bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum lipid and lipoprotein changes in ponies with experimentally induced liver disease
Authors: Bauer John E. , Meyer D. J. , Campbell Martha , McMurphy Rose
Published: January 2024

Alterations in serum lipid and lipoprotein concentrations in ponies with experimentally induced liver disease were investigated. Hepatocellular damage was induced, using a nonlethal dose of carbon tetrachloride. In a separate group of ponies, obstructive jaundice was induced by surgical ligation of the common bile duct. Over a 6-day period, blood samples were obtained from ponies after treatment with carbon tetrachloride and for 12 days in ponies subjected to surgery. Serum cholesterol and triglyceride concentrations were unaffected in both groups of ponies, except for significantly (P < 0.01) high triglyceride concentration in ponies of the ligated group during the second postsurgical week. This increase was most likely attributable to anorexia observed during that period. Hyperbilirubinemia was observed early in ponies of the ligated group; most of the bilirubin was of the conjugated type. Using electrophoretic and ultracentrifugal methods, serum lipoprotein alterations were detected only in ponies of the ligated group. Increases of very low-density and low-density lipoprotein cholesterol concentrations and decrease in high-density lipoprotein cholesterol concentration were found. Although no changes were seen in total serum cholesterol concentration, a redistribution of lipoprotein cholesterol was observed in ponies of the ligated group. Similar alterations in lipoprotein distribution have been found in dogs, rats, and human beings with obstructive jaundice and cholestasis. The association between serum lecithin:cholesterol acyl transferase activities and these lipoprotein alterations remains to be elucidated.
Production and partial characterization of monoclonal antibodies to the neotype strain of Mycobacterium bovis
Authors: Kuchinka Gary D. , Thoen Charles O. , Moennig Volker
Published: January 2024

Six monoclonal antibodies (mab) to virulent Mycobacterium bovis ATCC 19210 were produced, using a suspension of heat-inactivated whole cells. Immunoglobulin isotype for mab VMB6, VMB73, and VMB93 was IgG1, and for VMB31, VMB99, and VMB119, it was IgG2a. Monoclonal antibodies were examined for cross-reactivity to M tuberculosis, M kansasii, M fortuitum, M paratuberculosis, M avium serovars 1, 2, 4, 8, and 10, M chelonei, M phlei, M scrofulaceum, M smegmatis, Nocardia asteroides, and Rhodococcus equi. Monoclonal antibodies could be grouped on the basis of binding activity by elisa and immunoblot analysis, in which mab VMB6, VMB31, and VMB119 had binding activity to M bovis; mab VMB93 and VMB99 detected M bovis and M tuberculosis antigens, and mab VMB73 reacted with other mycobacterial species, as well as with N asteroides and R equi. Apparent molecular mass of antigens was 30 to 25 kilodaltons (kD) for VMB6, VMB31, and VMB119 and 63 kD for VMB93 and VMB99, and ranged from > 200 to 31 kD for VMB73, as estimated by immunoblot analysis. Monoclonal antibody binding activity to 18 field isolates of M bovis was evaluated, using elisa. Each of 18 field isolates was detected, using mab VMB6, VMB31, or VMB119; 10 isolates were detected, using mab VMB93/VMB99, and 14 were detected by use of mab VMB73. Use of mab in elisa failed to detect antigens from M bovis strain AN-5.
Pasteurella haemolytica lipopolysaccharide-induced arachidonic acid release from and neutrophil adherence to bovine pulmonary artery endothelial cells
Authors: Paulsen Daniel B. , Confer Anthony W. , Clinkenbeard Kenneth D. , Mosier Derek A.
Published: January 2024

Bovine pulmonary artery endothelial cells (bpaec) were labeled with 3H-arachidonic acid. Exposure of the labeled bpaec to Pasteurella haemolytica lipopolysaccharide (lps) resulted in a time- and dose-dependent release of radioactivity. The release was inhibited by 5 mM indomethacin, but inhibition was not caused by ≤ 500 μM indomethacin or hydrocortisone, which suggests that the release was caused primarily by a mechanism other than cyclooxygenase or phospholipase A2 metabolism of arachidonic acid.

Pasteurella haemolytica lps also caused increased adherence of bovine neutrophils to bpaec through independent effects on both cell types. The increased adherence was inhibited by treatment of either cell type with cycloheximide or actinomycin D prior to lps exposure, indicating that de novo protein synthesis was required in both cell types to promote the lps-induced adherence. Lipopolysaccharide may be an important factor in neutrophil-mediated effects in pneumonic pasteurellosis by causing increased neutrophil adherence and, thus, the vascular sequestration of neutrophils.

Together, these experiments provide additional evidence for the involvement of lps in pneumonic pasteurellosis. Moreover, they provide evidence of lps-induced endothelial activation, which could have broad ramifications in the inflammatory and immune responses of pneumonic pasteurellosis.
Strategic use of anthelmintics to prevent parasitic gastroenteritis in cow-calf herds in California
Authors: Baker Norman F. , Farver Thomas B.
Published: January 2024

On the basis of the hypothesis that the peak numbers of infective nematode third-stage larvae (L3) on herbage in winter months results from fall contamination of pastures, 2 methods to reduce fall contamination were tested. In trial 1, morantal sustained-release boluses were administered to 15 fall-calving cows on Sept 7, 1982. Fifteen untreated cows (controls) were placed on separate pastures. Numbers of L3 on herbage during the winter and spring were assessed by use of worm-free tracer calves.

In trial 2, 19 cattle due to calve in the fall were administered 200 μg of invermectin/kg of body weight, sc, on Sept 2, 1983. Also, 17 cattle similarly were given a placebo injection and served as control animals. Treated cattle were placed on the pasture used by control cattle in trial 1 and control cattle on the pasture used by treated cattle in trial 1. Worm-free tracer calves were again used to assess numbers of L3 on herbage.

In trial 1, tracer calves grazing the control animal pasture from January 14 to 28 acquired 37 times as many nematodes as did those grazing the treated animal pasture. In trial 2, the greatest difference observed was a 10- fold increase of nematodes in calves grazing control animal pastures, compared with worm numbers in tracer calves grazing the treated animal pasture.
Experimental model of hypochloremic metabolic alkalosis caused by diversion of abomasal outflow in sheep
Authors: Smith Donald F. , Lunn D. Paul , Robinson Gail M. , McGuirk Sheila M. , Nordheim Erik V. , MacWilliams Peter S.
Published: January 2024

Hypochloremic metabolic alkalosis accompanied by hypokalemia and hyponatremia was induced experimentally in 7 adult sheep by diversion (loss) of gastric contents through an Ivan and Johnston cannula placed in the cranial part of the duodenum just distal to the pylorus. Cannula placement was easily accomplished, and cannulae were tolerated well by the sheep. Volume of effluent produced during the 60- to 120-hour period of diversion ranged from 7.7 to 14.9 L and tended to be greatest during the first 24 hours. All sheep became dehydrated, with mean pcv and plasma total protein concentration increases of 94.2 and 61.7%, respectively. Plasma chloride concentration decreased in linear fashion from a prediversion mean of 113 mEq/L (range, 111 to 117 mEq/L) to an end-point mean of 54 mEq/L (range, 45 to 65 mEq/L). Plasma sodium and potassium concentrations also decreased, though potassium concentration increased terminally. There were rapid increases in arterial blood pH and bicarbonate and base excess concentrations during the first 48 hours after diversion. However, during the final stages of diversion, sheep developed superimposed metabolic acidosis with increased plasma lactate concentration and high anion gap.
Effect of in-house transport on murine plasma corticosterone concentration and blood lymphocyte populations
Authors: Drozdowicz Carla K. , Bowman Theresa A. , Webb Maria L. , Lang C. Max
Published: January 2024

The effect of in-house transport on plasma corticosterone concentration and blood lymphocyte populations of laboratory mice was investigated. Mice were transported within a research facility at 0900 hours in a pattern designed to simulate that commonly used by investigators prior to experimental manipulation. Plasma corticosterone concentration and wbc count were determined at 0.25, 2, 4, 8, 12, and 24 hours after transport.

A significant (P < 0.05) increase in plasma corticosterone concentration was seen in mice immediately after transport. The normal circadian rhythm of plasma corticosterone concentration was altered for the subsequent 24-hour period. Corresponding significant (P < 0.05) decreases in total WBC numbers, lymphocyte count, and thymus gland weight were observed. The decrease in total blood lymphocyte numbers at 4 hours was reflected in B- and T-lymphocyte populations. The subsequent acute increase in plasma corticosterone concentration was associated with alterations in the cellular components of the immune system. Results of the study indicated that routine in-house transport of laboratory mice should be considered a stressful stimulus.
Effects of sample handling on adrenocorticotropin concentration measured in canine plasma, using a commercially available radioimmunoassay kit
Authors: Hegstad Rebecca L. , Johnston Shirley D. , Pasternak Donna M.
Published: January 2024

A commercially available radioimmunoassay (ria) kit for measurement of human adrenocorticotropin (hacth) was validated for use in dogs. Assay sensitivity was 3 pg/ ml. Intra-assay coefficient of variation (× 100; cv) for 3 canine plasma pools was 3.0 (mean ± sd, 33 ± 0.99 pg/ ml), 4.2 (71 ± 2.4 pg/ml) and 3.7 (145 ± 3.7 pg/ml) %. Interassay cv for 2 plasma pools measured in 6 assays was 9.8 (37 ± 3.6 pg/ml) and 4.4 (76 ± 3.4 pg/ml) %, respectively. Dilutional parallelism was documented by assaying 2 pools of canine plasma at 3 dilutions and correcting the measured result for dilution. Corrected mean concentrations for the first pool were 33 (± 0.99), 36 (± 4.3), and 33 (± 6.8) pg/ml; corrected mean concentrations for the second pool were 145 (± 5.4), 141 (± 10.8) and 125 (± 3.4) pg/ml. Recovery of 1-39hacth added to canine plasma (6.25, 12.5, 25.0, 50.0, and 100.0 pg/ml) was linear and quantitative (slope = 0.890, R2 = 0.961). To test whether anticoagulant or the protease inhibitor, aprotinin, influences acth concentration in canine plasma, acth was measured in canine blood collected in 4 tubes containing anticoagulant: heparin (h), heparin + 500 kallikrein inhibitor units (KIU) of aprotinin/ml (ha), edta (e), and edta + aprotinin (ea). Plasma acth concentration was the same when samples containing h and ha, or ha and e were compared, and was significantly (P < 0.01) lower in samples containing ea. Plasma storage at - 20 C for 1 week or 1 month was not associated with significant change in acth concentration in canine plasma, using any of the 4 anticoagulant treatments. Plasma acth concentration measured after 6 months’ storage at —20 C was significantly (P < 0.01) lower for all anticoagulants used. Synthetic 1-39hacth added to canine blood was accurately recovered (88 to 109%, n = 3) from plasma containing edta, with or without aprotinin, whereas percentage recovery was overestimated by 18 to 91% in heparinized plasma. Plasma acth concentrations in edta- treated canine blood kept at 4 or 22 to 25 C for 15 to 90 minutes prior to centrifugation at 8 C were not significantly different. Plasma acth concentration in canine plasma was affected by storage tube material. Concentration of acth in canine plasma stored in borosilicate glass tubes for 1 week or 1 month at — 70 C was significantly higher than initial acth values (P ≤ 0.01), but was unchanged over time in plasma stored in polypro-pylene or polystyrene tubes.

Sample handling procedures affect canine plasma acth concentration measured by use of the ria kit. Optimal sample handling conditions for plasma acth measurement in dogs include use of edta anticoagulant, blood collected at 20 to 25 C (room temperature) followed by centrifugation within 15 to 90 minutes, and plasma storage in plastic (not glass) tubes for not longer than 1 month at −20 C.
Clinical and biochemical alterations in calves with nutritionally induced polioencephalomalacia
Authors: Sager Ricardo L. , Hamar Dwayne W. , Gould Daniel H.
Published: January 2024

Polioencephalomalacia (pem) was induced in calves by feeding a semipurified, low-roughage diet of variable copper and molybdenum composition. Two formulations resulting in Cu-insufficient and Cu-sufficient forms of the diet were fed (n = 10 and 4 calves, respectively); both diets induced pem. Clinical signs of disease developed as early as 15 days after transition to the experimental diets and included impaired vision, decreased response to external stimuli, and abnormal gait. Grossly evident cerebrocortical lesions consisted of laminar areas of cavitation and/or autofluorescence seen under uv illumination. Hepatic Cu concentration was decreased in calves fed the Cu-insufficient diet, but not below normal range. During the course of feeding either diet, rumen pH decreased, rumen volatile fatty acid concentrations increased, rumen and blood lactic acid concentrations increased, and rumen and plasma thiamine concentrations increased. The thiamine pyrophosphate effect on erythrocyte transketolase activity was unaltered in calves of either diet group. This nutritionally induced form of pem does not appear to be related to Cu deficiency or reduction in plasma or rumen thiamine concentration.
Pharmacokinetics of gentamicin in newborn to 30-day-old foals
Authors: Cummings Linda E. , Guthrie Alan J. , Harkins J. Daniel , Short Charles R.
Published: January 2024

Gentamicin sulfate, equivalent to 4 mg of gentamicin base/kg of body weight, was administered iv to 6 Thoroughbred foals on day 1 (12 to 24 hours of age) and at 5, 10, 15, and 30 days after birth. On day 40 after parturition, gentamicin was given to the mares at a dosage similar to that used in foals. Decay of serum gentamicin concentrations was best described by a 2-compartment model. Among foals, the overall elimination rate constant at 30 days of age was significantly (P < 0.05) greater than at days 1, 10, and 15. There was, however, no difference in the overall elimination rate constant between foals and mares. The volume of distribution (Vd), determined on the basis of total area under the disposition curve, did not change between day 1 and day 30. Mean values of Vd of foals were between 1.5 and 2.5 times higher than the mean Vd of the mares; however, only values from the foals at days 5 and 10 were significantly greater. Both age and interindividual differences were reflected in the total body clearance (ClB) of gentamicin. Total body clearance of gentamicin of foals on day 1 was less than that of foals on days 5, 10, and 30. Additionally, ClB of gentamicin on day 15 was less than that on day 30. There was no significant difference between ClB of foals and mares except for the day-30 group, which had a higher clearance rate than did the adults. Protein binding of gentamicin was < 30% in all groups, and there were no apparent age-related differences.
Quantitative and qualitative properties of host polymorphonuclear cells during experimentally induced Staphylococcus aureus mastitis in cows
Authors: Daley Michael J. , Oldham Elizabeth R. , Williams Thomas J. , Coyle Patricia A.
Published: January 2024

Polymorphonuclear cells have a critical role in the pathogenesis of bovine mastitis. We have documented that experimentally induced Staphylococcus aureus mastitis is associated with cyclic increase and decrease in the quantity of viable bacteria shed in the milk. Concomitant with this cycling of bacteria is an inverse cycling of the hosts cells within the milk. Such somatic cells were determined to be ≥ 95% polymorphonuclear cells. The quality of these cells was evaluated by measuring their relative efficiency of bacterial killing and phagocytosis at various times during an infection. Host polymorphonuclear cells had as much as 10,000-fold variation in the bactericidal failure rate for staphylococci during cell cycling. The most efficient bactericidal effect was observed at or near the peak of the somatic cell count (scc). The ability of these cycling cells to ingest fluorescent beads was also quantitated by use of flow cytometry. The percentage of phagocytic polymorphonuclear cells that ingested fluorescent latex beads ranged from 15 to 80% of the total cell population during cell cycling, and tended to be optimal at or near peak scc. In addition, the average number of beads ingested varied between 1 and 2 particles/polymorphonuclear cell, with as many as 17% of the phagocytic cells ingesting 4 or more beads at maximal efficiency. Polymorphonuclear cells from quarters infected with S aureus varied quantitatively (total scc) and qualitatively (bactericidal activity and phagocytic ability) during the course of an infection. Not only is the quantitity of host's phagocytic cells in the mammary gland central to the defense mechanism against infection, but the biological activation state appears to be equally important. The role of these cells in the pathogenesis of a cycling infection is presented in a model to explain the cyclic nature of mastitis.
Influence of an ω-3 fatty acid-enriched ration on in vivo responses of horses to endotoxin
Authors: Henry Michelle M. , Moore James N. , Fischer J. Kay
Published: January 2024

Because certain inflammatory processes are dependent on the fatty acid composition of the cellular membrane, dietary manipulations that replace ω-6 fatty acids with ω-3 fatty acids may modify inflammatory responses. We investigated the effect of supplemental dietary linseed oil, containing the ω-3 fatty acid, α-linolenic acid, on in vivo responses of horses to endotoxin. One group of horses (n = 6) was fed a control pelleted ration (0% linseed oil), and another group of horses (n = 6) was fed an 8% linseed oil pelleted ration. After 8 weeks of consuming these rations, all horses were given 0.03 μg of Escherichia coli 055:B5 endotoxin/kg of body weight, infused over 30 minutes. Horses were monitored over 24 hours. Compared with baseline values within each ration group, endotoxin infusion caused significant (P < 0.05) increase in rectal temperature, heart rate, and plasma concentration of thromboxane B2, 6-keto-prostaglandin F1α, and fibrinogen and significant (P < 0.05) decrease in total WBC count. Compared with baseline values within each ration group, endotoxin infusion failed to cause significant changes in prothrombin, activated partial thromboplastin, thrombin, or whole blood recalcification times, serum concentration of fibrin degradation products, pcv, or plasma total protein concentration. Before and after endotoxin infusion, horses given the linseed oil ration had longer mean whole blood recalcification time and activated partial thromboplastin time than did horses fed the control ration.
Vaccination of calves with a modified bacterin or oil-in-water emulsion containing alkali-detoxified Salmonella typhimurium lipopolysaccharide
Authors: Anderson Jamie , Smith Bradford P. , Ulrich J. Terry
Published: January 2024

Twenty-six clinically normal colostrum-fed dairy calves were allotted to 5 groups. Calves of groups 1 and 2 served as nonvaccinated controls and were challenge-exposed with variable numbers of organisms. Group-3 calves were vaccinated SC with a modified Salmonella typhimurium bacterin. The bacterin was composed of killed acid-hydrolyzed S typhimurium G30/C21 (Re-mutant) whole cells coated with alkali-hydrolyzed S typhimurium LT-2 lipopolysaccharide, as antigen, and monophosphoryl lipid A, as adjuvant. Calves of groups 4 and 5 were vaccinated with a 2% mineral oil-in-water emulsion containing lipopolysaccharide as antigen and monophosphoryl lipid A and trehalose 6-6′-dimycolate as adjuvants. Calves of groups 3-5 were vaccinated at 2 weeks of age and again at 4 or 6 weeks of age. Adverse reactions were not observed after vaccination. Calves were challenge-exposed orally at 6 or 8 weeks of age with 1.5 × 1011 (groups 1 and 4), or 3.0 × 1011 (groups 2, 3, and 5) colony-forming units of S typhimurium UCD 108-11.

Mortality after challenge exposure was 2 of 5 group-1 calves; 4 of 5 group-2 calves; 5 of 6 group-3 calves; 1 of 5 group-4 calves; and 4 of 5 group-5 calves. Statistical difference between calves of similarly challenge-exposed groups was not evident, indicating failure of either vaccine to protect calves of this age from oral challenge exposure with virulent S typhimurium.
Comparison of several combinations for anesthesia in rabbits
Authors: Hobbs B. A. , Rolhall T. G. , Sprenkel T. L. , Anthony K. L.
Published: January 2024

Few safe and effective anesthesia regimens have been described for use in rabbits, partially because of the susceptibility of this species to sometimes fatal respiratory depression. Although inhalant anesthetics are generally safer than injectable anesthetics, their use may be limited by lack of equipment or facilities. This study was conducted to compare effects of several injectable anesthetics in rabbits on response to noxious stimuli, heart rate, respiratory rate, and rectal temperature. Six injectable anesthetic combinations were administered to rabbits: xylazine-ethyl-(l-methyl-propyl) malonyl-thio-urea salt (emtu), ketamine-emtu, xylazine-pentobarbital, xylazine- acepromazine-ketamine (xak), ketamine-chloral hydrate, and ketamine-xylazine. All combinations induced a depression of respiratory rate. Although rectal temperature values were reduced to some degree in each group, the most profound hypothermia was induced by xak. The combination that induced the longest duration of anesthesia was xak. It was concluded that xak was preferable for longer periods of anesthesia (60 to 120 minutes), although it induces severe hypothermia. For short periods of anesthesia, xylazine-pentobarbital, xylazine- emtu, or ketamine-xylazine were deemed adequate; however, xylazine-emtu induced the best survivability and consistency.
Changes in phospholipids of alveolar lining material in calves after aerosol exposure to bovine herpesvirus-1 or parainfluenza-3 virus
Authors: Engen R. L. , Brown T. T.
Published: January 2024

Pulmonary lavage samples were collected from 90- to 130-day-old calves before and 6 days after aerosol inoculation with bovine herpesvirus-1 (bhv-1) or parainfluenza-3 (pi3) virus. Alveolar lining material was separated from lavage fluids by high-speed centrifugation and phospholipids were extracted from alveolar lining material and analyzed by high-performance liquid chromatography. Phosphatidylcholine and phosphatidylethanolamine were 74.2 ± 6.5% and 13.3 ± 2.8%, respectively, of the total phospholipid content in the surfactant obtained from calves before virus inoculation. Other phospholipids were represented by substantially lower percentages. Infection with either of the 2 viruses caused a significant (P < 0.05) decrease in the percentage of phosphatidylcholine to 66.0 ± 8.0% and 65.1 ± 10.8% in the calves inoculated with bhv-1 and pi3 virus, respectively. A significant (P < 0.05) increase in the percentage of phosphatidylethanolamine to 18.1 ± 2.2% and 17.8 ± 4.5% developed in calves inoculated with bhv-1 and pi3 virus, respectively. Infection with bhv-1 also induced an increase (not significant) in the percentage of phosphatidylinositol from 5.5± 2.8% to 7.8 ± 2.2%. A similar, but not significant, increase in the percentage of phosphatidylinositol was also seen in the calves inoculated with pi3 virus. Less substantial changes in the percentage of other phospholipids were detected after virus infection.
Immunity in swine inoculated with larvae or extracts of a pig isolate and a sylvatic isolate of Trichinella spiralis
Authors: Marinculic Albert , Gamble H. Ray , Urban Joseph F. , Rapic Damir , Zivicnjak Tatjana , Smith Harry J. , Murrell K. Darwin
Published: January 2024

Inoculation of swine with a sylvatic isolate of Trichinella spiralis, designated T s nativa, resulted in low numbers of muscle larvae, compared with muscle larvae accumulation in swine inoculated with a pig type of T s spiralis. Despite low infectivity of T s nativa for swine, primary inoculation resulted in high levels of immunity against challenge infection with T s spiralis. This immunity was expressed in accelerated expulsion of challenge adults from the intestine and reduced numbers of muscle larvae. Pigs inoculated with T s nativa developed cellular and humoral responses similar to those in pigs inoculated with T s spiralis. However, in immunoblots, sera from pigs inoculated with T s nativa recognized additional proteins in muscle larvae excretory-secretory (ES) products, compared with sera from pigs inoculated with T s spiralis. Active immunization of pigs with ES products from T s nativa resulted in numerically higher, but not significantly different levels of immunity, compared with pigs immunized with ES from T s spiralis. The highest levels of immunity were obtained in pigs immunized with a T s spiralis newborn larval extract. The combination of ES products and newborn larval extract did not result in additive levels of immunity. These results indicate that the major immune effector response to Trichinella sp in pigs is against the newborn larvae, regardless of the genetic type of Trichinella sp.
Replication of parainfluenza type-3 virus and bovine respiratory syncytial virus in isolated bovine type-II alveolar epithelial cells
Authors: Castleman W. L. , Northrop P. J. , McAllister P. K.
Published: January 2024

The objectives of our research were to determine whether bovine pulmonary type-II alveolar epithelial cells could be isolated from bovine lung and maintained in tissue culture and to determine whether isolated bovine type-II alveolar epithelial cells would support productive viral replication of bovine parainfluenza type-3 virus and bovine respiratory syncytial virus. Type-II alveolar epithelial cells were isolated from lungs of 4- to 7-day-old male Holstein calves by enzymatic dissociation of pulmonary tissue with trypsin and by separation of cells with the use of filtration and centrifugation on continuous Percoll gradients. Cells were further separated by panning on IgGcoated plastic plates and by lectin binding. Isolated type- II alveolar cells were maintained on basement membrane- coated tissue cultured plates. In culture, type-II cells formed alveolar structures and maintained other cytologic features of type-II cells, including osmiophilic lamellar inclusions. Cell cultures were inoculated with and supported productive replication of bovine parainfluenza type-3 virus and bovine respiratory syncytial virus. This was determined by recovery of infectious viruses from inoculated cell cultures and by identification of viral structures in type-II alveolar epithelial cells by transmission electron microscopy.
Use of a multivariable indexing score for hygiene variables in relation to egg production
Authors: Mohammed Hussni O. , Carpenter Tim E.
Published: January 2024

An indexing system for hygiene variables associated with egg production was developed by use of data collected from chicken flocks in southern California. The data were analyzed by factor and regression analysis.

On the basis of our findings, hygiene index in relation to egg production consists of ventilation system, cooling system, manure removal, and truck movement. Flocks kept under natural ventilation produced, on the average, 2% more hen-day eggs than flocks kept under artificial ventilation. Flocks placed in houses with roof sprinklers produced 3.3% more hen-day eggs, compared with flocks placed in houses with inside foggers and pad. Flocks kept under the system of frequent removal of manure produced 2% more hen-day eggs than flocks kept under the system for which the manure was removed less frequently. Flocks kept in farms that restricted trucks collecting dead birds from entering the premises produced 3.4% more hen-day eggs than those that allowed such trucks to enter the farm.
Effect of age on the concentrations of amino acids in the plasma of healthy foals
Authors: Zicker Steven C. , Spensley Michael S. , Rogers Quinton R. , Willits Neil H.
Published: January 2024

The concentrations of 23 ammo acids in the plasma of 13 healthy foals were determined before suckling, when foals were 1 to 2 days old, 5 to 7 days old, 12 to 14 days old, and 26 to 28 days old. The ratio of the branched chain amino acids to the aromatic amino acids was also calculated at the 5 time points. Analysis of the concentrations at the 5 ages revealed a significant temporal relationship for each amino acid ranging from a polynomial order of 1 to 4 inclusively. There were significant differences between several concentrations of amino acids in plasma at specific sample times; however, no consistent patterns were revealed. The concentrations of amino acids in healthy foals were markedly different from previously determined values in adult horses. The significant differences in the concentrations of amino acids in plasma of healthy foals at the 5 ages may represent developmental aspects of amino acid metabolism or nutrition.
Efficacy of a pseudorabies virus vaccine based on deletion mutant strain 783 that does not express thymidine kinase and glycoprotein I
Authors: van Oirschot J. T. , Moormann R. J. M. , Berns A. J. M. , Gielkens A. L. J.
Published: January 2024

The vaccine efficacy of a genetically engineered deletion mutant strain of pseudorabies virus, strain 783, was compared with that of the conventionally attenuated Bartha strain. Strain 783 has deletions in the genes coding for glycoprotein I and thymidine kinase.

In experiment 1, which had a 3-month interval between vaccination and challenge exposure, strain 783 protected pigs significantly (P < 0.05) better against virulent virus challenge exposure than did the Bartha strain. The growth of pigs vaccinated with strain 783 was not arrested, whereas that of pigs vaccinated with the Bartha strain was arrested for 7 days. Of 8 pigs given strain 783, 4 were fully protected against challenge exposure; none of the pigs given strain Bartha was fully protected.

In experiment 2, which had a 3-week interval between vaccination and challenge exposure, the growth of pigs vaccinated with strain 783 was arrested for 3.5 days, whereas that of pigs vaccinated with the Bartha strain was arrested for 6 days.

In experiment 3, pigs with moderate titer of maternal antibodies were vaccinated twice im or once intranasally with either strain 783 or Bartha and were challenge-exposed 3 months after vaccination. Pigs given strain 783 twice im were significantly (P < 0.05) better protected than were the other pigs. They had growth arrest of only 6 days, compared with 9 days for pigs of other groups, and shed less virus after challenge exposure. Results of this study indicate that the vaccine based on the deletion mutant strain 783 is more efficacious than is the Bartha strain of pseudorabies virus.
Cytotoxicity against autologous, allogeneic, and xenogeneic tumor targets by human recombinant interleukin-2-activated lymphocytes from healthy dogs and dogs with lung tumors
Authors: Mitchell Dawn H. , Withrow Stephen J. , Johnston Michael R. , Kruse Carol A.
Published: January 2024

Before dogs with lung tumors were treated by adoptive immunotherapy, the ability of canine blood lymphocytes (pbl) from the peripheral circulation to differentiate in vitro in the presence of human recombinant interleukin-2 (rIL-2) and become tumoricidal was investigated. The pbl from healthy dogs (n = 6) and dogs with lung tumors (n = 5) were grown in culture medium alone, in the presence of rIL-2 to generate lymphokine-activated killer (lak) cells, or with phytohemagglutinin (pha) and rIL-2 to generate autologous-stimulated lymphocytes (asl). After 4 days, cytotoxicity by the asl, lak, and pbl was determined in a 4-hour 51chromium-release assay. Target cells in the assay were short-term cultured enzyme digests of autologous (self), allogeneic (genetically different) primary tumors, and Raji, the xenogeneic human lymphoma cell line. The pbl cultured without rIL-2 were not cytotoxic against any tumor. However, when a dog's pbl were activated in vitro, they killed the dog's own tumor, asl more effectively than lak cells. Pulmonary adenocarcinomas and an osteosarcoma metastasis to lung were among the autologous tumors assayed. Against an allogeneic canine osteosarcoma, asl generated from healthy dogs were significantly more cytolytic than lak from healthy dogs, or than asl generated from tumorbearing dogs. Cytotoxicity was greater against allogeneic tumor than against Raji. Lectin-dependent cellular cytotoxicity, tested by including pha in the assay medium with lymphocytes and Raji cells, by asl and lak was greater than cytotoxicity of Raji without pha. Because asl were more cytolytic than lak against all targets in vitro, they may be more beneficial than lak for immunotherapy of canine tumors.
Differences in signs and lesions in sheep and goats with enterotoxemia induced by intraduodenal infusion of Clostridium perfringens type D
Authors: Blackwell Timothy E. , Butler Daniel G. , Prescott John F. , Wilcock Brian P.
Published: January 2024

Enterotoxemia was induced in 4 lambs and 4 goat kids by continuous intraduodenal infusion of a whole culture of Clostridium perfringens type D. Clinical signs, hematologic values, biochemical alterations, and postmortem lesions in the lambs and goat kids were compared. The 4 lambs and 4 goat kids died within 25 hours of beginning the infusions. Lesions were not observed in the gastrointestinal tract of the 4 lambs; however, severe hemorrhagic enterocolitis was found in the 4 goat kids. This difference between the lambs and goat kids in the lesions caused by experimentally induced enterotoxemia may explain the discrepancies reported between sheep and goats in clinical signs, response to treatment, and efficacy of vaccination observed in naturally induced enterotoxemia in the 2 species.
Kinetics of uptake and effects of topical indomethacin application on protein concentration in the aqueous humor of dogs
Authors: Spiess Bernhard M. , Mathis George A. , Franson K. L. , Leber A.
Published: January 2024

The pharmacokinetic properties of indomethacin and its effects on aqueous protein values were studied in 15 clinically normal Beagles. The dogs were treated every 6 hours with 1% indomethacin suspension in 1 eye, with the other eye serving as a control. After 24 hours, the dogs were anesthetized and samples of aqueous humor (ah) were drawn by aqueocentesis at 0, 15, 30, 60, and 90 minutes after initial paracentesis. Additional samples were drawn at the time of euthanasia, 180 (6 dogs) and 360 minutes (9 dogs) minutes after initial paracentesis. Blood samples were obtained at each treatment and at each aqueocentesis. The eyes were enucleated after dogs were euthanatized. Aqueous protein concentrations and indomethacin concentrations in ah, plasma, and different ocular tissues were determined.

Topical indomethacin administration had no effect on baseline protein concentrations of ah. It reduced protein concentrations in ah significantly at all times after initial aqueocentesis. This reduction was approximately 30%. Indomethacin in the ah is mostly protein-bound. Concentrations were 350 ng/ml in primary ah and 1,305 ng/ml in secondary ah, 90 minutes after initial aqueocentesis. Free-drug concentrations were relatively constant at about 220 ng/ml.

Indomethacin administered topically is readily absorbed by the ocular adnexae, reaching a steady-state concentration of 25 ng/ml in blood plasma 18 hours after the start of treatment. Plasma concentrations were 50 times lower than therapeutically effective concentrations. High indomethacin concentrations were found in the cornea only. Low concentrations were found in the iris and ciliary body, the lens, and in the choroid. On the basis of our findings, we conclude that topically administered indomethacin is effective in reducing protein concentrations in secondary ah and is rapidly eliminated from the eye.
Pigment epithelial function in canine retina
Authors: Kommonen Bertel , Dawson William W. , Farmer Ronald
Published: January 2024

The lateral distribution and temporal changes in the eye standing potential of 15 dogs with normal eyes (as determined by use of an ophthalmoscope and electroretinography) were measured by use of noninvasive methods. The standing potential was converted to an alternating potential by controlled eye movement. The light peak occurred 6 minutes after a stimulus intensity increase of 4 log units. The ratios of the highest measured voltage after the light step divided by the voltage measured immediately before the light step ranged from 1.27 to 2.07 (mean 1.74 ± sem-, 0.064). The responses typically decayed slowly after the light peak. The potential after the light peak did not return to prelight step values during the observation period. The field potential of the standing potential decreased nonlinearly in temporal direction from the outer canthus.
Developmental changes in the regulation of plasma growth hormone concentrations in Holstein calves
Authors: Sartin J. L. , Kemppainen R. J. , Cummins K. A. , Marple D. N. , Williams J. C.
Published: January 2024

A study was initiated to determine whether development of a functional ruminant digestive system was associated with alterations in plasma growth hormone (gh) concentration. Holstein bull calves were fed milk or milk with grain until studied at the age of 1 month (n = 12). Calves placed on pasture with some grain supplementation were studied at the age of 3 months (n = 6) to determine plasma gh concentration in an animal with fully developed ruminant metabolism. Blood samples were taken at 10-minute intervals for 5 hours, followed by administration of bovine gh-releasing factor (0.075 μg/kg of body weight) and subsequent blood sample collection for 1 hour. On the following day, a blood sample was collected via jugular cannula, clonidine (10 μg/kg) was administered, and blood samples were subsequently obtained. Data indicated that milk-fed calves had higher mean plasma gh concentration than did either milk/grain-fed or older calves. The difference in mean plasma gh concentration was related to higher secretory pulse amplitude. Pituitary responses to bovine gh-releasing factor did not differ among the 3 groups, but response to clonidine were greater in milk-fed calves than in calves of the other groups. These data indicate that the change from a nonruminant to a ruminant-type gastrointestinal tract, perhaps attributable to subsequent changes in metabolism, may induce changes in hypothalmic function to decrease gh concentration.
Luteinizing hormone and progesterone concentrations and induction of estrus after use of norgestomet ear implants or constant infusion of gonadotropin-releasing hormone in anestrous, nonlactating dairy goats
Authors: Bretzlaff K. N. , Nuti L. C. , Scarfe A. D. , Elmore R. G. , Capehart J. , Varner D. D. , Weston P. G.
Published: January 2024

Plasma luteinizing hormone and progesterone concentrations, time to onset of estrus, and pregnancy rates were determined in nonlactating anestrous does given 1 of 4 treatments: subcutaneous ear implants containing 3 mg of norgestomet for 9 days (nor; n = 6); subcutaneous administration, using osmotic minipumps, of 250 ng of gonadotropin-releasing hormone (GnRH)/h for 48 hours (GnRH; n = 6); 3 mg of nor for 9 days, followed immediately by 250 ng of GnRH/h for 48 hours (nor + GnRH; n = 6); or no treatment (control; n = 6). During the 72-hour period after removal of nor or insertion of GnRH pumps, 6 of 6, 0 of 6, 6 of 6, and 3 of 6 does were observed in estrus at a mean (± se) of 49 (± 3.0), 0(± 0), 32 (± 2.0), and 35 (± 13.8) hours in groups nor, GnRH, nor + GnRH, and control, respectively. Time from end of treatment to peak concentrations of luteinizing hormone were 56 ± 4.0, 28 ± 4.7, 34 ± 4.3, and 41 ± 9.7 hours (mean ± se) for nor, GnRH, nor ± GnRH, and control, respectively. Peak concentrations of luteinizing hormone were significantly greater and occurred significantly later in does given nor. Progesterone concentrations in does that became pregnant increased to concentrations ≥ 1.0 ng/ml 3 to 5 days after breeding and remained high.

Functional corpora lutea (cl) was found in 6 does that did not become pregnant, 1 cl was associated with pseudopregnancy and 1 cl was associated with ovulation prior to placement of the GnRH pumps. Functional cl failed to form in 10 of the 12 does in groups GnRH and control. Does had either continual low concentrations of progesterone (3 does) or short-term increases in concentrations of progesterone (7 does). Conception rates for does in groups nor, GnRH, nor + GnRH, and control were 83%, 0%, 50% and 0%, respectively. Four does given GnRH and 3 control does were observed in estrus and were bred during the subsequent 2-week period. All of these does, except 1 control became pregnant subsequent to these breedings.

The treatments nor and nor + GnRH were effective in inducing a synchronized estrus in dairy goats. However, the use of bucks to detect estrus may have introduced the buck effect and enhanced the performance of nor alone, which has not been this effective in other studies with small ruminants.
Fluorophotometric evaluation of experimental blood-aqueous barrier disruption in dogs
Authors: Ward Daniel A. , Ferguson Duncan C. , Kaswan Renee L. , Green Keith , Bellhorn Roy W.
Published: January 2024

A protocol for performing slit-lamp fluorophotometry of the anterior chamber in dogs was established. The technique was then used to develop a model of blood-aqueous barrier disruption that can be used for comparative testing of ophthalmic anti-inflammatory drugs. It was determined that barrier disruption induced by a slow, controlled paracentesis of a small volume of aqueous humor may provide the most reliable model for drug testing. Additionally, fluorophotometry proved to be a sensitive and accurate means of detecting breakdown of the blood-aqueous barrier.
Use of orthopedic markers for quantitative determination of proximal radial and ulnar growth in foals
Authors: Smith Barbara L. , Auer Joerg A. , Taylor Tex S. , Hulse Donald S. , Longnecker Michael T.
Published: January 2024

Cortical bone screws were implanted into the proximal portion of the right and left radius and ulna of 6 newborn Quarter Horse foals as radiographic markers for measurement of growth. Distance between markers on a lateral radiographic view was measured. Radiographs were taken at 2-week intervals until the horses were 8 weeks old, at 4-week intervals until they were 48 weeks old, and at 12-week intervals until they were 72 weeks old.

The proximal radius and ulna grew at similar rates during the 72-week period of evaluation, and growth continued throughout 72 weeks. The proximal radius grew 3.5 cm, and the ulna grew 3.4 cm. Although the rates of growth were similar, growth from the ulnar physis contributed only to the length of the olecranon; growth was not transmitted to the ulnar diaphysis distal to the cubital joint. The proximal radius slid distally in relation to the ulna as growth occurred at the proximal radial physis.

These findings suggest that transfixing the ulna to the radius while growth is occurring at the proximal radial physis impedes the natural shifting process, and subluxation of the elbow can result. Severity of subluxation would be inversely related to the age of the horse at the time of transfixation.
Effect of humidification on the airways of cats during high-frequency ventilation
Authors: Whitfield J. B. , Bjorling D. E. , Munnell J. F.
Published: January 2024

The effect of humidity on the histologic lesions induced by high-frequency jet ventilation was investigated in 12 healthy cats. After 16 hours of ventilation, the appearance of the tracheal epithelium ranged from normal to necrotic. The damage was considerably more severe in the trachea of cats of the group ventilated without added humidity. Increasing the relative humidity to 63% at 24 C had a protective effect, but further increasing the relative humidity to 92% at 35 C did not appear to provide significantly more protection. The bronchi and distal airways had minimal, if any, damage in all groups.
Comparison of phenotypic characteristics of Salmonella spp isolated from healthy and ill (infected) chickens
Authors: Nolan Lisa K. , Wooley Richard E. , Brown John , Payeur Janet B.
Published: January 2024

Phenotypic characteristics of 12 paired, Salmonella serotypes isolated from healthy and ill chickens were compared. Variables compared included antibiotic resistance profiles, production of colicins and siderophores, mannose-sensitive hemagglutination of erythrocytes, resistance to serum complement, carbon source utilization, presence and transmissibility of R plasmids, and invasiveness in primary chicken kidney cell culture. Differences were found between pairs for utilization of carbon sources, mannose-sensitive hemagglutination of erythrocytes, and invasiveness in cell culture.
Pathologic changes, tissue distribution, and extent of conversion to ethylenethiourea after subacute administration of zinc ethylene-bis-dithiocarbamate (zineb) to calves with immature rumen function
Authors: Nebbia Carlo , Ferrero Enrico , Valenza Federico , Castagnaro Massimo , Re Giovanni , Soffietti Maria Gennaro
Published: January 2024

The toxicity of zinc ethylene-bis-dithiocarbamate (zineb), a widely used fungicide, was studied in four 4-week-old Friesian calves with immature rumen function. Calves were first subjected to liver biopsy, and thereafter, 3 of them were orally administered 200 mg of zineb/kg of body weight daily for 80 days, whereas the fourth calf served as control and remained untreated. Clinical, hematologic, and pathologic (including ultrastructural) findings were recorded. The distribution in body fluids and tissues of the parent compound and one of its main metabolites, ethylenethiourea (etu), also was examined. Treated calves had unthrifty appearance and reduction in weight gain. They also had remarkable impairment of thyroid function, as reflected by reduction in serum concentrations of triiodothyronine and thyroxine and increase in weight of the thyroid gland associated with epithelial vacuolization and foci of hyperplasia. Moderate increase in liver glycogen content and impairment in maturation of germ cells were recorded consistently. Whereas zineb was widely distributed in body tissues, etu accumulated mainly in the liver and the thyroid gland, although noticeable concentrations also were attained in muscle. Data were consistent with involvement of etu mainly in the pathogenesis of thyroid gland lesions, and indicate that unweaned calves given zineb develop a clinicopathologic syndrome that does not differ qualitatively from that already described in adult cattle exposed to zineb.