bluuebunny/crossref_metadata_2025 huggingface dataset:
Production and characterization of monoclonal antibodies to porcine immunoglobulin gamma, alpha, and light chains
Authors: Paul Prem S. , Mengeling William L. , Malstrom Carolyn E. , Van Deusen Richard A.
Published: February 2025

Monoclonal antibodies (mab) to porcine immunoglobulins were produced by fusion of SP2/0 cells with splenic lymphocytes of mice that had been immunized with porcine IgG or IgA. Of 16 mab selected for detailed study, 13 reacted with heavy chains (7 anti-γ, 6 anti-α) and 3 reacted with light chains of native immunoglobulin. Several of the same mab (3 anti-γ chain, 1 anti-α chain, 3 anti-light chain) also reacted with denatured immunoglobulin by use of immunoblotting analysis. Collective results of competitive elisa, immunodiffusion, and immunoblotting analysis indicated that the 7 mab of anti-γ chain specificity were directed to 3 epitopes, the 6 mab of anti-α chain specificity were directed to at least 2 epitopes, and the 3 mab of anti-light chain specificity were directed to at least 2 epitopes that may have been located on different types of light chains. When tested by immunodiffusion with 5% polyethylene glycol incorporated in the agar matrix, all anti-γ chain and antilight chain mab, but no anti-α chain mab, had precipitating activity. When polyethylene glycol was not used, only 4 mab (all of the anti-γ chain specificity and of IgM isotype) had precipitating activity. These mab, with specificity for γ and α chains and those reported earlier with μ-chain specificity, should be invaluable in the detection and quantification of porcine immunoglobulin isotypes. These mab have potential applications in delineating the porcine immune response to selected immunogens.
Evaluation of the agar gel immunodiffusion test for diagnosis of subclinical paratuberculosis in cattle
Authors: Sherman D. M. , Bray B. , Gay J. M. , Bates F.
Published: February 2025

Concurrent bacteriologic culture of feces and agar gel immunodifiusion (agid) testing was performed on all cows and bred heifers over 14 months old in 10 dairy herds during a 32-month period to determine the effectiveness of the agid test for the detection of subclinical paratuberculosis. Herds were sampled 5 times and, when possible, culled animals were tested again at slaughter.

During 5 herd-wide samplings, Mycobacterium para-tuberculosis was isolated from 139 fecal specimens obtained from 109 cattle. Results of the agid test were simultaneously positive 40 of 139 times (28.8%). Thirty-six of the 109 cattle (33.0%) determined to be infected had a positive agid test result at some point during the 5 herd-wide samplings. When results of tests performed at time of slaughter were included, 117 cattle were identified as infected by culture methods; 55 of these (47.0%) were agid test-positive at some point during the study. The upper limit of the maximal false-positive rate for the agid test was 2.1%.

On the basis of colony counts from cultures, subclini-cally infected cows shedding higher numbers of M paratuberculosis in their feces were more likely to have positive agid test results (P < 0.0001). In known infected cattle, neither the culture nor agid test results were consistently positive on repeated testing.

Of 48 official calfhood paratuberculosis vaccinates tested as adults, 3 had positive agid test results and in 1 of these, M paratuberculosis was also isolated from the feces, indicating that the rate of false-positive agid test results in calfhood vaccinates is low.
Prevalence of Cryptosporidium sp in equids in Louisiana
Authors: Coleman S. U. , Klei T. R. , French D. D. , Chapman M. R. , Corstvet R. E.
Published: February 2025

In 1985, 22 pony foals reared in a helminth-free environment were tested daily for oocysts of Cryptosporidium sp by use of fecal flotation. Oocysts were found in all foals. Oocysts were first observed in feces collected from foals 9 to 28 days after birth. The mean period of oocyst shedding was 10 days and ranged from 2 to 18 days in individual foals. Diarrhea was observed in 14 of 22 (64%) foals and began before the period of oocyst shedding. Fecal samples also were examined for other infective agents. Salmonella poona was isolated from 1 foal that did not have diarrhea, and Coronavirus particles were observed in the feces of 2 foals with diarrhea. Cryptosporidium sp oocysts also were observed in feces of 2 of 17 Thoroughbred foals, 3 of 14 Quarter Horse foals, and 3 of 26 pony foals reared on pastures with their dams. Samples from pasture-reared foals were collected at irregular intervals. Of the 11 Cryptosporidium-positive fecal samples collected from pastured foals, 2 were from foals with diarrhea.

A similar survey was conducted during the 1986 foaling season, using the same procedures. Examination of 300 samples from 58 Quarter Horse, Arabian, and pony foals did not detect oocysts. Daily examination of feces from 10 pony foals reared under helminth-free conditions for 30 days also failed to detect Cryptosporidium oocysts.
Basal and bile salt-stimulated bile flow and biliary lipid excretion in ponies
Authors: Engelking Larry R. , Anwer M. Sawkat , Hofmann Alan F.
Published: February 2025

The role of bile salt in biliary lipid excretion was studied in 3 healthy ponies with chronic external biliary fistulas. After endogenous bile salt pool depletion, micelle-forming taurocholate or taurochenodeoxycholate was infused to replace excreted bile salt. Enterohepatic circulations were held open (total biliary diversion) throughout each study. Results indicated that biliary lipid excretion in ponies (113 ± 21 nmol/min/kg of body weight) is approximately 10 times less than that reported in rodents. Although the lipid composition (4.4% cholesterol, 5.6% phospholipid, and 90% bile salt) was within the predicted range for a single phase of micellar (or vesicular) liquid in solution, it was supersaturated with cholesterol because of low absolute concentrations of bile salt and phospholipid. Ponies, like guinea pigs, were determined to have a high bile salt-independent secretion of biliary lipid with little (or no) coupling to endogenous bile salt output. However, bile salt excretion induced by higher taurocholate infusion rates (ie, those greater than the physiologic range of 61 to 125 nmol/min/kg) was positively correlated with an increase in binary phospholipid excretion, but not cholesterol excretion, thus indicating that a threshold intracellular bile salt concentration may be associated with enhanced biliary phospholipid excretion in ponies. The apparent cholerectic effects of endogenous bile salts, taurocholate, and taurochenodeoxycholate (that is, the increment in bile flow per increment in bile salt recovered) were greater in ponies than reported for any other mammal.
Detection of bovine herpesvirus type 1 via an immunoperoxidase method, using monoclonal antibodies
Authors: Rodriguez M. , Heinlein A. Suarez , Ruiz M. , Metzler A. E. , Schudel A. A.
Published: February 2025

The sensitivity and specificity of the immunoperoxidase technique, using monoclonal antibodies, for the detection of bovine herpesvirus type 1 (bhv-1) was assessed and compared with viral isolation methods. In this study, bhv-1 antigens were detected in impression smears of brain obtained from calves in which bhv-1 was isolated. False-positive results were not observed after double-blind examination.

Preliminary identification of isolates as antigenic variants was possible by use of 3 monoclonal antibodies reactive with neurotropic and/or pneumotropic strains of bhv-1. Results were consistent with previous work in which characterization was performed by use of immunofluorescense and elisa.

The immunoperoxidase technique, using monoclonal antibodies, was determined to be specific and sensitive, compared with viral isolation, for the diagnosis of bhv-1 encephalitis. In addition, it has operative advantages in that the assay does not require tissue culture facilities, and results can be obtained within hours after specimens are obtained.
Morphologic features of the aqueous humor drainage pathways in horses
Authors: Samuelson Don , Smith Patricia , Brooks Dennis
Published: February 2025

The iridocorneal angle of the horse was anteriorly lined by a pectinate ligament, consisting of several layers of vertically oriented collagenous beams, that were interrupted by a network of extracellular spaces. The anterior chamber angle consisted mostly of a large uveal trabecular meshwork that was composed of widely-spaced, thick trabeculae. These trabeculae were attached in part posteriorly to extensions of the ciliary body musculature and anteriorly inserted into the prominent pectinate ligament. The corneoscleral trabecular meshwork was shaped hemiobovately and formed the external boundary of the iridocorneal angle. The extracellular spaces were smaller and more evenly spaced than those in the uveal trabecular meshwork. Uveal and corneoscleral trabecular meshwork beams were mostly composed of cores of collagen and elastin surrounded by several layers of basement membrane-like material and, in turn, were entirely enveloped by trabecular cells. An anterior narrow zone of broad corneoscleral trabeculae was composed of elastin-collagen cores surrounded by circular bundles of long-spacing collagen.

The angular aqueous plexus was extensive, forming much of the external border of the outer corneoscleral trabecular meshwork. A dense zone was associated with the angular aqueous plexus, completely encompassing these aqueous outflow vessels.

Posteriorly, the iridocorneal angle was confluent with a well-defined band of trabeculae that was situated between the ciliary body musculature and subjacent sclera and extended posteriorly to the anterior-most region of the choroid where these trabeculae tapered and ended. This region is referred to as the supraciliary trabecular meshwork and indicates a potentially extensive route for outflow of aqueous humor in the equine eye.
Effects of hypertension and sympathetic denervation on cerebral blood flow in newborn pigs
Authors: Fletcher Anthony M. , Leffler Charles W. , Busija David W.
Published: February 2025

To investigate the potential role of sympathetic nerves in preventing pronounced increases in cerebral blood flow, we evaluated the effects of abrupt hypertension on the cerebral circulation of newborn pigs with intact cerebral sympathetic innervation and after cerebral sympathetic denervation. Epinephrine infusion was used to induce abrupt increases in mean (± sem) arterial pressure (innervated pigs, 62 ± 3 mm of Hg to 115 ± 3 mm of Hg; denervated pigs, 71 ± 4 mm of Hg to 132 ± 4 mm of Hg) that remained increased for the 3 minutes of the study. Abrupt hypertension increased blood flow to all brain regions. In denervated pigs, the increased flow to the cerebrum was prolonged, compared with that in pigs with intact sympathetic innervation. Differences between pigs of the innervated and denervated groups were not apparent, with respect to blood flow to any other region (caudate region, brain stem, cerebellum). In newborn pigs, sympathetic nerves may attenuate hypertension-induced increases in blood flow to the cerebrum, but do not appear to affect flow to the rest of the brain.
Specificity of neutralizing and precipitating antibodies induced in healthy calves by monovalent modified-live bovine viral diarrhea virus vaccines
Authors: Bolin Steven R. , Ridpath Julia F.
Published: February 2025

Serum was obtained at weekly intervals after vaccination of 6 healthy calves with either of 2 commercially available monovalent modified-live bovine viral diarrhea (bvd) virus vaccines. Detectable neutralizing antibodies to each of 10 cytopathic and 10 noncytopathic isolates of bvd virus were produced by 1 or more of the calves by 14 days after vaccination, but no calf produced detectable neutralizing antibodies to all 20 bvd viruses. At that time, precipitating antibodies against viral-induced polypeptides of approximately 115,000; 80,000; 56,000; 48,000; 39,000; and 25,000 daltons were detected in sera from some calves. Also at that time, specificity of the antibodies for polypeptides of certain viruses was detected. At 21 days after vaccination, each calf produced neutralizing antibodies to all 20 bvd viruses. At that time, precipitating antibodies to each of the aforementioned viral induced polypeptides were detected in serum from each calf. Precipitating antibodies to viral induced polypeptides of 61,000 and 37,000 daltons were detected in samples of sera obtained from some calves at 42 days after vaccination.
Comparative virulence of two porcine group-A rotavirus isolates in gnotobiotic pigs
Authors: Collins J. E. , Benfield D. A. , Duimstra J. R.
Published: February 2025

The virulence of 2 porcine group-A rotavirus isolates was compared. Forty hysterotomy-derived 3-day-old gnotobiotic pigs were inoculated orally with 2 ml of intestinal homogenate containing either the Ohio State University (OSU) or the South Dakota State University (SDSU) strain of porcine rotavirus or were inoculated with medium only. Clinical signs of disease, body weight, distribution of viral antigen, fecal excretion of virus, and histologic lesions (observed by light and scanning electron microscopy) were determined. Morphometric measurements of villi and crypts were made. In pigs inoculated with OSU or SDSU strains, diarrhea began at postinoculation hours (pih) 19 to 48 and pih 24 to 54, respectively. None of the virus-infected pigs died as a consequence of infection and all had similar clinical signs of disease, body weight changes, and virus-shedding patterns, regardless of the strain of rotavirus with which they were infected. Microscopic findings in the small intestine of virus-infected pigs were similar, except that the SDSU strain caused more severe villus atrophy and villus fusion in the duodenum at pih 72 and 168 than was associated with the OSU strain. Viral antigen in the small intestine of pigs infected with either virus was observed by use of immunofluorescence at pih 24 and 72, but was seldom seen at pih 168.
Collection of bronchoalveolar lavage fluid in cats, using an endotracheal tube
Authors: Hawkins Eleanor C. , DeNicola Dennis B.
Published: February 2025

Bronchoalveolar lavage fluid was collected from 12 anesthetized cats by use of an endotracheal tube and syringe adapter. The safety of the technique was evaluated by monitoring mucous membrane color, capillary refill time, pulse rate, respiratory rate, ecg, and arterial blood gas tensions and by necropsy findings.

Group A consisted of 3 cats that were administered (by lavage) 4 aliquots of 20 ml of saline solution during anesthesia for placement of femoral artery catheters. Group B consisted of 4 cats that were administered a smaller total volume of saline solution (3 aliquots of 5 ml/kg of body weight) during a separate anesthetic period, other than the one for placement of catheters. Group C consisted of 5 cats administered 3 aliquots (5 ml/kg) of saline solution during a separate anesthetic period and administered supplemental oxygen for 5 to 10 minutes before and for 20 minutes after the lavage procedure.

Group-A cats had a prolonged recovery period that was attributed to the lengthy anesthetic period required for placement of femoral catheters. The effect was eliminated in the cats of the other groups in which the lavage procedure itself accounted for only 5 to 10 minutes of anesthetic time. Evaluation of mucous membrane color, capillary refill time, ecg, pulse, and respiratory rate revealed no persistent abnormalities. Transient increase in pulse and respiratory rate was seen in some cats.

Blood gas analysis revealed noticeable decrease in arterial oxygen pressures (Pao2) after the lavage procedure. In group-C cats, oxygen supplementation allowed the maintenance of normal or above normal Pao2. When oxygen was discontinued at 20 minutes, Pao2 was maintained at ≥ 60 mm of Hg. The variability in oxygen pressures did not appear to correlate with the volume of fluid remaining in the lungs.

Histologic evaluation of the lungs revealed no changes attributable to the lavage procedure. Most cats had minimal to mild inflammatory changes, and 4 cats had moderate to moderately severe bronchopneumonia. These changes were reflected in the bronchoalveolar lavage fluid, indicating that they were present at the time of lavage.
Scanning electron microscopy of corrosion casts of the optic nerve microcirculation in dogs
Authors: Brooks Dennis E. , Samuelson Don A. , Gelatt Kirk N. , Smith Patricia J.
Published: February 2025

Scanning electron microscopy of vascular corrosion casts of the optic nerve region in normal and glaucomatous Beagles demonstrated that the blood supply to the laminar optic nerve is derived from short posterior ciliary arteries, cilioretinal arteries, and longitudinal pial vessels. The short posterior ciliary arteries formed a ring of striated pillars around the scleral canal. The central retinal artery was not present in the dog. Differences between the casts in normal and glaucomatous dogs were not detected.
Ultrastructural changes in laminar optic nerve capillaries of Beagles with primary open-angle glaucoma
Authors: Brooks Dennis E. , Samuelson Don A. , Gelatt Kirk N.
Published: February 2025

Ultrastructural examination of optic nerve capillaries in the canine lamina cribrosa revealed many spherical, membrane-bound, electron-dense inclusions that closely resembled Weibel-Palade bodies, in pericytes and endothelial cells of preglaucomatous, early, moderately, and advanced affected Beagles with hereditary primary open-angle glaucoma. This ultrastructural difference between the laminar capillary endothelial cells of normal and glaucomatous Beagles could represent a functional vascular disorder, because Weibel-Palade bodies are associated with microcirculatory abnormalities.
Efficacy of various treatment regimens, using liposomal streptomycin in cows with brucellosis
Authors: Nicoletti Paul , Lenk Robert P. , Popescu Mircea C. , Swenson Christine E.
Published: February 2025

Thirty cows naturally infected with Brucella abortus were treated by various routes, using free or liposomal streptomycin or a combination of liposomal streptomycin and a long-acting oxytetracycline preparation. Of 21 cows treated with liposomal streptomycin alone, 3 (14%) were culture negative and 3 had 10 or fewer bacterial colonies isolated from tissues obtained at necropsy. Thirteen (62%) cows continued to shed organisms in udder secretions and were considered treatment failures. Of 9 cows that were given a combination of liposomal streptomycin and long-acting oxytetracycline, 5 (56%) were cured, 3 had 10 or fewer colonies on culture plates of tissue after necropsy and only 1 continued to shed B abortus in udder secretions after treatment. Eleven cows were given streptomycin liposomes by intramammary infusion with or without im administration of long-acting oxytetracycline. The most effective regimen consisted of 2 intramammary infusions of streptomycin liposomes and 2 doses of oxytetracycline administered im. Of 5 cows treated thusly, 2 were cured and all others had fewer than 10 B abortus colonies isolated from tissues obtained at necropsy.
In vitro antimicrobial activity of sulfonamides against some porcine pathogens
Authors: Mengelers M. J. B. , van Klingeren B. , van Miert A. S. J. P. A. M.
Published: February 2025

The minimal inhibitory concentrations (mic) of sulfonamides were determined against Bordetella bronchiseptica (n = 10), Pasteurella multocida (n = 10), Haemophilus pleuropneumoniae (n = 20), and Streptococcus suis (n = 10) strains isolated from pigs with atrophic rhinitis, pneumonia, or meningitis.

Sulfonamides tested in an agar dilution method were sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfamethazine, sulfadoxine, sulfisoxazole, sulfamerazine, sulfamethoxazole, sulfamethoxypyridazine, sulfanilamide, sulfatroxazole, and sulfisomidine.

Results indicated that monotherapy of S suis infections with sulfonamides should not be encouraged because the mic50 of all sulfonamides investigated was > 32 μg/ml. The mic50 of the sulfonamides against B bronchiseptica ranged from 0.5 to 8 μg/ml, against P multocida from 2 to 32 μg/ml, and against H pleuropneumoniae from 8 to 64 μg/ml.

The mic50 of sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfamerazine, and sulfamethoxazole for the gram-negative bacteria did not exceed 16 μg/ml. Among these compounds, sulfamethoxazole had the highest activity. The frequently prescribed sulfamethazine had an overall low antimicrobial activity.
Effects of inoculations with Eimeria zuernii on young calves treated with decoquinate or narasin with or without dexamethasone
Authors: Fitzgerald P. R. , Mansfield M. E.
Published: February 2025

Sixteen 7-week-old Holstein male calves were inoculated with sporulated oocysts of Eimeria zuernii. Four calves (controls) were euthanatized and necropsied at 14 and 20 days after inoculation (dai). Two calves were treated with 20 mg of dexamethasone (im) on 13, 14, and 15 dai and euthanatized and necropsied 17 dai and 2 calves were given similar treatments and necropsied 20 dai. The 8 other calves were euthanatized and necropsied 20 dai. Two were started on the anticoccidial drug decoquinate in feed 13 dai; 2 others were given decoquinate on the same schedule plus dexamethasone on 13, 14, and 15 dai. Two calves were given the antibiotic narasin in feed beginning 13 dai and 2 calves were given parasin on the same schedule plus dexamethasone on 13, 14, and 15 dai.

All calves, except 2 controls necropsied 14 dai and 4 calves given decoquinate, discharged moderate-to-large numbers of oocysts in feces and had moderate-to-severe changes in fecal consistency. Histologic examintions revealed large numbers of endogenous stages in tissues of calves treated or not treated with dexamethasone. Few endogenous stages were observed in tissues from calves that were given decoquinate or decoquinate plus dexamethasone. Calves given narasin or narasin plus dexamethasone had moderate-to-large numbers of endogenous stages in the tissues.
Endogenous prostaglandin F2α release induced by physiologic saline solution infusion in utero in the mare: Effect of temperature, osmolarity, and pH
Authors: Pascoe David R. , Stabenfeldt George H. , Hughes John P. , Kindahl Hans
Published: February 2025

Thirty mares with normal estrous cycles were allotted equally to 5 groups and infused with 250 ml of saline (NaCl) solution in utero on the seventh day after ovulation to test the effects of temperature, osmolarity, or pH of the saline solution on prostaglandin F2α (pgf2α) release and luteolysis. Intrauterine infusion of phosphate-buffered saline solution failed to alter the duration of the luteal phase, compared with the control group. Similarly, increasing the temperature of phosphate-buffered saline solution to 42 C or increasing (600 mosm) or decreasing osmolarity (< 10 mosm) did not change the duration of the luteal phase. Decreasing the pH of saline solution to 3 caused significant (P < 0.0001) releases of pgf2α from the uterus within the first hour after infusion, and the luteal phase was shortened to 8.8 ± 1.0 days (mean ± sem; control, 15 ± 1.2 days). The results of this study showed that pH is the main factor in eliciting pgf2α release by intrauterine infusion of a saline solution, whereas increased temperature and osmolarity have no effect on the release of pgf2α.
Hemodynamic effects of high-frequency oscillatory ventilation in halothane-anesthetized dogs
Authors: Bednarski Richard M. , Muir William W.
Published: February 2025

Hemodynamic effects of spontaneous ventilation, intermittent positive-pressure ventilation (ippv), and high-frequency oscillatory ventilation (hfov) were compared in 6 dogs during halothane anesthesia. Anesthesia was induced with iv thiamylal Na and was maintained with halothane (end-tidal concentration, 1.09%). During placement of catheters, dogs breathed spontaneously through a conventional semiclosed anesthesia circuit. Data were collected, and dogs were mechanically ventilated, using ippv or hfov in random order. Ventilation was adjusted to maintain PaCO2 between 38 and 43 mm of Hg during ippv and hfov. Cardiac index, aortic blood pressure, and maximum rate of increase of left ventricular pressure were significantly (P < 0.05) less during hfov than during spontaneous ventilation, whereas right atrial and pulmonary artery pressure were significantly greater during hfov than during spontaneous ventilation. During ippv, only the maximum rate of increase of left ventricular pressure was significantly less than that during spontaneous ventilation.
Evaluation of the effects of intra-articular injection of dimethylsulfoxide on normal equine articular tissues
Authors: Welch R. D. , DeBowes R. M. , Liepold H. W.
Published: February 2025

To evaluate the effects of intra-articular injection of dimethylsulfoxide (dmso) on normal equine articular structures, 7 adult horses with clinically normal carpi were allotted to 2 treatment groups (group A, n = 4; group B, n = 3). In each horse after collection of synovial fluid samples, the right antebrachial carpal and middle carpal joints were aseptically injected with 2 ml of a 40% solution of 90% medical grade dmso in lactated Ringer solution, and the corresponding joints of the left forelimb (controls) were injected with 2 ml of lactated Ringer solution. In group-A horses, 2 ml of synovial fluid was obtained prior to injections of 40% dmso at 24 hours and 72 hours, for a total of 3 injections. At necropsy, synovial fluid, synovial membrane, and articular cartilage specimens were obtained. Group-B horses were injected with 40% dmso in the same sequence; however, the series was repeated following a 1-week interval.

Clinical evaluation of these horses revealed no evidence of carpal inflammation associated with any injection in any group. Synovial fluid analysis of dmso-injected and control joints revealed insignificant differences in leukocyte counts and total protein content.

There was no evidence of cartilage degradation on gross, histologic, or histochemical evaluation of any of the joints. Intercellular matrix staining of the articular cartilage failed to reveal any observable difference in glycosaminoglycan content between injection with dmso or lactated Ringer solution.
Numbers of Sertoli cells, quantitative rates of sperm production, and the efficiency of spermatogenesis in relation to the daily sperm output and seminal quality of young beef bulls
Authors: Berndtson William E. , Igboeli Gaius
Published: February 2025

Data from 34 yearling Hereford or Angus bulls were used to investigate relationships of testicular size, quantitative rates of sperm production, Sertoli cell numbers, numbers of germ cells supported per Sertoli cell, and the efficiency of spermatogenesis to daily sperm output and seminal quality. Two ejaculates were collected by electroejaculation from each bull on each of 2 days/week throughout the study. The percentage of progressively motile sperm and the percentage of morphologically normal sperm were determined from aliquots of fresh semen. Additional aliquots of semen were frozen in glass ampules or plastic straws and subsequently evaluated for postthaw motility and percentage of sperm with intact acrosomes. Sertoli cell numbers, the numbers of germcells per Sertoli cell, and the efficiency of spermatogenesis were unrelated to the quality of fresh or frozen semen (P > 0.05). In first ejaculates, the numbers of sperm and motile sperm were related (P < 0.05) to testicular parenchymal weight (r = 0.38 and 0.50), daily sperm production (r = 0.45 and 0.53), and spermatids per gram of testicular parenchyma (r = 0.35 and 0.34). Testicular parenchymal weight and daily sperm production also were related to daily sperm output and to the average daily motile sperm output of these bulls (P < 0.05), but could account for < 25% of the variability in these end points among bulls.
Interaction of turkey complement with Escherichia coli isolated from turkeys
Authors: Ellis Marlene G. , Arp Lawrence H. , Lamont Susan J.
Published: February 2025

The role of turkey complement in a serum bactericidal reaction was determined using serum-sensitive and serum-resistant Escherichia coli isolated from turkeys. Inactivation of complement by heating serum (56 C for 40 minutes) or by treating serum with 10 mM EDTA eliminated bactericidal activity. Serum-sensitive E coli organisms were killed by turkey serum treated with 10 mM ethylene glycol-bis-β-(aminoethyl ether)-N,N,N',N'-tetraacetic acid and 5 mM MgCl2. Exposure of normal turkey serum to serum-sensitive or serum-resistant E coli resulted in equivalent reductions in hemolytic activity of serum. Treatment of serum-resistant E coli with antibody rendered the bacteria sensitive to bactericidal effects of normal turkey serum. Serum-sensitive E coli organisms were readily killed by an alternative complement pathway, serum-sensitive and serum-resistant E coli activated the complement system equally well, and antibody was required for complement-mediated killing of certain serum-resistant E coli organisms from turkeys.
Kinematic analysis of cutting horses working a mechanical flag
Authors: Clayton Hilary M.
Published: February 2025

High-speed cinematography was used to record the movements of 12 cutting horses performing a standard test with a mechanical flag. Based on their previous competitive performances, horses were classified into 2 groups: group 1, composed of 5 moderately successful or average performers that had won < $35,000 in purse money; and group 2, composed of 7 highly successful or elite performers that had amassed > $35,000 in competition earnings. Analysis of the results indicated that, compared with horses of the average group, the elite horses had faster reaction times in response to the start and cessation of flag movement (P < 0.01), and were positioned closer to the flag during all stages of the trial (P < 0.05). Discriminant analysis was used to construct a mathematical formula that could be used to classify an individual horse into 1 of the 2 alternative groups, based on the set of measurements. Two predictor variables were selected that described the maximal distance between the horse and the flag during the run and the part of the body that was moved first in response to the initial flag movement. The accuracy of the predicted group membership, compared with the actual group membership, was 100%.
Treatment of Brucella melitensis infection in mice by use of liposome-encapsulated gentamicin
Authors: Hernández-Caselles T. , Vera A. , Crespo F. , Villalaín J. , Gómez-Fernández J. C.
Published: February 2025

Liposomes with entrapped gentamicin were used to treat mice with infection attributable to Brucella melitensis. Liposomes bearing positive charge and formed by egg yolk lecithin, cholesterol, and stearylamine were effective in the elimination of B melitensis residing in liver and spleen. Negatively charged liposomes, formed by egg yolk lecithin, cholesterol, and dicetyl phosphate were also effective in suppression of the infection in liver, but were less so in suppression of the infection in the spleen. Free gentamicin was less effective than the encapsulated antibiotic. At 20 hours after administration of gentamicin encapsulated in liposomes, the gentamicin concentrations in liver and spleen were similar, regardless of the charge of the liposomes—neutral, positive, or negative. However, positively charged liposomes were more efficient than were other liposome types for the treatment of brucellosis caused by B melitensis.
Response of equine airway smooth muscle to acetylcholine and electrical stimulation in vitro
Authors: Mason Diane E. , Muir William W. , Olson Lynne E.
Published: February 2025

Smooth muscle strips from the midcervical portion of the trachea and bronchial smooth muscle strips from third-generation airways of horses were placed in tissue baths, and isometric contractile force was measured. Active force was measured in response to electrical stimulation and exogenous acetylcholine. Square-wave electrical stimuli were applied at various voltages (10, 12, 15, 18, 20, 25 V), frequencies (3, 5, 10, 15, 20, 25, 30 Hz), and pulse durations (0.2, 0.5. 1.0. 1.5, 2.0 ms). Isometric contractile force increased as voltage, frequency, and pulse duration increased. Maximal contractile response to electrical stimulation was obtained at 18 V, 25 Hz, and 0.5 ms. Atropine (10-6M) or tetrodotoxin (3 × 10-6M) blocked the contraction, indicating that the contractile response was attributable to the release of neurotransmitter from cholinergic nerves.

Cumulative concentration-response curves to acetylcholine (10-9M through 10-4M) were determined. Isometric contractile force increased as acetylcholine concentration increased. There was a significant (P < 0.05) difference in the 50% effective dose for acetylcholine in tracheal smooth muscle and bronchial smooth muscle. The mean (± sd) contractile reponse to maximal electrical stimulus was 89% (± 7.4%) of that in response to 10-4M acetylcholine in tracheal smooth muscle and was 68% (± 10.4%) of the response to 10-4M acetylcholine in bronchial smooth muscle.
Interaction between Pasteurella haemolytica, sulfadiazine/trimethoprim, and bovine viral diarrhea virus
Authors: Clarke Cyril R. , Short Charles R. , Corstvet Richard E. , Nobles Debbie
Published: February 2025

A study was designed to develop and define a sc tissue chamber as a suitable device for establishing a soft-tissue infection model in cattle and to use this model to study the interaction between Pasteurella haemolytica, sulfadiazine/trimethoprim, and bovine viral diarrhea virus (bvdv). Thermoplastic tissue chambers were implanted in the paralumbar fossae of 20 calves. At 35 days after implantation, calves were allotted to 4 groups of equal size and the calves in 2 groups were inoculated intratracheally with a New York-1 strain of bvdv. At 45 days after implantation, all chambers were inoculated with a 6-hour culture of P haemolytica serotype 1. Starting 36 hours after bacterial inoculation, sulfadiazine/trimethoprim was administered iv once a day to half of the virus-inoculated calves and to half of those calves that had not been exposed to virus. Inoculation of P haemolytica into tissue chambers resulted in the establishment of a localized soft-tissue infection, characteristic of pneumonic pasteurellosis. Despite the maintenance of chamber antimicrobial concentrations that exceeded minimal bactericidal concentrations established in vitro, the infections were not sterilized. This lack of efficacy was associated with decreased pH and increased protein concentrations in chamber fluids after inoculation. Infection with bvdv, which is thought to depress host defenses, had no effect on the response of P haemolytica to sulfadiazine/trimethoprim administration. Observation of responsive antibody titers, bacterial phagocytosis, and high leukocyte viability within P haemolytica-infected chambers documented functional host defenses within tissue chambers.
Influence of isoprinosine on lymphocyte function in virus-infected feeder pigs
Authors: Flaming K. P. , Blecha F. , Fedorka-Cray P. J. , Anderson G. A.
Published: February 2025

Pseudorabies is a porcine herpesvirus of major importance in the swine industry. Isoprinosine is an immunomodulating drug that has been shown to be beneficial in treating herpesvirus infections. Twenty-four 7-week-old pigs were allotted within litters to 1 of 4 groups: control, isoprinosine (iso), pseudorabies virus (prv), or isoprinosine and pseudorabies virus (iso-prv). Isoprinosine was administered daily for 16 days to the iso and iso-prv groups (75 mg/kg of body weight/day, po). Immunity in pigs in the prv and iso-prv groups was challenged with pseudorabies virus (105 tcid50 units) on day 4. Rectal temperatures and viral excretion were monitored daily; total and differential leukocyte counts, lymphocyte response to mitogens, and interleukin-2 production were monitored every 4 days. Pigs challenge-inoculated with pseudorabies virus became ill, with the iso-prv group most severely affected. Rectal temperatures were high (P < 0.05) in virally challenged pigs on days 5 to 12 and 14 to 16; isoprinosine did not alter this effect. Pseudorabies virus-infected pigs had leukocytosis (P < 0.05) on days 12 and 16, primarily caused by neutrophilia. Concanavalin A-stimulated lymphocyte proliferation was decreased (P < 0.06) in both prv and iso-prv groups on day 12, compared with control pigs, but only in the prv group on day 16. Pokeweed mitogen-stimulated lymphocyte proliferation was decreased (P < 0.02) in iso-prv pigs on day 8 of the experiment. Interleukin-2 concentrations, pooled over all sampling days, were decreased (P < 0.03) in pseudorabies virus-infected pigs. Viral excretion was not altered by isoprinosine treatment. These data suggest that pseudorabies virus infection decreased lymphocyte proliferative responses and interleukin-2 production in pigs, and that isoprinosine did not mitigate these effects.
Isoproterenol- and salbutamol-induced relaxation of acetylcholine- and histamine-induced contraction of equine trachealis muscle in vitro
Authors: Olson L. E. , Perkowski S. Z. , Mason D. E. , Muir W. W.
Published: February 2025

Strips of trachealis muscle were dissected from the mid-cervical portion of the trachea of horses that were free of y respiratory tract disease, and the overlying epithelium and mucosa were removed. Muscle strips were suspended in tissue baths that were filled with Krebs-bicarbonate solution, aerated with 5% CO2 in oxygen and maintained at 37 C. Isometric tension was continuously recorded. The increase in active isometric tension was concentration dependent when acetylcholine (10−9 to 10−4M) or histamine (10−9 to 10−4M) was added to the tissue baths in 0.5-logarithmic increments. When the tissues were contracted with acetylcholine (3.1 × 10−6M) or histamine (10−4M), the decrease in active isometric tension was concentration dependent when isoproterenol (10−9 to 10−4M or salbutamol (10−9 to 10−4M) was added to the tissue baths in 0.5-logarithmic increments. There was no difference between the response to isoproterenol and salbutamol when tissues from the same horses were compared whether the tissues were contracted in response to acetylcholine (3.1 × 10−6M) or histamine (10−4M). Relaxation was antagonized by 10−6M propranolol. The degree of relaxation obtained in these muscle strips was considerably less than that reported from other species’ tracheal muscle strips that had the epithelium and mucosa intact. We concluded that equine tracheal smooth muscle contains β-adrenoceptors that can be stimulated by either a mixed β-1, β-2 agonist or a selective β-2 agonist.
Effect of probenecid administration on cephapirin pharmacokinetics and concentrations in mares
Authors: Juzwiak James S. , Brown Murray P. , Gronwall Ronald , Houston A. E.
Published: February 2025

Cephapirin (20 mg/kg of body weight, iv) was administered before and after 3 doses of probenecid (25, 50, or 75 mg/kg, intragastrically, at 12-hour intervals) to 2 mares. Clearance and apparent volume of distribution, based on area under the curve, were negatively correlated with probenecid dose. Clearance of cephapirin was decreased by approximately 50% by administration of 50 mg of probenecid/kg.

Serum, synovial fluid, peritoneal fluid, csf, urinary, and endometrial concentrations of cephapirin were determined after 5 doses of cephapirin (20 mg/kg, im, at 12-hour intervals) without and with concurrently administered probenecid (50 mg/kg, intragastrically) to 6 mares, including the 2 mares given cephapirin, iv. Highest mean serum cephapirin concentrations were 16.1 ± 2.16 μg/ml at 0.5 hour after the 5th cephapirin dose [postinjection (initial) hour (pih) 48.5] in mares not given probenecid and 23.7 ± 1.30 μg/ml at 1.5 hours after the 5th cephapirin dose (pih 49.5) in mares given probenecid. Mean peak peritoneal fluid and synovial fluid cephapirin concentrations were 6.2 ± 0.57 μg/ml and 6.6 ± 0.58 μg/ml, respectively, without probenecid administration and 12.3 ± 0.46 μg/ml and 10 ± 0.78 μg/ml, respectively, with concurrent probenecid administration.

Mean trough cephapirin concentrations for peritoneal and synovial fluids in mares given probenecid were 2 to 3 times higher than trough concentrations in mares not given probenecid. Overall mean cephapirin concentrations were significantly higher for serum, peritoneal fluid, synovial fluid, and endometrium when probenecid was administered concurrently with cephapirin (P < 0.01). Cephapirin was not detected in csf samples. Overall mean urinary cephapirin concentrations (2.47 mg/ml without concurrent probenecid administration and 3.06 mg/ml with concurrent probenecid) were not significantly different (P > 0.05). Mean trough serum probenecid concentration was 61.2 ± 5.28 μg/ml. Highest serum probenecid concentration was 148.8 ± 5.97 μg/ml, 2 hours after the 5th cephapirin dose (pih 50). Probenecid administration increased serum, synovial fluid, peritoneal fluid, and endometrial concentrations of cephapirin in mares.
Whole blood platelet aggregation in uremic dogs
Authors: Forsythe LeeAnn T. , Jackson Marion L. , Meric Susan M.
Published: February 2025

Whole blood platelet aggregation responses to collagen, arachidonic acid, and adenosine diphosphate were determined by use of the impedance method in 22 dogs with serum urea concentrations ≥ 20 mmol/L, which was attributable to renal disease, and in 25 healthy control dogs. The median changes in impedance for the control dogs were 23 ohms for collagen, 18 ohms for arachidonic acid, and 6 ohms for adenosine diphosphate. The median changes in impedance in uremic dogs were 25 ohms for collagen, 21 ohms for arachidonic acid, and 15 ohms for adenosine diphosphate. There were no significant differences in platelet aggregation responses to collagen, arachidonic acid, and adenosine diphosphate between uremic and control dogs. Hemorrhagic tendencies were not detected in uremic dogs by use of whole blood platelet aggregation. Results of this study suggest that platelet aggregation by use of the whole blood platelet aggregometer is not abnormal in uremic dogs, but does not exclude the possibility of a platelet aggregation defect undetected by the whole blood system.
Serum distribution of iodine after oral administration of ethylenediamine dihydriodide in cattle
Authors: Maas J. , Berg J. N. , Petersen R. G.
Published: February 2025

Serum concentrations of iodine were determined after cattle were given ethylenediamine dihydriodide (eddi) orally at dosages ranging from 0.0 (placebo) to 0.77 mg/kg of body weight/day. The serum iodine concentration was correlated with the dosage of eddi. A rate of 0.11 mg eddi/kg/day was correlated with serum iodine concentrations (20 to 80 μg/dl) previously found to be effective in preventing foot rot in cattle. A linear dose-response curve that was generated could be helpful in predicting dosage of eddi if the serum iodine concentration is known.
Influence of supplemental selenium on humoral immune responses in weaned beef calves
Authors: Swecker W. S. , Eversole D. E. , Thatcher C. D. , Blodgett D. J. , Schurig G. G. , Meldrum J. B.
Published: February 2025

Influence of supplemental Se on humoral immune response was measured in 60 weaned beef calves with marginal blood Se status. Calves were fed a Se-deficient diet consisting of corn silage, corn grain, and soybean meal. Blood Se concentrations, primary and secondary humoral immune responses to hen egg lysozyme inoculation, and weight gain were determined in a 70-day trial.

Calves fed 20 mg of Se/kg of mineral mixture ad libitum had lower antibody responses (P < 0.02), compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, im, or with calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture. Calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture had higher (P < 0.001) blood Se concentrations on day 70, compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, im. Selenium supplementation had no effect on weight gain.
Comparison of the effects of Sesbania drummondii on the hepatic microsomal monooxygenase systems of chickens and rats
Authors: Banton Marcy I. , Flory Wayne , Jowett Peter L. H. , Winston Gary W.
Published: February 2025

Sesbania drummondii, a toxic leguminous shrub found throughout the southeastern United States, induces different responses in chicken vs rat hepatic microsomal monooxygenase systems. Groups of 4- to 8-week-old Sprague-Dawley rats and White Leghorn chickens were given extracts of S drummondii by gavage for 3 days. Doses, which were 0.4 and 0.8% of daily body weights, respectively, for the rats and chickens, were adjusted to induce similar clinical lesions in the 2 species. The hepatic microsomal monooxygenase systems of control and treated animals were compared, using cytochrome P-450 content, cytochrome b5 content, nadh- and nadph-cytochrome c-reductase activity, and 6 cytochrome P-450 mediated enzyme activities. Increases of twofold in the cytochrome P-450 content, nadph-cytochrome c-reductase, aminopyrine-N-demethylase, aniline hydroxylase, ethoxycoumarin-O-deethylase, and aryl hydrocarbon hydroxylase activities; fourfold in the aldrin epoxidase activity; and 15-fold in the ethoxyresorufin-O-deethylase activity were observed in the S drummondii-treated chickens. In contrast, the treated rats had nearly twofold decreases in these values, suggesting a species-specific effect of S drummondii on microsomal monooxygenase systems, ie, induced with S drummondii.
Influence of limb temperature on sensory nerve conduction velocity in horses
Authors: Wheeler S. J.
Published: February 2025

Sensory nerve conduction velocity was measured in the lateral palmar nerve of 8 horses. The limb temperature was manipulated by external means and monitored. Alterations in the nerve conduction velocity related to limb temperature variation were identified at both increased and decreased temperatures. These were quantified and a mean value of 2.15 ± 0.2 m/s/degree Celsius was determined. The effect of altered limb temperature should be considered in nerve conduction velocity determinations.
Waveform analysis and reproducibility of visual-evoked potentials in dogs
Authors: Sims Michael H. , Laratta Louis J. , Bubb Wendy J. , Morgan Rhea V.
Published: February 2025

Visual-evoked potentials (vep) and electroretinograms (erg) were recorded from 10 normal light-adapted adult dogs, using a 3 × 5 matrix of light-emitting diodes as a stimulator. Visual-evoked potentials were recorded from 4 scalp electrodes overlying cortical areas, whereas electroretinographic activity was recorded by 2 scalp electrodes placed near the eye and by a conjunctivally placed electrode. The waveform of the vep consisted of 3 major positive waves (Pl through P3), with peak latencies in the 20- to 70-ms range. Waveform reproducibility was assessed by comparing peak latencies from vep recorded on 2 separate days approximately 1 week apart. The peak latencies for Pl through P3 did not differ (P ≥ 0.05) between first and second recording sessions.

To substantiate the postretinal origin of vep, recordings were made before and after unilateral optic nerve transsections in 4 dogs. Electroretinograms were also measured before and after surgery to assess the integrity of the retina. Postsurgically, vep were absent when the eye on the surgically treated side was stimulated. Stimulation of the contralateral eye induced vep with the same waveform shape, but latencies were slightly prolonged (P ≤ 0.05) compared with presurgical recordings. The only effect of optic nerve transsection on the ipsilateral erg was a prolongation (P ≤ 0.05) of the b-wave. However, when postsurgical erg values were compared with those from the intact side after surgery, there were no differences.