bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of zeranol on reproduction in beef bulls: Scrotal circumference, serving ability, semen characteristics, and pathologic changes of the reproductive organs
Authors: Deschamps J. C. , Ott R. S. , McEntee K. , Heath E. H. , Heinrichs R. R. , Shanks R. D. , Hixon J. E.
Published: February 2025

Effects of zeranol on scrotal circumference, serving ability, semen characteristics, and postmortem measurements of the genital organs were determined in beef bulls from 9 to 20 months of age. Group 1 (n = 5) served as a nonimplanted control group. Group 2A (n = 5) was implanted with 36 mg of zeranol at birth and at 3 and 6 months of age. Group 2B (n = 5) was implanted with 36 mg of zeranol every 3 months from birth through 18 months of age. Scrotal circumference was adversely affected by zeranol in groups 2A and 2B, but values approached those of group 1 with increasing age. Serving ability was also affected adversely but tended to recover with increasing age. Semen quality was low in groups 2A and 2B and did not improve with increasing age.

There was no difference in testicular weight, vesicular gland weight, and penis length among groups when bulls were slaughtered at 20 months of age. Epididymal weight was greater in group-2B bulls and was most likely a consequence of epididymal lesions. Histologic examination of the genital organs revealed that zeranol induced adenomyosis and sperm granulomas in the caudae epididymidis and markedly altered the structure of the sexual accessory glands of bulls in groups 2A and 2B. Alterations in the vesicular glands were characterized by reduced alveolar development and an increase in connective tissue. Low epithelium associated with focal areas of squamous metaplasia were common in the prostate of groups 2A and 2B bulls. Lesions in the bulbourethral glands were characterized by low glandular epithelium, focal areas of squamous metaplasia, cystic collecting ducts, and an increase in connective tissue. Groups 2A and 2B had more abnormal seminiferous tubules than did group 1. Lesions in groups 2A and 2B may have been direct effects of zeranol or may have resulted from reduced testosterone secretion.
Inhibition of macrophage adenylate cyclase by the α-methylene-γ-lactone moiety of sesquiterpene lactones from forage plants
Authors: Elissalde Marcel H. , Ivie G. Wayne
Published: February 2025

Inhibition of murine macrophage adenylate cyclase activity by sesquiterpene lactones isolated from toxic forage plants was highly correlated with the presence of the α-methylene-γ-lactone moiety on the molecule (ie, hymenovin and helenalin). Tenulin, a sesquiterpene lactone which does not contain this reactive moiety, caused minimal inhibition of the enzyme. Reaction of the α-methylene-γ-lactone moiety of hymenovin and helenalin with cysteine decreased the number of reactive moieties available to alkylate the enzyme, thus decreasing the inhibition of adenylate cyclase by these 2 sesquiterpene lactones. As the reaction time available for the reduction by cysteine of the α-methylene-γ-lactone moiety decreases, the amount of adenylate cyclase inhibition increases. Stimulation of the hymenovin- or helenalin-inhibited adenylate cyclase by prostaglandin E1 or E2 or by sodium fluoride did not reverse the inhibition of the enzyme, but did stimulate the undamaged adenylate cyclase in the sesquiterpene lactone treatment groups to the same degree as in the nontreated control. These data indicate that sesquiterpene lactones containing an α-methylene-γ-lactone moiety are potent inhibitors of macrophage adenylate cyclase activity. This moiety may have a significant role in the toxicity of some sesquiterpene lactones in poisonous plants when ingested by livestock.
Tetramine cupruretic agents: A comparison in dogs
Authors: Allen K. G. D. , Twedt D. C. , Hunsaker H. A.
Published: February 2025

The cupruretic effects of 2 tetramine (N,N'-bis (2-aminoethyl) alkane diamine) chelators were examined in healthy dogs fed a commercial dog food containing 12.2 μg of copper/g of dry diet. Two groups of 3 dogs each were given either 300 mg of 2,2,2-tetramine tetrahydrochloride or 2,3,2-tetramine tetrahydrochloride for 23 consecutive days. Serum and 24-hour urine samples obtained before drug administration and during therapy were analyzed for copper, zinc, and iron concentrations. Both tetramines produced a significant cupruresis without significant changes in serum copper or in serum or urine zinc and iron concentrations. The 2,3,2-tetramine tetrahydrochloride produced a 4- to 9-fold greater cupruresis than did 2,2,2-tetramine tetrahydrochloride and resulted in a daily loss of more than 2 mg of copper in the urine. The dogs had no laboratory or clinical evidence of toxic side effects to either cupruretic agent during the treatment period. The results of the present study indicate that 2,3,2-tetramine should be an effective decoppering drug for use in dogs.
Cross protection of mice and swine given live-organism vaccine against challenge exposure with strains of Erysipelothrix rhusiopathiae representing ten serovars
Authors: Sawada Takuo , Takahashi Toshio
Published: February 2025

Mice and swine vaccinated (subcutaneous inoculation) with live acriflavine-fast attenuated Erysipelothrix rhusiopathiae, strain Koganei 65-0.15 (serovar 2), were challenge exposed with 10 strains of E rhusiopathiae pathogenic for swine; the latter strains comprised serovars 9 and 10 and other previously undetermined.

Vaccinated mice did not die after they were challenge exposed (subcutaneous inoculation) with serovars 4, 6, 7, 8, 9, 10, 15, 16, or N, but vaccinated mice challenge exposed with strain 2553 (serovar 20) had 30% mortality. Nonvaccinated control mice died after they were challenge exposed with all serovars tested.

One of 2 vaccinated swine challenge exposed (intradermal inoculation) with each of strains 911 (serovar 8), 2179 (serovar 10), or 2553 developed localized urticarial lesion at the site of intradermal inoculation. Vaccinated swine challenge exposed with serovars 4, 6, 7, 9, 15, 16, or N did not have clinical signs of acute swine erysipelas. Nonvaccinated control swine developed localized lesions at the site of intradermal challenge inoculation.
Experimental infection and abortion of pregnant guinea pigs with a unique spirillum-like bacterium isolated from aborted ovine fetuses
Authors: Bryner J. H. , Ritchie A. E. , Pollet Lori , Kirkbride C. A. , Collins J. E.
Published: February 2025

Study was made of the pathogenicity of a spirillum-like, anaerobic, gram-negative bacterium, originally isolated from aborted lambs, for pregnant guinea pigs. Reproducible conditions for propagation and preservation of the bacterium were determined as requisite for the preparation of cultures for animal inoculation.

A preliminary experiment was done with 10 pregnant guinea pigs to test for an infective dose of organisms that would produce abortion. High-passage cultures (n = 50) were used to inoculate these guinea pigs intraperitoneally. Six of 10 guinea pigs aborted, and the organism was cultured from fetal tissues of 5 guinea pigs.

Isolates from 3 of the 6 guinea pigs were propagated through 4 passages on blood agar and used to infect 3 groups, each of 5 guinea pigs. A 4th group of 5 guinea pigs was inoculated with the original culture. Three of 5 animals in the first 3 groups, which had been given the low-passage cultures from the preliminary trial, and 2 of 5 guinea pigs in the 4th group, which had been given the original culture, aborted. Antibody against the spirillum was detected in 19 of 30 inoculated guinea pigs.

The major microscopic lesions were acute suppurative placentitis and splenitis. This bacterium retained pathogenic properties sufficient to cause infection, abortion, and microscopic lesions in two-thirds of the guinea pigs, in spite of high in vitro passage. The organism has unique ultrastructures, and its genus and species are yet to be determined.
Serologie survey of viral antibodies in the Peruvian alpaca (Lama pacos)
Authors: Rivera Hermelinda , Madewell Bruce R. , Ameghino Enrique
Published: February 2025

Sera from more than 100 alpacas (Lama pacos) from the Peruvian southern sierra were examined for antibodies to 8 viruses known to infect other domestic animals. On the basis of these serologic findings and previously published serologic or clinical data, it is now known that the alpaca can be infected with the following viruses: parainfluenza-3, bovine respiratory syncytial virus, bovine herpesvirus-1, bluetongue virus, border disease virus, influenza A virus, rotavirus, rabies virus, vesicular stomatitis virus, foot-and-mouth disease virus, and contagious ecthyma virus.
Effects of xylazine on equine intestinal vascular resistance, motility, compliance, and oxygen consumption
Authors: Stick J. A. , Chou C. C. , Derksen F. J. , Arden W. A.
Published: February 2025

Isolated jejunal segments were perfused at a constant blood flow rate to determine simultaneously the effects of xylazine on intestinal vascular resistance, motility, compliance, and oxygen consumption in 12 anesthetized ponies. Xylazine was infused into the artery perfusing the intestinal segment (group 1), or into the jugular vein as a single iv bolus (group 2), or 3 times as iv boluses repeated at 10-minute intervals (group 3). Dose-response curves in group 1 indicated a biphasic response to the drug with vasoconstriction, increased motility, and increased oxygen consumption at lower doses followed by a return toward base-line values at higher doses. Intestinal compliance decreased at lower doses, but increased at higher doses. A single iv bolus of xylazine (group 2) induced systemic hypotension for 30 minutes, and increased intestinal vascular resistance for 10 minutes accompanied by increased motility, and repeatedly administered iv boluses of xylazine (group 3) increased and prolonged these effects. The results indicated that xylazine, especially in repeated doses, may decrease bowel viability by simultaneously increasing intestinal vascular resistance, motility, and oxygen consumption.
Clearance of nasal mucus in nonanesthetized and anesthetized dogs
Authors: Whaley Sandra L. , Wolff Ronald K. , Muggenburg Bruce A.
Published: February 2025

Clearance rates for nasal mucus in the maxillary turbinate region were measured in 8 Beagle dogs. 99mTc Macroaggregated albumin (10 μl) was instilled in the nasal maxillary region of dogs under general anesthesia. A gamma camera was used to detect movement of the 99mTc macroaggregated albumin in the nose for 1 hour after it was instilled. Velocity of mucus was measured in the 8 dogs each under 3 conditions of anesthesia: (a) anesthesia with pentobarbital given iv (20 mg/kg of body weight), (b) anesthesia with halothane gas, and (c) no anesthesia. Mean velocities (± SD) were 3.7 ± 1.4 mm/min in dogs anesthetized with pentobarbital, 4.3 ± 2.5 mm/min in dogs anesthetized with halothane, and 3.4 ± 1.7 mm/min in awake dogs. The differences between the 3 anesthetic conditions were not significant at the P < 0.05 level. Use of anesthesia at a light surgical plane provides a controlled method for measurement of clearance of nasal mucus with minimal alterations from the nonanesthetized state.
Cross protection of mice and swine inoculated with culture filtrate of attenuated Erysipelothrix rhusiopathiae and challenge exposed to strains of various serovars
Authors: Sawada Takuo , Takahashi Toshio
Published: February 2025

Mice and swine inoculated subcutaneously with culture filtrate vaccine prepared from acriflavine-fast attenuated Erysipelothrix rhusiopathiae strain Koganei 65-0.15 (serovar 2), were challenge exposed to 20 pathogenic strains of E rhusiopathiae of 18 serovars and type N. Vaccinated mice survived after challenge exposure to serovars lb, 2, 8 (strain Goda), and type N, but mortality occurred in vaccinated mice challenge exposed to other strains: 20% to 30% mortality in mice challenge exposed to serovars la, 11, 12, 15, 16, or 21; 40% to 50% mortality in mice challenge exposed to serovars 4, 5, 6, 7, or 8 (strain 911); and 60% to 80% mortality in mice challenge exposed to serovars 9, 10, 18, or 19. All vaccinated mice died after challenge exposure with strain 2553 (serovar 20). Non-vaccinated control mice died after challenge exposure to all strains.

Of 2 vaccinated swine challenge exposed to strain 2553, 1 developed a local urticarial lesion at the site of intradermal exposure. Vaccinated swine challenge exposed to serovars la, lb, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 18, 19, 21, or type N did not have clinical signs of acute erysipelas. Nonvaccinated control swine developed acute generalized erysipelas or localized urticarial lesions at the site of intradermal exposure.
Common internal parasites found in the stomach, large intestine, and cranial mesenteric artery of Thoroughbreds in Kentucky at necropsy (1985 to 1986)
Authors: Lyons E. T. , Tolliver S. C. , Drudge J. H. , Swerczek T. W. , Crowe M. W.
Published: February 2025

A total of 278 Thoroughbreds (< 1 to 31 years old) were examined at necropsy (July 9, 1985, to Feb 2, 1986) in Kentucky for various internal parasites. Examination was not made of all the horses for each of the parasites.

Specific parasites recovered from the stomach of foals (n = 30) and yearlings and older horses (n = 96) and percentage (in parentheses) of each age category infected, respectively, were as follows: Gasterophilus intestinalis 2nd instar (53% and 32%) and 3rd instar (37% and 24%); G nasalis 2nd instar (7% and 8%) and 3rd instar (7% and 10%); Habronema spp immature (7% and 13%); H muscae (3% and 8%); Draschia megastoma (3% and 5%) and lesions (0% and 2%); and Trichostrongylus axei (0% and 3%).

Parasites in the large intestine included Anoplocephala perfoliata, which was found in the cecum of 30% of the foals (n = 87) and in 60% of the yearlings and older horses (n = 186). Probstmayria vivipara and immature Oxyuris equi were not found in the colon and rectum of any of the horses (n = 53 foals and n = 101 yearlings and older); mature O equi were not sought.

Examination of the cranial mesenteric artery for Strongylus vulgaris revealed immature and/or mature specimens in 9% of foals (n = 87) and 14% of yearlings (n = 44); lesions of S vulgaris were present in 25% of foals (n = 87) and 34% of yearlings (n = 44).
Pathogenesis of simulated natural infections with Ostertagia ostertagi in calves
Authors: Wiggin C. J. , Gibbs H. C.
Published: February 2025

The possibility of a mucosal hypersensitivity reaction and its relationship to the pathogenesis of simulated natural infections with Ostertagia ostertagi were studied in calves. Four groups of 4 calves each were used. One group was used as noninfected control; a 2nd group was given increasing doses of infective larvae; a 3rd group was given increasing doses of larvae and these were removed by succeeding treatment with an anthelmintic; and a 4th group was given an initial dose of larvae which was then eliminated with an anthelmintic. All calves given larvae became sensitized, as shown by an intradermal skin test. The continuously infected calves had significantly (P < 0.05) higher fecal egg counts, eosinophil counts, plasma pepsinogen values, and worm burdens and significantly (P < 0.05) lower lymphocyte counts than did the other groups of calves. These animals also had the most extensive mucosal pathologic changes. The group given intermittent larval challenge exposures followed by an anthelmintic showed decreased lymphocyte values, but these were not significant. Plasma pepsinogen values of this group increased between every challenge exposure and treatment, a 3-day period. This indicated that a mucosal hypersensitivity reaction had occurred in these calves at these times, because they were shown to have been sensitized, and challenge-exposure infections were not present for sufficient time to have produced direct pathologic effects. It therefore seems that a part of the pathologic changes in O ostertagi infections may be the result of the continuous challenge exposure experienced by the animals through a constant intake of larvae from pasture and the intestinal reaction to this challenge exposure.
Methionine toxicosis in cats
Authors: Maede Yoshimitsu , Hoshino Takuo , Inaba Mutsumi , Namioka Shigeo
Published: February 2025

Cats given dl-methionine (1 g/kg of body weight/day) developed severe hemolytic anemia with marked increase of methemoglobin (MetHb) concentration and Heinz-body formation at treatment-day 6 to 10. Cats fed 0.5 g of me-thionine/kg for 52 days had a moderate Heinz-body hemolytic anemia with methemoglobinemia at treatment days 17 to 31, but thereafter recovered from the anemia despite continuation of methionine feeding, indicating an adaptation of the cats. In vitro, significant (P < 0.01) increases of MetHb concentration and Heinz-body formation were observed when rbc were incubated with plasma from cats fed (1 g of methionine/kg) or with 10 mM 3-methylthiopropionate, a product of methionine ca-tabolism. However, these increases were not observed when rbc were incubated with 10 mM methionine. Seemingly, excessive methionine intake leads to production of an intermediate of the methionine catabolism that may affect rbc directly as an intensive oxidizing agent, resulting in an excessive oxidation of hemoglobin to MetHb and Heinz-body formation.
Determination of bromide ion concentration in Greyhound urine by ion chromatography
Authors: Moore Howard , Riusech David J. , Duer Wayne C.
Published: February 2025

An ion chromatographic method was used to determine Br ion in the urine of Greyhounds. Phenol was added to the urine, before filtration through a 30,000-molecular weight cutoff filter and to the eluant (pH 11, NaOH-Na2CO3), as a preservative. Urine from 103 racing Greyhounds resulted in a mean ± sd of 3.60 ± 2.72 mg of Br/L of urine. Urine samples obtained from a Greyhound, to which 2 g of KBr was administered, yielded a diurnal elimination pattern with a half-life of 7.6 days.
Effect of shipping stress on clincopathologic indicators in F344/N rats
Authors: Bean-Knudsen David E. , Wagner Joseph E.
Published: February 2025

A variety of hematologic, serum chemistry, and cytochrome P450 variables from 20 F344/N rats were measured and analyzed statistically to determine the effects of shipping stress on clinicopathologic indicators. Additionally, whole body, liver, and total kidney weights were recorded and compared. Ten rats were assayed upon receipt (stressed group), and 10 additional rats were held on a wire substrate for 12 days (poststress group) and assayed. Significant differences were detected between the 2 groups in ratio of total kidney weight to body weight, segmented neutrophil count, monocyte count, eosinophil count, and serum cholesterol, serum potassium, serum aspartate transaminase, and serum lactate dehydrogenase values.
Toxoplasma gondii cysts in placentas of experimentally infected sheep
Authors: Dubey J. P.
Published: February 2025

To determine the presence of tissue cysts in ovine placentas, 6 ewes were inoculated orally with 10,000 Toxoplasma gondii oocysts at 60 days of gestation. The ewes were euthanatized and necropsied 21, 52, 56, 57, 57, and 62 days after T gondii inoculation, and placental cotyledons from each ewe were collected and homogenized. To distinguish between the presence of tachyzoites that are killed by acid pepsin solution and bradyzoites (from cysts) unaffected by this solution, a portion of each homogenate was inoculated into mice and another portion was inoculated into mice after digestion in acid pepsin solution. Toxoplasma gondii was isolated in 26 of 34 (76.4%) of mice inoculated with nondigested placentas of all 6 ewes and in 16 of 34 (47%) mice inoculated with digested placenta of 5 of 6 ewes. Seemingly, cysts do occur in placental tissue, but the digestion method was inferior, compared with the nondigestion method for recovery of T gondii from placenta.
Development of a defined medium for Haemophilus somnus isolated from cattle
Authors: Inzana Thomas J. , Corbeil Lynette B.
Published: February 2025

Nutritional factors that influence the growth of Haemophilus somnus were examined, and a defined medium was developed. Optimal growth of H somnus in broth occurred under conditions of maximum aeration. Nutritional components required for or enhanced growth of most H somnus isolates in the defined medium included uracil, d-glucose, isotonic NaCl, Na2HPO4, nicotinamide, flavin mononucleotide, pantothenic acid, pyridoxine, and a variety of salts and amino acids. The defined medium supported optimum growth of 18 of 21 isolates of H somnus from cattle.
Seroreactivity of Peruvian sheep and goats to small ruminant lentivirus-ovine progressive pneumonia virus
Authors: Madewell B. R. , Ameghino E. , Rivera H. , Inope L. , De Martini J.
Published: February 2025

Sera from 3,369 sheep and 1,394 goats in Peru were examined by agar-gel immunodiffusion for antibodies to ovine progressive pneumonia virus (oppv). The point prevalence rates for antibodies to oppv in sheep were 1.7% to 40.6% (mean, 19.02%) in the 7 flocks studied, whereas for goats, the point prevalence rates for antibodies that cross-reacted with oppv in 12 herds were 0.0% to 45.1%. For sheep, a direct association between increasing age and increasing seroreactivity to oppv was established, and there was evidence to indicate that lambs born to primiparous ewes and raised separated from all other sheep after they were weaned may have been less likely to become infected with oppv than those lambs born to multiparous ewes and not separated from other sheep after they were weaned. For goats, antibodies to oppv were detected in 7 of 12 herds studied, the highest infection rate being present within a herd in the Lima department (district).
Effects of flunixin meglumine and dexamethasone on aqueous protein values after intraocular surgery in the dog
Authors: Krohne Sheryl D. G. , Vestre W. A.
Published: February 2025

Effects of flunixin meglumine and/or dexamethasone on aqueous protein concentrations were evaluated in dogs during and after intraocular surgery. Flunixin meglumine plus dexamethasone had the greatest inhibitory effect on postoperative aqueous protein increases with 64.2% inhibition over base-line aqueous protein values 24 hours after surgery. Dexamethasone alone had a 45.6% inhibition and flunixin meglumine alone had a 22.4% inhibition. Treatment with these drugs separately or in combination had a marked effect in decreasing postoperative inflammation.
Cystometrography and urethral pressure profiles in healthy horse and pony mares
Authors: Clark E. Susan , Semrad Susan D. , Bichsel Pierre , Oliver John E.
Published: February 2025

Cystometrography and urethral pressure evaluations were performed in 7 horse mares and 5 pony mares before and after sedation with xylazine. Before sedation, mean ( ± sd) maximal bladder contraction pressure was 91.4 ± 16.5 cm of H2O in horses and was 86.0 ± 14.4 cm of H2O in ponies, and maximal urethral closure pressure was 49.1 ± 19.4 cm of H2O in horses and 37.7 ± 14.4 cm of H2O in ponies. A significant difference was not found between values of nonsedated vs sedated animals. Only values for threshold volume were significantly different (P < 0.05) between nonsedated horses (1,982 ± 1,241 ml) and ponies (825 ± 412 ml).
Antigenic characteristics of enterotoxigenic and nonenterotoxigenic isolates of Bacteroides fragilis
Authors: Myers Lyle L. , Shoop Douglas S.
Published: February 2025

Fecal isolates of enterotoxigenic (44 isolates) and nonenterotoxigenic (25 isolates) Bacteroides fragilis were obtained from diarrheic calves (62 isolates), lambs (2 isolates), and pigs (5 isolates). Using a Microtiter whole-cell agglutination test and gel double-diffusion analysis, the isolates were reacted with nonabsorbed rabbit antisera prepared against 13 isolates of enterotoxigenic B fragilis (etbf). Isolates of B fragilis were antigenically diverse. Thirty-seven (84%) of the 44 isolates of etbf comprised 13 serogroups on the basis of reaction in the agglutination test. Fourteen (56%) of the 25 isolates of non-etbf comprised 4 of the 13 groups. Compared with results of the gel-diffusion test, most isolates had a different agglutination test reaction pattern against the 13 antisera. Isolates of etbf could not be distinguished from non-etbf. Antigenic heterogeneity of B fragilis facilitated differentiation of individual isolates, a capability that may be useful in future epidemiologic and virulence studies.
Effect of levamisole on the clinical and immunologic responses to oral vaccine of Treponema hyodysenteriae
Authors: Jenkins E. M. , Nash Stephen , Hill Weanetta , Mosley Jonathan
Published: February 2025

Conventionally raised crossbred Hampshire pigs were vaccinated orally with attenuated Treponema hyodysenteriae in combination with an anthelmintic, levamisole or dichlorvos. Pigs in group I (n = 9) were treated with levamisole and vaccinated with attenuated T hyodysenteriae and those in group II (n = 9) were treated with levamisole and permitted to commingle (contact exposure) with group I. Pigs in group III (n = 9) were vaccinated in a similar manner and were treated with dichlorvos. Pigs in group IV (n = 9) were treated with dichlorvos and permitted to commingle with group III. Control pigs (group V; n = 9) were not given any anthelmintic, nor were they vaccinated; they were housed separately.

During the 8-week interval between vaccination and challenge inoculation, 4 total days and 8 total days of diarrhea were observed in pigs in groups I and II, respectively. Likewise, 5 total days and 10 total days of diarrhea were seen in groups III and IV, respectively. In all groups, the pigs tended to shed the organism in their feces after they were vaccinated or challenge inoculated, as determined by a fluorescent antibody technique (fat) and culture procedure (cp). Overall mean shedding patterns of 5.5% and 24.5% identified by cp and fat, respectively, were seen in the 2 levamisole-treated groups (I and II). In contrast, mean shedding patterns of 4% and 18% of the isolation attempts were detected by cp and fat, respectively, in the 2 dichlorvos-treated groups. Diarrhea and shedding of T hyodysenteriae in the controls (group V) did not occur.

During the 4-week interval after pigs were challenge inoculated, diarrhea was seen for 1 day in groups I and II, for 2 days in groups III and IV, and for 121 days in the control group. The T hyodysenteriae shedding patterns increased numerically to overall means of 12.5%, as determined by cp and 32% as determined by fat for the levamisole-treated groups. There was an overall mean decrease to 2.5% shedding as determined by cp and an increase to 27% as determined by fat in the dichlorvos-treated groups. In contrast, there were sheddings of 50% and 80% as determined by cp and fat, respectively, in the control group. Pigs given levamisole developed mean geometric titers of 1:52 and 1:62 in the dichlorvos-treated groups III and IV, respectively. After the pigs were challenge inoculated, the serum titers increased from 1:86, compared with 1:20 and 1 to 168 for the dichlorvos-treated and nontreated controls, respectively. All vaccinated groups exhibited mean positive cell-mediated immune responses after vaccination and challenge inoculation were done. The control group had a mean borderline positive cell-mediated immune response after challenge inoculation was done.
Udder edema in cattle: Effect of furosemide, hydrochlorothiazide, acetazolamide, or 50% dextrose on venous blood pressure
Authors: Vestweber Jerome G. E. , Al-Ani Falah K. , Johnson Dallas E.
Published: February 2025

Before injection of diuretic drugs, blood pressures were determined in the cranial superficial epigastric veins (milk vein) and jugular veins of 15 Holstein cows with udder edema at parturition and of 15 healthy (control) cows at parturition. Cows with udder edema had a significant (P ≤ 0.05) mean increase in cranial superficial epigastric venous pressure at parturition, compared with that of control cows.

After iv administration of 500 mg of furosemide in cows with udder edema, the mean cranial superficial epigastric venous blood pressure significantly (P ≤ 0.05) decreased within 5 minutes, remained at the decreased pressure for 90 minutes, and then returned to near pretreatment pressures by 210 minutes after furosemide injection; however, furosemide did not significantly affect the jugular venous blood pressure of these cows. Furosemide injection did not significantly affect the cranial superficial epigastric or jugular venous blood pressure in the control cows.

After iv administration of hydrochlorothiazide (250 mg), acetazolamide (500 mg), or 50% dextrose (500 g), the cranial superficial epigastric and jugular venous blood pressures in cows with udder edema at parturition were not significantly different from those in cows without udder edema at parturition during the 210-minute evaluation period after injection of the drugs.
Epidermal cell renewal in seborrheic skin of dogs
Authors: Baker Benjaman B. , Maibach Howard I.
Published: February 2025

Epidermal cell renewal time of seborrheic skin was estimated in 8 adult Cocker Spaniels and 5 adult Irish Setters, using autoradiography after [3H]thymidine was given intradermally. Cell renewal time of the viable epidermis was approximately 7 days. Seemingly, the seborrheic skin observed in these Cocker Spaniels and Irish Setters was associated with an altered rate of epidermal keratinization.
Phagocytic function of equine neutrophils exposed to Mycoplasma felis in vitro and in vivo
Authors: Rosendal S. , Lumsden J. H. , Viel L. , Physick-Sheard P. W.
Published: February 2025

Neutrophils were isolated from the peripheral blood of adult equids (group 1) and were purified on a density gradient of polyvinylpyrrolidone-coated silica gel. A bactericidal assay was developed, using an equine skin isolate of Staphylococcus epidermidis as target bacterium in medium containing pooled fresh equine serum for opsonization. Significant (P < 0.05) killing was observed after 60 or 120 minutes' incubation. Reduction in bactericidal function of blood neutrophils was not found after incubation with a virulent strain of Mycoplasma felis for 30 or 60 minutes. Similarly, the function of blood and pleural neutrophils of ponies with M felis-induced pleuritis (group 2) was not different from the function of similar neutrophils from sham-inoculated control ponies (group 3). The number of viable M felis organisms was markedly reduced in the presence of fresh equine serum and equine-specific antibodies, but not when the serum was heat inactivated. Equine neutrophils did not phagocytize M felis. Seemingly, M felis did not impair bactericidal activity of equine neutrophils. Therefore, this mechanism does not predispose equids to bacterial pleuritis.
Clinical, virologic, and histopathologic observations of induced porcine parvovirus infection in boars
Authors: Thacker B. J. , Joo H. S. , Winkelman N. L. , Leman A. D. , Barnes D. M.
Published: February 2025

Twelve 8- to 12-month-old crossbred boars were inoculated with a virulent strain (NADL-8) of porcine parvovirus (ppv). Hemicastrations were performed on 6 boars 3, 7, 10, 14, 21, and 28 days after an im injection of 108 median cell culture infectious dose (ccid50) of ppv (n = 3) or injection of 107.4 ccid50 given intratesticularly (it, n = 3). Noninfected cell culture medium (0.25 ml) was injected into each testicle of a 7th boar (it inoculated control). Virus or viral antigen was detected in testicular and epididymal tissues up to 14 days after inoculation. Direct immunofluorescence indicated that viral antigen was mainly associated with the vasculature of the interstitium. Microscopic lesions were not evident in the testicles and epididymides of im inoculated boars. Acute-to-chronic testicular degeneration was evident in the it inoculated boars, as well as in the it inoculated control boar.

Six boars were inoculated im or orally/nasally with 107.9 ccid50 of ppv. Semen was collected twice weekly for 8 weeks after inoculation. Virus was not detected in any ejaculates. Semen also was collected from 4 boars for 5 weeks before inoculation, and preinoculation and postinoculation semen quality was compared. Pronounced changes in sperm output, ejaculate volume, motility, or morphologic defects were not observed. The reproductive consequences of experimental ppv infection in boars were minimal because reproductive function was unaffected and venereal transmission of ppv was not detected.
Pharmacokinetics of phenobarbital in the horse
Authors: Duran S. H. , Ravis W. R. , Pedersoli W. M. , Schumacher J.
Published: February 2025

Pharmacokinetics of phenobarbital was examined in 6 mature horses after 12 mg of phenobarbital/kg of body weight was infused over 20 minutes. Biexponential decrease in serum phenobarbital concentrations was observed with a distribution-phase half-life of 0.101 ± 0.086 hour (mean ± sd) and a terminal-phase elimination half-life of 18.3 ± 3.65 hours. The volume of distribution at steady state was 0.803 ±0.070 L/kg. Total body clearance of phenobarbital was 30.8 ± 6.2 ml/h/kg. The high clearance in the horse seems to explain the markedly shorter half-life of phenobarbital in this species. Seemingly, 6.65 mg of phenobarbital/kg as a 20-minute infusion given every 12 hours would provide approximate peaks of 29 µg/ml and troughs of 15 µg/ml. A loading dose of 12 mg of phenobarbital/kg would be appropriate for this regimen.
Tropism of border disease virus for oligodendrocytes in ovine fetal brain cell cultures
Authors: Anderson Charles A. , Higgins Robert J. , Waldvogel Andreas S. , Osburn Bennie I.
Published: February 2025

Primary dissociated ovine brain cell cultures prepared from 50- or 140-day-old fetuses were inoculated with border disease virus (bdv). The cells present in the cultures were identified, using immunofluorescence procedures and sera against various cns cell-specific markers. These markers were glial fibrillary acidic protein, myelin basic protein, myelin-associated glycoprotein, neuron-specific enolase, neurofilament protein, and fibronectin. Double-labeling immunofluorescence techniques for visualization of bdv antigen and of the cns cell markers were used to evaluate the pattern of individual cell susceptibility 48 hours after infection. In cultures from fetuses of both ages, about half of the infected cells were glial fibrillary acidic protein-positive astrocytes. Scattered myelin-associated glycoprotein-positive oligodendrocytes were positive for bdv antigen, but only in the infected cultures from the older fetuses. Fibronectin-positive cells were not infected with bdv. In infected and noninfected cultures, cells positive for neuron-specific enolase, myelin basic protein, or neurofilament protein were not seen. Therefore, the remaining infected cells in all the cultures were not identified by the cell-specific markers used. Results of these in vitro experiments indicate that bdv does not selectively infect oligodendrocytes, and that such a selective pattern of infection may not be the basis for the in vivo congenital hypomyelination in sheep with border disease.
Efficacy of a morantel sustained-release bolus for control of gastrointestinal parasites in winter-grazed steers in Mississippi
Authors: Hawkins J. A. , Evans R. R. , Taylor C. E. , Couvillion C. E. , Illyes E. F. , Wilkins C. P. , Johnson-Delivorias M. H. , Tyler T. D.
Published: February 2025

From Nov 22,1983 through May 15,1984, 36 crossbred steers were allotted into 3 treatment groups (12/group) and were grazed on separate 3.4-hectare pastures. On Nov 22, 1983, the steers were administered a single morantel sustained-release bolus (msrb), orally (group 1), or a single dose of thiabendazole (tbz; 66 mg/kg of body weight, orally; group 2), or were left untreated (group 3; controls). Animal weights, nematode egg counts in fecal specimens, and plasma pepsinogen concentrations were monitored monthly. At the termination of the study, 4 steers from each treatment group were slaughtered and necropsied and worm counts were determined. A set of parasite-free tracer calves (3/treatment group) were grazed with each treatment group for 1 month, beginning on Nov 22,1983; a second set of tracer calves (3/group) were grazed with each treatment group for 1 month, beginning Apr 3,1984. At the end of their respective grazing periods, tracer calves were held for 3 weeks and then were slaughtered and necropsied and their worm counts were determined.

Mean nematode egg counts in fecal specimens of group 1 (msrb treated) were significantly lower (P < 0.05) than that of the tbz-treated or nontreated steers. Differences in worm counts were not found between treatment groups. Differences in worm counts of tracer calves were not found among the 3 groups for November 1983 nor for April 1984. Steers treated with the msrb had a higher mean weight gain (P < 0.06) than did the control or tbz-treated steers.
Plasma antithrombin-III values in healthy horses: Effect of sex and/or breed
Authors: Bernard William , Morris Debra Deem , Divers Thomas J. , Ramberg Charles
Published: February 2025

Plasma antithrombin-III (AT-III) values were determined in 74 healthy horses by an automated spectrophotometric assay. The mean plasma AT-III value was 218% ± 18% of normal human plasma. Plasma AT-III values did not differ significantly (P < 0.05) among Thoroughbred, Standardbred, Quarter Horse, and other breeds or among mares, geldings, or stallions.
Efficacy of Corynebacterium pseudotuberculosis bacterin for the immunologic protection of sheep against development of caseous lymphadenitis
Authors: LeaMaster Brad R. , Shen David T. , Gorham John R. , Leathers Charles W. , Wells Homer D.
Published: February 2025

The efficacy of a Corynebacterium pseudotuberculosis bacterin to protect sheep immunologically against development of, caseous lymphadenitis was evaluated in controlled challenge-exposure experiments. Sixty-three mixed-breed, white-faced lambs were used. The lambs were 10 to 12 weeks old and were randomly assigned to 3 groups (21 lambs/group). Group 1 was vaccinated once, using 2 ml of a C pseudotuberculosis bacterin (given subcutaneously) in the right axillary region at the beginning of the study. Group 2 was vaccinated twice; the 1st vaccination was given at the same time that lambs in group 1 were vaccinated and the 2nd vaccination was given 4 weeks later. Group 3 (nonvaccinated controls) was given physiologic saline solution (2 ml, subcutaneously). Each lamb was challenge exposed (ie, given 2 ml of live Corynebacterium pseudotuberculosis inoculum [6 × 106 colony-forming units/ml], subcutaneously at 4 different sites) during the 20th week of the study. All lambs were killed and necropsied during week 33. The mean number of abscesses per lamb was 7 for group 1, 4 for group 2, and 32 for group 3. Significant differences in the size of the abscesses were not found between the groups. Results of the study indicated that the vaccine provided immunologic protection of lambs against challenge exposure to Corynebacterium pseudotuberculosis.
Effect of fluoride ingestion on dental fluorosis in sheep
Authors: Milhaud Guy E. , Borba Marco A. , Krishnaswamy Shushila
Published: February 2025

The effects of fluoride ingestion (3.5 mg/kg of body weight) were evaluated in 9 ewes at 6 through 9, 10 through 13, or 14 through 17 months of age (3 ewes/age group). In the 3 groups, the plasma fluoride concentration rapidly increased to 0.45, 0.46, and 0.50 µg/ml, respectively, and decreased rapidly to 0.1 µg/ml after fluoride was removed from the ration. In 5 of the 9 ewes, this short-term exposure caused symmetrical, moderate damage to the molars, which is characteristic of fluorosis in sheep. In 7 of the 9 ewes, abnormal gaps were found between incisors, which are not characteristic of fluorosis in sheep.

Fluoride accumulation was higher in the roots of the incisors and in the dentine of the molars and was particularly evident in teeth that were developing when fluoride was administered; however, the fully developed teeth and teeth that developed several months after administration of fluoride also were affected. The increase in fluoride concentration in the enamel was confined to a maximum of 2 molars. The abnormal wear of the molars was not directly linked to fluoride accumulation.
Efficacy of fenbendazole-medicated feed blocks against gastrointestinal nematode infections in calves
Authors: Blagburn Byron L. , Hanrahan Lynn A. , Hendrix Charles M. , Lindsay David S.
Published: February 2025

An anthelmintic trial was conducted to determine the efficacy of fenbendazole (fbz) incorporated into two types of feed blocks given daily for 3 or 10 days to calves naturally parasitized with gastrointestinal nematodes. Each treated calf consumed 5 mg of fbz/kg of body weight. The fbz was > 99% effective in removing adults of Haemonchus contortus, Ostertagia ostertagi, O lyrata, Cooperia punctata, C pectinata, C onchophora, Trichostrongylus axei, Bunostomum phlebotomum, and Oesophagostomum ra-diatum. Fenbendazole was also > 99% effective against immature nematodes recovered from the small intestine, which were thought to be mainly Cooperia spp. Efficacy was similar for fbz in each of the two types of feed block carriers and for the 3- and 10-day regimens. Calves readily consumed feed blocks containing fbz and did not have adverse reactions to fbz.
Echocardiographic evaluation of equine aortic insufficiency
Authors: Reef Virginia B. , Spencer Pamela
Published: February 2025

Echocardiographic evaluation of 23 horses with aortic insufficiency was performed, using M-mode (n = 23) and 2-dimensional real-time echocardiography (n = 14 of 23). Echocardiograms were evaluated for abnormalities of aortic and mitral valves and alterations in motion of these valves. Changes in left ventricular chamber size and function, as well as aortic root size, were evaluated. The presence of other cardiac disease was also evaluated. Horses with aortic insufficiency had significant increases (P < 0.01) in mean values of left ventricular chamber size, aortic root diameter, and shortening fraction. Left ventricular free wall thickness also was significantly decreased (P < 0.01).

Valvular abnormalities were seen echocardiographically in all 23 horses. Eighteen horses with aortic insufficiency had thickened valves, whereas two horses had lesions associated with vegetative endocarditis. High-frequency vibrations of the septal leaflet of the mitral valve were noticed in all horses, whereas similar vibrations of the aortic valve were seen in six horses.

The presence of a bounding arterial pulse correlated significantly (P < 0.05) with increased left ventricular chamber size at end diastole and shortening fraction, indicating a marked left ventricular volume overload. A reliable diagnosis of aortic insufficiency can be made with the detection of bounding arterial pulses in concert with a holodiastolic decrescendo grade II to V/V murmur with maximal intensity over the aortic valve area, radiating toward the left cardiac apex.
Skeletal muscle perfusion during prolonged 2.03% end-tidal isoflurane-02 anesthesia in isocapnic ponies
Authors: Manohar Murli , Gustafson Rand , Nganwa David
Published: February 2025

Effects of 1.55 minimum alveolar concentration isoflurane 02 anesthesia (2.03% end-tidal isoflurane) on blood flow in the up-(nondependent) and down-(dependent) positioned skeletal muscles were studied at 60,120, and 180 minutes in 6 healthy isocapnic ponies in right lateral recumbency on a nonpadded hardwood floor. Measurements were made, using 15-μm diameter radionuclide-labeled microspheres injected into the left ventricle, and comparisons were made with data obtained from ponies in the conscious state.

Isoflurane administration caused a sharp reduction in cardiac output and systemic pressure (P < 0.01), but total peripheral resistance did not change significantly. In the triceps brachii, gluteus medius, biceps femoris, and vastus lateralis of both sides, blood flow decreased significantly during 1.55 minimum alveolar concentration isoflurane anesthesia (P < 0.01), and fluctuations did not occur with increasing duration of anesthesia. In masseter muscles, perfusion values during the 3 hours of anesthesia were not significantly different from values in awake ponies. Despite the fact that 4 ponies developed marked edema of the dependent masseter muscle, 1 pony without masseter edema developed postanesthetic forelimb lameness and 2 of the 4 ponies with masseter edema had generalized hind limb weakness after anesthesia; significant differences in blood flow between up- and down-positioned muscles were not observed.

During isoflurane-O2 anesthesia in ponies, a sharp significant decrease in skeletal muscle blood flow was observed (P < 0.01). Decreased equine skeletal muscle perfusion during isoflurane anesthesia also may be accompanied by accentuated O2 loss from the arterial blood via the countercurrent O2 exchange between large arterioles and venules.
Pathogenesis of rotavirus infection in various age groups of chickens and turkeys: Clinical signs and virology
Authors: Yason C. V. , Schat K. A.
Published: February 2025

Age-related susceptibility patterns of turkeys, broilers, and specific pathogen-free (spf) White Leghorn chickens to experimentally induced infection with turkey or chicken rotavirus isolates were compared. The following determinants were evaluated: clinical signs, onset and duration of virus production, viral titers, involvement of intestinal villi in the replication of the virus, and the development of antibodies against the virus. Older turkeys and chickens were more susceptible than were their younger counterparts, turkeys were more susceptible than were broiler and White Leghorn chickens (regardless of age), and broiler chickens were slightly more susceptible than were age-matched White Leghorn chickens. Turkeys developed diarrhea, accompanied by high viral titers within 1 day after inoculation with virus. Viral antigen was found in the epithelial cells of the intestinal villi throughout the intestinal tract and some cells of the cecal tonsils. Antibodies could be detected as early as 4 to 5 days after inoculation. These findings were more pronounced in turkeys inoculated at 112 days of age than in birds inoculated at a younger age. Age-related susceptibility patterns were similar in White Leghorn and broiler chickens. Infection was subclinical in birds < 56 days old, whereas older birds developed soft feces. Egg production in the White Leghorn chickens decreased after being inoculated with virus at 350 days of age.
Experimentally induced Cassia roemeriana poisoning in cattle and goats
Authors: Rowe Loyd D. , Corrier Donald E. , Reagor John C. , Jones Larry P.
Published: February 2025

The dried, ground aerial portions of the plant Cassia roemeriana were administered to each of seven calves at a dosage of 10 g/kg of body weight/day for 2 to 10.5 days and to each of six goats at a dosage of 10 g/kg/day for 5 days or 5 or 7 g/kg/day for 23 to 25 days. Experimentally induced C roemeriana poisoning in both species resulted in hepatopathic poisoning characterized by a brief survival period (3.9 to 7.9 days), moderate-to-severe hepatocellular damage, and little or no evidence of injury to skeletal muscle or resulted in myopathic poisoning characterized by a longer period of survival, mild-to-severe skeletal myopathy, and mild hepatocellular injury. The minimal dosage that induced hepatopathic poisoning (also the minimal lethal dosage) was 10 g/kg/day for 3 days in calves and for 5 days in goats. The minimal dosage that induced the myopathic syndrome (as determined by the earliest increase in serum creatine kinase activity) was 10 g/kg/day for 6 days for calves and 5 g/kg/day for 10 to 16 days for goats.