bluuebunny/crossref_metadata_2025 huggingface dataset:
Noneffectiveness of verapamil in preventing halothane-induced malignant hyperthermia in susceptible swine
Authors: McGrath C. J. , Lee J. C. , Rempel Wm. E.
Published: February 2025

Pietrain pigs susceptible to malignant hyperthermia (mh; porcine stress syndrome) were treated with the slow-channel calcium blocker verapamil and then subjected to halothane testing. There was no significant delay in the onset of mh among pigs (3 groups) given different doses of verapamil (1, 5, and 10 mg/kg) and saline control Pietrain pigs. The mortality due to mh (83.3%) was significantly higher among the pigs given the largest dose (10 mg/kg) than in the other groups. Verapamil was not effective in preventing or delaying a mh reaction. This antiarrhythmic drug should be used cautiously during a mh reaction in susceptible individuals.
Maximum-distention retrograde urethrocystography in healthy male dogs: Occurrence of vesicoureteral reflux
Authors: Feeney Daniel A. , Johnston Gary R. , Osborne Carl A. , Tomlinson Michael J.
Published: February 2025

Twenty-four healthy, mature male Beagles were examined radiographically for vesicoureteral reflux (vur) by maximum-distention retrograde urethrocystography. Bilateral vur was observed in 9 dogs and unilateral vur was observed in 3 dogs. The vur occurred when the bladder was füll or nearly full when maximum bladder filling was defined by trigonal-prostatic urethral dilation. The refluxed contrast medium reached the renal pelves in all but 3 of the 21 affected ureters.
Rapid purification of avian influenza virus for use in enzyme-linked immunosorbent assay
Authors: Abraham Albert , Sivanandan V. , Newman J. A. , Maheswaran S. K.
Published: February 2025

A rapid and easy purification method was developed to obtain avian influenza antigen for use in immunochemical assays. This was achieved by rapid concentration of virus from infective allantoic fluid, using 8% (w/v) polyethylene glycol 8000, and later, by purification on gel permeation chromatography through controlled-pore glass beads. Rabbit anti-turkey globulins were made specific for turkey globulins, using affinity chromatography, conjugated to hor seradish peroxidase and used in enzyme-linked immunosorbent assay.

A significant increase in specificity and sensitivity of the enzyme-linked immunosorbent assay was observed when purified antigen was used in place of a crude antigen preparation. This purified antigen eliminated the false-positives obtained as a result of the turkeys being previously vaccinated with egg-grown virus vaccines (Newcastle disease virus), The details of the technique and the importance of antigen preparation are discussed.
Effect of aztreonam on the growth of Pasteurella multocida in the lung
Authors: Collins Frank M.
Published: February 2025

Specific-pathogen-free ICR mice were infected aerogenically with Pasteurella multocida and, beginning 1 hour later, were treated with aztreonam (50 mg/kg of body weight). The number of viable bacilli in the lungs, liver, and spleen were determined at intervals for up to 36 hours. Aztreonam was bactericidal for growing bacilli in vitro and, when injected 1 and 5 hours after aerogenic exposure, provided > 80% protection after dosage at the level of 12.5 mg/kg. Below this dosage level, viable organisms persisted in the lungs and the spleen and many of the minimally treated mice eventually died of pasteurellosis. The survivors developed active immunity as a result of the continued sublethal infection. Aztreonam protects mice against an aerogenic infection with highly virulent Ρ multocida and may be useful in the prevention and treatment of pasteurellosis in cattle.
Relationship of cutaneous delayed hypersensitivity to protection from challenge exposure with Salmonella typhimurium in calves
Authors: Merritt Frank F. , Smith Bradford P. , Reina-Guerra Mario , Habasha Faisal , Johnson Eugene
Published: February 2025

The purpose in this investigation was to relate cutaneous delayed hypersensitivity reactions to the degree of immunity induced in calves given a live virulent or a modified-live strain of Salmonella typhimurium. Calves were placed into 1 of 5 groups on the basis of the vaccinal strain given and route of the vaccination: (I) nonvaccinated controls, (II) vaccinated twice by im inoculation with small doses of the live virulent strain, (III) vaccinated (im) twice with the modified-live strain, (IV) vaccinated (orally) twice with the modified-live strains, and (V) vaccinated (im, and then orally) twice with the modified-live strain. Skin testing was performed by intradermal injection of fragmented S typhimurium as antigen. Double skin fold thickness and visual assessments were recorded at 3, 6, 24, 48, and 72 hours after antigen was administered. Biopsy samples for histopathologic evaluation were obtained. After vaccination and skin testing were complete, calves were orally challenge exposed with 1.5 × 1011 virulent S typhimurium.

Cutaneous delayed-type hypersensitivity reactions (48 hours) were observed in all except controls (group I) and 2 of 3 calves vaccinated orally with the modified-live vaccine strain (group IV). Significant correlations between positive skin tests and protection from challenge exposure were observed except in group V calves, in which positive skin test results were seen, but adequacy of the immunity (or survival after challenge exposure) was inconsistent.
Controlled and clinical evaluations of the anthelmintic activity of a levamisole pour-on formulation against gastrointestinal nematodes in cattle
Authors: Guerrero Jorge , Seibert Barbara P. Campbell , Newcomb Kathleen M. , Michael Bruce F. , Garcia-Naranjo Fernando , Rogiers Marcel
Published: February 2025

Beef-type calves (n = 107) with naturally occurring helminth infections were used in a series of 3 controlled experiments to study the anthelmintic activity of a new pour-on formulation of levamisole. In the 1st experiment, the efficacy of a single treatment of levamisole pour-on at a rate of 10 mg/kg of body weight was determined, using a placebo pour-on in a similar volume as a control. In the 2nd experiment, calves were treated with levamisole pour-on at doses of 0 (nontreated control), 7.5, 10, or 12.5 mg/kg of body weight. In the 3rd experiment, the anthelmintic efficacy of the optimal dose of levamisole pour-on (10 mg/kg of body weight) was compared with that of injectable levamisole at the recommended rate (6 mg/kg of body weight). In all 3 studies, levamisole pour-on, at a dosage of 10 mg/kg of body weight, was efficacious (90% to 100%) against the adult forms of Trichostrongylus axei, Haemonchus placei, Ostertagia ostertagi, Cooperia spp, Oesophagostomum radiatum, Nematodirus spp, and Bunostomum phlebotomum. Efficacy was moderate to good against Capillaria bovis, and poor or inconsistent against Strongyloides papillosus and Trichuris ovis.

Clinical tests of anthelmintic efficacy and local tolerance of levamisole pour-on were conducted in 371 beef and dairy cattle in Mexico. Fecal egg counts were consistently reduced 2 weeks after a single application of levamisole pour-on at a dosage of 10 mg/kg of body weight. Local reactions were limited to various degrees of dry hair coat for up to 2 weeks at the application site. Hair loss or skin abnormalities were not observed in any of the treated cattle.
Responses of equine neutrophils to contagious equine metritis organism and its lipopolysaccharides
Authors: Bertram Timothy A. , Jensen Allen E.
Published: February 2025

Morphology and function of equine neutrophils were evaluated after combination with contagious equine metritis organism (cemo) or 1 of 2 cemo lipopolysaccharides (lps). The 2 lps (lps-a; lps-p) isolated from the cemo contained 14- and 16-carbon fatty acids, ketodeoxyoctanate, hexose, and heptose, but were morphologically distinct. Neutrophils exposed to lps had fewer granules, whereas those exposed to cemo had more granules than did the controls (phosphate-buffered saline solution). Neutrophil iodination was significantly increased with 10 and 25 μg of lps-a, but not significantly altered by lps-p or cemo. Staphylococcus aureus ingestion was not influenced by cemo and was mildly decreased by lps-a. These results indicate that cemo may have at least 2 functionally and morphologically distinct, but chemically similar, lps and that 1 of these lps (lps-a) may enhance neutrophil killing by stimulating neutrophil iodinating mechanisms.
Comparison of complement fixation test and enzyme-linked immunosorbent assay for detection of early infection with Mycoplasma hyopneumoniae
Authors: Piffer I. A. , Young T. F. , Petenate Ademir , Ross R. F.
Published: February 2025

The relative merits of the complement-fixation test (cf) and enzyme-linked immunosorbent assay (elisa) for the detection of the early antibody response to Mycoplasma hyopneumoniae were evaluated. Discriminant analysis, a statistical procedure, was used to avoid difficulties associated with variation in background color and nonspecific reactions obtained with elisa with different sera. Specific-pathogen-free pigs were exposed by contact to other specific-pathogen-free pigs which had been inoculated with M hyopneumoniae intratracheally (experiment A) or intranasally (experiment B) 18 to 21 days previously. Sera were collected from each pig before contact exposure and once a week until necropsy. Antibodies were detected by cf at postexposure (pe) week 3 in animals in experiment A (6 of 18) and at pe week 5 in experiment B (3 of 12). The elisa antibodies were detected at 2 weeks after beginning of contact exposure in experiments A (4 of 18) and B (1 of 12). Examination of pooled data for experiments A and B indicated that elisa was substantially (P < 0.05) more sensitive for detection of antibodies than was the cf test at 3 to 5 weeks after contact exposure began. At pe weeks 6 and 7, both tests were similarly effective in detecting M hyopneumoniae antibodies.
Caprine aflatoxicosis: Serum electrophoresis and pathologic changes
Authors: Miller Doris M. , Clark J. Derrell , Hatch Roger C. , Jain Anant V.
Published: February 2025

Pathologic changes and serum electrophoretic patterns were determined in 30 male goats given aflatoxin B1 (afb1) orally at 4 dosage levels (mg/kg of body weight/day): 0.1 for 34 days; 0.2 for 18 days; 0.4 for 10 days; or 0.0 for 29 days. Goats given afb1 had increased mean concentrations of γ-globulins and most had decreased mean concentrations of β-globulins, although these changes in serum proteins were not significant (P > 0.05). At necropsy, ascites, pale livers, petechial hemorrhages, nasal discharge, and icterus were present. Microscopic changes included bile ductule proliferation, hepatocytic karyomegaly, hepatocellular degeneration, pneumonia, rhinitis, and proximal renal tubular nephrosis. Goats given the 2 smaller dosage levels of afb1 lived longer and had more severe lesions. Goats may be a good model for the study of ruminant aflatoxicosis.
Tetrameres columbicola (Nematoda: Spiruridae) infection of pigeons: Ultrastructure of the gravid female in glands of the proventriculus
Authors: Simpson Charles F. , Carlisle J. W. , Conti Joseph A.
Published: February 2025

The light and electron microscopies of Tetrameres columbicola gravid females in sections of the parasitized proventriculus of pigeons were studied. By light microscopy, the most conspicuous structures in the sectioned parasite were the intestine, ovary, and especially the uterus that contained numerous eggs. By electron microscopy, there was a thick mat of pigment-coated microvilli on the surfaces of the intestinal epithelial cells. The germinal zone of the ovary contained nonmembrane-bound oocytes, but oocytes were confined by a membrane in the growth zone of the ovary. The core of the spermatheca contained oocytes and the periphery harbored sperm. In this location, the unfertilized oocyte had pseudopods; sperm had invaginations of the plasma membrane. After fertilization, there was proliferation of ribosomes within the oocyte.

Embryonating eggs in the uterus had thick shells and were partially enveloped by elongations of the uterine epithelial cells. Surfaces of the epithelial cells were pleated and they had electron opaque areas at the points of the pleats. Larvae in eggs had a well developed annulated cuticle and muscular layer.

Somatic muscle cells had tailed appendages that protruded into the pseudocoelom. The single layer of cells beneath the hypodermis had lateral processes at the base of the cells that interdigitated with similarly elongated processes of adjacent muscle cells. Striated fibers were present in the central portion of the cells.
An evaluation of ivermectin in the treatment of sarcoptic mange in dogs
Authors: Scheidt Vicki J. , Medleau Linda , Seward R. Lee , Schwartzman Robert M.
Published: February 2025

A colony of mixed-breed dogs (n = 298) naturally infested with Sarcoptes scabiei was treated, twice, with 200 μg of ivermectin/kg of body weight subcutaneously at 14-day intervals. After the initial injection, positive skin scrapings from 20 treated dogs decreased from 7 to 1 and the degree of pruritus decreased. In contrast, positive skin scrapings from 22 nontreated dogs increased from 10 to 14, and there was an additional deterioration in the condition of the skin and an increase in the degree of pruritus. Complete control was noticed in all treated dogs by posttreatment day 28 (14 days after a 2nd injection) based on negative skin scrapings.
Protection by vaccination against bovine leukemia virus infection in sheep
Authors: Onuma M. , Hodatsu T. , Yamamoto S. , Higashihara M. , Masu S. , Mikami T. , Izawa H.
Published: February 2025

Four preparations were tested as potential vaccines to protect sheep against bovine leukemia virus (blv) infection. Purified glycoprotein (gp) 51 and protein (p) 24 antigens from the virus and glutaraldehyde-fixed fetal lamb kidney (flk) cells chronically infected with blv or sheep fibroblasts transformed with blv (SF-28 cells) were used to inoculate 12 sheep. Each vaccine was given 3 times 2 and 4 weeks apart to 3 sheep. Six sheep vaccinated with gp51 antigen or fixed flk cells developed complement-fixing antibody against gp51; the titers ranged from 1:8 to 1:128 at the time of virus challenge exposure at postinoculation week 9. Although the 6 sheep inoculated with p24 antigen or fixed SF-28 cells developed antibody against the respective inoculum, none of these sheep had gp51 antibody at the time of challenge exposure. All 12 vaccinated and 2 control sheep were challenge exposed with blv-infected lymphocytes, and cells from the sheep subsequently were tested for infection by syncytium assay.

Sheep inoculated with gp51 antigen or flk cells were protected, but sheep inoculated with p24 antigen or SF-28 cells became infected. The cytotoxic activity of lymphocytes from protected and nonprotected sheep was not different from that of normal sheep. Seemingly, purified gp51 antigen or fixed flk cells were capable of preventing blv infection in sheep. Humoral immune responses to gp51 appears to have an important role in protection against blv infection, whereas cytotoxic activity of lymphocytes does not.
Hemolysis in gel test for detection of bovine antibodies to Brucella abortus: Comparison of antigens and test modifications
Authors: Dillender M. J. , Buening G. M. , McLaughlin K. K.
Published: February 2025

Killed Brucella abortus strain 1119-3 cells were treated with hot phenol/water or dimethyl sulfoxide to extract soluble crude lipopolysaccharide antigen. Antigen preparations were characterized with respect to protein and lipopolysaccharide content and were compared for efficacy in the hemolysis-in-gel test (higt) for detecting anti-Brucella antibodies.

All antigens were equally effective in sensitizing bovine rbc in the higt and in detecting the presence of anti-Brucella antibodies. A slide modification of the higt was developed and compared with the plate higt. Seemingly, both tests were comparable.
Effect of acetohydroxamic acid on prevention of canine struvite uroliths
Authors: Krawiec Donald R. , Osborne Carl A. , Leininger Joel R. , Griffith Donald P.
Published: February 2025

Long-term administration of acetohydroxamic acid (aha) to dogs with experimentally induced urease-positive staphylococcal urinary tract infections, and bladder zinc disk foreign bodies inhibited urolith growth in 2 dogs and prevented urolith growth in 4 dogs. Inhibition and prevention of urolith growth were associated with reduction in urine urease activity, crystalluria, pyuria, hematuria, and proteinuria. Lesions in the urinary tract of aha-treated dogs were less severe than those of infected control dogs. Administration of aha for 6 months induced mild morphologic abnormalities in rbc, but did not cause hemolytic anemia.
Vascular pathways of the anterior segment of the canine eye
Authors: Sharpnack Douglas D. , Wyman Milton , Anderson Bettina G. , Anderson Wesley D.
Published: February 2025

The vasculature of the anterior segment of the canine eye was studied by preparing intravascular casts with a methyl methacrylate resin. Specimens were examined and results were recorded with the aid of stereoscopic dissecting and scanning electron microscopes.

The arterial supply was via anterior ciliary and long posterior ciliary arteries. An arterial circle derived from dorsal and ventral anterior ciliary arteries was identified in the anterior sclera. The long posterior ciliary artery contributed branches to the choroid, anterior sclera, and anterior border of the ciliary processes. Radial iris arterioles arose from the major arterial circle of the iris and ended blindly at the pupillary margin. Radial ciliary arteries arose from the major arterial circle of the iris and ran posteriorly and supplied the ciliary processes and muscle and fused with the choroidal vasculature. Each ciliary process was supplied by an afferent arteriole from the radial ciliary artery. Sphincters could be seen at branch points within the vascular net of the ciliary processes.
Hematologic values in healthy neonatal, weanling, and juvenile kittens
Authors: Meyers-Wallen Vicki N. , Haskins Mark E. , Patterson Donald F.
Published: February 2025

Blood samples were taken by jugular venipuncture from healthy kittens ranging in age from birth to 17 weeks. Complete blood cell counts, including rbc indices, provided data on reference blood values in kittens. Age-dependent rbc changes observed were decreases in pcv and hemoglobin (Hb) and mean cell Hb concentrations in neonatal kittens and a subsequent increase in pcv, Hb concentration, and rbc count in juvenile kittens. Leukocyte changes included an increasing wbc count from birth through the weanling period, increases in lymphocyte numbers in the neonatal and juvenile age groups, and increases in eosinophil numbers in the juvenile period.
Spermatozoa and testes in the boar: Correlative analysis of sperm morphologic features, seminiferous epithelial area, and testes weight
Authors: Basurto-Kuba V. M. , Heath E. , Wagner W. A.
Published: February 2025

Testicular tissue and sperm from the cauda epididymidis of 300 boars were obtained in 6 collections during 1 year at a Chicago abattoir. Seventy-five boars (25%) had ≥ 1 sperm abnormality present at rates that could result in infertility. These abnormalities and their frequency criteria were: proximal droplets ≥ 15%, loose heads ≥ 10%, abnormal middle pieces ≥ 10%, abnormal acrosomes ≥ 10%, bent tails ≥ 15%, coiled tails ≥ 15%, and abnormal head shapes > 5%.

These 75 abnormal boars were then compared with a control group of 75 boars selected at random from the remaining 225 boars. Frequency of sperm abnormalities, testicular and epididymal weights, relative seminiferous epithelial areas (sea), and the degree of testicular lesions were used in making comparisons. Testicular lesions were scored on a scale of 1 (normal) to 5. The sea was measured and was expressed as the mean area of 50 tubules. The sea was negatively correlated with proximal droplets and abnormal middle pieces in abnormal boars and abnormal head shapes in control boars. The mean sea was 8.71 and 5.60 cm2 for control and abnormal boars, respectively. The overall mean score for testicular lesions was 1.72 and 3.17 for control and abnormal boars, respectively.
Diagnosis of mycoplasmal pneumonia of swine: Sequential study by direct immunofluorescence
Authors: Amanfu W. , Weng C. N. , Ross R. F. , Barnes H. J.
Published: February 2025

An improved direct fluorescent antibody test was evaluated for specificity and efficacy in diagnosing mycoplasmal pneumonia of swine. A sequential study was carried out in which pigs inoculated with a pneumonic lung suspension containing Mycoplasma hyopneumoniae strain 11 were euthanatized at postinoculation (pi) weeks 2 to 12. Fluorescent coating of M hyopneumoniae was detected primarily on bronchial and bronchiolar epithelial surfaces of lungs with gross lesions of pneumonia. Fluorescence was observed to be most intense at pi weeks 4 to 6, with a tendency to decrease in intensity from pi weeks 8 to 12. This indicated that there may be a decrease in number of M hyopneumoniae cells in the more advanced stages of the disease. The use of a counterstain (chelated azo-dye) provided an excellent color contrast and permitted making unambiguous interpretation of results.
African swine fever in neonatal pigs: Passively acquired protection from colostrum or serum of recovered pigs
Authors: Schlafer Donald H. , Mebus Charles A. , McVicar John W.
Published: February 2025

The effect of passively acquired antibodies on the course of African swine fever (asf) virus infection was investigated in hysterotomy-derived neonatal pigs fed colostrum from an asf-recovered sow or given asf virus antiserum.

Thirty neonatal pigs were assigned to 5 study groups: (i) colostrum-deprived, (ii) fed colostrum from a normal sow, (iii) fed colostrum from an asf-recovered sow, (iv) given asf virus antiserum, and (v) noninoculated controls. Pigs were inoculated oronasally with 106.1 median hemadsorption units (HAd50) of a Dominican Republic asf virus isolate.

The progression of asf infection was monitored by measure of rectal temperature, viremia titers, antibody response, and observation of attitude. The clinical course of asf infection was markedly different in young pigs in the various study groups.

On postinoculation day (pid) 4, asf viremia titers for pigs receiving colostrum from an asf-recovered sow or asf virus antiserum (mean = 3.2 ± 1.88 log10 HAd50, n = 10 pigs) were significantly lower (P < 0.001) than viremia titers of colostrum-deprived pigs or of those fed normal colostrum (mean viremia titer = 7.8 ± 0.55 log10 HAd50, n = 14 pigs). All pigs not given colostrum or serum (n = 15 pigs) from swine recovered from asf were dead by pid 16. By pid 30, only 1 pig that received colostrum or antiserum (n = 10 pigs) from the sow recovered from asp had died.

To determine whether the protective effect of asf antiserum resided within the immunoglobulin (Ig) fraction, 4 pigs that had acted as noninoculated controls for the 1st experiment were given 125 mg of ammonium sulfate precipitated Ig from the asf virus antiserum used in the initial study (intraperitoneally). The 5th pig was not given Ig (nontreated-inoculated control). All 5 pigs were inoculated oronasally with 106.1 HAd50 of Dominican Republic asf virus. The nontreated control pig died on pid 10 and 3 Ig-treated pigs died on pid 17, 23, and 24. The 4th Ig-treated pig survived. Although administration of precipitated asf Ig did not completely protect against clinical asf infection or death, the course of infection was markedly altered.
Anatomy of the tarsal tendons of the equine tibialis cranialis and peroneus tertius muscles
Authors: Updike Susan J.
Published: February 2025

Tendons of insertion of the equine tibialis cranialis muscle and peroneus tertius muscle (pt) were dissected grossly. Precise areas of tendon attachment and fiber arrangements within the tendons were described for the dorsal and medial tendons of the tibialis cranialis, and for the superficial lateral, deep lateral, dorsal, and medial tendons of the pt. Direct attachment of the dorsal and medial tendons of the pt into the periosteum of the central and 3rd tarsal bones and the 3rd metatarsal bone indicates that the pt may be involved in the pathogenesis of hock lamenesses.
Adverse effects of antibiotics on the development of gut-associated lymphoid tissues and the serum immunoglobulins in chickens
Authors: Naqi S. A. , Sahin N. , Wagner G. , Williams J.
Published: February 2025

Study was done of the distribution and relative densities of immunoglobulin (Ig)M-, IgG-, and IgA-producing cells in the gut-associated lymphoid tissues and the spleen (sp) of control and antibiotic-treated chickens between 3 and 28 days of age. Specific Ig in the serum also were quantitated simultaneously. Antibiotic treatment included preincubation dipping of fertile eggs in gentamicin solution (500 mg/L), injection of chicks with gentamicin (0.2 mg/chick, subcutaneously), and inclusion of chlortetracycline in the diet (200 mg/kg).

At 3 days, the gut-associated lymphoid tissues of control chicks carried few Ig-positive cells, except the bursa of Fabricius in which all 3 classes of Ig-bearing cells were present in relatively large numbers. The sp had few, but equal, numbers of IgM- and IgA-positive cells at this age. As control birds grew older, IgM-positive cells dominated in the sp, followed by the IgA cells. Cell populations fluctuated in the bursa of Fabricius of chicks until 21 days of age when IgM and IgA cells stabilized at a higher density than the IgG-positive cells. The cecal tonsils had no Ig-positive cells at 3 days, mostly IgM cells by 7 days, but equal numbers of the 3 types of cells by 28 days.

The large intestines had few IgM-positive cells at 3 days and no IgG cells at 3 or 7 days. The numbers of IgM and IgA cells were approximately equal in the large intestine of the chicks from 7 days until 28 days. Maternally acquired IgG predominated in sera of chicks until 14 days of age, followed by the IgM. At 28 days, there was more IgM in the serum than IgG. Serum IgA was not detectable until 14 days of age, and its concentration remained at a lower level than IgM or IgG values.

Antibiotic-treated chickens generally carried lower densities of Ig cells than did the respective controls. However, statistically significant (P < 0.05) differences were apparent only with respect to Ig cell populations in the cecal tonsils and the large intestines. The treated chickens also had significantly lower serum IgM concentrations at 28 days of age.
Location of cryptosporidia: Review of the literature and experimental infections in calves
Authors: Anderson Bruce C.
Published: February 2025

Cryptosporidium, a protozoan, was present in the gastrointestinal tract of calves, lambs, goats, deer, foals, cats, rats, mice, guinea pigs, rabbits, monkeys, human beings, birds, reptiles, and fish. The usual location was the gastrointestinal tract with emphasis on the lower portion of the small intestine. In birds, cryptosporidia were also present in the respiratory tract and conjunctiva. In human beings, cryptosporidia were present in specimens from the respiratory tract. Immunologic impairment may allow a more widespread distribution of the parasite in a given animal and may be related to increased susceptibility.

Experimental cryptosporidial infections in newborn calves resulted in the establishment of the organisms in jejunum, ileum, cecum, and colon. Middle and lower portions of the jejunum and ileum appeared to have the largest numbers of organisms at 5 to 7 days after inoculation, as determined by histologic examinations.
Epidemiology of bovine brucellosis in the Mexicali Valley, Mexico: Results of path analysis
Authors: Salman Mowafak D. , Meyer Margaret E. , Cramer James C.
Published: February 2025

Twenty-eight known or hypothesized variables in the epidemiology of bovine brucellosis were examined by path analysis to determine the contribution of each variable to seropositivity of cattle in Mexicali, Mexico. The variables that contributed significantly to bovine seropositivity were area size of farm premises, percentage of animals on a premises that were inseminated artificially, local marketing of the products from a premises, size of investment in the livestock, whether or not dairying was the major agricultural activity of the premises, and the policy of the owner or manager with regard to disposal of reactor animals. The contributions of all other variables were insignificant.
Excretion of [3H]prednisolone in clinically normal and experimentally infected bovine udders
Authors: Geleta J. N. , Shimoda Wilbert , Mercer H. Dwight
Published: February 2025

The excretion rate of [3H]prednisolone from clinically normal and experimentally infected udders of 10 lactating cows was studied. Each quarter of 6 cows was injected with a single dose of [3H]prednisolone mixed with nonradioactive prednisolone equivalent to 10 mg in 10 ml of peanut oil base. Each of the remaining 4 cows was given 40 mg of nonradioactive prednisolone and [3H]prednisolone in 60% ethanol iv. Control and postadministration samples of blood, milk, and urine were examined for radioactivity. The effects of [3H]prednisolone were evaluated in the same cows, first in clinically normal udders, then 2 weeks later in udders experimentally infected with Streptococcus agalactiae.

Absorption and elimination of prednisolone were the same before and after induced infection. Within 3 hours after intramammary injection, 95% of the labeled prednisolone was absorbed systemically, < 5% of this dose was recovered in milk, and 29% was excreted in urine. After iv injection of [3H]prednisolone, < 0.2% of the total radioactivity was recovered in milk and < 46% was excreted in urine.

Clinical mastitis induced by S agalactiae was moderate. Circulating blood leukocytes and somatic cells in the milk of normal cows remained essentially unchanged. The leukocyte response to induced infection was rapid in blood and milk. Large numbers of leukocytes were noticed in the milk and a severe leukopenia occurred. Prednisolone treatment did not alter the number of somatic cells in milk or reduce the inflammatory response of experimentally infected cows.
Humoral and cellular immune responses in cattle and sheep inoculated with Sarcocystis
Authors: Gasbarre Louis C. , Suter Pamela , Fayer Ronald
Published: February 2025

Cattle inoculated with Sarcocystis bovicanis ( = Sarcocystis cruzi) and sheep inoculated with Sarcocystis ovicanis were monitored for the appearance of Sarcocystis-specific antibodies and lymphocytes in the peripheral circulation. Anti-Sarcocystis antibody was identified by enzyme-linked immunosorbent assay, whereas antigen-reactive lymphocytes were discerned by an in vitro lymphocyte blastogenic assay. The antigens used were the soluble fraction recovered from disrupted bradyzoites of mature sarcocysts. Cattle developed anti-Sarcocystis immunoglobulin (Ig)M responses, beginning 3 to 4 weeks after inoculation, and IgG1 antibody responses, beginning 5 to 6 weeks after inoculation. The increase in IgM antibody was relatively brief, returning to near preinfection levels in 2 to 3 months. In contrast, IgG1 antibody levels remained high for at least 5 to 6 months. Neither IgG2 nor IgA antibody responses were demonstrable in cattle. In sheep, the IgG antibody levels followed a time course similar to that seen in cattle, except that the increase was slightly delayed (6 to 8 weeks after inoculation was done). Measurable IgM antibody response was not seen in sheep.

Cellular immunoresponsiveness as judged by in vitro lymphocyte blastogenesis in cattle was different from that in sheep. Sarcocystis-specific lymphocytes were demonstrable in the circulation of cattle within 15 days after they were inoculated, but the activity decreased rapidly. In sheep, reactive cells were not evident until 3 to 4 weeks after inoculation were done, but peripheral blood lymphocytes taken from these sheep as long as 5 to 6 weeks after the inoculations remained capable of mounting strong blastogenic responses.

Neither the enzyme-linked immunosorbent assay nor the blastogenic assay showed species specificity. Animals immunized with a given species of Sarcocystis gave similar in vitro responses to antigens from the immunizing species and to other species of Sarcocystis. This apparent lack of specificity is probably due to the presence of cross-reacting determinants in the crude antigen preparations used.
Quantitative analysis of long-bone growth in the horse
Authors: Fretz P. B. , Cymbaluk N. F. , Pharr J. W.
Published: February 2025

Long-bone growth at the distal ends of the radial bones, the distal ends of the 3rd metacarpal bones, the distal ends of the 3rd metatarsal bones, and the proximal ends of the proximal phalangeal bones (of thoracic and pelvic limbs) was quantitatively analyzed in 9 Thoroughbred-Quarter Horse foals from birth to 2 years of age, Metal growth markers were surgically implanted in the bones of the animals at 2 to 4 days of age. Radiographs of the bones were made on the day of surgical manipulation, the next day, and then once a week for 8 months, and once a month thereafter for an additional 18 months. On each radiograph, the intervals between the growth markers were measured and plotted, and these accumulated growth data were subjected to statistical analyses. Growth curves, cumulative growth, and relative growth rates were determined. The ages of radiographic growth plate closure also were determined.

Total bone growth observed in these foals was proportionately greater than that observed in a similar study of Shetland-Welsh ponies, probably indicating a breed difference. The most rapid growth rate at the 5 anatomic sites in the foals occurred from birth to 10 weeks of age; however, in the distal part of the radius, there was a continuous, though declining growth rate until 60 weeks of age, whereas in the distal ends of the 3rd metacarpal and metatarsal bones and the proximal end of the proximal phalanges growth ceased abruptly and nearly plateaued after 10 weeks of age. Angular limb deformities of the fetlocks must therefore be recognized and treated quickly after the foal is born, whereas growth retardation procedures involving the distal part of the radius—although optimally performed during the first 10 weeks of life—also may be successful if performed after 10 weeks of age. It was evident that the radiographic appearance of a growth plate does not reflect the capability of the cartilage cells to produce longitudinal growth and that clinicians treating angular limb deformities in foals must use growth rates and measurements as bases for selecting surgical patients.
Amikacin sulfate in mares: Pharmacokinetics and body fluid and endometrial concentrations after repeated intramuscular administration
Authors: Brown Murray P. , Embertson Rolf M. , Gronwall Ronald R. , Beal Carolyn , Mayhew Ian G. , Curry Stephen H.
Published: February 2025

Six mares were given 5 im injections (at 12-hour intervals between doses) of amikacin sulfate at a dosage of 7 mg/kg of body weight. Serum amikacin concentrations were measured serially throughout the study; synovial, peritoneal, endometrial, and urine concentrations were determined after the last injection. Amikacin concentrations of the csf were measured serially in 3 of the 6 mares; 1 of the 3 mares had septic meningitis. Mean serum amikacin concentrations peaked at 1 to 2 hours after im injection. The highest mean serum concentration was 19.2 μg/ml (1.5 hours after the 5th injection). The highest mean synovial concentration was 10.8 μg/ml at 2 hours after the 5th injection; the highest mean peritoneal concentration was 16.2 μg/ml at 3 hours after the 5th injection. The mean endometrial amikacin concentration was 2.5 μg/g (1.5 hours after the 5th injection). Amikacin reached a csf concentration of 0.97 μg/ml in the mare with meningitis, but amikacin was not detected in csf of healthy mares. Urine concentrations reached 1,458 μg/ml. Pharmacokinetic values were estimated after the 1st injection (elimination rate constant = 0.31/hour; half-life = 2.3 hours; apparent volume of distribution = 0.26 L/kg), and after the 5th injection (elimination rate constant = 0.28/ hour; half-life = 2.6 hours; apparent volume of distribution = 0.30 L/kg); significant differences were not observed.
Transruminal palpation of abdominal arteries of the permanently fistulated dairy cow
Authors: McCarthy P. H.
Published: February 2025

A description is given of the arteries within the abdominal cavity of the live permanently fistulated dairy cow which are palpated through the wall of the rumen. It is considered (a) that transruminal palpation of arteries within the abdominal cavity of the live fistulated animal is a realistic aid to the teaching of veterinary anatomy after the student has performed the relevant routine dissection of the embalmed cadaver, and (b) that this technique, as a method of instruction may complement rectal palpation of the live cow, where a majority of the branches of the celiac artery and the cranial mesenteric artery are not routinely within reach of the operator.

The possibility of taking blood samples at any time from specified arteries supplying the ruminorecticulum and spleen in the fistulated dairy cow is considered.
Cell-mediated immune response in cattle to bovine respiratory syncytial virus
Authors: Field E. W. , Smith M. H.
Published: February 2025

Cattle inoculated with bovine respiratory syncytial virus (brsv) were evaluated for the development of a cell-mediated immune response. Results of the leukocyte migration-in-hibition test under agarose and the delayed hypersensitivity test indicated that a cell-mediated immune response was elicited after intranasal inoculation of calves with brsv. Migration inhibition in the leukocyte migration-inhibition test was detected by postinoculation day (pid) 5 and reached maximum inhibition on pid 21. Inhibition of leukocyte migration was still evident by pid 42 when values were still appreciably greater than preinoculation values. All of the calves inoculated with brsv developed a delayed hypersensitivity skin response when challenge exposed intradermally with brsv antigen.
Bacteria isolated from lymph nodes of California slaughter swine
Authors: Morse Jeffrey W. , Hird David W.
Published: February 2025

Lymph nodes from 280 slaughter swine from 9 California ranches were examined for the presence of aerobic microflora. Genera of interest which were isolated (and percentage of animals from which they were isolated) included Salmonella (4.3%), β-hemolytic streptococci (8.2%), Mycobacterium avium-complex (6.4%), Corynebacterium pyogenes (0.4%), and Aeromonas hydrophila (5.7%). Patterns of bacterial isolations from swine herds may be of assistance in predicting herd health problems.
Pathogenesis of experimental bovine respiratory syncytial virus infection in sheep
Authors: Trigo F. J. , Breeze R. G. , Evermann J. F. , Gallina A. M.
Published: February 2025

Conventionally reared lambs, seronegative to bovine respiratory syncytial virus (rsv), were inoculated with bovine rsv by an aerosol route. A mild clinical response, characterized by transient fever at postinoculation day (pid) 4, occurred and was accompanied by serous oculonasal secretions in < 50% of the infected lambs. A decrease in total wbc was observed on pid 6 and 11, with a reduction in the total numbers of lymphocytes.

Bovine rsv was recovered from nasal secretions of inoculated lambs from pid 2 to 6. The lambs were euthanatized, and at necropsy, the virus was only isolated from lambs killed between pid 2 and 4. Serum neutralizing antibodies were noticed as early as pid 6 and peaked at pid 13 to 15. Neutralizing antibodies were also detected at low concentration in pulmonary washings. Viral antigen was mainly located in alveolar walls and occasionally in bronchiolar epithelium and alveolar macrophages in lambs killed between pid 2 to 4. Later, specific fluorescence was only present in alveolar walls and was not observed in tissue from lambs killed after pid 22. Budding and free virus-like particles were observed by electron microscopy in type I and type II alveolar epithelial cells. Outstanding macroscopic lesions were not seen. Histologically, mild bronchiolitis and alveolitis were observed.
Interactions of cold stress and Pasteurella haemolytica in the pathogenesis of pneumonic pasteurellosis in calves: Changes in pulmonary function
Authors: Slocombe R. F. , Derksen F. J. , Robinson N. E.
Published: February 2025

Thirteen healthy neonatal Holstein calves were cold stressed twice by hosing with cold water for 20 minutes, 12 hours between hosings. Measurements of the pattern of ventilation [tidal volume (VT), respiratory frequency (f), minute ventilation (), and functional residual capacity (frc)], gas exchange properties of the lungs [alveolar ventilation (), oxygen uptake () CO2 production (), dead space ventilation (), dead space/tidal volume ratio (VD/VT), arterial oxygen tension (Pao2), arterial CO2 tension (Paco1) and alveolar-arterial oxygen difference (AaDO2)] and of the mechanical properties of the pulmonary system [dynamic compliance (Cdyn), pulmonary resistance (RL), and total respiratory system resistance (RRS)] were taken.

Calves responded to chilling by increasing and necessitating an increase in . This was accomplished by increasing with reciprocal decreases in f so that remained constant. There was no change in Cdyn, RL, or AaDO2.

Seven of these 13 calves were then exposed to intratracheal inoculation of 2 × 109 organisms of Pasteurella haemolytica, the remaining calves serving as controls. Within 1 hour, calves exposed to P haemolytica had increased , f, VD/VT, and . There was a decrease in Pao2 associated with increased AaDO2, but no change in Paco2, Cdyn or RL. By 3 hours after inoculation, there were pronounced changes in Pao2 and AaDO2, and Cdyn was reduced below base-line values. By 12 hours after inoculation, calves infected with P haemolytica had increased RL and RRS and Paco2, in addition to the previously mentioned changes.

Data from Pasteurella-exposed calves indicate that gas exchange impairment and peripheral lung injury occur rapidly and that increases in airway resistance develop relatively late in the disease. The early changes probably arise from ventilation-perfusion mismatching in injured lung segments. These data indicate that respiratory tract injury in pasteurellosis of calves is initiated from the parenchyma and is not the result of extension of lesions from conducting airways.
Demonstration of the inclusion appendage of Anaplasma marginale in nymphal Dermacentor andersoni
Authors: Kocan Katherine M. , Ewing S. A. , Hair Jakie A. , Barron Selwyn J.
Published: February 2025

Dermacentor andersoni nymphs were placed in stockinettes and allowed to feed on a splenectomized calf with experimentally induced anaplasmosis when the parasitemia was 3%-5%. Nymphs were selected on each of the 6 days of feeding and every 5 days from repletion through molting to the adult stage (25 days postrepletion); they were killed and midgut tissues were processed and examined by light and electron microscopies. No stages of A marginale were seen in tissues of feeding ticks. Visualization of individual components of gut contents was difficult owing to presence of the concentrated, electrondense blood meal containing hemoglobin. Inclusion appendages were observed in midgut tissues of nymphs at 5 and 10 days postrepletion, but not at 20 or 25 days. The morphology of the appendages was similar to that described for inclusion appendages commonly associated with anaplasmal inclusions in bovine erythrocytes. Some appendages were free in the lumen of the midgut and occurred either alone or with clusters of small vesicular particles. Occasionally, initial bodies like those generally found in bovine erythrocytes were seen with the appendage, but most of them were swollen and appeared to be degenerating. Frequently, inclusion appendages were observed attached to the luminal surface of the midgut cell membrane by a blunt, electron-dense attachment complex. The attachment of the appendage appeared to be extracellular, with the pointed end extending into the lumen. Often, small particles were observed immediately across the cell membrane from where the appendages were attached; the small particles appeared to be generated from the appendage itself and to have passed through the membrane of the midgut cells. The possible role of the inclusion appendage and of small particles in the infection of tick midgut cells is discussed.
Campylobacter jejuni and Campylobacter coli inoculation of neonatal calves
Authors: Warner David P. , Bryner John H.
Published: February 2025

Three groups of neonatal calves were inoculated orally with pathogenic strains of Campylobacter jejuni or C coli. The calves developed a mild, self-limiting enteritis characterized by thick mucoid feces. Bacteremia and fecal shedding of Campylobacter were sporadic in all inoculated calves. Two groups of calves were killed 1 to 3 weeks after inoculation to study the pathogenesis of infection. Postmortem culture of tissues revealed C jejuni or C coli most frequently in the ileum, cecum, colon, and blood. Clinical or pathologic differences between C jejuni-inoculated and C coli-inoculated calves were minimal.
Construction of acid-base alignment nomograms to estimate buffer base and base-excess concentrations in arterial blood from immature pigs
Authors: Hannon John P.
Published: February 2025

Acid-base characteristics of a population of immature domestic pigs were used to construct a blood acid-base alignment nomogram with scales to estimate porcine buffer base concentration. The nomogram was based on average plasma bicarbonate concentration of 31.6 mEq/L and plasma albumin and globulin values of 25.4 and 32.2 g/L, respectively. A measurement temperature of 38 C was assumed. Subsequently, this nomogram was used to construct a blood acid-base alignment nomogram with scales to estimate porcine base-excess concentration. The nomogram was based on the assignment of zero-base excess to blood with a pH of 7.50 and a PCO2, of 40 mm of Hg. Construction details, including tabular data reflecting the acid-base characteristics of porcine plasma and erythrocytes, are provided.
Persistence of encysted Toxoplasma gondii in tissues of pigs fed oocysts
Authors: Dubey J. P. , Murrell K. D. , Fayer Ronald
Published: February 2025

Ten pigs were fed 100 to 10,000 Toxoplasma gondii oocysts. Two pigs died 7 and 11 days later, and 8 pigs were euthanatized at days 38, 38, 91, 126, 168, 169, 170, and 171. From the euthanatized pigs, portions of 15 organs digested in pepsin-HCl solution were inoculated into mice, as a bioassay for viable T gondii. Such organisms were isolated from the brain and heart of these 8 pigs, from the tongue of 7, from thigh muscles of 5, from the diaphragm of 4, from kidneys, liver, and small intestines of 2, and from salivary glands and eyes of 1 pig; but not from lungs, spleen, spinal cord, mesenteric and prescapular lymph nodes of any pig. Results indicate that T gondii can persist in edible tissues of living pigs for at least 171 days and that heart and brain may be the most suitable porcine tissues for epizootiologic surveys.
Immunologic relationships between equine herpesvirus type 1 (equine abortion virus) and type 4 (equine rhinopneumonitis virus)
Authors: Fitzpatrick D. R. , Studdert M. J.
Published: February 2025

The specificity of selected immune responses to equine herpesvirus type 1 (ehv-1) and type 4 (ehv-4) was examined in 3 colostrum-deprived specific-pathogen-free foals. Single foals were vaccinated with inactivated ehv-1, inactivated ehv-4, or control cell lysate plus adjuvant followed by successive intranasal challenge exposures with ehv-1 and ehv-4 or with ehv-4 and ehv-1. Vaccination with inactivated virus preparations elicited cellular immune responses and antibody which were augmented by subsequent challenge exposures.

Cellular immune responses, as measured by in vitro lymphocyte blastogenesis, were cross-reactive after foals were given either ehv-1 or ehv-4. Serum virus-neutralizing antibody responses were type-specific for foals given ehv-1, but were cross-reactive after ehv-4 administrations.

It was concluded that diseases caused by ehv-1 and ehv-4 may be more effectively controlled with a bivalent vaccine containing both ehv-1 and ehv-4 than with the presently used monovalent vaccines based on ehv-1 alone.