bluuebunny/crossref_metadata_2025 huggingface dataset:
Concentrations of progesterone and luteinizing hormone in the serum of diestrous bitches before and after hysterectomy
Authors: Olson P. N. , Bowen R. A. , Behrendt M. D. , Olson J. D. , Nett T. M.
Published: February 2025

Blood was collected from 6 adult bitches (3 pregnant and 3 nonpregnant) daily for 59 days after the onset of diestrus, and serum progesterone concentrations were determined. The bitches were hysterectomized at various times during diestrus [diestrus day (dd) 5, 15, or 25] to determine whether the uterus has a role in maintaining luteal function in the pregnant or nonpregnant bitch. Concentrations of serum luteinizing hormone (lh) were also measured to determine whether lh concentrations decrease when luteal function abates (experiment 1). All 6 bitches in experiment 1 had progesterone concentrations > 1.0 ng/ml during the 2-month period, indicating that neither the pregnant nor nonpregnant uterus was necessary for maintaining luteal function in the bitch. Concentrations of lh appeared to increase in the serum of 5 of the 6 bitches when progesterone concentrations were declining, indicating that cessation of luteal function does not appear to result from a lack of lh.

Blood was collected from the 6 bitches used in experiment 1 twice weekly during the 2nd diestrus after hysterectomy (experiment 2) to determine whether alterations in luteal function that might be observed during experiment 1 were due to some aspect of the surgical procedure, rather than to absence of a uterus. Progesterone concentrations in the serum were lower (P < 0.05) during the 10 days after surgery in the 2 bitches hysterectomized on dd 5 than in the 4 bitches remaining intact during this period (experiment 1). In contrast, a similar decrease was not apparent when blood was collected from these same 2 bitches twice weekly during a similar period in the 2nd diestrus after hysterectomy (experiment 2). Therefore, some aspect of the surgical procedure, rather than removal of a uterine luteotropin, probably accounted for the temporary decrease in progesterone concentrations in the serum of the 2 bitches hysterectomized on dd 5.

Seemingly, neither the pregnant nor nonpregnant uterus was necessary for maintaining luteal function in the bitch and luteal function does not appear to cease due to a lack of lh. Anesthesia, surgical manipulation of the uterus, or reduction of arterial blood supply to developing corpora lutea may result in depressed luteal function when bitches are hysterectomized early in diestrus.
Diagnosis of naturally occurring Fasciola hepatica infections in cattle with an enzyme-linked immunosorbent assay
Authors: Wescott R. B. , Farrell C. J. , Shen D. T.
Published: February 2025

Sera from 100 herds of cattle located in the state of Washington were examined with an enzyme-linked immunosorbent assay for antibody to Fasciola hepatica in a screening procedure that included 5 to 10 samples/herd. Twenty-eight herds contained infected cattle and F hepatica was most prevalent in 3 distinct geographic areas. Subsequent retesting of all sera available from 14 herds (mean of 109 samples/herd) revealed that the screening procedure correctly detected 7 of 7 operations in which > 40% of samples were positive or suspect and 3 of 3 operations in which 12% to 13% of the samples were positive or suspect. One of 3 herds considered negative after screening was found to contain a few (7%) positive samples and 1 herd considered possibly infected was negative on retest. These results were compared with those obtained by fecal examination for F hepatica eggs in 9 of the 14 herds. A good correlation (5 of 5) was found in which a high percentage (48% to 85%) of sera were positive or suspect. Fasciola eggs were not found in samples from 2 herds with few (7% to 12%) positive or suspect sera or in 2 herds that were negative by an enzyme-linked immunosorbent assay.
Application of an enzyme-linked immunosorbent assay for detection of Brucella antigens in vaginal discharge of cows
Authors: Chen I-Ming , Thoen Charles O. , Pietz Donald E. , Harrington Rube
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) was developed for detecting Brucella abortus. Carbodiimide cyanamide was used as an antigen-coupling agent and NH4Cl was used to neutralize residual active charges present on the cuvette surface. Suitable elisa reactions were observed in vaginal swabs placed in phosphate-buffered saline solution. The elisa described may be useful under controlled laboratory conditions for detecting B abortus-infected cows shedding bacteria in vaginal secretions.
Immune response of pregnant cows to bovine rotavirus immunization
Authors: Saif Linda J. , Smith K. Larry , Landmeier Bonnie J. , Bohl Edward H. , Theil Kenneth W. , Todhunter Debra A.
Published: February 2025

Fifteen pregnant Holstein cows were freely assigned to 3 experimental groups (5 cows in each group). Cows in group I were inoculated im and intramammarily (IMm) with Ohio Agricultural Research and Development Center (OARDC) tissue culture-propagated modified-live Nebraska calf diarrhea bovine rotavirus with added adjuvant (OARDC vaccine-immunized cows). Group II cows were given im injections of a commercial modified-live rotavirus-coronavirus vaccine (commercial vaccine-immunized cows), and the remaining 5 cows were noninoculated controls (group III). Rotavirus antibody in colostrum and milk was mainly associated with immunoglobulin (Ig)G1, and less so with IgG2, IgA, and IgM, as analyzed by the enzyme-linked immunosorbent assay (elisa), using monospecific anti-bovine IgG1, IgG2, IgM, and IgA sera. In serum, the rotavirus antibody was distributed almost equally between IgG1 and IgG2. The same relationships appeared in both immunized and nonvaccinated cows.

All OARDC vaccine-injected cows had virus-neutralization (vn) and elisa IgG1 rotavirus antibody titers in serum and mammary secretions at significantly increased levels (at least 100-fold; P < 0.05) compared with the titers in groups II (commercial vaccine-immunized cows) and III (controls). Serum, colostrum, and milk antibody titers from these latter 2 groups did not differ statistically. The elisa IgG2, IgA, and IgM rotavirus antibody titers also were significantly greater in mammary secretions from OARDC vaccine-immunized cows than in groups II and III cows. There was a high correlation between elisa IgG1 and vn rotavirus antibody titers for all samples tested (r = 0.97, P < 0.001), but elisa IgG1 antibody titers were consistently higher than vn titers. The elisa IgG1 and vn antibody titers of milk samples collected from cows 30 days after parturition were higher from the OARDC vaccine-immunized cows (elisa IgG1, geometric mean titer (gmt) = 3,511; vn gmt = 1,689) than were titers from the group II cows (elisa IgG1 gmt = 39; vn gmt = 33) or group III cows (elisa IgG1 gmt = 21; vn gmt = 19).

These results indicate that im plus IMm immunization of pregnant cows, using modified-live bovine rotavirus with added adjuvant, may significantly enhance serum, colostrum, and milk rotavirus antibody titers, whereas im vaccinal inoculation of pregnant cows with a commercial modified-live rotavirus-coronavirus vaccine may not.
Structural proteins of equine infectious anemia virus and their antigenic activity
Authors: Nishimura Masaaki , Nakajima Hideo
Published: February 2025

Using purified equine infectious anemia (eia) virus labeled with 3H-glucosamine or 14C-protein hydrolysate, structural proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. As a result, 2 glycoproteins and 10 proteins with molecular weights (mol wt) ranging from 12,000 to 115,000 daltons were demonstrated, Of 12 structural proteins, 3 proteins, namely a glycoprotein with mol wt of 76,000 (gp76) and 2 proteins with mol wt of 25,000 (p25) and 12,000 (p12), respectively, had distinct antigenic activity from one another in immunodiffusion. Development of antibodies against gp76 and p25 was compared in infected horses. The antibody to gp76 appeared earlier and stronger than to p25 in horses infected with the homologous virus strain.

The fraction with glycoproteins was found to have hemagglutinating activity which was inhibited by the serum sample from horses infected with equine infectious anemia virus.
Effects of butorphanol, flunixin, levorphanol, morphine, and xylazine in ponies
Authors: Kalpravidh M. , Lumb W. V. , Wright M. , Heath R. B.
Published: February 2025

The analgesic and behavioral effects of butorphanol (0.22 mg/kg), flunixin (2.2 mg/kg), levorphanol (0.033 mg/kg), morphine (0.66 mg/kg), and xylazine (2.2 mg/kg), given im were observed in 8 ponies. These ponies were instrumented to measure response objectively to painful superficial and visceral stimuli. Effects on the cardiopulmonary system and rectal temperature also were evaluated in 6 of these ponies. Observations were conducted before drug injection (base-line values) and after injection at 30, 60, 120, 180, and 240 minutes.

Xylazine provided the highest pain threshold for the first 60 minutes and a sedative effect for 105 minutes. The effects for superficial pain and visceral pain persisted 3 hours and 4 hours, respectively. Morphine produced good analgesia for superficial pain (30 minutes), whereas butorphanol provided good effect for visceral pain (4 hours). A slight degree of analgesia for visceral pain was obtained after morphine (1 hour) and levorphanol (4 hours); flunixin did not induce analgesia. Butorphanol, levorphanol, and morphine stimulated motor activity. Behavioral effects did not occur after flunixin was given.

Xylazine decreased systolic, diastolic, and mean blood pressures. Marked increases in these pressures, heart rate, and respiratory rate were observed after morphine was given. Changes of central venous pressure, rectal temperature, and blood gas values remained within base-line limits after both drugs were given. Butorphanol increased heart rates for 1 hour; flunixin and levorphanol did not alter any of the above values.
Isolation of Haemophilus somnus antigens and their use as vaccines for prevention of bovine thromboembolic meningoencephalitis
Authors: Stephens L. R. , Little P. B. , Wilkie B. N. , Barnum D. A.
Published: February 2025

Antigens extracted from Haemophilus somnus were examined for their suitability as vaccines for prevention of thromboembolic meningoencephalitis and as antigens in immunologic tests for detection of susceptible cattle.

Saline extraction of whole H somnus cells produced an outer membrane complex (omc) that contained 2 major antigens when tested against antiserum to intact cells by Immunoelectrophoresis. Anion exchange chromatography was used to separate an anionic antigen (aa) from the more cationic antigen (ca). According to chemical analysis and polyacrylamide gel electrophoresis, both aa and ca were complex mixtures—probably, outer membrane fragments. Enzyme-linked immunosorbent assays were used to measure serum levels of immunoglobulin (Ig) G and IgM against aa and ca in cattle vaccinated with whole cells, omc, ca, or aa. Protection of vaccinated cattle was assessed after iv challenge exposure to H somnus.

Moderate IgG and IgM responses occurred when cattle were given 2 vaccinal doses of 0.1 mg or 1.0 mg of whole cells, omc, or aa. Two of 10 cattle given 2 vaccinal doses (1.0 mg) of omc died after iv challenge exposure, whereas 8 of the 10 controls died, indicating significant protection (P < 0.05). All of the 10 cattle given 2 vaccinal doses (1.0 mg) of aa were protected from iv challenge exposure, whereas 5 controls died (P < 0.05). Two vaccinal doses of either 0.1 mg or 1.0 mg of ca produced high IgG and IgM responses. However, 3 of 10 cattle given 2 vaccinal doses (1.0 mg) of ca died after iv challenge exposure, as did 3 of the 10 controls, indicating that ca was not protective. Immunity to antigenic determinants in aa was necessary for protection against experimental thromboembolic meningoencephalitis, but the susceptibility of control or vaccinated cattle could not be predicted from prechallenge anti-aa or anti-ca antibody levels.
Plasma pentachlorophenol concentrations in calves exposed to treated wood in the environment
Authors: Osweiler G. D. , Olesen B. , Rottinghaus G. E.
Published: February 2025

Six calves were fed grain and hay from a pentachlorophenol (pcp)-treated feeder twice daily. Samples of blood were collected twice a week. Plasma pcp concentrations increased rapidly to a maximum of 1,086 µg/L within 10 days. After the 3rd week, calves were denied access to the treated feeder; pcp values returned rapidly to near base line (before calves were fed from the treated feeder).

After base-line plasma pcp values were reached, 4 of the 6 calves were housed in a total confinement building and exposed (by inhalation) to lumber that was commercially treated with pcp. The building itself was free of structural pcp-treated lumber. The ratio of building volume to treated wood surface was approximately 49 to 1. During the 3 weeks the calves were confined, pcp values did not increase and were markedly lower than those associated with oral exposure to treated wood.

Oral dosing of calves with pcp in capsules—0.05 and 0.5 mg/kg—resulted in maximal plasma pcp values of 1,449 and 9,555 µg/L, respectively.

Oral exposures (feeding from contaminated feeder; capsule) appeared to be more important than inhalation in causing increased plasma pcp concentrations in cattle. Exposure from these sources may be estimated by comparison with experimental values from dose-response studies. Feeding from treated feeders resulted in lower plasma pcp values than did dosing with 0.05 mg/kg daily.
In vitro susceptibility of Escherichia coli of swine origin to carbadox and other antimicrobials
Authors: Das Naba K.
Published: February 2025

Swine fecal Escherichia coli isolates were tested with the Microtiter broth dilution method for susceptibility to carbadox and 11 other antimicrobials. Of the 138 strains, 136 were resistant to sulfadiazine, 120 to tetracycline, 95 to streptomycin, and 63 to carbadox. Resistance to the remaining antimicrobials also was noted in various degrees, with the exception of amikacin, to which all strains were susceptible. Carbadox-resistant strains also were resistant to other antimicrobials. The multiple resistance pattern was most common to sulfadiazine and tetracycline or a combination of sulfadiazine, tetracycline, and streptomycin.
Anatomic, physiologic, and pharmacologic properties of the feline bulbospongiosus muscle
Authors: Bowen J. M. , Hughes Betsy J. , Bradley W. E.
Published: February 2025

Histologic examination was used to determine the anatomic organization of the feline bulbospongiosus muscle (bsm). Bilaterally symmetrical cranial, middle, and caudal muscle fiber groups were identified. The caudal group was the largest of the 3 groups. Mean cross-sectional diameter of nonfixed bsm fibers was 79 µm. Muscle spindles were not observed in serial histologic sections. The innervation of the bsm was provided by the deep perineal nerve. Contractile properties of the bsm were determined in vitro, using direct muscle stimulation. Mean time-to-peak tension values were 71.4 ms and 62.7 ms at 30 C and 37 C, respectively, and were longer than that for the feline periurethral striated muscle and external anal sphincter muscle, but slightly shorter than that for the slow-twitch soleus muscle. Stimulation frequency at peak tetanic tension was 40 Hz, twitch-to-tetanus ratio was 0.30, and stimulus interval at peak tension for double response was 44 ms.

Electrophysiologic properties examined were resting potentials and miniature end-plate potentials (mepp). Mean resting potential was 68 mV. The mepp had low mean amplitude (0.57 mV), fast mean rise time (0.99 ms), and low maximal frequency (0.06 Hz). Only focally recordable mepp were observed. Pharmacologic properties were investigated by alternating direct and indirect stimulation. The latter was accomplished by electric field stimulation of intramuscular nerve fibers. A high sensitivity of the bsm to d-tubocurarine blockade was present. The results of this study support classification of the bsm as a slow-twitch muscle.
Elimination of plasmidic resistance to ampicillin and of enterotoxinogenicity in certain enteric gram-negative bacteria after incubation with high concentrations of amprolium
Authors: Ozanne Gérard , Mathieu Léo G. , Martin Denis
Published: February 2025

We have observed that treatment with high concentrations of a thiamine analog (amprolium) can lead to the elimination of the plasmidic resistance to ampicillin and the production of enterotoxin in wild Escherichia coli strains and in E coli and Salmonella typhimurium strains which had received the pKM101 plasmid through bacterial conjugation. By computer analysis, we also have determined that there is a highly significant (P < 0.01) synergism between ampicillin and amprolium which reduces considerably the growth of certain enteric bacterial strains which have a plasmidic resistance to ampicillin and which were not markedly affected by amprolium alone, in our experimental conditions. Our data indicate that the rate of loss of the plasmid pKM101 after treatment of R+ bacterial strains with amprolium can be increased.
Morphologic features, structure, and adherence to bovine turbinate cells of three Haemophilus somnus variants
Authors: Ward Gilbert E. , Nivard Jeanne R. , Maheswaran Samuel K.
Published: February 2025

Three colony variants (translucent, small opaque, and large opaque) of Haemophilus somnus recovered during infection studies of chicken embryos were examined using electron microscopy. Ruthenium red-strained H somnus preparations revealed no capsule in any variants. Pili were not seen on phosphotungstate-negative stained preparations.

The translucent variant was thin-walled and had an irregular, pleomorphic rod shape. The small opaque variant had a thicker cell wall and an even rod shape. The large opaque variant had the thickest, most rigid wall of the 3, with uniform rod morphologic features. When each of the 3 variants was allowed to contact bovine epithelial turbinate cells, the translucent and small opaque were significantly (P < 0.01) more adherent than was the large opaque variant.
Comparative pathologic features and development of Sphaeridiotrema globulus (Trematoda) infections in the mute swan and domestic chicken and chicken chorioallantois
Authors: Huffman Jane E. , Fried Bernard , Roscoe Douglas E. , Cali Ann
Published: February 2025

The natural infection of Sphaeridiotrema globulus in the mute swan and the experimental infection in the chicken resulted in an ulcerative hemorrhagic enteritis. Swans and chickens died from the resultant blood loss. Culturing of the parasite on the chorioallantoic membrane of the chicken egg resulted in hemorrhage and a cellular response of the chorioallantois to the trematode. Experimental infections in the domestic chicken and chicken embryo can be of use for the study of ulcerative hemorrhagic enteritis produced by the trematode, pathologic features, identification of the metacercaria to the adult, and developmental aspects of the parasite.
Effect of ammonia on the quantitative clearance of Escherichia coli from lungs, air sacs, and livers of turkeys aerosol vaccinated against Escherichia coli
Authors: Nagaraja K. V. , Emery D. A. , Jordan K. A. , Sivanandan V. , Newman J. A. , Pomeroy B. S.
Published: February 2025

Turkeys were given an aerosol vaccine to determine their ability to clear a virulent inhaled pathogenic strain of Escherichia coli, while they were being maintained in the presence of atmospheric NH3. Turkeys were exposed to 2 concentrations of NH3 (10 and 40 μl/L of air). More E coli was found in lungs, air sacs, and livers of turkeys exposed to NH3. Turkeys not exposed to NH3 had better clearance of E coli. Vaccination against E coli improved the rate of clearance of E coli in birds not exposed to NH3.
Effect of age on susceptibility of pigs to Mycoplasma hyopneumoniae pneumonia
Authors: Piffer Itamar A. , Ross Richard F.
Published: February 2025

The effect of age on susceptibility of pigs to Mycoplasma hyopneumoniae was compared in 2 experiments. In experiment A, pigs 3, 6, and 12 weeks of age were contact-exposed to pigs with established M hyopneumoniae infection for 27 days and then evaluated for pneumonia at necropsy done at 42 days after exposure began. In experiment B, pigs 3 and 11 to 12 weeks of age were contact-exposed for 20 days and then placed in separate, isolated hog houses until necropsy was done at 49 days after exposure began. Evaluations at necropsies revealed that no differences existed between age groups concerning occurrence or severity of pneumonia. Likewise, immunofluorescence and culture evaluations of lung tissue revealed that no significant differences existed among age groups concerning detection of M hyopneumoniae or time of seroconversion to the organism. Under conditions of this study, no differences were detected in susceptibility of pigs between 3 and 12 weeks of age.
Characterization of two serotypes of adenovirus isolated from sheep in the central United States
Authors: Lehmkuhl Howard D. , Cutlip Randall C.
Published: February 2025

Two serotypes of adenovirus were isolated from lambs assembled at a ram testing station. The isolates were identified as adenoviruses on the basis of their morphologic and physicochemical characteristics. One isolate (RTS-42) was neutralized by antiserum to ovine adenovirus serotype 5, whereas the other strain (RTS-151) was not neutralized by the antisera to ovine adenovirus serotypes 1 through 5 or bovine adenovirus 1 through 8.
In vivo and in vitro reactivation of latent pseudorabies virus in pigs born to vaccinated sows
Authors: van Oirschot J. T. , Gielkens A. L. J.
Published: February 2025

Latency of pseudorabies virus (prv) was established in 8 of 9 pigs born to 2 vaccinated sows. Pigs had high, low, or no maternal antibody titers at the time of the initial inoculation. At postinoculation months 3 to 4, latent prv could be reactivated in vivo by the administration of large doses of corticosteroids. In most pigs, the stress-simulating treatment resulted in recrudescence of virus shedding after lag periods of 4 to 11 days.

In 3 pigs, virus shedding was without clinical signs of disease, whereas clinical signs that developed in 4 pigs appeared to be due to the corticosteroid treatment, rather than to the reactivation of prv. Pigs with a log10 neutralizing antibody titer of ≤ 2.55 at the onset of corticosteroid treatment had a booster response. Reactivated prv spread to sentinel pigs housed with the inoculated pigs.

Reactivation of prv was also demonstrated in vitro. Explant cultures of trigeminal ganglia from pigs killed between postinoculation months 4 to 5 produced infectious virus.

Restriction endonuclease analysis indicated that the reactivated prv was indistinguishable from virus isolated shortly after the primary infection. Seemingly, pigs with maternal antibodies can become latently infected and therefore may be regarded as potential sources of dissemination of prv.
Vertical migration of infective larvae of equine strongyles in sandy clay loam
Authors: Houston R. S. , Fincher G. T. , Craig T. M.
Published: February 2025

The migration of infective strongyle larvae through sandy clay loam soil was determined by evaluating the burial of horse dung as a method of reducing parasitism in horses. Equine feces containing 325 strongyle eggs/g of feces were buried at depths of 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0, and 30.0 cm below the pasture surface in sandy clay loam soil. Herbage samples were taken periodically from above the buried feces and were analyzed to determine the maximum vertical migration of infective larvae. The greatest distance of migration was 20 cm which occurred 31 days after the feces were buried. However, the number of larvae reaching the herbage from this depth represented only 0.0004% of the eggs initially buried.
Laser therapy in the horse: Histopathologic response
Authors: Kaneps A. J. , Hultgren B. D. , Riebold T. W. , Shires G. M. H.
Published: February 2025

Surgical incisions were made in the skin and superficial digital flexor tendons in horses. A low intensity laser therapy device was used to treat the limbs. After laser therapy was completed, skin and superficial digital flexor tendons from incised laser-irradiated, incised-control, and nonincised-control limbs were compared microscopically. Qualitative differences between laser irradiated and nonirradiated tissues were not found. The laser therapy device used in this study may be of insufficient power to affect wound healing.
Infectious bovine keratoconjunctivitis: Enhancement of Moraxella bovis pili immunogenicity with diphtheriatetanus toxoids and pertussis vaccine
Authors: Pugh G. W. , Kopecky Κ. E. , McDonald T. J.
Published: February 2025

A study was conducted to determine whether diphtheria-tetanus-toxoids and pertussis vaccine (dpt) would enhance the immunogenicity of homologous Moraxella bovis pili fractions. Thirty-six calves were divided into 4 groups (I, II, ΙII, and IV) of 9 calves each. Calves in group I were not vaccinated and served as controls. Calves in group II were vaccinated with pili fractions only. Calves in group III were vaccinated with dpt only. Calves in group IV were vaccinated with dpt and pili. Vaccination consisted of 2 inoculations, 21 days apart. Fourteen days after the last vaccinal inoculation was done, the eyes of all calves were exposed to a hemolytic homologous strain of M bovis.

The percentage of eyes with disease was significantly less in calves given dpt and pili (P < 0.001) and calves given pili only (P < 0.05) than in calves given dpt only or nonvaccinated calves. The lesions were less severe in calves vaccinated with pili only than in calves not vaccinated with pili. Serologic results also showed a positive relationship between the development of serum antibodies against pili and immunity. The results indicate that dpt enhanced the immune response and if used as an adjuvant, might be useful in the development of a vaccine against infectious bovine keratoconjunctivitis.
Acid-base balance and selected hematologic, electrolytic, and blood chemical variables in calves nursing cows: One week through fifteen weeks
Authors: Reece William O.
Published: February 2025

Definition was given to acid-base balance, erythrocyte variables, serum iron, and several plasma variables in nursing calves, beginning at 1 week of age to 15 weeks of age. Of all the variables measured (once a week), arterial blood pH was the only one for which there was a significant difference due to sex of the calves (female calves had blood slightly more acidic than did male calves). Significant differences due to time were noted for the erythrocyte variables and for plasma potassium and chloride ion and serum iron concentrations. There were no significant changes from week to week for the acid-base balance variables. A significant sex × time interaction was noted for serum iron concentration–after week 6, the concentration of iron in female calves was higher than it was in male calves.
Response of cattle upon reexposure to Anaplasma marginale after elimination of chronic carrier infections
Authors: Magonigle R. A. , Newby T. J.
Published: February 2025

Sixteen cattle serotest-negative for anaplasmosis with either no previous exposure (2 animals) or cleared 8 months earlier of their carrier state by chemotherapy (14 animals) were each exposed to Anaplasma marginale. Anaplasma serotest titers were determined by complement-fixation and rapid card agglutination tests conducted during a 63-day trial period. Serologic reactions indicated that all cattle (both groups) were converted to seropositive by the 21st day after exposure. Fluctuations in pcv were seen in the 2 groups between days 21 and 35. However, parasitemia levels were detectable only in the 2 previously unexposed control cattle.

Three splenectomized calves, given 10 ml of blood from 3 of the former carrier cattle 14 days after the latter were reexposed, developed severe clinical and hematologic signs of anaplasmosis and seroconverted from negative to positive on both serologic tests. The need to acquire a better understanding of immunity in anaplasmosis is discussed.
Clinical and immunologic responses of pigs to African swine fever virus isolated from the Western Hemisphere
Authors: Hamdy F. M. , Dardiri A. H.
Published: February 2025

Pigs in the United States were exposed to African swine fever (asf) virus isolated from pigs in Brazil and the Dominican Republic. The former were examined for clinical response, lesions, viremia, and antibody response. Sequential blood samples were tested for the presence of asf virus by the hemadsorption test (in swine buffy coat cell culture) and for antibody to asf virus by the enzyme-linked immunosorbent assay. The incubation period was 3 to 5 days; inoculated pigs had fever for 8 to 16 days (mean 12.5 days) and viremia at 3 to 35 days after inoculation and few died. Inoculated pigs developed antibodies at 7 days after inoculation which were detectable until the termination of the experiment (10th month).

Reinoculation of some of the surviving pigs with the homologous isolate at approximately 6 months after exposure did not induce clinical response, viremia, nor anamnestic antibody response. In contrast, challenge exposures of convalescent pigs with the Lisbon-60 viral strain approximately 5 weeks after exposure to the Brazilian strain produced death, in spite of an anamnestic antibody response.
Comparative efficacy of sulfamethazine and sulfathiazole in feed for control of Bordetella bronchiseptica infection in swine
Authors: Kobland J. D. , Gale G. O. , Maddock H. M. , Garces T. R. , Simkins K. L.
Published: February 2025

Seventy-two conventionally raised pigs were challenge exposed intranasally when approximately 3.5 weeks old with yolk-grown Bordetella bronchiseptica. Twenty-four pigs acted as noninfected, nonmedicated controls. Feed containing sulfamethazine or sulfathiazole (110 mg/kg of feed) was initiated in 2 groups of 24 infected pigs each 3 days after challenge exposure and was fed continuously for 56 days. Twenty-four infected pigs were given nonmedicated feed.

Challenge exposure with the B bronchiseptica resulted in nasal bordetellosis characterized by isolations of the test organism from nasal cavities of infected control pigs at > 90% frequency through 28 days and from at least 50% of the pigs through 56 days. Moderate turbinate atrophy developed with a 48% increase in mean turbinate space in infected control pigs at necropsy. Performance was not affected by the infection which was confined to the nasal cavity.

The B bronchiseptica isolation rate decreased faster (P < 0.01) in the sulfamethazine group than in the sulfathiazole group. By day 42, sulfamethazine-medicated pigs were negative for B bronchiseptica in nasal swab samples; whereas 8% to 17% of sulfathiazole-medicated pigs were positive from days 42 to 56. Turbinate spacing measurements averaged 11% less in the sulfamethazine group than in the sulfathiazole group.
Assessment of smooth muscle function in Sesbania drummondii toxicosis in Gallus domesticus
Authors: Venugopalan C. S. , Flory W. , Tucker T. A. , Hebert C. D. , Strain G. M.
Published: February 2025

An in vitro assessment based on tissue responsiveness to 2 agonists—histamine and carbachol—was made on smooth muscle activity in chickens experimentally poisoned with sesbania. Crude extracts of Sesbania drummondii were prepared and 2 dosage levels, 0.25% and 0.5% of body weight, were used. The birds were dosed orally with the extract for 3 consecutive days, and on the 4th day segments of ileum and lung were collected from each bird. The isometric contractions of each tissue, produced by the addition of histamine or carbachol in graded concentrations, were recorded. The cumulative concentration-effect curves for the tissues to the agonists were constructed and compared with respective control curves.

The results indicated the responsiveness of the tissues in the treated groups was significantly decreased, compared with that of tissues in the controls. Responses of both intestinal and parenchymal strips in the chickens given the higher dosage (0.5%) were decreased significantly, whereas in those given the smaller dosage (0.25%), only parenchyma had a significant response. This indicates that the activity of smooth muscles in general was depressed by sesbania. The effect was more evident in the lung than in the intestine. Therefore, an active principle in the extract which affects smooth muscle, rather than causing direct irritation, may exist.

This assessment of smooth muscle activity is sensitive and was effective in detecting changes in tissues from sesbania-treated birds which had not shown any clinical signs. The results also support the possibility that smooth muscle involvement could be a primary cause of toxicity in sesbania poisoning.
Determination of phagocytosis of 32P-labeled Staphylococcus aureus by bovine polymorphonuclear leukocytes
Authors: Dulin Anne M. , Paape Max J. , Weinland Bernard T.
Published: February 2025

A procedure for the measurement of phagocytosis by bovine polymorphonuclear leukocytes (pmn) of 32P-labeled Staphylococcus aureus was modified so that a larger number of samples could be compared in a single run, and smaller volumes of sample, pmn, and 32P-labeled S aureus could be used. Results were highly reproducible, with a coefficient of variation between duplicate determinations of ≤ 2%. Lysostaphin was prepared from the supernatant of S staphylolyticus and was compared with a commercially available preparation. Effects of lysostaphin on pmn and influence of incubation media on release of 32P from 32P-labeled S aureus by lysostaphin were examined.
Motility of the distal portion of the jejunum and pelvic flexure in ponies: Effects of six drugs
Authors: Adams Stephen B. , Lamar Carlton H. , Masty Jerome
Published: February 2025

Bipolar stainless steel electrodes were surgically implanted in 4 ponies to record myoelectrical and mechanical activity of the distal portion of the jejunum and pelvic flexure. After determining normal activity, the effects of neostigmine, xylazine, flunixin meglumine, dipyrone, panthenol, and atropine sulfate were determined. Flunixin meglumine, dipyrone, and panthenol had no effect on the motility of the jejunum or pelvic flexure. Xylazine and atropine sulfate decreased motility of the distal portion of the jejunum and pelvic flexure, with atropine sulfate having a greater effect and lasting longer. Neostigmine stimulated propulsive motility in the pelvic flexure only.
Electrical stimulation on skin wound healing in the horse: Preliminary studies
Authors: Steckel R. R. , Page Ε. H. , Geddes L. A. , Van Vleet J. F.
Published: February 2025

The effect of low-level direct-current stimulation on skin wound healing in the horse was assessed. Self-sustaining electrical circuits with electrodes were implanted subcutaneously in or near the wound. Stimulation by direct current (10 or 20 μA) was used to determine the effect on equine skin healing.

The efficacy of electrotherapy was evaluated by sequentially comparing the clinical appearance of the wound and measuring the size of the granulating wound bed. The histologic appearance of the healing stimulated wounds was compared with that in nonstimulated control wounds created on 9 horses. Seemingly, electrical stimulation had no discernible effect on experimentally created skin wounds. Clinical observation and histologic examination of the wounds indicated that severe tissue reaction from the implanted electrodes and concurrent local infection produced local detrimental effects to wound healing.
Benzimidazole resistance of equine strongyles: Critical tests of several classes of compounds against population B strongyles from 1977 to 1981
Authors: Drudge J. H. , Tolliver S. C. , Lyons Ε. T.
Published: February 2025

From 1977 to 1981, critical tests were conducted on 10 horses naturally infected with population B strongyles. Drugs tested were: oxibendazole (obz), 10 mg/kg of body weight (n = 1); albendazole, 10 mg/kg (n = 1); a mixture of thiabendazole (tbz), 44 mg/kg and trichlorfon, 40 mg/kg (n = 1); a mixture of tbz at 44 mg/kg with piperazine (ppz) at 55 mg of base/kg (n = 1); febantel (fbt), 6 mg/kg (n = 3), 12 mg/kg (n = 1), or 24 mg/kg (n = 1); and pyrantel (prt) pamoate, 6.6 mg of base/kg (n = 1).

Large strongyles, Strongylus vulgaris (9 horses) and S edentatus (5 horses), were effectively removed (100%) by each compound and mixture. Five species of small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus), previously singled out in this population as resistant to 5 benzimidazoles (tbz, mebendazole, cambendazole, fenbendazole, and oxfendazole), but not obz, were efficaciously removed by obz, albendazole, the mixture of tbz plus ppz, fbt (24 mg/kg), or prt. These 5 small strongyle species were resistant to fbt (6 mg/kg) in 3 foals and Cylicostephanus minutus was also resistant in 2 of 3 foals to fbt (6 mg/kg). Doubling the dose of fbt to 12 mg/kg increased the average removal of the 5 basic species plus Cylicostephanus minutus to 88%. The mixture of tbz and trichlorfon was relatively ineffective against 3 species (C catinatum, C coronatum, and Cylicostephanus longibursatus), but unexpectedly efficacious (86% to 99%) for 2 species (Cylicocyclus nassatus and Cylicostephanus goldi). Consistently effective removal of immature small strongyles was recorded only for the mixture of tbz with ppz, fbt (24 mg/kg), or prt.
Hematologic and immunologic responses of Holstein calves to a fire ant toxicant
Authors: Evans Donald L. , Jacobsen Karen L. , Miller Doris M.
Published: February 2025

Holstein calves (3 to 5 months of age) were used to develop an animal model sensitive to environmental toxicants. In the present study, the fire ant toxicant AMDRO was fed (113.5 g/day/calf) to weanling castrated calves (9 test and 9 controls) for 7 weeks. As early as 14 days after the start of the AMDRO feeding, leukopenia was observed. Differential counts revealed significant non-transient decreases in lymphocytes and eosinophils. Eosinopenia was observed from days 21 to 49 of AMDRO treatment. Variability in hematocrit and hemoglobin values in treated and control calves precluded making a determination of trends due to toxicant exposure.

The AMDRO treatment did not produce significant decreases in primary or secondary antibody responses to keyhole limpet hemocyanin or to Brucella abortus vaccination. It also did not produce suppression of cellular immunity, as determined by delayed-type hypersensitivity response to bacille Calmette-Guérin. Potential effects of AMDRO on thermoregulatory mechanisms were indicated by significant depressions of rectal temperature observed after 25, 32, and 39 days’ treatment.
Antileishmanial activity of liposome-encapsulated meglumine antimonate in the dog
Authors: Chapman W. L. , Hanson W. L. , Alving C. R. , Hendricks L. D.
Published: February 2025

Experimental infections of Leishmania donovani in mixed-breed dogs were induced to determine the antileishmanial efficacy of liposome-encapsulated meglumine antimoniate (lema). Each dog was inoculated iv with 1.0 ± 0.2 × 108 amastigotes of a Khartoum strain of L donovani/kg of body weight. The antileishmanial agents (lema or unencapsulated meglumine antimoniate) were given once daily, iv, for 1, 4, or 10 consecutive days beginning the 12th day after inoculation. The dogs were killed 3 or 4 days after completion of therapy, and parasites in the spleens were quantified.

A single injection of lema (0.61 mg of Sb/kg of body weight) resulted in 89% suppression and 4 consecutive daily injections of lema (1.94 mg of Sb/kg/day) resulted in 95.8% suppression of splenic parasites. The dose of lema that would give 50% suppression (sd50) was estimated as approximately 0.029 mg of Sb/kg. The sd50 for unencapsulated drug was estimated as approximately 24 mg of Sb/kg. The liposome-encapsulated drug was estimated to be more than 700 times more efficacious than the unencapsulated drug. Seemingly, liposomes can markedly reduce the drug dosage required for equivalent treatment of visceral leishmaniasis in dogs.
Bone strain in the equine tibia: An in vivo strain gauge analysis
Authors: Hartman W. , Schamhardt H. C. , Lammertink J. L. M. A. , Badoux D. M.
Published: February 2025

Rosette strain gauges were bonded to the cranial, caudal, and medial surfaces of the tibia in the middiaphyseal region of 6 adult ponies. While the ponies were walking, the cranial side was mainly subjected to tension, and the caudal side, to compression. The compression strain on the caudal side was 1.5 times greater than the tension strain on the cranial side. None of these principal strains was aligned along the long axis of the bone; both deviated laterally from the long axis. On the medial surface, the principal strain deviated caudally about 40° from the long axis. From analysis of the strain patterns on the 3 sides of the bone, it could be concluded that during loading of the tibia, torsion was superimposed on craniocaudal bending. The strain pattern was not affected after transection of the cranial tibial muscle, as determined by measuring with the same gauges before and after surgical interference. The contribution of the cranial tibial muscle in reducing the strain in the tibial cortex was therefore very small.
Bone strain in the equine tibia: Inertia as a cause of the presupport peak
Authors: Schamhardt H. C. , Hartman W. , Lammertink J. L. M. A. , Badoux D. M.
Published: February 2025

Strain tracings obtained from the tibial cortex of walking ponies reveal peaks in the principal tension and compression strains occurring immediately before and after the support phase. Evidence is presented that the presupport peak is caused by inertial forces.
Treatment of metritis with antibiotics or prostaglandin F2α and influence of ovarian cyclicity in dairy cows
Authors: Steffan J. , Agric M. , Adriamanga S. , Thibier M.
Published: February 2025

From 4 dairy herds with a high prevalence of metritis, 153 cows with clinical metritis diagnosed at 30 days after calving were allotted randomly to 3 groups: (1) intrauterine antibiotics (chloramphenicol, framycetine) given in 3 doses, 1 week between doses (n = 53); (2) prostaglandin F2α given im in 2 doses, 14 days between doses (n = 61); and (3) control cows given a placebo (n = 39). To further evaluate the efficiency of the treatments, uterine swabs were prepared from 59 of the cows; Corynebacterium pyogenes was isolated in 51% of the cows. All isolated bacteria were susceptible to chloramphenicol and 85% to neomycin and related antibiotics (framycetin). The overall clinical recovery rates, estimated by 60 days after parturition, were identical (49%) in the 2 treated groups vs 33% in controls. The mean interval from calving to conception was 147 days in the controls and was shortened by 16 days in group 1 and 24 days in group 2.

The physiologic status, ie, ovarian cyclicity, was shown to exert a significant influence on the time required for recovery. On the average, anestrous cows recovered in 14 days and conceived 34 days later than did cycling cows.
Culture characteristics and tumorigenicity of the equine sarcoid-derived MC-1 cell line
Authors: Fatemi-Nainie S. , Anderson L. W. , Cheevers W. P.
Published: February 2025

MC-1 is an equine sarcoid-derived cell line which spontaneously releases a retrovirus possessing genomic sequence homology with an inducible endogenous retrovirus of normal equine cells. A complete characterization of MC-1 tumor cells was undertaken, including morphology, growth kinetics, and saturation density, selective growth in semisolid media, uptake of 2-deoxyglucose, and tu-morigenicity in athymic nude mice. MC-1 cells, in contrast to normal equine dermal fibroblasts, exhibit all of the characteristics of malignantly transformed cells.
Comparison of uterine protein content and distribution of bacteria in the reproductive tract of mares after intrauterine inoculation of Haemophilus equigenitalis or Pseudomonas aeruginosa
Authors: Strzemienski Paul J. , Benson Charles E. , Acland Helen M. , Kenney Robert M.
Published: February 2025

Two groups of 3 mares were inoculated with Haemophilus equigenitalis or Pseudomonas aeruginosa on the 1st day of estrus. Uterine flushing samples were recovered on day 3 of estrus and day 8 after ovulation for each cycle. Mares were killed 22, 25, and 30 days after inoculation with P aeruginosa and 45, 46, and 49 days after inoculation with H equigenitalis. Pseudomonas aeruginosa was recovered from the uterus of 2 mares 48 hours after inoculation. Although the initial flushing sample of 1 of these 2 mares had an increased total protein concentration, there appeared to be little difference between protein concentrations of other uterine flushing samples.

Haemophilus equigenitalis was recovered from the uterus of each of the 3 mares at postmortem. One mare had a slight, purulent discharge from the vulva. Total protein values were not increased in flushing samples from this mare after inoculation with H equigenitalis. Total protein values decreased in the last flushing sample of each of the 2 remaining mares. Swabbing the uterus was more effective than was homogenizing the uterine mucosa in isolating H equigenitalis.
Experimental infection of domestic swine with Baylisascaris procyonis from raccoons
Authors: Kazacos Kevin R. , Kazacos Evelyn A.
Published: February 2025

Six 8-week-old ascarid-naive pigs which were experimentally infected with 72,000 embryonated Baylisascaris procyonis eggs of raccoon origin developed lesions limited to the intestines and liver. Intestinal lesions consisted of multifocal areas of inflammation by macrophages, eosinophils, and lymphocytes in the mucosa and submucosa, in association with Baylisascaris larvae; similar lesions were seen in the mesenteric lymph nodes. Typical white, granulation type, multifocal interstitial hepatitis (“milk-spots”), 1 to 5 mm in diameter, were seen in the livers by 7 days, with resolution by 47 days. Microscopically, these consisted of multifocal areas of marked periportal and interlobular edema, and influx of eosinophils, and large intralobular aggregates of eosinophils.

At 47 days, hundreds to thousands of small white granulomas were seen on the serosa of the intestines; microscopically, they were discrete collections of macrophages, lymphocytes, and eosinophils in the submucosa and muscle layers surrounding nonviable remnants of Baylisascaris larvae. Larvae or lesions were not seen in other tissues, including the brain.

These experiments indicated that B procyonis will undergo limited migration in swine and can produce typical white spots in the liver. The larvae were killed by cellular reactions in the intestinal wall and liver, and, unlike the situation in most other animals infected with this parasite, no somatic migration or cns disease occurred after infection.