bluuebunny/crossref_metadata_2025 huggingface dataset:
Pilot study on the treatment with thioproline of 24 small animals with tumors
Authors: Grier Ronald L. , Merkley David F. , Roth James A.
Published: February 2025

Thioproline (thiazolidine-4-carboxylic acid) was administered in a 16-week trial by either im or subcutaneous routes to 23 dogs and 1 cat with solid tumors (12 animals) and incompletely excised malignant tumors (12 animals). Acute partial responses were observed in 3 of the 12 animals with solid tumors. In a mammary gland carcinoma and oral fibrosarcoma, there was tumor enlargement by the 4th day of drug therapy followed by partial regression. Drug activity appeared to be directed against tumor blood supply. Tumor progression occurred in 11 of the 12 other animals (incompletely excised tumors). Although 4 of 5 dogs with intranasal tumors were alive and relatively free of tumorous signs at 9 months or more after surgical operation was done, there was no microscopic evidence of reverse transformation or cytostatic activity in the 2 intranasal tumors that were reoperated upon. There was no hematologic or biochemical toxicosis noted. Apparent pain from injection and abscess formation were the most frequent complications from parenteral administration and would preclude using this method on a long-term basis.
Distribution of immunoglobulin-bearing cells in the gut-associated lymphoid tissues of the turkey: Effect of oral treatment with intestinal microflora
Authors: Naqi S. A. , Cook Jeanne , Sahin Nigar
Published: February 2025

One-day-old turkeys (Meleagris gallopavo) were orally inoculated with the intestinal contents of an adult turkey, and the intestinal tissues were studied by immunofluorescence for immunoglobulin (Ig)-bearing cells at 3, 7, 14, and 21 days of age. Microflora inoculation increased numbers of Ig-bearing cells in the gut-associated lymphoid tissues; the most uniform effects were observed at 3 days of age. As the birds grew older, this uniformity in response to the microflora inoculation was not evident in all the tissues. In the bursa of Fabricius and the large intestine of the inoculated birds, IgM-bearing cells were more numerous throughout the study period. Compared with noninoculated control turkeys, IgA-bearing cells in the cecal tonsils, and IgG- and IgA-bearing cells in the small intestine were increased at all age intervals.
Changes in the microscopic anatomy of the bovine teat canal during mammary involution
Authors: Comalli M. P. , Eberhart R. J. , Griel L. C. , Rothenbacher H.
Published: February 2025

Changes in the microscopic anatomy of the bovine teat canal were examined during mammary involution. Morphometric analyses revealed a significant (P < 0.05), temporary dilatation of the teat canal lumen on day 7 of the nonlactating period. Additionally, the teat canal epithelium physiologically atrophied as evidenced by decreased cross-sectional area and thickness during the first 30 days of the nonlactating period, significantly so (P < 0.05) between days 0 and 7. This physiologic atrophy was due mainly to a reduction in area and thickness of the stratum granulosum and may have resulted from continuing keratinization, a process that led to increased thickness of the keratin layer and formation of a functional plug during later stages of involution.

Changes in cells of the stratum granulosum indicated a decrease in the rate of epithelial cell maturation during involution. The mitotic index (percentage of basal cells in mitosis) of the teat canal epithelium decreased significantly (P < 0.05) between days 0 and 7 of the nonlactating period. Bacteria, observed in histologic sections, appeared to colonize only certain regions of the keratin layer. Seemingly, changes in the teat canal during mammary involution may be important factors in changing susceptibility to new intramammary infection during the early and mid-nonlactating periods.
Aspects of bacteriology and endocrinology of cows with pyometra and retained fetal membranes
Authors: Olson Jerry D. , Ball Leslie , Mortimer Robert G. , Farin Peter W. , Adney William S. , Huffman E. Michael
Published: February 2025

In an effort clarify the pathogenesis of pyometra, 20 cows with retained fetal membranes and 20 without, but with contemporary calving dates were studied. They were palpated and their uteri were subjected to sample collections for bacteriologic cultural examinations twice weekly for 4 weeks. Blood samples were obtained each day and evaluated for serum progesterone concentration.

Three cows without and 3 with retained fetal membranes developed pyometra during the study, resulting in 3 groups designated control (con), cows with retained fetal membranes (rfm), and cows with pyometra (pyo).

Bacterial isolations occurred less frequently the con group than in the pyo and rfm groups. Growth patterns of bacteria also varied between groups. Coliform and incidental bacteria disappeared from the uterus of the pyo group by the end of the 3rd week. In contrast, heavy growth of Corynebacterium pyogenes and gram-negative anaerobic bacteria developed during this same period the pyo group.

In cows with pyometra, the significant persistent pathogenic bacteria recovered were C pyogenes and gram-negative anaerobic bacteria, especially Fusobacterium necrophorum and Bacteroides melaninogenicus. Anaerobic bacteria were isolated simultaneously with C pyogenes in most cows of the pyo group, but less often in con and rfm groups, and highest growth levels were present near the time of ovulation. Clinically, pyometra usually developed about 10 days after observation of concurrent ovulation and high growth levels of C pyogenes and gram-negative anaerobic bacteria.

A hypothesis is presented for development of pyometra in the cow.
Pharmacokinetic disposition of theophylline in horses after intravenous administration
Authors: Kowalczyk D. F. , Beech J. , Littlejohn D.
Published: February 2025

The pharmacokinetics of theophylline were determined in 6 healthy horses after a single iv administration of 12 mg of aminophylline/kg of body weight (equivalent to 9.44 mg of theophylline/kg). Serum theophylline was measured after the iv dose at 0.25, 0.5, 1, 2, 4, 6, 8, 12, and 15 hours. Serum concentration plotted against time on semilogarithmic coordinates, indicated that theophylline in 5 horses was best described by a 2-compartment open model and in 1 horse by a 1-compartment open model. The following mean pharmacokinetic values were determined; elimination half-life = 11.9 hours, distribution half-life = 0.495 hours, apparent specific volume of distribution = 0.885 ± 0.075 L/kg, apparent specific volume of central compartment = 0.080 L/kg, and clearance = 51.7 ± 11.2 ml/kg/hr.

Three horses with reversible chronic obstructive pulmonary disease were serially given 1, 3, 6, 9, 12, and 15 mg of aminophylline/kg in single iv doses (equivalent to 0.8, 2.4, 4.7, 7.1, 9.44, and 11.8 mg of theophylline/kg, respectively). The horses were exposed to a dusty barn until they developed clinical signs of respiratory distress and were then given the aminophylline. Effects of increasing doses on different days were correlated with clinical signs, blood pH, and blood gases. The 3 horses had a decrease in the severity of clinical signs after the 9, 12, or 15 mg doses of aminophylline/kg. The horses at 0.5 hour after dosing had a significant decrease in (43.6 ± 5.5 to 39.4 ± 6.7 mm of Hg, P < 0.001) and a significant increase in blood pH (7.38 ± 0.017 to 7.41 ± 0.023, P < 0.001). There were no significant changes in (75.6 ± 11.1 to 70.5 ± 8.4 mm of Hg), heart rate (45.7 ± 6.1 to 47.0 ± 7.0/min) and respiratory rate (19.7 ± 5.4 to 20.7 ± 3.0/min) at 0.5 hour.
Hemodynamics in the guinea pig after anesthetization with ketamine/xylazine
Authors: Hart Mark V. , Rowles John R. , Hohimer A. Roger , Morton Mark J. , Hosenpud Jeffrey D.
Published: February 2025

The resting hemodynamics were determined in 8 guinea pigs after they were anesthetized with ketamine/xylazine. Measurements were made of blood pressure, heart rate, cardiac output, arterial blood gases, and pH. These measurements were obtained initially at 4 to 5 hours after an injection (im) of ketamine HC1 (25 mg) and xylazine (0.15 mg) was given to anesthetize the animals for catheterization (period 1), again 5 days after the operation (period 2), and finally 4 to 5 hours after a 2nd injection of ketamine/xylazine (period 3). There were no differences in heart rates, respiratory rates, or cardiac outputs among the 3 study periods. However, arterial blood pressure was slightly, but significantly, lowered after, and presumably due to, instrumentation (62 ± 4 mm of Hg, P < 0.05) when compared with the 5-day postoperative period (67 ± 7 mm of Hg) or after the readministration of anesthetics (66 ± 7 mm of Hg). The partial pressure of carbon dioxide in the arterial blood was slightly lower (4 mm of Hg, P < 0.05) in both acutely postanesthetic periods (period 1 and period 3) than in the same animals at postoperative day 5 (period 2). This study has demonstrated that resting hemodynamics measured shortly after this anesthesia with ketamine/xylazine are not largely different from those in chronically instrumented animals.
Colonization and persistence of Escherichia coli in axenic and monoxenic turkeys
Authors: Dominick M. A. , Jensen A. E.
Published: February 2025

Sites of colonization and persistence of virulent (O78) and avirulent (O2) Escherichia coli were determined in 3-week-old axenic turkeys. Colonization of O78 in turkeys infected with Streptococcus faecalis was also determined. Colonization and persistence of E coli in the intestinal tract and lung were not correlated with virulence. Both serotypes persisted in high titer in crop, ileum, ceca, colon, and lung. Persistence of E coli in the liver was positively correlated with virulence, although both serotypes were recovered from the liver in the absence of bacteremia, indicating possible intestinal translocation of E coli to the liver. A reduction in intestinal colonization and translocation of O78 was determined in monoxenic turkeys infected with S faecalis. In contrast, S faecalis had no effect on lung titers of O78. Air sacculitis, pericarditis, and pneumonia were observed in axenic and monoxenic turkeys infected with O78. Bacteremia was detected in a turkey exposed to O78.
Serum immunoreactive gastrin concentrations in the dog: Basal and postprandial values measured by radioimmunoassay
Authors: Gabbert N. H. , Nachreiner R. F. , Holmes-Wood Phyllis , Kivela Joanne Hazard
Published: February 2025

A commercially available radioimmunoassay designed for quantitating human gastrin was evaluated for use in quantitating dog gastrin Because of the similarities in molecular structures of the two, the assay appears to be useful for dogs. Serum gastrin concentration in 12 fasting dogs averaged 64.8 pg/ml. After dogs were fed, the concentration increased to 117.8 pg/ml within 30 minutes and returned to base line by 90 minutes A standard feeding procedure may be useful in evaluating dogs with gastrinoma.
Kinetics of phagocytosis in the normal canine iridocorneal angle
Authors: Samuelson Don A. , Gelatt Kirk N. , Gum Glenwood G.
Published: February 2025

Microspheres of 3 different sizes were infused separately into the eyes of dogs with normotensive and hypertensive intraocular pressures. Latex spheres (0.5 or 1.0 μm) or 3.0 μm plastic spheres were added to Ringer's solution with 6% gelatin. Initially, this mixture was injected into the anterior chamber of dogs with intraocular pressures of 20, 50, or 75 mm of Hg. After 10, 20, 30, 60, or 90 minutes had elapsed, the dogs were euthanatized and the gelatin was hardened. Tissues were subsequently studied by light and transmission electron microscopies. Phagocytosis of the 0.5 and 1.0 μm spheres by trabecular cells was first detected within 10 minutes and within 20 minutes for the 3.0 μm spheres. Migration of cells in the corneoscleral trabecular meshwork was observed after 30 minutes. Phagocytosis was less active at hypertensive pressures and had larger sphere sizes. Microspheres in the uveal trabecular meshwork were ingested mostly by macrophages and polymorphonuclear leukocytes.
Age-related changes in the cat testis and epididymis
Authors: Elcock Laura Hart , Schoning Polly
Published: February 2025

Forty-two pairs of testes and epididymides were obtained from clinically healthy cats and were examined histologically for age-related changes. All of the following testicular features increased with age: thickness of the testicular tunica adventitia, the amount of lipofuscin in the interstitial cell, hyperplasia of interstitial cells, vacuolation of Sertoli cell cytoplasm, degeneration of seminiferous tubules and thickness of the seminiferous tubular basement membrane. Two spermatoceles were found in the oldest cat. Age-related changes in the cat epididymis included increased thickness of the epididymal tunica adventitia, occasional intraepithelial cysts and hyperplasia of the epithelium, and one spermatocele in the head of the epididymal duct. Lymphocytic foci were common in testicular and epididymal connective tissue of cats of all ages and were reactive in the 2 oldest cats. Several changes were most frequent in 3- to 6.9-year-old cats: eosinophilic to amphophilic round cytoplasmic bodies in interstitial cells, proteinaceous tubular luminal debris, and spermatozoa in the epididymal duct. Cats < 1 year old had significant (P < 0.05) amounts of seminiferous tubular degeneration and a high percentage of epididymal intraepithelial cysts and hyperplasia.
Effect of ivermectin on performance of beef cattle on Georgia pastures
Authors: Ciordia H. , McCampbell H. C. , Calvert G. V. , Plue R. E.
Published: February 2025

A total of 469 cows and calves from 2 herds, each on 6 pastures, was used to evaluate the anthelmintic efficacy and animal-performance benefits of ivermectin given subcutaneously at a dosage of 200 μg/kg to nursing beef calves and their dams during a grazing season. Pastures were paired across the 2 herds. Three pasture groups from 1 herd were randomly assigned to either a nonmedicated control or to a medicated group. Treatment assignments were reversed in the other herd. The control groups comprised 110 cows and 108 calves, whereas 127 cows and 124 calves were treated with ivermectin (200 μg/kg).

The cows were treated once, in late spring, and the calves were treated twice, once in late spring and again in midsummer. Cattle from one herd were weighed on days −12, 21, 49, 77 (day of 2nd treatment for calves), and 105, and the other herd was weighed on days −6, 23, 57, 86 (day of 2nd treatment for calves), and 113. Rectal fecal samples for nematode egg counts were obtained from approximately 25% of the cattle in each pasture on weighing days; usually, the same cattle were sampled each time.

Calves treated with ivermectin gained (P < 0.05) more weight than control calves up to the 2nd treatment date and up to the termination of the study. There was no significant difference between treated and control cows, with regard to weight gain over either interval. Treated calves had fewer positive fecal egg counts (P < 0.01) and passed fewer eggs (P < 0.05) after both treatments than did control calves. There were no differences in either number of eggs or number of negative cows between treatment groups. Adverse reactions attributable to treatment were not seen.
Calcium in the turkey yolk sac during late development and postembryonic involution
Authors: Cheville Norman , Coignoul Freddy
Published: February 2025

Yolk sacs (ys) were examined by gross, histochemical, and electron microscopic techniques from incubation day 12 to 10 days of age. Weights were maximal at 22 days of incubation and declined markedly thereafter; by 7 days of age, the yolk was completely absorbed. Endodermal cells of ys epithelium were highly polar with nuclei, mitochondria, and glycogen in basal areas and lipid globules and intralysosomal yolk granules near luminal surfaces. Yolk laminar spherules were first seen at day 16 of incubation. They increased progressively with incubation and disappeared rapidly after hatching. Spherules stained for calcium, glycosaminoglycans, and alkaline phosphatase in late incubation and were considered calcium storage structures. Histochemical evidence of intracellular calcium loading of yolk matrix (from 18 days of incubation until 5 days of age) suggested a specific calcium transport function of ys epithelium.
Bacterial growth in whey from mastitic and nonmastitic quarters
Authors: Mattila T. , Syväjärvi J. , Sandholm M.
Published: February 2025

Growth of Escherichia coli and Staphylococcus aureus was analyzed by turbidometry in 456 selected whey samples. The samples had been graded mastitic or nonmastitic as determined by antitrypsin assay and bacteriologic examination. Whey samples from inflamed quarters (antitrypsin increased) and infected quarters significantly promoted bacterial growth as compared with whey samples from control quarters. The growth-stimulatory effect was limited to the diseased quarters, since control quarters from the same animals did not support enhanced bacterial growth. The observations indicate that in chronic mastitis, the inflammatory process leads to changes in the whey that promote bacterial growth in vitro.
Pathogenesis of Staphylococcus aureus mastitis: Bacteriologic, histologic, and ultrastructural pathologic findings
Authors: Gudding Roar , McDonald John S. , Cheville Norman F.
Published: February 2025

Three lactating cows were experimentally infected with Staphylococcus aureus ATCC 29740 (Newbould 305 strain). Cows were euthanatized 2 to 216 hours after inoculation. Bacteriologic and microscopic examinations showed that S aureus attached to epithelial cells of the mammary gland in vivo. The histopathologic changes observed were progressive swelling, vacuolar degeneration of epithelial layers, and multiple foci of epithelial erosions and ulcers throughout the ductal system. The cellular response of the infected glands was demonstrated by a rapid increase in the number of somatic cells in the secretion and by accumulation of neutrophils below, within, and on the epithelium of the teat and lactiferous sinuses. The inflammatory response did not prevent infection nor subsequent pathologic changes in the inoculated glands.
Pharmacokinetics of 4-aminopyridine in cattle
Authors: Kitzman Joseph V. , Wilson Robert C. , Booth Nicholas H. , Zahner Joanne M. , Hendricks H. Lamar , Bush Parshall B.
Published: February 2025

Concentrations of 4-aminopyridine hydrochloride in plasma of cattle were measured over an 8-hour period following a bolus IV injection (0.3 mg/kg). The drug was assayed by a gas-liquid chromatographic method using a nitrogen-phosphorus detector. Plasma 4-aminopyridine hydrochloride vs time data best fit a 2-compartment pharmacokinetic model. Distribution half-life was 12.08 minutes; elimination half-life, 128.96 minutes; volume of the central compartment, 1.48 L/kg; volume of distribution based on total area, 3.07 L/kg; volume of distribution at steady state, 2.75 L/kg; and body clearance, 16.57 ml/min/kg.
Effects of whole blood clots, time, and implant size on vascularization and collagen deposition along Teflonensheathed carbon fibers implanted in ewes
Authors: Stein Larry E. , Pijanowski Gerald J.
Published: February 2025

Seventy-two subcutaneous implants were examined to evaluate connective tissue response to Teflonensheathed carbon fibers and whole blood clots.

Carbon fibers significantly (P ≤ 0.001) increased vascularization and collagen formation within the Teflon sheath. Carbon fibers provide a potentially strong scaffold that would physically support cell migration during wound healing, However, obvious foreign body reactions occurred, which indicate that further studies on the biologic features of carbon fiber are needed before carbon fibers become entirely acceptable for long-term implantation.

Compared with no-clot controls, Teflon tubes containing only whole blood clots stimulated a significant (P ≤ 0.001) wound-healing response, including organized collagen fiber formation. Other variables tested in this study such as length and diameter of the Teflon tubes did not significantly influence connective tissue responses.
Meperidine-acepromazine-pentobarbital anesthesia in cats: Reversal by 4-aminopyridine and yohimbine
Authors: Hatch Roger C. , Zahner Joanne M. , Booth Nicholas H.
Published: February 2025

SUMMARY AND CONCLUSIONS

Groups of atropinized cats (6/group) were given im meperidine (5.5 mg/ kg of body weight) plus acepromazine (0.25 mg/kg). Forty minutes later, the cats were anesthetized to disappearance of pedal reflexes with 1% pentobarbital iv. Volume of anesthetic was recorded. Five minutes later, the cats were given iv saline solution (2 ml; control group), the antagonists 4-aminopyridine (4-AP; 0.5 mg/kg), yohimbine (0.4 mg/kg), or a combination of 0.5 mg of 4-AP/ kg plus 0.4 mg of yohimbine/kg. Mean arousal time (mat), walk time (mwt), respiratory rate, and heart rate were measured. Emergence phenomena also were recorded.

Meperidine plus acepromazine caused mydriasis and mild sedation without ataxia or marked protrusion of the 3rd eyelid. The cats did not resist restraint for venipuncture. The pooled mean dosage level of pentobarbital required for anesthesia was 12.3 mg/kg. Control group mat and mwt were 66.2 minutes and 126 minutes, respectively. Marked residual sedation lasted several hours. In cats given 4-AP plus yohimbine, mat and mwt were decreased to 4.4 minutes and 36.5 minutes, respectively. These values were not significantly shorter than those same values in cats given 4-AP or yohimbine alone (P > 0.05), but the combination of 4-AP plus yohimbine produced a qualitatively better reversal of anesthesia than did 4-AP or yohimbine alone. Emergence was smooth in all 4 groups; mild-to-moderate residual sedation lasted 2 to 4 hours in the principals. Relapses, drug side effects, and behavioral aberrations were not observed. Mean respiratory rates and heart rates decreased during anesthesia but these values were not excessively depressed or stimulated at any time. Cardiac irregularities were not detected by palpation or auscultation. Meperidine-acepromazine-pentobarbital anesthesia may prove suitable for short surgical procedures in healthy cats. The anesthetic state can be smoothly and permanently reversed within minutes with 4-AP plus yohimbine without producing undesirable effects.
Immunity to toxoplasmosis in hamsters
Authors: Elwell Michael R. , Frenkel J. K.
Published: February 2025

Protective immunity to Toxoplasma was studied in hamsters. Immunity developed in 2 to 3 weeks after vaccinations were performed. Vaccination with live RH, T-45, and ts-4 strains afforded the best protection against challenge exposure with the most pathogenic RH strain used, Even a killed-toxoplasma vaccine protected all hamsters against the slightly less pathogenic T-1 strain through 24 weeks, but it did not protect hamsters against challenge exposure with the RH strain. Both ts-4, a nonpersistent strain, and killed-toxoplasma vaccine provided protective immunity in hamsters that was not dependent upon premunition, Toxoplasma antibody titers in hamsters given the 2 vaccines were similar. However, there was a difference in the quality of immunity: fever and body weight loss were seen in hamsters vaccinated with the killed-toxoplasma vaccine after they were challenge exposed with T-1 strain, whereas these changes were rarely seen in hamsters given the live-toxoplasma vaccine and then challenge exposed with RH strain. Delayed-type hypersensitivity to Toxoplasma antigen always appeared before protective immunity and was detected in all hamsters by 4 days after vaccination with live-toxoplasma strains. Although the development of delayed-type hypersensitivity preceded protective immunity, it was not indicative that protective immunity was present or would develop.
Indwelling rumino-reticulum bolus radio beacon
Authors: Kath Gary S. , Egerton John R. , Geiger Richard
Published: February 2025

A miniature battery-powered radio beacon attached to a stainless steel bolus housing an osmotic pump is described. When the bolus, of sufficient size and density to be retained in the reticulum, is administered to ruminants the radio signal can be received, using a standard AM broadcast receiver up to a range of 1.5 m. The unit allows making a simple and inexpensive verification that the drug delivery system is still within the rumino-reticulum during long-term drug delivery studies and making an external estimation of the internal anatomic location of the device.
Preliminary study of the pharmacokinetics and toxicopathy of deoxynivalenol (vomitoxin) in swine
Authors: Coppock R. W. , Swanson S. P. , Gelberg H. B. , Koritz G. D. , Hoffman W. E. , Buck W. B. , Vesonder R. F.
Published: February 2025

Study was made of the pharmacokinetics and toxicopathy of deoxynivalenol (don, vomitoxin) given iv to swine. In the 24 hours after swine were given don, clinical signs of vomiting, diarrhea, muscular weakness, tremors, and twilight coma were similar to those observed with other 12, 13-epoxytrichothecenes. Hypoglycemia and pancreatic islet cell lesions were observed which indicated that don-induced changes in intermediary metabolism may be an insidious aspect of don intoxication. Histopathologic examination of all organ systems revealed pancreatic acinar and islet cell necrosis and mild lympholysis of the mesenteric lymph nodes. The renal excretion of don was altered by iv infusion of saline solution. Pharmacokinetic findings may indicate that don was both secreted and reabsorbed by the renal tubules. The half-life of don ranged from 2.08 to 3.65 hours. Residues of don were not found in skeletal muscle of swine at 24 hours after dosing.
Isolation and identification of caliciviruses from dogs with enteric infections
Authors: Evermann J. F. , McKeirnan A. J. , Smith A. W. , Skilling D. E. , Ott R. L.
Published: February 2025

Caliciviruses were isolated from 7 dogs and 1 captured coyote with enteritis. There was a high fatality rate in dogs 4 to 16 weeks of age. The occurrence in these dogs of concurrent infection with known enteric pathogens such as Salmonella sp, canine parvovirus, canine coronavirus, and canine rotavirus did not allow making any conclusions regarding the pathogenicity of this newly recognized calicivirus. The caliciviruses were characterized by electron microscopy and were further identified as being closely related to feline calicivirus by immunoelectron microscopy with specific antibody.
Staphylococci in canine urolithiasis: Species identification, using a commercially available tray micromethod
Authors: Case Lisa C. , Ling Gerald V. , Biberstein Ernst L. , Ruby Annette L. , Jang Spencer S.
Published: February 2025

Fifty-one coagulase-positive staphylococcal isolates from canine urinary calculi or from the urine of dogs with documented urolithiasis, and 17 coagulase-positive staphylococcal isolates from human beings and cattle were identified by a commercially available tray micromethod, as well as by conventional methods. Canine isolates had previously been classified as Staphylococcus aureus on the basis of a positive tube coagulase test. After 5 hours’ incubation, the tray method identified all 51 canine urolithiasis isolates as S intermedius, rather than S aureus. All human and bovine isolates were identified as S aureus. Conventional methods supported these findings.
Arthritis associated with ovine progressive pneumonia
Authors: Cutlip Randall C. , Lehmkuhl Howard D. , Wood Richard L. , Brogden Kim A.
Published: February 2025

Chronic nonsuppurative arthritis developed in carpal and tarsal joints of border Leicester sheep that were naturally or experimentally infected with ovine progressive pneumonia (opp) virus. Clinical signs of arthritis began at 1 to 6.2 years of age (1 to 5.7 years after inoculation of opp virus) and slowly progressed in severity until the sheep died or were killed. The joint lesions were characterized by edema, hyperemia, hyperplasia, and necrosis of the synovial membrane; by necrosis and erosion of articular bone; by necrosis and fibrosis of subchondral bone; and by extensive periarticular fibrosis. The opp virus alone was isolated from arthritic joints. In 7 of 14 sheep, the arthritis was associated with interstitial pneumonitis induced by the virus. Therefore, it was concluded that opp virus was the cause of arthritis in this group of sheep.
Single intravenous and multiple intramuscular dose pharmacokinetics and tissue residue profile of gentamicin in sheep
Authors: Brown Scott A. , Riviere J. Edmond , Coppoc Gordon L. , Hinsman Edward J. , Carlton William W. , Steckel Robert R.
Published: February 2025

Single and multiple dose gentamicin regimens were compared in sheep to determine the relevant pharmacokinetic differences. Seven mature sheep were given 10 mg/kg of gentamicin by iv bolus. Serum concentrations were monitored for 19 days. Four weeks after the initial bolus, gentamicin was administered im (3 mg/kg every 8 hours) for 7 days. Ewes were euthanatized and necropsied at 1, 8, and 15 days after termination of the im regimen and the tissues were assayed for gentamicin. Serum concentrations were analyzed using a triexponential equation. The iv kinetic studies revealed an α half-life (t½) of 0.31 ± 0.14 hours, β t½ of 2.4 ± 0.5 hours, and γ t½ of 30.4 ± 18.9 hours. Multiple im dose kinetic studies revealed a β t½ of 2.8 ± 0.6 hours and γ t½ of 82.1 ± 17.8 hours. After multiple dosing, γ t½ was significantly longer than after the single iv bolus (P < 0.05), Twenty-four hour urine collection accounted for 75% to 80% of the total iv dose. Renal cortical gentamicin concentration reached 224 μg/g of tissue and then decreased, with a 90-hour t½. Renal medullary gentamicin concentration reached 18 μg/g with a 42-day t½. After multiple dosing, liver gentamicin concentration reached 11 μg/g and skeletal muscle concentrations were ≤ 0.6 μg/g. Route or duration of administration significantly affected the γ-phase serum concentrations, which may influence gentamicin nephrotoxicosis. The present study also illustrated the complexities in predicting aminoglycoside withdrawal times for food-producing animals before slaughter.
Iron and transferrin in acute experimental Salmonella cholerae-suis infection in pigs
Authors: Kramer Theodore T. , Griffith Ronald W. , Saucke Lois
Published: February 2025

The effects of experimental Salmonella cholerae-suis inoculation with a virulent and an avirulent strain on serum iron (si), total iron-binding capacity (tibc), and transferrin (tf) were evaluated.

Inoculation of virulent strain 38 was followed by significant (P < 0.05) decreases of si, tibc, and tf. Exposure to avirulent strain 33 was followed by moderate decreases of si, tibc, and tf. When exposure to avirulent strain 33 was followed by challenge exposure with virulent strain 38, the si, tibc, and tf values remained at initial values or were higher. Negative correlation was observed between rectal temperature and si and tibc values, but was significant (P < 0.0001) only 7 days after inoculation of the virulent strain 38.
Antifungal sensitivity testing for equine keratomycosis
Authors: Coad Christopher T. , Robinson Nettie M. , Wilhelmus Kirk R.
Published: February 2025

We evaluated 31 fungal specimens obtained from equine corneas over a 10-year period, 1973 to 1983. More than half were received in late summer and early autumn, and the number tended to increase in frequency during the 1980s. These isolates included 13 different genera and 20 different species. The prevalent genus was Aspergillus (35%). On the basis of examinations for tube-dilution minimal inhibitory concentrations and minimal fungicidal concentrations of 16 fungal isolates, the imidazole antibiotics such as miconazole and ketoconazole consistently showed the lowest geometric mean titers for filamentous fungi. Because fungal sensitivities varied considerably among different species in vitro sensitivity testing is suggested as an aid in the determination of optimal therapy.
Cross-reactivity of a monoclonal antibody with bovine, equine, ovine, and porcine peripheral blood B lymphocytes
Authors: Lewin Harris A. , Calvert C. Chris , Bernoco Domenico
Published: February 2025

Ficoll-thrombin purified suspensions of bovine, equine, ovine, and porcine peripheral blood lymphocytes were fractionated on nylon-wool columns. The percentages of surface immunoglobulin (SIg+)-bearing lymphocytes in the adherent (B-cell enriched) and nonadherent (T-cell enriched) fractions were determined for individual animals using fluorescein isothiocyanate conjugated species-specific anti-Ig sera. Subsequently, the human leukocyte antigen DR-specific monoclonal antibody, H4, was tested for its ability to recognize a cross-reactive antigen on the fractionated lymphocytes, using the microcytotoxicity technique. The H4 plus complement killed a percentage of lymphocytes equivalent to the percentage of SIg+ lymphocytes in the adherent and nonadherent fractions.

In a parallel experiment, a 2 fluorochrome technique was used to visualize bovine lymphocytes that were SIg+ and H4+. Lymphocytes that were SIg+ also stained with ethidium bromide (orange fluorescence) after complement-mediated cytotoxicity. Seemingly, H4 recognizes an evolutionarily conserved major histocompatibility complex encoded class-II-like determinant on the B lymphocytes of cattle, horses, sheep, and swine.
Base excess as a prognostic and diagnostic indicator in cows with abomasal volvulus or right displacement of the abomasum
Authors: Simpson D. F. , Erb H. N. , Smith D. F.
Published: February 2025

The case records of 102 cows with abomasal volvulus and 71 cows with right-side displacement of the abomasum (rda) were examined to determine whether the preoperative base-excess concentration of the extracellular fluid could be used both as a prognostic indicator for postoperative recovery in cattle with abomasal volvulus and as an aid in differentiating between abomasal volvulus and rda. The survival rate of cows with abomasal volvulus decreased as the base excess concentration decreased (P = 0.08); the lowest survival rate was observed in cows with base excess ≤ −0.1 mEq/L. There was a significant difference (0.01 < P < 0.025) among base excess ranges between abomasal volvulus and rda. All cows with preoperative base-excess concentrations ≤ −5.0 mEq/L had abomasal volvulus, rather than rda.
Effect of hydrocortisone on circulating lymphocyte numbers and their mitogen-induced blastogenesis in lambs
Authors: Collins Michael T. , Suàrez-Güémes Francisco
Published: February 2025

The effect of hydrocortisone on the number of circulating lymphocytes and their blastogenic response was studied in 20 feedlot lambs given combinations of 3 treatments: hydrocortisone (25 mg/kg of body weight, 4 times a day, im), feed changes (100% roughage to 90% concentrate over a 6-day period), and oral inoculation of Pasteurella haemolytica biotype T (109 to 1011 bacteria/day via stomach tube) to develop a model for reproduction of septicemic pasteurellosis.

Hydrocortisone caused lymphopenia and inhibited the blastogenic response of peripheral blood lymphocytes to phytohemagglutinin and concanavalin A mitogens. A synergistic effect was observed between hydrocortisone injections and feed changes resulting in higher than expected serum hydrocortisone concentrations and lower circulating lymphocyte counts. Seemingly, stress-induced increases in serum hydrocortisone concentrations cause suppression of the immune response of feedlot lambs. The combined effect of feed changes and stress on the immune response of lambs may explain the role of these 2 factors in the pathogenesis of septicemic pasteurellosis.
Delayed-type hypersensitivity responses induced by bovine colostral components
Authors: Radosevich Jeanette K. , Scott Gerald H. , Olson George B.
Published: February 2025

Transfer factor-type substances obtained from leukocytic cells and fluid portions of bovine colostrum caused effective passive transfer of delayed-type hypersensitivity responses across species barriers. Passive transfer of Brucella abortus sensitivity was obtained with equal regularity when using components derived from peripheral blood and colostrum of dams sensitized at 3 and 9 months of age. Colostral feedings to calves caused the passive transfer of delayed-type hypersensitivity as early as 2 days after parturition. The findings indicated that colostral components were important in the process of cell-mediated immunity.
Dermal responses to Ostertagia ostertagi in Ostertagia ostertagi- and Cooperia punctata-inoculated calves
Authors: Snider Theron G. , Klesius Phillip H. , Haynes T. Barry
Published: February 2025

Calves harboring patent Ostertagia ostertagi or Cooperia punctata were given intradermal injections of O ostertagi 3rd-stage larval antigen. The initial injections were followed 30 days later by a 2nd series of injections. Skin thickness was measured at injection sites for 72 hours after injection. Selected injection sites including saline solution control sites were biopsied at 30 minutes, at 3, 24, 48, and 72 hours, and at 30 days after injection.

After the 1st series of injections, there was a clear distinction in dermal reactions between O ostertagi-inoculated calves and C punctata-inoculated calves; after 24 hours, reactions were not seen in the C punctata-inoculated calves. Marked dermal reactions occurred in the O ostertagi-inoculated calves. The reactions at 30 minutes and 3 hours were characterized by slight-to-extensive infiltration of neutrophils and dermal edema. The 24-hour cellular reaction was principally due to neutrophil and eosinophil infiltration with edema and necrosis. Reactions at 48 to 72 hours were due to eosinophils and perivascular accumulations of macrophages and lymphocytes. Necrosis, neutrophils, and edema were present in foci where fragments of nematodes were located. On reinjection, a clear distinction in dermal reactions between calves was not seen based on the type of nematode infection.

Thirty days after dermal inoculation, large nodules developed at the site of the initial antigen injection. The nodules were characterized by marked intradermal proliferation of lymphocytes in a follicular pattern with occasional macrophages and rare multinucleated giant cells.
Bovine herpesvirus-1 infection of cattle; Kinetics of antibody formation after intranasal exposure and abortion induced by the virus
Authors: Guy James S. , Potgieter Leon N. D.
Published: February 2025

The kinetics of antibody formation in Holstein heifers after primary and secondary intranasal inoculation of bovine herpesvirus-1 (bhv-1) and after bhv-1-induced abortion was determined. Sera were fractionated by gel filtration and ion-exchange chromatography. The antibody activity within serum immunoglobulin (Ig) isotypes was assessed, using a plaque-reduction neutralization assay.

The primary immune response to bhv-1 infection was characterized by the appearance of IgM and IgG antibodies in serum by postinoculation day (pid) 7. Maximal IgG antibody activity occurred at pid 35 in nonpregnant heifers and at pid 14 in pregnant heifers. Thereafter, IgG antibody activity declined slowly in both groups of heifers. Maximal IgM antibody activity occurred at pid 14 in both groups of heifers and declined rapidly thereafter. The IgG antibody activity during primary immune responses was restricted to the IgG1 subclass.

Secondary responses were characterized by anamnestic IgG antibody responses. Antibody activity was present within the IgG1 and IgG2 subclasses during secondary immune responses, but the increase in antibody activity during this period was primarily in the IgG2 subclass. Secondary IgM antibody formation was elicited by abortion induced by the intra-amniotic inoculation of bhv-1, but not by reexposure by the intranasal route.

Abortion occurred in 1 heifer 28 days after intranasal bhv-1 inoculation. Abortion in this heifer was not associated with a secondary antibody response.

The nature of bhv-1 antigenic exposure in the bovine determined the relative distribution of anti-bhv-1 antibody activity in serum IgM, IgG1, and IgG2. The formation of IgM antibody, with the exception of secondary intranasal exposure, indicated recent bhv-1 antigenic exposure. Primary immune responses were differentiated from secondary immune responses by the presence of IgGl antibody and by the absence of IgG2 antibody.
Impairment of sympathetic pulmonary vasoconstriction by 3-methylindole in cattle
Authors: Perry Michael B. , Atwal Onkar S. , Eyre Peter
Published: February 2025

Sixteen Holstein cattle allotted into 4 groups (4 cattle/group) were each given a single oral dosage of 0.2 g of 3-methylindole (3MI)/kg of body weight. The groups were killed at 12, 24, 48, and 72 hours, respectively, after 3MI administration. Comparison of clinical signs, pathologic pulmonary lesions, and in vitro pulmonary artery responses to pharmacologic stimuli was made between the 4 treated groups and 8 control Holstein cattle of similar age.

Clinical signs of pulmonary distress first appeared 8 to 12 hours after 3MI administration. After 20 hours, clinical signs included dyspnea, moderate depression, and a marked expiratory grunt. A partial remission of these clinical signs was seen between 30 and 45 hours after 3MI administration. After remission, the cattle had clinical signs of severe dyspnea and depression and expiratory grunts were more pronounced.

Pathologic pulmonary lesions, including heavy rubbery lungs, dilated interlobular septae, and subplural air bullae characteristic of pulmonary edema and interstitial emphysema were observed. The lungs of treated cattle did not collapse when the thorax was incised at necropsy.

In vitro pulmonary artery strips contracted dose dependently to norepinephrine (ne). Group I tissues (12 hours after 3MI administration) responded similarly to control samples. Group II tissues (24 hours after 3MI administration) had a significant inhibition (P < 0.05) in response to ne stimulation as compared with controls, Group III samples (48 hours after 3MI administration) had a return to normal in ne sensitivity, which correlated positively with the remission of clinical signs as observed just before euthanasia of group III cattle. Group IV tissues (72 hours after 3MI administration) had a marked (P < 0.05) inhibition in ne sensitivity that correlated with severe clinical signs.

The concurrent clinical remission and return in α-adrenoceptor functions may indicate that the pulmonary homeostatic sympathoadrenal response to 3MI is a significant component in 3MI-induced pulmonary disease. The data indicated that the pulmonary vasculature may be an important primary target of 3MI-induced pneumotoxicosis.
Pathologic changes associated with induced small intestinal strangulation obstruction and nonstrangulating infarction in horses
Authors: Sullins Kenneth E. , Stashak Ted S. , Mero Kendall N.
Published: February 2025

Arteriovenous (ischemic strangulation obstruction, iso) or venous (hemorrhagic strangulation obstruction, hso) occlusions were created in the jejunum of 5 anesthetized horses and were left in situ for 1-, 2-, or 3-hour intervals. Segments were evaluated grossly for color, thickness, and motility. The horses were euthanatized, and the degree of mucosal slough, edema, congestion, and hemorrhage was determined histologically.

Segments subjected to iso became dark, but did not contain edema or hemorrhage. Segments subjected to hso were characterized by progressive congestion, edema, and hemorrhage especially in the mucosal layer. Histologically, the mucosal epithelium was affected approximately equally by iso or hso, although more gross changes were evident in segments subjected to hso.
Parasites in lungs of dead equids in Kentucky; Emphasis on Dictyocaulus arnfieldi
Authors: Lyons E. T. , Tolliver S. C. , Drudge J. H. , Swerczek T. W. , Crowe M. W.
Published: February 2025

Prevalence of natural infections of parasites from the lungs of 488 dead Thoroughbreds in Kentucky was investigated. The horses varied from 1 to 32 years of age; 419 horses were from 215 farms and 69 horses were from 68 individual sources for which a specific farm was not identified. Examinations of the lungs were made from Mar 1, 1983 through Feb 29, 1984.

Dictyocaulus arnfieldi was recovered from 56 (11%) of the horses. Other parasites found were larvae of Parascaris equorum in 37 (8%) and of Habronema/Draschia in 67 (14%) of the horses. The possible effect of ivermectin treatment on the prevalence of D arnfieldi in the lungs is discussed.

Presence of D arnfieldi in 20 other selected dead equids was also investigated.
Variation of fiber types in the triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris of horses
Authors: Hoven R. van den , Wensing Th. , Breukink H. J. , Meijer A. E. F. H. , Kruip T. A. M.
Published: February 2025

The distribution of type-I and type-II fibers in 9 different parts of the musculi triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris was studied to determine whether biopsies from these muscles give reliable information. All 4 investigated muscles were not homogeneous in their fiber-type distribution. Large differences existed among different muscle parts. The percentage of type-I fibers increased toward the deeper and cranial parts of the muscles. In the same zone of the gluteus muscle, differences of 30% were found for type-I fibers. Therefore, results obtained by biopsies of muscles must be interpreted with caution.
Simultaneous cecostomy and ileal cannulation with a modified flexible T cannula in gilts
Authors: Hamilton Calvin R. , Dove Charles R. , Zinn Gene M. , Veum Trygve L.
Published: February 2025

A surgical procedure was developed for the simultaneous cannulation of the ileum and fistulation of the cecum in breeding-age gilts to study the effects of enteric microflora on the nutritional requirements and/or status of the pig. Flexible T-shaped cannulae were made from plastic tubing, placed surgically in the caudal part of the ileum, and exteriorized in the right paralumbar fossa. After the exteriorization of the cecal apex in the right flank area, a cecal fistual was made caudoventral to the ileal cannula. Prececocolonic contents could be collected from the ileal cannulae and/or substances could be infused into the cecum. The flexible cannulae were light weight (35 g), were easily replaced when dislodged with minimal tissue trauma and minimal discomfort to the animal, and had good animal tolerance and patency in long-term experiments. The cecal fistulae allowed the direct introduction of various substances into the cecum. There was little external projection from the abdominal wall, and the fistulae were subject to minimal leakage. The procedure did not adversely affect the subsequent health or performance of the 43 gilts used in the experiment. Postmortem examination of gilts euthanatized 12 to 26 weeks postoperatively revealed normal tissue adhesions around the surgical sites with no detrimental effects on the gastrointestinal tract.