bluuebunny/crossref_metadata_2025 huggingface dataset:
Binding of 125I-labeled endotoxin to bovine, canine, and equine platelets and endotoxin-induced agglutination of canine platelets
Authors: Meyers K. M. , Boehme M. , Inbar O.
Published: February 2025

Endotoxin from Escherichia coli O127:B8, Salmonella abortus-equi and S minnesota induced clumping of some canine platelets (plt) at a final endotoxin concentration of 1 μ/ml. Endotoxin-induced clumping of canine plt was independent of plt energy-requiring processes, because clumping was observed with canine plt incubated with 2-deoxy-d-glucose and antimycin A. The plt responded to adenosine diphosphate before, but not after, incubation with the metabolic inhibitors. Endotoxin induced a slight and inconsistant clumping of bovine and equine plt at high (mg/ml) endotoxin concentration. High-affinity binding sites could not be demonstrated on canine, bovine, and equine plt, using 125I-labeled E coli O127:B8 endotoxin. Nonspecific binding was observed and appeared to be due primarily to an extraneous coat on the plt surface that was removed by gel filtration. The endotoxin that was bound to plt did not appear to modify plt function. An attempt to identify plasma proteins that bound physiologically relevant amounts of endotoxin was not successful. The significance of the endotoxin-induced clumping or lack of it on the pathophysiology of endotoxemia is discussed.
Antibody response in lacteal secretions of cows after immunization with various concentrations of staphylococcal and streptococcal antigens
Authors: Opdebeeck J. P. , Norcross N. L.
Published: February 2025

A total of 55 lactating Holstein cows were randomly allocated to 6 groups. Five of these groups (No. 2 through 6) were inoculated on 2 occasions in the region of the external inguinal lymph node with various concentrations of 3 bacterial antigens. Saline solution was administered to group 6 as a control. The antigen preparations consisted of a Staphylococcus aureus bacterin, a Streptococcus agalactiae bacterin, and staphylococcal a-toxoid. These antigens were administered as a composite preparation suspended in saline solution. The concentration of antibody in the lacteal secretions, represented by immunoglobulin G specific for each of the 3 vaccine antigens, was monitored during the 18-week experimental period by enzyme-linked immunosorbent assay. The concentration of each of the 3 vaccine components which was required to stimulate a maximal immune response in the lactating gland appears to have been established.
Studies on immunity to Haemophilus pleuropneumoniae infections in mice
Authors: Sebunya T. N. K. , Saunders J. R.
Published: February 2025

SUMMARY AND CONCLUSIONS

A murine model of experimentally induced Haemophips pleuropneumoniae respiratory tract infections was developed and used to evaluate the efficacy of bacterins.

Various doses of 3 H pleuropneumoniae strains (serotype 1 and 5) were administered intranasally (in) to groups of anesthetized Swiss White mice. The accumulated mortality per group at 5 days after they were inoculated was used to calculate the median lethal dose (ld50), which ranged between 1.4 × 106 and 5.4 × 107 bacteria. There was correlation between dose administered, incubation period of the disease, and mortality. The induction of H pleuromeumoniae disease in the mouse was reproducible and resembled that of naturally occurring porcine Haemophilus pleuropneumonia.

The murine model of exposure was used to evaluate the efficacy of H pleuropneumoniae serotype 5 (strain B786760) bacterins administered subcutaneously (sc) and in. Vaccination by sc route induced slightly higher titers of specific seroagglutinins, compared with the response indluced by the in route, and the former was more effective in protecting mice against in challenge with H pleuropneunoniae. However, vaccination was not efficacious in mice given a challenge dose > 1.2 ldm. The percentage survival rates in the sc and in vaccinated mice were significantly greater than in the control groups at P < 0.01 and P < 0.05, respectively.
Aprindine for treatment of ventricular arrhythmias in the dog
Authors: Muir William W. , Bonagura John D.
Published: February 2025

Aprindine hydrochloride was administered iv and orally to 20 dogs with ventricular tachycardia. Seventeen of the 20 dogs had been unsuccessfully treated with conventional antiarrhythmic drugs. Fifteen of the 20 dogs converted to sinus rhythm after iv aprindine therapy, 4 dogs demonstrated marked slowing of their ventricular tachycardia, and 1 dog showed an increase in the rate of ventricular tachycardia. Emesis, ataxia, salivation, and nystamus were observed in 7 dogs after iv aprindine therapy. One dog developed clinical and laboratory evidence compatible with acute hepatitis.
Occurrence and characterization of plasmids in field isolates of Bordetella bronchiseptica
Authors: Graham Amy C. , Abruzzo George K.
Published: February 2025

Twenty-seven isolates of Bordetella bronchiseptica were examined for the presence of plasmid DNA. Eleven of the isolates contained plasmids. An attempt was made to correlate the presence of plasmids with resistance to a number of antibiotics or heavy metals or with production of bacteriocins. Eight of the isolates contained a plasmid of approximately 35 megadaltons molecular weight; these isolates were all resistant to 1 mM mercuric chloride. There were no other correlations between plasmid content and any of the phenotypes tested. The plasmids conferring resistance to mercuric chloride were transferred by conjugation to Escherichia coli K-12. The plasmid-bearing isolates were then compared with their isogenic plasmidless parent for resistance to a number of antibiotics. Isolates acquiring the plasmids demonstrated increased resistance to streptomycin and ampicillin, as well as to mercuric chloride. The 8 plasmids were also analyzed by restriction endonuclease digestion.
Comparison of two dose rates and two management systems for synchronization of estrus in cattle
Authors: Donaldson L. E. , Glaphin S. P. , Green G. A.
Published: February 2025

Two dose rates and 2 management systems for the synchronization of estrus in cattle, using prostaglandin F2α (pgf2α), were compared within 3 dairy and 3 beef herds. There was no statistical difference in responses between herds or breeds. There was no statistical difference between the estrous response produced by the 12.5-mg dose rate (53.6%) and that produced by the 25-mg dose rate (56.7%, P = 0.5). The 10-day, 1-injection management system produced a 21.7% better estrous response than that produced by the 2-injection system (64.5% vs 42.8%, respectively; P = 0.0001). Most (79.5%) of the difference in estrous response between management systems was accounted for by cows not responding to the 2nd injection of the 2-injection system. The interval from injection to estrus after 1 pgf2α injection was shorter than after 2 pgf2α injections (63.6 ± 25.2 vs 70.3 ± 23.8 hours, respectively). The percentage of all cows in the artificial insemination program that were in estrus 56 to 80 hours after injection was 27.4%.
Experimentally induced Fasciola hepatica infection in young calves
Authors: Hall R. F. , Lang B. Z. , Waldhalm D. G. , Farrell C. J. , DeLong W. J. , Everson D. O.
Published: February 2025

Twenty-four calves between 1 and 66 days of age (allotted to 3 age groups) were each inoculated with 100 Fasciola hepatica metacercariae to determine their susceptibility to fluke infection. Studies included measuring the immune response, as determined by enzyme-linked immunosorbent assay, fecal egg counts (to evaluate the length of the life cycle between times of metacercariae ingestion and fluke maturation), and the numbers of flukes in the liver of the calves at slaughter.

Fasciola hepatica ova started appearing in the feces of calves, all ages, at 60 days after inoculations were done and reached average maximal number by 80 to 90 days. The enzyme-linked immunosorbent assay results indicated that the oldest group of calves had significantly (P < 0.01) greater antibody concentration from 6 weeks until the 18th to 20th week after inoculation than did the 2 younger groups. At slaughter, calves in the 52- to 66-day age group had mean fluke numbers significantly (P < 0.01) greater than did calves in the 1- to 27-day and 35- to 44-day age groups.
Socialization as a factor in resistance to infection, feed efficiency, and response to antigen in chickens
Authors: Gross W. B. , Siegel Paul B.
Published: February 2025

Chickens were habituated to human beings (socialized) by being talked to, offered food, and handled gently. After 7 weeks of socialization, the birds were challenge exposed with Escherichia coli. When compared with ignored groups, the socialized birds showed more than a 60% reduction in the prevalence of death and pericarditis. Furthermore, small flocks of socialized birds were more uniform in their response to E coli than were similar nonsocialized flocks. Socialized chickens also had improved feed efficiency and increased antibody response to canine rbc. Socialization was also applied easily to larger flocks of chickens.
Influence of density and location on degradation of sustained-release boluses given to cattle
Authors: Riner John L. , Byford Ronnie L. , Stratton Louie G. , Hair Jakie A.
Published: February 2025

To better understand the factors involved in erosion of sustained-release ruminal boluses, studies were conducted to determine the relationship between density of the bolus and location in the forestomachs and the influence of these factors on bolus erosion. Boluses with densities of 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, and 2.4 g/cm3 were produced from inert materials and administered to 6 fistulated Hereford heifers. A minimum density of 1.6 g/cm3 was required to prevent regurgitation from the ruminoreticulum and a minimum of 2.0 g/cm31 for retention in the reticulum. Release of oxytetracycline from 2 boluses placed in the reticulum or in the rumen was measured in 12 fistulated Hereford heifers. Boluses retained in the reticulum had higher rates of release (P < 0.05) than those in the rumen. The smaller reticular compartment apparently caused greater contact between individual boluses and resulted in more rapid erosion.
Serotypes of Pasteurella haemolytica in sheep in the midwestern United States
Authors: Frank G. H.
Published: February 2025

Nasal secretions were collected from healthy lambs from flocks in Iowa and the surrounding states for 2 consecutive years. The 1st year, 322 lambs from 61 flocks yielded 202 Pasteurella haemolytica isolates, representing 9 established serotypes and 30 untypeable isolates. The 2nd year, 249 lambs from 49 flocks yielded 73 isolates, representing 9 established serotypes and 7 untypeable isolates. More isolates belonged to serotype 2 than to any other serotype. Serotypes 3, 4, and 10 (members of biotype T), were not isolated. Serotype 12 was also isolated and identified.
Immediate effects of metrizamide myelography on electromyographic findings in dogs
Authors: Knecht Charles D. , Hathcock John T. , Redding Richard W.
Published: February 2025

Electromyographic (emg) findings were recorded before, immediately after, and 5 minutes after metrizamide myelography and epidurography in 13 clinically normal dogs. Motor unit potentials were observed immediately after injection in 6 of 13 myelograms, 6 of 11 ventrodorsal epidurograms 1 of 12 lateral epidurograms. Because emg abnormalities did not persist for 5 minutes, reliable emg can be recorded after metrizamide myelography and epidurography.
Porphyrin values and treatment of feline solar dermatitis
Authors: Irving R. A. , Day R. S. , Eales L.
Published: February 2025

Sixteen cats with solar dermatitis were examined for heme biosynthesis abnormalities, and the results were compared with data obtained from 142 normal cats. Evidence of feline porphyria related to solar dermatitis was not established; however, carotenoid therapy was often successful.
Experimental lead toxicosis in ponies: Comparison of the effects of smelter effluent-contaminated hay and lead acetate
Authors: Burrows G. E. , Borchard R. E.
Published: February 2025

Grass hay produced in the Coeur d'Alene River Basin of northern Idaho was fed to a group of 4 ponies. The hay contained Pb in concentration of 423 ± 82 mg/kg and Cd in concentration of 10.8 ± 1.4 mg/kg, resulting in daily exposures of the ponies to approximately 7.4 mg of Pb/kg and 0.19 mg of Cd/kg/day. The results in this group of ponies were compared with those from a group fed noncontaminated grass hay and given a daily dose of 10 mg of Pb/kg of body weight, in the form of lead acetate. Clinical toxicologic signs, hematologic changes, and blood and tissue Pb concentrations were similar in the 2 groups. However, the severity of the disease process appeared to be greater in the ponies fed the Pb- and Cd-contaminated hay. This was shown clearly by the shorter interval between onset of clinical changes and death in the ponies fed contaminated hay. The possibility of multiple heavy metal effects is discussed. Clinical toxicologic signs observed include incoordination, labial paresis, pharyngeal paresis, cns depression, anorexia, and body weight loss. Anemia or marginal anemia was common and was often accompanied by the appearance of nucleated rbc and Howell-Jolly bodies in peripheral blood. Neither the hematologic response nor the blood Pb concentrations were reflective of the severity of poisoning, although blood Pb concentrations were > 0.35 μg/ml once clinical signs of toxicity were observed. Liver, kidney, spleen, brain, and bone Pb concentrations and liver, kidney, and brain Cd concentrations were increased in both the ponies fed contaminated hay and the ponies given lead acetate.
Dynamics of nonclinical bovine intramammary infections with major and minor pathogens
Authors: Rainard P. , Poutrel B.
Published: February 2025

Udder infections were recorded in 3 herds throughout a lactation period with bacteriologic examination being done at 3-week intervals. New infection rates and levels of infection at calving differed significantly (P < 0.001) between herds, but persistence of infection did not. Of the 324 infections, 80.5% lasted up to drying off. Of quarters infected with major pathogens, 16.8% eliminated their infection (63% became reinfected); 20.8% of quarters infected with minor pathogens eliminated their infection (43% became reinfected).

Significant differences in persistence of infections, quarter clearing rate (defined as the rate at which infected quarters become and remain noninfected) and ability to give way to and to take place of a preexistent infection, did not occur between Corynebacterium bovis and major pathogens. Though 66% of coagulase-negative staphylococci infections persisted up to drying off, they disappeared more frequently (P < 0.01).
Complete immobility produced in dogs by xylazineatropine: Antagonism by 4-aminopyridine and yohimbine
Authors: Wallner Barbara M. , Hatch Roger C. , Booth Nicholas H. , Kitzman Joseph V. , Clark J. A Derrell , Brown John
Published: February 2025

SUMMARY AND CONCLUSIONS

Fasted, atropinzeed crossbred dogs of both sexes (6 dogs/group) were injected im with a standard dose (2.2 mg/kg) of xylazine. When fully sedated, the dogs were given an iv injection of a large dose (0.5 mg/kg) of atropine sulfate. The dogs became completely relaxed and immobile. Pedal, jaw, tongue, palpebral, and righting reflexes were decreased or abolished. The cough reflex remained intact. Respiration was not depressed. Heart rate increased somewhat, and mucous membranes retained a healthy pink color. The dogs did not respond to auditory or pin-prick stimuli and could not be aroused.

When fully immobilized (3 to 13 minutes), the dogs were injected iv with saline solution (controls), 4-aminopyridine (4-ap; 0.3 mg/kg), yohimbine (0.125 mg/kg), or the combination of 4-ap + yohimbine. Mean times to ability to walk on leash after injection of test substances were as follows: 76 minutes for controls; 25.4 minutes for dogs given 4-ap; 8.7 minutes for dogs given yohimbine; and 4.8 minutes for dogs given 4-ap + yohimbine. Mean times for total recovery of spontaneous activity and eating were 3.8 hours, 2.5 hours, 1.1 hours, and 1.6 hours, respectively. Relapse to unconsciousness did not occur in dogs given 4-ap, yohimbine, or 4-ap + yohimbine. During early recovery, several dogs treated with 4-ap + yohimbine had mild delirium, typical of a large dose of atropine. Otherwise, recovery was without unusual effects.

Four atropinized dogs were immobilized with xylazine-atropine (large dose). Cannulas and electrodes were placed for measurement of lead II ecg, biceps femoris bipolar emg, parietal monopolar eeg, and femoral arterial pressure. Respiration was measured by pneumograph cuff and by a minute volume meter attached to an endotracheal tube. All margins of wounds (used in instrumentation) were moistened with lidocaine.

The iv injection of the combination of 4-ap + yohimbine caused (in order)—(i) a decrease in initially elevated arterial pressure and an increase in respiratory rate, depth, and minute volume (“respiratory lift” was also observed in intact dogs), (ii) slight increase in heart rate without cardiac arrhythmias, (iii) emg activity preceding and accompanying gross muscle movements; (increased frequency of high voltage slow waves and of superimposed low voltage activity in eeg tracings [also preceding and accompanying gross muscle movements]); and (iv) behavioral arousal in 2 to 4 minutes.

The results indicate that dogs can be safely and completely immobilized with a combination of xylazine-atropine (large dose), that this immobile state may be useful in conducting several minor surgical procedures in veterinary practice, and that surgical operation might be performed with supplemental xylazine and local anesthetic. A major advantage of inducing this immobility with xylazine-atropine (large dose) is its prompt antagonism by 4-ap + yohimbine.
Effects of tylosin feeding on the antibiotic resistance of selected gram-positive bacteria in pigs
Authors: Christie P. J. , Davidson J. N. , Novick R. P. , Dunny G. M.
Published: February 2025

SUMMARY AND CONCLUSIONS

The effect of tylosin on macrolide resistance of gram-positive bacteria of pigs was determined. After an initial base-line period during which the pigs were given antibiotic-free feed, 1 group of 8 pigs was given tylosin feed (100 g/US ton of feed), and a 2nd group of 7 was given antibiotic-free feed. Samples were taken at 2- to 3-week intervals. For each pig, rectal, skin, and nasal swab samples were collected for enumeration of fecal streptococci and skin and nasal staphylococci. Percentages of macrolide resistant organisms of each group were tabulated on the basis of colony counts from antibiotic free and erythromycin-containing plates. After the introduction of tylosin into the feed of 1 group, a clear difference between the 2 groups with respect to the macrolide resistance of their gram-positive microflora was observed. The data indicate that tylosin feeding results in an increase in macrolide resistance of the bacterial flora of pigs.
Cardiopulmonary effects of thiopental/lidocaine combination during anesthetic induction in the dog
Authors: Rawlings Clarence A. , Kolata Ronald J.
Published: February 2025

The cardiopulmonary effects and tendencies to produce ventricular arrhythmias were evaluated in 13 dogs given a surgical plane of anesthesia by thiopental (iv) or a combination of thiopental and lidocaine (iv). Thiopental (22 mg/kg of body weight) was compared with a combination of thiopental (11 mg/kg) and lidocaine (8.8 mg/kg). Preanesthetic agents were not given. Both methods for iv anesthesia provided a smooth induction suitable for easy intubation. The thiopental/lidocaine combination had a shorter duration, produced no arrhythmias, and resulted in less cardiopulmonary depression than did thiopental alone. Bigeminy developed after intubation during 19 of 20 thiopental inductions as compared with that in 0 of 22 thiopental/lidocaine inductions. The bigeminies were preceded by systemic hypertension and tachycardia which developed as the trachea was being intubated. The increase in aortic pressure and heart rate was minimal after intubation during the thiopental/lidocaine inductions. Five minutes after administration of thiopental alone, increases in heart rate, aortic pressure, total peripheral vascular resistance, and left ventricular systolic and end-diastolic pressures were observed. When these increases in rate, preload, and afterload were considered in relation to a stabile maximum positive first derivative of left ventricular pressure, left ventricular contractility was considered to be decreased. Mild respiratory acidosis and hypoxemia were present at 5 and 10 minutes after thiopental induction. Because the combination of thiopental/lidocaine had less cardiopulmonary depressive effects and protected against arrhythmias, it would appear to be a good method for anesthetic induction of the patient with cardiopulmonary disease. In the patient with normal cardiopulmonary function, thiopental produces only a moderate and reversible depression.
Hemagglutination with formalin-fixed erythrocytes for detection of canine parvovirus
Authors: Mathys A. , Mueller R. , Pedersen N. C. , Theilen G. H.
Published: February 2025

Formalin-fixed rhesus macaque erythrocytes were tested for their suitability in a hemagglutination (ha) test for detection of canine parvovirus in feces. Formalin fixation of the rbc had no adverse influence on ha sensitivity or specificity, simplified the test procedure, and provided a practical means for standardization of ha results.
Vaccination of pony foals with M-like protein of Streptococcus equi
Authors: Srivastava S. K. , Barnum D. A.
Published: February 2025

The M-like protein of Streptococcus equi was precipitated with alum and inoculated into rabbits and foals. Samples were tested for serum and nasal passive hemagglutinating antibody (pha) levels and for the stimulation response of lymphocytes. The highest pha titers in rabbits occurred at the time of the 3rd dose or 13 days after the 3rd dose. These titers decreased by 26 days after the 3rd dose, but increased after the rabbits were given a booster dose.

Foals showed maximal mean stimulation indices and serum pha levels at 15 days after the 3rd M-like protein vaccination. The pha titers of these foals did not change significantly throughout the postvaccination and postchallenge period, whereas the stimulation indices decreased. Sera collected from foals with pha (10 × log2) titers of 10 had a strong mouse-protecting ability. This ability to protect mice decreased with decreased pha titers. Highest nasal antibody levels in the vaccinated foals were detected at either 15 or 21 days after the 3rd vaccine dose was given. These levels were significantly higher in those foals which were given the vaccine im and intranasally than in the foals vaccinated by the im route alone.

Three of 5 vaccinated foals developed the disease after an intranasal challenge exposure with S equi, and another 5 were resistant to a challenge exposure to a foal with acute disease.
Effects of transportation, surgery, and antibiotic therapy in ponies infected with Salmonella
Authors: Owen Rh. ap Rh. , Fullerton J. , Barnum D. A.
Published: February 2025

Seventeen ponies were infected with Salmonella typhimurium and then 15 were variously stressed by transportation and/or surgery and 9 were given oxytetracycline. Indications of Salmonella reactivation occurred in all the stressed ponies.

Diarrhea due to a reactivation of the Salmonella infection did not develop until > 3 days after stress, although maximal shedding of organisms occurred within 24 hours. A neutropenia generally occurred within 24 hours after stress and lasted about 5 days. A rectal temperature > 39 C usually did not occur. An increase in serologic titer was noticed in about half of the ponies.

Transportation had a major role in reactivating the Salmonella infection, and 1 pony died of peracute colitis. The use of oxytetracycline prolonged the excretion of Salmonella; therefore, this drug should not be used after stress, particularly transportation, in ponies that have diarrhea or are known to be Salmonella carriers.
Early arterial injury-induced myointimal proliferation in canine pulmonary arteries
Authors: Keith James C. , Schaub Robert G. , Rawlings Clarence
Published: February 2025

Transmission electron microscopy was used to study the early vascular response induced by arterial damage with heartworm infection. The pulmonary arteries were examined in dogs 4 days after experimental transplantation of 6 to 8 Dirofilaria immitis adults. Evan’s blue dye was given iv and followed in 60 minutes by perfusion fixation with 1% glutaraldehyde. Endothelial cell junctions were disrupted and rounded endothelial cells were observed. Macrophages and neutrophils adhered to abnormal endothelial cells. Focal areas had platelet aggregates adhered to exposed subendothelial structures. Platelets were activated and degranulated. Areas of the internal elastic lamina appeared to be disrupted, and smooth muscle cell processes from the tunica media extended through these regions of disruption. Smooth muscle cells were oriented toward the arterial lumen and some had migrated to the surface. These findings are compatible with the response to injury theory of myointimal proliferation.
Efficacy of ivermectin in controlling Strongyloides westeri infections in foals
Authors: Ludwig K. G. , Craig T. M. , Bowen J. M. , Ansari M. M. , Ley W. B.
Published: February 2025

Twenty-eight foals whose dams were treated im with ivermectin (200 μg/kg of body weight) on the day of parturition were compared with 35 foals whose dams were administered only the vehicle. The effect of ivermectin on the vertical transmission of Strongyloides westeri and foal heat diarrhea was determined by a comparison of results obtained in the 2 groups. Foals from treated mares had significantly fewer S westeri eggs per gram of feces from 17 to 28 days postpartum. There were no differences observed in the frequencies of severity of foal heat diarrhea between the treated and control groups.

In another experiment, using the same foals, 32 foals were treated im with ivermectin (200 μg/kg) at 21 days of age and were compared with 31 foals administered only the vehicle. Significantly fewer S westeri eggs were recovered from the ivermectin-treated foals on day 26 to day 32, the completion day of the trial.
Campylobacter hyointestinalis (new species) isolated from swine with lesions of proliferative ileitis
Authors: Gebhart Connie J. , Ward G. E. , Chang K. , Kurtz H. J.
Published: February 2025

Intestines from 48 swine with enteric disease were examined by bacteriologic cultural technique for the presence of various Campylobacter species. Histopathologic techniques were used to determine whether the submitted specimens had lesions of either swine proliferative ileitis or other enteric diseases. Three species of Campylobacter were identified as Campylobacter jejuni/coli, Campylobacter sputorum ss mucosalis, and Campylobacter hyointestinalis (proposed new species) on the basis of biochemical characteristics and response to various inhibitory substances.

The C hyointestinalis was isolated from 18 of 27 (67%) swine with proliferative ileitis and from only 1 of 21 (5%) swine with other enteric diseases. The C sputorum ss mucosalis was obtained from 16 of 27 (59%) swine with proliferative ileitis and from 2 of 21 (10%) swine with other enteric disease. The C jejuni/coli was isolated from 2 of 27 (7%) swine with proliferative ileitis and from 8 of 21 (38%) swine with other enteric disease.

The new organism, C hyointestinalis, was catalase-positive, hydrogen sulfide positive in triple sugar iron agar, glycine tolerant, intolerant to 3.0% sodium chloride, able to grow at 25 C, sensitive to cephalothin, and resistant to nalidixic acid. On the basis of these characteristics, C hyointestinalis was differentiated from other campylobacters isolated from swine and from other sources.
Plasma lipids and lipoproteins of fasted ponies
Authors: Bauer John E.
Published: February 2025

Plasma lipids and lipoproteins were studied in a group of healthy ponies in which food was withheld for 208 hours. Increases in plasma triglycerides and cholesterol and loss of weight were consistent with increases in free fatty acids circulating to the liver of these animals due to lipid mobilization from adipose tissue. Plasma triglycerides underwent the greatest absolute increase, with 30 times higher levels at the end of the fasted period than those of the fed control animals. Plasma cholesterol concentrations increased to a lesser extent and appeared to plateau at a level twice that of the control group. Total and direct plasma bilirubin concentrations increased to about 5 times their normal value by day 2 of the fast and seemed to plateau at this time.

Separation of the plasma lipoproteins on agarose-gel electrophoresis indicated an increase of the pre-β band in the fasted animals. Isolation of the lipoproteins at the commonly used density ranges for human lipoproteins revealed the pre-β band as having a hydrated density of < 1.006 g/ml which is consistent with a very low-density lipoprotein (vldl) fraction. Compositional analysis of the various lipoproteins indicated no appreciable differences among the low-density lipoprotein (ldl) and high-density lipoprotein (hdl) fractions in fed or fasted animals. The vldl from fasted ponies, however, although containing about the same relative amount of triglyceride, had 50% less protein and 50% more cholesterol than did the vldl of fed ponies. Consequently, vldl in fasted ponies was triglyceride-enriched when compared with its lower protein content. The concentration of this lipoprotein fraction also was appreciably higher in the fasted ponies. Although the equine liver appears able to secrete large amounts of triglyceride in the form of vldl in response to a large fatty acid influx, interferences with the normal metabolism of this vldl may be occurring leading to the hyperlipoproteinemia observed in the present studies.
Influence of antibiotics and intramammary antibiotic products on phagocytosis of Staphylococcus aureus by bovine leukocytes
Authors: Ziv G. , Paape M. J. , Dulin A. M.
Published: February 2025

Antibiotics and vehicles used in the treatment and prevention of mastitis were tested in vitro to determine effects on phagocytosis of 32P-labeled Staphylococcus aureus ([32P]sa) by bovine polymorphonuclear leukocytes (pmn) isolated from milk. Ampicillin, lincomycin, erythromycin, tetracycline, neomycin, penicillin G, streptomycin, cephalothin, nitrofurantoin, gentamicin, dicloxacillin, rifampin, trimethoprim, amikacin, novobiocin-penicillin, polymyxin B, and tiamulin were tested at in vitro concentrations of 1,000, 500, and 10 μg/ml, and sulfamethoxazole and chloramphenicol at 4,000, 2,000, and 10 μg/ml of incubation mixture. These dilutions were equivalent to antibiotic values in milk at 0, 6, and 12 hours after injection into the mammary gland. Vehicles included peanut oil, mineral oil, 3% cabosil in peanut oil, 2% aluminum monostearate in peanut oil, 25% polyethylene glycol (peg) in an aqueous base, 25% peg in mineral oil, and 25% peg in peanut oil. These were tested at dilutions of 1:100, 1:1,000, 1:5,000, and 1:10,000.

The percentage of phagocytosis was determined and was compared with the percentage of phagocytosis in phosphate-buffered saline solution (pbss). Antibiotics and vehicles were diluted in 0.0132M pbss (pH 7.4); combined with skimmed milk, pmn (12.5 × 106), and [32P]sa (50 × 106); and incubated for 1 hour (37 C, no rocking) followed by rocking for 1 hour. A minimum of 2 runs for the antibiotics and 3 runs for the vehicles were performed with all concentrations or dilutions assayed in a single day's run. Phagocytosis was significantly (P < 0.05) reduced at the high and intermediate concentrations for tiamulin, nitrofurantoin, rifampin, chloramphenicol, and amikacin, and at the high concentrations for gentamicin, tetracycline, and novobiocin-penicillin. The only vehicle that inhibited phagocytosis significantly was peanut oil without additives at the 1:100 dilution.
Efficiency and precision of electroimmunoassay for canine factor VIII-related antigen
Authors: Benson Roger E. , Jones Douglas W. , Dodds W. Jean
Published: February 2025

Factors that improved the efficiency, precision, and sensitivity of the electroimmunoassay for canine factor VUI-related antigen were investigated. These included rapid electrophoresis, increased rocket heights, deletion of the gel-washing step, and doubling of the sample capacity per plate. The modified assay was reliable and accurate, could be completed within 3 hours, and permitted twice as many determinations. Other experimental variables that affected the assay were the type of agarose and sample diluent, storage conditions of samples before assay, source of antibody, and use of 2 mM calcium lactate.
Canine hip dysplasia: Differences in pectineal muscles of healthy and dysplastic German Shepherd Dogs when two months old
Authors: Ihemelandu Emeruwa C. , Cardinet George H. , Guffy Mark M. , Wallace Larry J.
Published: February 2025

One pectineal muscle was removed from each of 23 purebred German Shepherd Dogs when 2 months old. Transverse frozen sections of each muscle were prepared and stained for the histochemical demonstration of myofibrillar adenosine triphosphatase activity which permitted differentiation of the constituent myofibers into type I, type II, and type intermediate myofibers. The mean size and total number of myofibers per section, as well as the mean size and total number of each myofiber type per section, were determined. From those measurements, the absolute and relative myofiber and nonmyofiber compositions of each section were estimated. When the dogs were 24 months old, their hip joints were evaluated and graded for the presence of hip dysplasia by radiographic and pathoanatomic examinations. Subsequently, the pectineal muscle measurements were statistically analyzed: (i) to determine whether they were correlated with the status of the coxofemoral joints when the dogs were 24 months old and (ii) to determine whether differences existed between the muscles of dogs which developed normal hips and those which developed hip dysplasia.

The pectineal muscles of dogs which developed hip dysplasia had significantly smaller type I and type II myofibers than did the pectineal muscles of dogs which developed normal hips. The pectineal muscles of dysplastic dogs were composed of a smaller myofiber component and a larger nonmyofiber component. These measurements also were correlated with the graded status of the coxofemoral joints. The total number of myofibers and the number of each myofiber type per section did not differ significantly. Critical value analyses indicated that the determination of the myofiber and nonmyofiber compositions of pectineal muscles in 2-month-old dogs may be potentially useful in predicting the subsequent development of normal or dysplastic hips. Results of these observations indicate that the composition of pectineal muscles in young dogs predisposed to hip dysplasia is an important associative or causal factor related to the development of hip dysplasia in the dog.
Immunoglobulin E antibodies to pollens augmented in dogs by virus vaccines
Authors: Frick Oscar L. , Brooks Dale L.
Published: February 2025

An inbred “atopic dog colony” was established to study the effect of viruses on immunoregulation of immunoglobulin (Ig) E antibodies. Dogs were selected for high skin reactivity to grass and weed pollens. Their offspring were inoculated with pollen extracts in alum immediately after routine vaccinations (attenuated live-virus vaccines for canine distemper and infectious canine hepatitis, and a killed bacterin for Leptospira). Heat labile antipollen IgE antibodies were measured by passive cutaneous anaphylaxis. Pups vaccinated for canine distemper before being given pollen extracts had many more IgE antibodies than did their control littermates who were not vaccinated until after the last pollen extract injection. This may be a natural example of the “allergic breakthrough phenomenon.”
Capillary and venous blood compared with arterial blood in the measurement of acid-base and blood gas status of dogs
Authors: van Sluijs F. J. , de Vries H. W. , De Bruijne J. J. , van den Brom W. E.
Published: February 2025

Acid-base and blood gas status of capillary blood from the ear was compared with acid-base and blood gas status of arterial and venous blood in dogs with induced hypoxemia, hypercapnea, and hypovolemia. It was concluded that capillary blood samples can replace arterial blood samples for the measurement of acid-base and blood gas status of dogs with severe impairement of lung function. When circulation is impaired capillary blood samples cannot replace arterial blood samples for the measurement of acid-base and blood gas status of dogs. With impaired capillary circulation, the capillary-arterial differences become unacceptably large. It is, therefore, advisable to submit samples of capillary blood for analysis only if circulation is not impaired and microtubes can be filled quickly and easily.
Experimental infections of horses with Legionella pneumophila
Authors: Cho Sang-Nae , Collins Michael T. , Reif John S. , McChesney Albert E.
Published: February 2025

Attempts to infect horses with Legionella pneumophila were undertaken to determine pathogenicity and to evaluate the possibility that horses serve as a reservoir for the organism. A previous study showed that the prevalence of antibodies to L pneumophila in the equine population exceeded 30% of over 600 sera examined.

Horses were infected experimentally with the Philadelphia 1 or Bloomington 2 strain of L pneumophila iv or by aerosolization. Signs of clinical illness were restricted to a transient febrile response. A transient decrease in circulating lymphocytes occurred 2 days after inoculation.

At necropsy, only moderate generalized lymphadenopathy was noted. Histologically, the lungs contained evidence of a low-grade inflammatory response characterized by focal proliferation of alveolar lining cells, with few neutrophils and eosinophils. Lymph nodes had evidence of reactive hyperplasia. The tissue response to Bloomington 2 strain was slightly more pronounced than that to Philadelphia 1.

Attempts to reisolate L pneumophila from blood and nasal or pharyngeal swabs were unsuccessful. The organism was not isolated by culturing tissues obtained at necropsy, nor was it demonstrated by tissue-staining techniques. However, all horses exhibited a marked increase in agglutinating antibodies to L pneumophila serogroups (sg) 1 and 3 as early as 4 days after inoculation. The serologic response was confirmed by indirect immunofluorescence and was shown to consist predominantly of immunoglobulin M by 2-mercaptoethanol treatment. Agglutinating antibodies persisted at least 4 months after infection.

On the basis of these studies, the pathogenicity of L pneumophila sg 1 and 3 for the horse appears to be low. There is no evidence to support a role for the horse in the maintenance of these organisms in nature. Horses may be exposed in the environment and maintain a relatively long-lived serologic response to L pneumophila. However, it is also possible that they become infected with other strains of L pneumophila or Legionella-like organisms more pathogenic for horses, or other non-Lagionella bacteria, which elicit a cross-reacting serologic response to L pneumophila sg 1 to 4.
Caprine α- and β-mannosidase activities: Effects of age, sex, and reproductive status and potential use in heterozygote detection of β-mannosidosis
Authors: Dunstan Robert W. , Cavanagh Kevin , Jones Margaret Z.
Published: February 2025

Effects of age, sex, and reproductive status on caprine plasma α- and β-mannosidase activities were studied. The potential use of these plasma assays was evaluated for heterozygote detection of caprine β-mannosidosis in populations of control goats and a breeding herd composed of known and putative heterozygotes for β-mannosidosis.

In the control population, the mean plasma α- and β-mannosidase activities decreased in both sexes with maturity. Male goats generally had higher plasma mannosidase activity than did females, and plasma β-mannosidase activity was affected by the reproductive status of the goats examined. Although putative carriers in the β-mannosidosis breeding herd could not be differentiated from age- and sex-matched controls, known carriers had plasma β-mannosidase values intermediate between those of control and affected goats. The lack of any correlation between α- and β-mannosidase activities excluded α-mannosidase as a reference enzyme for carrier detection, but there are still differences between known carriers and the control population with respect to the α- and β-mannosidase ratio.
Experimental production of rabbit mucoid enteritis
Authors: Toofanian F. , Targowski S.
Published: February 2025

Rabbit mucoid enteritis (mucoid enteropathy) is a subacute fatal disease of weanling rabbits with unknown cause. Mucoid enteritis was experimentally produced by ligating the large intestines in rabbits. Of the rabbits with ligated cecum and those with ligated colon, 70% and 45%, respectively, had excessive production of mucus and passed large amounts of mucus with feces, closely resembling the naturally occurring mucoid enteritis. Injection of oxytetracycline into the cecum at the time of ligation prevented the development of mucoid enteritis, and injection of cholestyramine markedly reduced the frequency of the disease in the rabbits with ligated cecum.
A possible central opiate mechanism involved in the inhibition of food intake and reticular motility by duodenal dl-lactic acid infusion in sheep
Authors: Duranton Albert , Buéno Lionel
Published: February 2025

Intraduodenal infusion of dl-lactic acid was performed in sheep fitted with a permanent cannula into the lateral cerebral ventricle and nichrome electrodes on the reticulum in order to record its electrical activity during periods of controlled food intake in a series of experiments subsequently repeated in animals fasted for 12 hours. A solution of 0.2M dl-lactic acid was infused at a rate of 1 ml/min during the 1st hour of a 3-hour period of feeding with or without previous intracerebroventricular (icv) or iv administration of naloxone (2.4 and 10 μg/kg).

During lactic acid infusion, the food intake and the frequency of reticular contraction (measured during eating) were reduced by 48% and 19%, respectively—these effects being prolonged for the 1st hour after infusion.

Previous icv administration of naloxone (2.4 μg/kg) partially blocked the effects of lactic acid on food intake (63%) and frequency of reticulum contractions (58%). These effects were abolished for the largest dose of naloxone (10 μg/kg) administered icv, whereas its iv administration did not affect significantly the effects of lactic acid.

It is concluded that the duodenal lactic acid concentration may have a role in the control of food intake by a mechanism involving central opiate mediation.
Occurrence of Mycoplasma sp (2D) in Texas sheep flocks
Authors: Livingston C. W. , Gauer Betty B.
Published: February 2025

Mycoplasma isolated from the reproductive tracts obtained from 4 sheep flocks in Texas had identical biochemical characteristics and were serologically similar to Mycoplasma sp (2D), a species that apparently occurs only in Australia.
Pharmacokinetics and protein binding of morphine in horses
Authors: Combie Joan. D. , Nugent Thomas E. , Tobin Thomas
Published: February 2025

Morphine could be detected in horses dosed with 0.1 mg of drug/kg of body weight for up to 48 hours in blood and 144 hours in urine. This dose of morphine elicited no observable effects and is a suggested analgesic dose. Computer analysis revealed that a 3-compartment open system was the best fitting model with a serum half life (t1/2(β)) of 87.9 minutes and a urine (t1/2(β)) of 101.1 minutes. Binding to equine serum proteins was linear over a drug concentration range of 3.88 × 10-5M to 3.50 × 10-8M and averaged 31.6%, In rbc-partitioning experiments, 78.1% of the drug was found in the plasma fraction. The data indicated that a horse should not be given morphine closer than 1 week before a race.
Reaction of convalescent bovine antisera with strain-specific antigens of parapoxviruses
Authors: Rosenbusch Ricardo F. , Reed David E.
Published: February 2025

Two strains of papular stomatitis (ps) virus, 1 of milker’s nodules (mn) virus and 1 of contagious ecthyma (ce) virus possessed 2 distinct external structures when examined by electron microscopy. The innermost, designated coat was closely apposed to the tubular surface, whereas the outer envelope loosely surrounded the virion. When convalescent sera from cattle infected with ps virus were used for immunoelectron microscopy, antibody reacted with coats and envelopes of the ps virus strains, but only with coats of mn and ce viruses. Convalescent sera from cattle infected with ps or mn virus contained complement-dependent antibodies cytolytic to cells infected with the homologous virus. In an indirect immunofluorescence test, the sera reacted with homologous strains to higher titers than with heterologous strains.
Acute and chronic changes in adenohypophyseal hormone secretion in sheep during zeranol administration
Authors: Elsasser T. H. , Bolt D. J. , Bradley B. D. , Roper M.
Published: February 2025

The effect of zeranol on circulating plasma concentrations of 5 adenohypophyseal (anterior pituitary gland) hormones was investigated in growing, castrated male sheep in 3 studies: after im injection of 1 mg of zeranol (acute study), during a 6-week period after subcutaneous implantation of 12 mg of zeranol (chronic study), and during a 4-hour continuous iv infusion of gonadotropin-releasing hormone (Gn-RH) plus thyrotropin releasing hormone (trh), 10 μg/hour. The sheep used in the chronic study (challenge study) were the same animals used in the 6-week implant study. Plasma concentrations of luteinizing hormone (lh), follicle-stimulating hormone (fsh), prolactin (prl), thyroid-stimulating hormone (tsh), and growth hormone (gh) were measured by specific radioimmunoassay.

Injection of zeranol resulted in a transient decrease in circulating lh and prolonged reduction in fsh concentrations during the 24-hour sampling period. Plasma concentrations of prl, tsh, and gh in zeranol-injected and control animals were not different. Implantation of zeranol caused chronic reduction in plasma lh and fsh, an increase in prl, and no change in plasma gh or tsh concentrations compared with values for control animals. In the challenge study, iv infusion of Gn-RH and trh caused a significant increase in the concentration of each of the 5 hormones compared with preinfusion values, regardless of zeranol treatment, When the hormone-response profiles were compared between zeranol-treated and control sheep in this challenge study, only the lh response was different—being greater in zeranol-treated sheep. Generally, the administration of zeranol resulted in a more pronounced alteration in basal and stimulated secretion of reproductive hormones such as lh, fsh, and prl than in gh or tsh, which are more commonly associated with growth and development.
Effect of ambient temperature upon the surface temperature of the equine limb
Authors: Palmer Scott E.
Published: February 2025

Ten clinically healthy adult horses were examined with the portable infrared thermometer at ambient temperatures of 5, 15, and 25 C to evaluate the thermal response of limbs of the horse to variations of ambient temperature. Limb surface temperature varied in direct proportion to changes in the ambient temperature, with considerable variation occurring among individual horses, especially at the lower temperatures. Areas of proximal parts of the limbs were more resistant to temperature variation than were distal parts. Ambient temperature had a statistically significant, but clinically unimportant, effect upon the bilateral symmetry (right side/left side) of limb surface temperature. At all ambient temperatures, the mean variation between left side and right side target areas was < 1 degree C.