 2. Group-3 cows had pregrazing indole concentration on day 7. Ruminal indole concentration did not differ (P > 0.05) between groups 1 and 2. Ruminal indole concentration was lower (P < 0.01) in group-3 cows on all sample collection days, except day 10, compared with that in the other groups. Monensin reduced (P <0.01) 3MI formation on days 1 and 7 in group-2 cows, compared with group-1 cows. Group-3 cows had lower 3MI concentration than did group-1 cows (P <0.01) on days –1, 1, 4, and 7. Monensin, when fed with dry hay and wilted forage, reduced (P <0.01) 3MI formation on days 4 and 7 in group-3 cows, compared with cows that were only given monensin (group 2). Group-3 cows also had lower (P < 0.05) 3MI concentration, compared with group-2 cows on day 1. Results indicated that monensin reduced ruminal formation of 3MI. Feeding dry hay and wilted forage to cattle during the change to lush pasture resulted in further reduction in the amount of 3MI formed by ruminal microorganisms. To maximize the effectiveness of monensin in reducing 3MI formation, dry hay plus wilted forage should be fed to pastured cattle for at least 4 days after they are allowed access to lush pasture.
Definition of the gracilis musculocutaneous flap for distant transfer in cats
Authors: Gregory C. R. , Gourley I. M. , Snyder J. R. , Ilkiw J.
Published: January 2024

Dissection, injection, and surgical studies in feline cadavers and in anesthetized cats were conducted to determine the feasibility of using the gracilis muscle as the basis for a free musculocutaneous flap. The vascular pedicle of the flap consisted of the femoral artery and vein. Mean length (1.6 ± 0.2 cm) of the vascular pedicle and mean artery (1.33 ± 0.19 mm) and vein (2.55 ± 0.38 mm) diameters were satisfactory for microvascular transfer. Fluorometry revealed overlying cutaneous perfusion in the flaps on the basis of their muscle vascular pedicles. To ensure survival of the flap, the muscular branches of the femoral artery and vein supplying the gracilis muscle had to be carefully preserved during surgical elevation of the flap.
Relation among body condition score, milk production, and serum urea nitrogen and cholesterol concentrations in high-producing Holstein dairy cows in early lactation
Authors: Ruegg Pamela L. , Goodger William J. , Holmberg Charles A. , Weaver Leon D. , Huffman E. Michael
Published: January 2024

Body condition scoring (using a 5-point scale with quarter-point divisions) was performed on 66 Holstein dairy cows that began their second or later lactation in August, September, or October 1988. Body condition was scored, beginning on postpartum day 4(± 1) and subsequently at postpartum days (± 1) 18, 32, 46, 60, 73, and 87. Blood samples were obtained on the same dates. Kilograms of milk produced per cow was measured daily. Body condition score and changes in body condition score were evaluated in relation to daily milk production, cumulative 80- day milk yield, and serum urea nitrogen and cholesterol concentrations.

Average daily milk production during week 1 was indicative of cumulative 80-day production, but not of 305- day milk yields. Cows that calved with body condition score ≥ 3.50 did not differ in average daily milk production, cumulative 80-day milk yield, or 305-day milk yield, compared with cows that calved with body condition score < 3.50. Cows that calved with body condition score ≥ 3.50 lost more condition than did cows that calved with body condition score < 3.50. Body condition score at calving and amount of body condition loss interacted with the rate of change in daily milk production.

Serum urea nitrogen concentration did not differ for cows grouped by cumulative 80-day milk production or for cows grouped by amount of condition loss. Serum cholesterol values were higher than previously reported values and increased directly with milk production. Serum cholesterol values were inversely related to condition loss, but changes in cholesterol concentration were not related to condition loss.
Adhesion of bacteria to the cecal mucosal surface of conventional and germ-free chickens infected with Eimeria tenella
Authors: Baba Eiichiroh , Wakeshima Hajime , Fukui Kazunori , Fukata Tsuneo , Arakawa Akira
Published: January 2024

When Salmonella typhimurium and Clostridium perfringens were tested in conventional chickens, larger numbers of Styphimurium and C perfringens adhered to Eimeriatenella-infected ceca than to uninfected ceca. In germ-free chickens, Styphimurium and C perfringens adhered to the E tenella-infected cecal mucosa more than to the uninfected cecal mucosa, but fewer Bacteroides vulgatus and Bifidobacterium thermophilum adhered to the E tenella-infected ceca than to the uninfected ceca. Many bacteria adhered to the lesions caused by E tenella as observed by scanning electron microscopy. On the basis of our findings, we suggest that infection with E tenella upsets the balance of competitive adherence of bacteria, allowing more colonization of Styphimurium and C perfringens.
Effect of macrophages and in vitro infection with parainfluenza type 3 and respiratory syncytial viruses on the mitogenic response of bovine lymphocytes
Authors: Adair B. M. , Bradford H. E. L. , Mackie D. P. , McNulty M. S.
Published: January 2024

Bovine blood lymphocytes, depleted of macrophages by absorption on plasma-gelatin coated plastic flasks, followed by passage through Sephadex G-10 columns, failed to respond to pokeweed mitogen stimulation Adherent monocytes or alveolar macrophages added to purified lymphocyte preparations at 10% or less were able to restore the transformation response.

Exposure of alveolar macrophages or purified lymphocytes to 2 bovine respiratory syncytial virus strains for 24 hours substantially reduced the transformation response when mixed with uninfected lymphocytes or macrophages. Exposure of alveolar macrophages or purified lymphocytes to 2 bovine parainfluenza type 3 virus strains produced a similar reduction in activity after 48 hours. Heat inactivation of the viruses removed their inhibitory ability. Immunofluorescence studies revealed that both alveolar macrophages and lymphocytes were permissive for parainfluenza type 3 virus, whereas only a small number of alveolar macrophages and lymphocytes were infected with respiratory syncytial virus. The results suggest that both viruses are capable of adversely affecting the interaction between macrophages and lymphocytes, although the mechanisms by which this is achieved may be different.
Association between serum cytotoxicity and selected clinical variables in 240 horses admitted to a veterinary hospital
Authors: MacKay Robert J.
Published: January 2024

A total of 378 serum samples from 240 hospitalized horses and 47 sera from healthy control horses were assayed for growth effects on actinomycin d-treated L929 cells. On average, patient and control sera stimulated cell growth; however, mean percentage of the relative growth index (rgi) of sera from clinical cases was significantly (P < 0.001) lower than that of control sera. Approximately 35% of patient sera and 6% of control sera had tumor necrosis factor-like cytotoxic activity for L929 cells (ie, rgi < 100%). Sera from horses with either peritoneal leakage of gastrointestinal tract contents or any bacterial infection were significantly (P < 0.05) more cytotoxic than sera from horses that did not have these clinical factors. A clear tendency was evident for horses that had the highest serum cytotoxicity (rgi < 75%) to also have clinical profiles suggestive of endotoxemia. Fever, leukopenia, diarrhea, and gastrointestinal tract leakage were significantly (P < 0.05) overrepresented among these horses, compared with horses without serum cytotoxicity. Bacterial infections and abdominal surgeries were also increased in this group, but not significantly. Of the 14 horses with serum rgi < 75%, 13 had some form of gastrointestinal tract disease and the other had gram-negative septicemia. Survival to discharge was significantly (P < 0.05) lower among horses in the high-cytotoxicity group than among horses without serum cytotoxicity. Diarrhea and bacterial infections were the only clinical factors found more frequently in horses with low serum cytotoxicity than in horses without serum cytotoxicity. The finding of circulating cytotoxic activity in horses at risk for endotoxemia was consistent with the proposed role for tumor necrosis factor as an important mediator of inflammation.
Determination of total protein concentration and viscosity of synovial fluid from the tibiotarsal joints of horses
Authors: Korenek Nancy L. , Andrews Frank M. , Maddux Jeanne M. , Sanders William L. , Faulk David L.
Published: January 2024

Viscosity of synovial fluid (sf) from 29 clinicadly normal horses was determined by use of a rotational cone and plate microviscosimeter. Total protein concentration in the sf of the 29 horses, as measured with a refractometer, was < 2.5 g/dl. When the Coomassie brilliant blue test was used to determine total protein concentration in sf for 15 horses, the mean value was 1,088 mg/dl. Viscosity values at 60, 30, 12, 6, 3, and 1.5 revolutions/min (rpm) spindle speed were 4.41 ± 1.54 centipoise (cp), 5.29 ± 1.94 cp, 6.76 ± 2.76 cp, 8.52 ± 4.27 cp, 10.41 ± 6.30 cp, and 13.07 ± 9.05 cp, respectively.

Synovial fluid viscosity increased with decreasing rpm and shear rate, but the shape of the curve for each horse fitted the asymptotic curve.

The rotational cone and plate microviscosimeter was an accurate instrument in measuring sf viscosity at multiple rpm or shear rates in horses. The values obtained on clinically normal horses in this study will serve as a baseline for comparison in the evaluation of horses with joint disease.
Percutaneous transabdominal hepatic needle biopsies in dogs
Authors: Hitt Mark E. , Hanna Paul , Singh Amreek
Published: January 2024

Ninety-six (4/dog) percutaneous transabdominal hepatic needle biopsy specimens were obtained from 24 dogs each weighing 10 to 24 kg. Two biopsies were performed in each dog prior to and 5 days after hepatopathy was experimentally induced. Information pertaining to the difficulty encountered in obtaining hepatic tissue is reported for the first of each pair of biopsies. All specimens were of diagnostic quality for light and electron microscopic evaluation. Adverse consequences (morbidity or mortality) resulting from the biopsy technique were not observed by monitoring of vital signs in the immediate postprocedure period and at 4 weeks. Recovery to an ambulatory state was seen in ≤ 30 minutes, except in 1 dog, in which prolonged recovery was attributed to acetylpromazine-induced hypotension.
Light and scanning electron microscopic studies of the extrahepatic bile duct of sheep with experimentally induced Fasciola hepatica infection
Authors: Lee C. G. , Zimmerman G. L. , Duimstra J. R.
Published: January 2024

Changes in the common bile duct that contained adult Fasciola hepatica of sheep were evaluated by light (lm) and scanning electron microscopy (sem). Nine ewes were inoculated with F hepatica metacercariae and necropsied 18 weeks after inoculation. The proximal portion of the common bile duct (cbd) that contained adult flukes was recovered and examined by lm and sem. The cbd from 2 noninoculated ewes were used for control.

On gross examination, cbd were markedly large because of the adult flukes, which were free in the lumen of the ducts. Extensive hemorrhage was not found either in intrahepatic or in extrahepatic bile ducts of any sheep. Histologic examination revealed changes, such as villous hyperplasia and hypertrophy of the epithelium; cell infiltration, predominately with eosinophils or macrophages; and arterial intimal proliferation. By sem, the epithelial surface of the cbd appeared intact. Villous hyperplasia and hypertrophy of the epithelium observed by lm was clearly seen by sem. Epithelial damage, seen as small areas of denuded surface by lm and sem, was confined to a few areas of the mucosa. Lack of extensive hemorrhage and confined epithelial damage were evaluated relative to the mode of feeding of adult flukes.
Skeletal muscle fiber size in untrained and endurance-trained horses
Authors: López-Rivero José L. , Agüera Eduardo , Monterde José G. , Vivo Joaquín , Rodríguez-Barbudo María V.
Published: January 2024

The mean area and minimal diameter of 3 histochemically determined myofiber types (1, 2A, and 2B; myosin ATPase in acid buffer) were calculated in middle gluteal muscle biopsy specimens from 62 stallions, 47 Andalusians and 15 Arabians, ranging in age from 6 to 12 years. Fourteen Andalusians and 7 Arabians were untrained, and the remainder were actively endurance-trained. The 6-month training schedules involved walking, slow trotting, and cantering. Fourteen Andalusians were moder-ately endurance-trained, whereas the other 19 Andalusians and 8 Arabians were strongly endurance-trained. Significant differences were not recorded between untrained and endurance-trained Arabians with respect to the area (type 1, 3,194 ± 869 μm2 and 3,150 ± 370 μm2; type 2A, 3,819 ± 890 μm2 and 3,380 ± 356 μm2; and type 2B, 4,872 ± 962 μm2 and 4,417 ± 646 μm2) or minimal diameter (type 1, 52.2 ± 7.4 μm and 52.8 ±3.1 μm; type 2A, 58.1 ± 6.7 μm and 55.0 ± 2.8 μm; and type 2B, 65.3 ± 6.4μm and 63.4 ± 4.3 μm) of the 3 fiber types, nor between untrained and endurance-trained Andalusians with respect to the area (untrained, 3,990 ± 690 μm2; moderately endurance-trained, 3,882 ± 347 μm2; and strongly endurance-trained, 3,758 ± 510 μm2) and minimal diameter (untrained, 58.1 ± 4.7 μm; moderately endurance-trained, 59.7 ± 2.7 μm; and strongly endurance-trained, 58.7 ± 4.5 μm) of 2A fibers. Moderately endurance-trained Andalusians had larger 2B fibers (area 18.6%; minimal diameter 14.3%) than untrained Andalusians, and the minimal diameter of type-1 and type-2B fibers was greater in strongly endurance-trained Andalusians than in untrained Andalusians (9.5% for type 1; 10.0% for type 2B). These results suggest minimal effects of endurance training on the myofiber size of adult Andalusians and Arabians, but a tendency toward increased type-1 and -2B fiber size was found for Andalusians.
Anatomic and radiographic study of the lacrimal apparatus of llamas
Authors: Sapienza John S. , Isaza Ramiro , Johnson Richard D. , Miller Thomas R.
Published: January 2024

The anatomy of the nasolacrimal duct of llamas was examined grossly and radiographically in 2 llamas. Dacryocystorhinography was performed on cadaver heads, using a radiographic aqueous contrast agent. Anatomic casts of the nasolacrimal apparatus were obtained by cannulation of the duct and use of polyurethane cast material. Dacryocystorhinography accurately revealed the nasolacrimal apparatus and compared favorably with gross dissections and polyurethane casts.
Viscosity and rheologic properties of blood from clinically normal horses
Authors: Andrews Frank M. , Korenek Nancy L. , Sanders William L. , Hamlin Robert L.
Published: January 2024

Blood viscosity (bv) was measured in 32 healthy horses at 6 spindle speeds (60, 30, 12, 6, 3, and 1.5 rpm) and for pcv of 40%, using a digital rotational cone and plate microviscometer. Also, in 7 of 32 horses, bv was measured 3 times each, for 3 pcv values (20, 40, and 60%), and at each spindle speed to determine effect of pcv on bv and machine and among-horse variations. Total plasma protein and fibrinogen concentrations were measured in all horses, using a standard refractometer and heat precipitation, respectively. In 7 of 32 horses, quantitative fibrinogen concentration was measured, using a quantitative fibrinogen assay. Plasma protein and fibrinogen concentrations were measured to determine their effect on bv.

Plasma total protein (6.0 to 7.5 g/dl) and fibrinogen (100 to 400 mg/dl) concentrations were within normal reference range for our laboratory. In this study of healthy horses, mean (± sd) bv values obtained for each pcv value and at each spindle speed were: for pcv of 20%, 2.39 ± 0.33 centipoise (cp) at 60 rpm, 2.52 ± 0.35 cp at 30 rpm, 2.80 ± 0.37 cp at 12 rpm, 2.96 ± 0.48 cp at 6 rpm, 3.04 ± 0.62 cp at 3 rpm, and 2.93 ± 0.96 cp at 1.5 rpm; for pcv of 40%, 3.98 ± 0.29 cp at 60 rpm, 4.40 ± 0.38 cp at 30 rpm, 5.26 ± 0.59 cp at 12 rpm, 6.36 ± 0.93 cp at 6 rpm, 7.34 ± 1.46 cp at 3 rpm, and 8.33 ± 2.61 cp at 1.5 rpm; and for pcv of 60%, 7.21 ± 0.91 cp at 60 rpm, 8.27 ± 1.05 cp at 30 rpm, 10.46 ± 1.38 cp at 12 rpm, 13.69 ± 1.82 cp at 6 rpm, 18.12 ± 2.81 cp at 3 rpm, and 23.44 ± 3.45 cp at 1.5 rpm.

Blood viscosity increased with decreasing rpm and shear rate. Blood viscosity also increased with increasing pcv at each spindle speed. The bv for healthy horses at pcv of 40% was fitted to an asymptotic model. The estimated coefficients were:

Significant (P < 0.05) correlation between total plasma protein concentration and bv was found for pcv of 40% at all spindle speeds. Furthermore, significant (P < 0.05) correlation between quantitative plasma fibrinogen concentration and bv was found for pcv of 60% at the lower spindle speeds (6, 3, and 1.5 rpm).

The sd of measurement error and the among-horse sd for the digital rotational cone and plate microviscometer were greatest at the low spindle speeds for all pcv. The least variation was found for pcv of 20%.

The digital rotational cone and plate microviscometer is an accurate instrument for measuring bv at multiple pcv and spindle speeds in horses. Packed cell volume, plasma protein concentration, and fibrinogen concentration appear to affect bv in horses. Blood viscosity values obtained in this study will give insights into factors affecting bv in horses and will serve as a baseline for comparison with values in diseased horses.
Detection and antigenicity of chlamydial proteins that bind eukaryotic cell membrane proteins
Authors: Baghian A. , Schnorr K. L.
Published: January 2024

Chlamydia psittaci proteins capable of binding eukaryotic cell membranes were identified and antigenically characterized. Cell membrane proteins (cmp) of noninfected cells were labeled with biotin (b-cmp), then were extracted with 1% Triton X-100. Nitrocellulose membrane strips containing sodium dodecyl sulfate-polyacrylamide gel electrophoresis-resolved proteins of chlamydial elementary bodies (eb) were reacted with the b-cmp extract, followed by addition of streptavidin-conjugated horse radish peroxidase. Among the various strains of chlamydiae examined, a protein of approximately 16 to 18 kDa consistently bound b-cmp. A second larger protein, ranging in molecular mass from 24 to 32 kDa, also bound b-cmp. Immunoblotting techniques were used to analyze the reactions of antisera from immunized and experimentally infected animals to these proteins. A rabbit polyclonal antiserum produced against the 18-kDa adhesin of a serovar-1 strain of C psittaci (B577) reacted strongly with 18-kDa proteins of all C psittaci strains, but weakly with that of C trachomatis. Mouse antisera raised against the serovar-2 (FC-Stra) 28-kDa protein reacted only with proteins of the homologous serovar. Sera from experimentally infected animals did not react with the C trachomatis 18-kDa adhesion protein, but did react in 2 patterns with related and nonrelated C psittaci isolates. Two rabbits inoculated with infective serovar-1 eb and 1 rabbit inoculated with a serovar-2 strain reacted specifically with the 18-kDa proteins of their homologous serovars. In contrast, 2 other rabbits inoculated with the same serovar-2 strain produced antisera that reacted with all C psittaci 18-kDa proteins, as did serum from a similarly inoculated bull. The reason for the 2 types of responses to infection remains to be determined.
Use of progesterone in microspheres for maintenance of pregnancy in mares
Authors: Ball Barry A. , Wilker Clynn , Daels Peter F. , Burns Patrick J.
Published: January 2024

Administration of progesterone in poly(d-, l-lactide) microspheres was used to maintain pregnancy in mares after luteolysis was induced by treatment with prostaglandin F2α at day 14 of pregnancy. Mares were given vehicle only (control, n = 6) or 0.75 g (n = 7), 1.5 g (n = 8), or 2.25 g (n = 5) of microencapsulated progesterone at days 12 and 22 of pregnancy. Serum progesterone concentrations were determined daily, and pregnancy was evaluated by transrectal ultrasonography on alternate days. Significantly (P < 0.05) more mares given 1.5 or 2.25 g of progesterone (6 of 8 and 4 of 5 mares, respectively), but not those given 0.75 g (3 of 7 mares), maintained pregnancy through day 32, compared with control mares (0 of 6). Progesterone concentrations decreased significantly (P < 0.025) in all groups after administration of prostaglandin F2α at day 14, and significant (P < 0.05) effects of time and treatment on progesterone concentrations were found between days 12 and 22, and 22 and 32. Although treatment with 1.5-g and 2.25-g doses of microencapsulated progesterone improved maintenance of pregnancy, compared with that of vehicle-treated controls, administration of 2.25 g of microencapsulated progesterone appeared to be most efficacious in maintenance of pregnancy during the study interval.
Inotropic mechanisms of dopexamine hydrochloride in horses
Authors: Muir William W.
Published: January 2024

Mechanisms responsible for the positive inotropic effects of dopexamine were investigated in 8 halothane-anesthetized horses. The hemodynamic effects of increasing infusions of dopexamine (5, 10, 15 μg/kg of body weight/min) were determined before and after sequential administration of specific antagonists. Using glycopyrrolate and chlorisondamine, and atenolol and ICI 118,551, muscarinic and nicotinic ganglionic, and β1, and β2-adrenergic receptor blockade, respectively, was induced. Dopexamine infusions induced increase in heart rate, cardiac output, systolic and mean arterial blood pressure, and maximal rate of left ventricular pressure development (+ dP/dtmax). Right atrial pressure and systemic vascular resistance decreased. Parasympathetic and ganglionic blockade attenuated cardiac output, systolic and mean aortic blood pressures, and + dP/dtmax responses to dopexamine infusion. Dopexamine-induced increase in heart rate was potentiated by parasympathetic and ganglionic blockade. β1-Adrenergic receptor blockade decreased heart rate, cardiac output, arterial blood pressure, and + dP/dtmax from baseline values and markedly reduced the response to dopexamine infusion. β2-Adrenergic receptor blockade induced further decrease in hemodynamic variables from baseline values and completely abolished the cardiostimulatory effects of dopexamine on + dP/dtmax. These data indicate that baroreflex activity, β1- and β2-adrenergic receptor stimulation may be an important cause of dopexamine's positive inotropic effects in horses.
Efficacy of buparvaquone as a therapeutic and clearing agent of Babesia equi of European origin in horses
Authors: Zaugg J. L. , Lane V. M.
Published: January 2024

We evaluated the efficacy of buparvaquone in eliminating infection with Babesia equi of European origin in carrier horses and in splenectomized horses with experimentally induced acute infection. When administered at the rate of 5 mg/kg of body weight, iv, 4 times at 48-hour intervals, buparvaquone prompted rapid abatement of parasitemia. However, secondary and tertiary recrudescent parasitemias invariably returned with establishment of the carrier state. Buparvaquone, at the dosage evaluated, had transitory therapeutic efficacy against acute B equi infection in splenectomized horses, but was unable alone to clear carrier infection.
Effects of exercise stress on various immune functions in horses
Authors: Wong C. W. , Smith S. E. , Thong Y. H. , Opdebeeck J. P. , Thornton J. R.
Published: January 2024

Chemotactic locomotion and luminol-dependent chemiluminescence of neutrophils, mitogen-induced lymphocyte blastogenesis, serum cortisol concentration, immunoglobulin quantification, and leukocyte counts were determined to evaluate the effect of a single strenuous exercise in horses. Increased serum cortisol concentration (P < 0.01) and an increased neutrophil-to-lymphocyte ratio (P < 0.05) indicated that horses had been stressed. The chemotactic index and peak chemiluminescence production decreased significantly (P < 0.05 and P < 0.01, respectively) 1 day after exercise. Mitogen-induced blastogenesis of lymphocytes and serum immunoglobulin values remained unchanged in response to exercise. Results of this study indicated that a single bout of exercise may transiently impair neutrophil antimicrobial functions and nonspecific defense mechanisms, but not specific immunity in horses.
Detection of African swine fever viral antigens in paraffin-embedded tissues by use of immunohistologic methods and polyclonal antibodies
Authors: Fernandez Antonio , Perez José , Carrasco Librado , Sierra Miguel A. , Sanchez-Vizcaino M. , Jover Amador
Published: January 2024

Tissues obtained from pigs inoculated with African swine fever virus (asfv), fixed by vascular perfusion using glutaraldehyde, and embedded in paraffin or araldite were used for an immunohistologic electron microscopic study. To detect asfv antigens, 4 methods were used on paraffin sections with or without pretreatment of the tissues. Use of biotinylated anti-asfv antiserum combined with avidin-biotin complex and peroxidase proved to be the most suitable method, and antigen was detected in tissues infected with 2 asf viruses of different virulence.

Use of the glutaraldehyde fixation method should ensure optimal morphologic (structural and ultrastructural) data while allowing an immunohistologic study, and add to knowledge of the pathogenesis of asf.
Search for bovine papilloma virus DNA in bovine ocular squamous cell carcinomas (boscc) and boscc-derived cell lines
Authors: Rutten Victor P. M. G. , Klein Wim R. , De Jong Mieke A. C. , Quint Wim , Otter Wim Den , Ruitenberg E. Joost , Melchers Willem J. G.
Published: January 2024

Although the cause of bovine ocular squamous cell carcinoma (boscc) is attributed to viruses in addition to cofactors (eg, uv light), to our knowledge, the final causative agent has not been described. Bovine papilloma virus (bpv)- like particles were detected in approximately 33% of various putative precursor lesions of boscc. In contrast, it was reported that, using bpv-specific antibodies, it was not possible to detect viral antigens in boscc. Fourteen established boscc and 9 boscc-derived cell lines were examined for bpv dna. Probes of all 6 known bpv types were used in various hybridization assays. Neither Southern blot analysis, under high and low stringency conditions, nor in situ hybridization resulted in detection of bpv dna. Papilloma viruses were not observed in electron microscopic studies. Results exclude direct association between boscc and bpv types 1 to 6, or as yet unknown closely related bpv types. However, bpv may contribute to induction of precursor lesions or events leading to carcinogenic transformation, without being relevant for maintenance of the tumor.
Antibody response to and maternal immunity from an experimental psittacine beak and feather disease vaccine
Authors: Ritchie Branson W. , Niagro Frank D. , Latimer Kenneth S. , Steffens W. L. , Pesti Denise , Campagnoli Raymond P. , Lukert Phil D.
Published: January 2024

Adult umbrella cockatoos, Moluccan cockatoos, African grey parrots, and a yellow-headed Amazon parrot were inoculated im or sc with β-propiolactone-treated psittacine beak and feather disease (pbfd) virus. Thirty- to 45-day-old African grey parrot, umbrella cockatoo, and sulphur-crested cockatoo chicks also were vaccinated with the same inoculum. The hemagglutination inhibition (hi) and agar-gel diffusion tests were used to assay for post-vaccination development of anti-pbfd virus antibodies. All adult vaccinates seroconverted and had increases in hi and precipitating antibodies. The vaccinated chicks had increased concentrations of hi antibodies, but precipitating antibodies could not be detected. To demonstrate that chicks from vaccinated hens are protected from pbfd virus challenge, 3 African grey parrot chicks and 2 umbrella cockatoo chicks from vaccinated hens and 1 African grey parrot chick and 1 umbrella cockatoo chick from nonvaccinated hens were exposed to purified pbfd virus. Chicks from the vaccinated hens remained clinically normal during the 50-day test period. Chicks from the nonvaccinated hens developed clinical and histologic lesions of pbfd. Infected tissues from these birds were confirmed to contain viral antigen, using immunohistochemical staining techniques. The pbfd virus was recovered from the affected birds. These findings indicate that adult and 30- to 45-day-old psittacine birds will seroconvert following vaccination with β-propiolactone-treated pbfd virus. Also, hens inoculated with β-propiolactone-treated pbfd virus produce chicks that are, at least temporarily, resistant to virus challenge.
Characterization of monoclonal antibodies against Actinobacillus pleuropneumoniae serotype 5
Authors: Nakai Toyotsugu , Kawahara Kazuyoshi , Horiguchi Yasuhiko , Danbara Hirofumi , Kume Katsumi
Published: January 2024

Two monoclonal antibodies against Actinobacillus pleuropneumoniae serotype 5, designated as 5MAb-l and 5MAb-6, were characterized. Enzyme-linked immunosorbent assay-inhibition tests with whole-cell antigens obtained from strains of serotype 1 through 12 of A pleuropneumoniae revealed that 5 MAb-1 bound to only serotype-5 strains. The epitope recognized by 5MAb-l was a carbohydrate that was sensitive to periodate oxidation and resided on the structure of β-l,6-linked d-galactose in an O-antigen polysaccharide of serotype-5 lipopolysaccharide. Analysis of these results revealted that the O-antigen polysaccharide of lipopolysaccharide was 1 of the antigenic determinants responsible for the serotype specificity of A pleuropneumoniae. On the other hand, 5MAb-6 reacted with strains of serotype 1 through 10 in varying degrees and its epitope was located on polypeptides sensitive to proteinase K. In an immunoblotting analysis, 5MAb-6 reacted with 2 polypeptide bands, with molecular weights of approximately 41,500 and 28,000, in the outer membrane protein-rich fraction obtained from strains of serotype 1 through 10. These results indicated that outer membrane proteins from several serotype strains of A pleuropneumoniae possessed common antigenic determinants.
Influence of wound shape on wound contraction in horses
Authors: Madison John B. , Gronwall Ronald R.
Published: January 2024

Three sets of paired circular and square full-thickness skin wounds were made on the dorsum of the metacarpus (n = 48) of 8 horses. Each wound was 6.25 cm2 in area. The wounds were treated topically with an ointment, nonadherent dressing, and bandaged with a snug elastic wrap. Wounds were photographed every other day until healing was complete. Wound areas were measured and exponential and linear wound healing models were applied to the wound healing data generated. Wound healing variables measured for each wound were: number of days to healing, maximal size attained, rate of wound contraction (calculated by use of first-order and linear models), final wound size, and percentage of wound that healed by contraction.

The exponential model fit the data significantly better than the linear model. The maximal size attained by circular wounds was significantly smaller than the maximal size attained by square wounds. Wound shape did not influence the rate of wound healing. On the basis of our findings, conversion of circular defects to square defects would not speed wound healing.
Reference hematologic values and morphologic features of blood cells in healthy adult llamas
Authors: Van Houten D. , Weiser M. G. , Johnson L. , Garry F.
Published: January 2024

Hematologic values and cellular morphologic features were evaluated for 38 healthy adult llamas. Reference ranges were determined for pcv, reticulocyte concentration, leukocyte concentration, and leukocyte differential counts. The approach used in this study was to focus on hematologic values that may be determined by use of techniques readily available to the practicing veterinarian and nonveterinary laboratory. Unique cellular morphologic features commonly observed and interpreted as normal included large granular lymphocytes, hyposegmented eosinophil nuclei, folded erythrocytes, and hemoglobin crystals.
Effects of xylazine on airway function in ponies with recurrent airway obstruction
Authors: Broadstone Richard V. , Gray Peter R. , Robinson N. Edward , Derksen Frederik J.
Published: January 2024

The effect of iv administration of the α2-adrenoceptor agonist xylazine hydrochloride (0.5 mg/kg of body weight) was examined in ponies with recurrent obstructive pulmonary disease, commonly called heaves. Six ponies with the disease (principals) were studied during clinical remission and during an acute attack of airway obstruction precipitated by stabling and feeding of dusty hay. Six control ponies were also studied. In principal ponies with airway obstruction, xylazine administration significantly (P < 0.05) decreased pulmonary resistance and increased dynamic compliance, but did not affect Pao2 or Paco2. The α2-antagonist yohimbine blocked the pulmonary effects of xylazine. Administration of saline solution was without effect in both groups of ponies at all periods and xylazine did not have effect in controls or in principals in clinical remission.
Acute toxicity of paraherquamide and its potential as an anthelmintic
Authors: Shoop W. L. , Haines H. W. , Eary C. H. , Michael B. F.
Published: January 2024

Paraherquamide, an oxindole alkaloid metabolite of Penicillium paraherquei and P charlesii, is a new anthelmintic with potential broad-spectrum use. In initial trials, it had an excellent safety profile in cattle and sheep at doses efficacious against a dozen or more helminths, but recently it produced unexpected and severe toxicosis in dogs at doses far below those that were safe in the ruminants. To provide data on which to build rational safety tests in the future, we tested the acute toxicity of paraherquamide administered po to male CD-1 mice and compared its profile with the most potent anthelmintic known, ivermectin. The estimated doses lethal to 50% of a group of mice were 14.9 and 29.5 mg/kg of body weight for paraherquamide and ivermectin, respectively. The no-effect doses were 5.6 and 18.0 mg/kg for paraherquamide and ivermectin, respectively. Signs of intoxication in paraherquamide-treated mice, if they developed, emanated within 30 minutes of administration, irrespective of dose, and consisted of either mild depression with complete recovery or a 5- to 10-minute period of breathing difficulty followed by respiratory failure and death by 1 hour after treatment. Gross necropsy findings in paraherquamide-treated mice that died in the high-dose group were normal. Ivermectin-related toxicity was slower and more predictable, taking place over a 3-day period, with dose-dependent signs of intoxication consisting of tremors, ataxia, recumbency, coma, and death. Necropsy of ivermectin-treated mice that died in the high-dose group revealed dehydration, a condition most likely resulting from the coma-induced state. These observations are congruent with clinical data from dog studies and suggest that if broad-spectrum use of ivermectin (expected to be approx 0.2 mg/kg) is unlikely because of idiosyncratic toxic effects in certain dogs, then use of a compound for dogs with an acute safety factor half of ivermectin, such as paraherquamide, would be even more unlikely. These data are also coupled with observations from anthelmintic trials to suggest that ivermectin possesses a substantially greater therapeutic index than does paraherquamide as a broad-spectrum antiparasiticide for ruminants. Although paraherquamide has a lesser therapeutic index, a strategic use for it as an anthelmintic against ruminant parasites that have become resistant to any or all of the other modern broad-spectrum anthelmintics can be suggested.
Pharmacokinetics of norfloxacin and its N-desethyl- and oxo-metabolites in broiler chickens
Authors: Anadón A. , Martinez-Larrañaga M. R. , Velez C. , Díaz M. J. , Bringas P.
Published: January 2024

Norfloxacin was given to 2 groups of chickens (8 chickens/group) at a dosage of 8 mg/kg of body weight, iv and orally. For 24 hours, plasma concentration was monitored serially after each administration. Another group of chickens (n = 30) was given 8 mg of norfloxacin/kg orally every 24 hours for 4 days, and plasma and tissue concentrations of norfloxacin and its major metabolites desethylenenorfloxacin and oxonorfloxacin were determined serially after the last administration of the drug. Plasma and tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were measured by use of high-performance liquid chromatography. Pharmacokinetic variables were calculated, using a 2-compartment open model. For norfloxacin, the elimination half-life (t1/2β) and the mean ± sem residence time for plasma were 12.8 ± 0.59 and 15.05 ± 0.81 hours, respectively, after oral administration and 8.0 ± 0.3 and 8.71 ± 0.23 hours, respectively, after iv administration. After single oral administration, norfloxacin was absorbed rapidly, with Tmax of 0.22 ± 0.02 hour. Maximal plasma concentration was 2.89 ± 0.20 μg/ml. Oral bioavailability of norfloxacin was found to be 57.0 ± 2.4%. In chickens, norfloxacin was mainly converted to desethylenenorfloxacin and oxonorfloxacin. Norfloxacin parent drug and its 2 major metabolites were widely distributed in tissues. Considerable tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were found when norfloxacin was administered orally (8 mg/kg on 4 successive days). The concentration of the parent fluoroquinolone in fat, kidneys, and liver was 0.05 μg/g on day 12 after the end of dosing.
Effect of various vaccination procedures on shedding, latency, and reactivation of attenuated and virulent Pseudorabies virus in swine
Authors: Mengeling William L. , Lager Kelly M. , Volz David M. , Brockmeier Susan L.
Published: January 2024

Various procedures of vaccination for Pseudorabies were compared for their effects on shedding, latency, and reactivation of attenuated and virulent Pseudorabies virus. The study included 6 groups: group 1 (10 swine neither vaccinated nor challenge-exposed), group 2 (20 swine not vaccinated, but challenge-exposed), and groups 3 through 6 (10 swine/group, all vaccinated and challenge-exposed). Swine were vaccinated with killed virus im (group 3) or intranasally (group 4), or with live virus im (group 5) or intranasally (group 6). The chronologic order of treatments was as follows: vaccination (week 0), challenge of immunity by oronasal exposure to virulent virus (week 4), biopsy of tonsillar tissue (week 12), treatment with dexamethasone in an attempt to reactivate latent virus (week 15), and necropsy (week 21).

Vaccination im with killed or live virus and vaccination intranasally with live virus mitigated clinical signs and markedly reduced the magnitude and duration of virus shedding after challenge exposure. Abatement of signs and shedding was most pronounced for swine that had been vaccinated intranasally with live virus. All swine, except 4 from group 2 and 1 from group 4, survived challenge exposure. Only vaccination intranasally with live virus was effective in reducing the magnitude and duration of virus shedding after virus reactivation. Vaccination intranasally with killed virus was without measurable effect on immunity.

Of the 55 swine that survived challenge exposure, 54 were shown subsequently to have latent infections by use of dexamethasone-induced virus reactivation, and 53 were shown to have latent infections by use of polymerase chain reaction (pcr) with trigeminal ganglia specimens collected at necropsy. Fewer swine were identified by pcr as having latent infections when other tissues were examined; 20 were identified by testing specimens of olfactory bulbs, 4 by testing tonsil specimens collected at necropsy, and 4 by testing tonsillar biopsy specimens. Eighteen of the 20 specimens of olfactory bulbs and 3 of the 4 tonsil specimens collected at necropsy in which virus was detected by pcr were from swine without detectable virus-neutralizing antibody at the time of challenge exposure. One pig that had been vaccinated intranasally with live virus shed vaccine virus from the nose and virulent virus from the pharynx concurrently after dexamethasone treatment. Evaluation of both viral populations for unique strain characteristics failed to provide evidence of virus recombination.
Cardiopulmonary effects of etomidate in hypovolemic dogs
Authors: Pascoe Peter J. , Ilkiw Jan E. , Haskins Steve C. , Patz John D.
Published: January 2024

Cardiopulmonary effects of etomidate administration were studied in hypovolemic dogs. Baseline cardiopulmonary data were recorded from conscious dogs after instrumentation. Hypovolemia was induced by withdrawal of blood from dogs until mean arterial pressure of 60 mm of Hg was achieved. Blood pressure was maintained at 60 mm of Hg for 1 hour, by further removal or replacement of blood. One milligram of etomidate/kg of body weight was then administered iv to 7 dogs, and the cardiopulmonary effects were measured 3, 15, 30, and 60 minutes later. After blood withdrawal and prior to etomidate administration, heart rate, arterial oxygen tension, and oxygen utilization ratio increased. Compared with baseline values, the following variables were decreased: mean arterial pressure, mean pulmonary arterial pressure, central venous pressure, pulmonary wedge pressure, cardiac index, oxygen delivery, mixed venous oxygen tension, mixed venous oxygen content, and arterial carbon dioxide tension. Three minutes after etomidate administration, central venous pressure, mixed venous and arterial carbon dioxide tension, and venous admixture increased, and heart rate, arterial and venous pH, and arterial oxygen tension decreased, compared with values measured immediately prior to etomidate administration. Fifteen minutes after etomidate injection, arterial pH and heart rate remained decreased. At 30 minutes, only heart rate was decreased, and at 60 minutes, mean arterial pressure was increased, compared with values measured before etomidate administration. Results of this study indicate that etomidate induces minimal changes in cardiopulmonary function when administered to hypovolemic dogs.
Safety of ceftiofur sodium administered intramuscularly in horses
Authors: Mahrt Charles R.
Published: January 2024

Ceftiofur sodium, a broad-spectrum cephalosporin antibiotic, was evaluated for safe use in horses. Male or female horses were allotted to groups and were given either saline solution (control), or 2.2, 6.6, or 11 mg of an aqueous solution of ceftiofur sodium/kg of body weight/d, im, for 30 or 31 days. These dosages are expressed in terms of the ceftiofur free acid, and represent 1 to 5 times the proposed therapeutic dosage (2.2 mg/kg/d) administered for 3 times the maximal recommended duration of 10 days. Some of the horses were euthanatized and necropsied on day 31 or 32. The other horses were evaluated for an additional 30 days, and some were euthanatized and necropsied on day 60. The following types of data were collected: clinical observation; physical examination; pelleted food consumption; body weight; hematologic, serum biochemical, and urinalysis findings; organ weight; gross necropsy observations; and histopathologic findings.

Ceftiofur sodium was generally well tolerated at the exaggerated doses and treatment durations used in these safety studies. Slight to mild decrease in pelleted food consumption was detected in horses given 6.6 or 11 mg of ceftiofur sodium/kg/d. Decreased food consumption began on day 2 and lasted for approximately 9 to 12 days. Generally, mild skeletal muscle irritation was detected by gross and microscopic examination of the injection sites of horses given ceftiofur sodium. Prevalence and severity of the muscle irritation tended to increase with increasing concentration of the dosing solution. Increases in serum aspartate transaminase and creatine kinase activities were detected in some of the ceftiofur-treated horses, and were attributed to mild skeletal muscle irritation at the injection sites. Slight increases in numbers of circulating neutrophils and plasma concentration of fibrinogen were detected in the blood of some ceftiofur-treated horses, and were attributed to mild inflammation at the injection sites or possibly in the large intestine because of a change in bacterial flora.
Use of enzyme immunoassay and reverse-phase high-performance liquid chromatography to detect and confirm identity of dexamethasone in equine blood
Authors: Friedrich Anita , Schulz Rüdiger , Meyer Heinrich H. D.
Published: January 2024

An enzyme immunoassay (eia) was developed for detection of dexamethasone in equine blood. Dexamethasone 21-hemisuccinate-bovine serum albumin was used for immunization of rabbits, and prednisolone 21-hemisuccinate-horseradish peroxidase was used as enzyme conjugate. The assay had sensitivity in the low-picogram range (detection limit, 0.3 pg/well, 50% inhibition of binding at 4.5 ± 0.7 pg/well). Apart from Cortisol, which was recognized by the antiserum at concentration > 8.5 ng/ml, the dexamethasone antiserum failed to interfere with endogenous steroids, but cross-reacted with triamcinolone, flumethasone, and betamethasone. Thus, the antiserum was used to perform simultaneous screening for these synthetic glucocorticoids and to confirm their identity by combining reverse-phase high-performance liquid chromatography (rp-hplc) and eia. The immunoreactivity obtained by direct serum measurements was characterized by means of 2 independent rp-hplc systems. Serum extracts were submitted to rp-hplc systems I and II, and the fractions were tested by eia. Immunoreactive peaks were identified by comparing their retention time with that of the standard glucocorticoids used for calibration. Coinjection of an internal standard (methylprednisolone) in rp-hplc system II yielded reproducible relative retention times. The effectiveness of the test system was evaluated, using blood from a horse treated with commonly used veterinary preparations of dexamethasone. Administration of the free alcohol of dexamethasone and of dexamethasone 21-trioxaundecanoate, both given iv, was detected, and the identity of each was confirmed for up to 48 hours. Intramuscular administration of dexamethasone 21-isonicotinate was continued for at least 14 days after injection of a therapeutic dose. The technique provided higher sensitivity and practicability than do analytic techniques currently available for glucocorticoid testing in horses and proved reliable in confirming the identity of dexamethasone, triamcinolone, flumethasone, and betamethasone in equine blood samples.