bluuebunny/crossref_metadata_2025 huggingface dataset:
Aromatic-dependent Salmonella typhimurium as modified live vaccines for calves
Authors: Smith Bradford P. , Reina-Guerra Mario , Hoiseth Susan K. , Stocker Bruce A. D. , Habasha Faisal , Johnson Eugene , Merritt Frank
Published: February 2025

Strains of Salmonella sp with complete nonreverting aromatic biosynthesis (aro) defects are expected to be nonvirulent, in respect to invasive infection, because they need the aromatic metabolites paraaminobenzoate (for making folate) and dihydroxybenzoate (for making enterochelin) which are not available in host tissues. Derivatives with transposon-generated complete nonreverting aro− defects were prepared from 3 mouse-virulent strains of S typhimurium, namely, FIRN, WRAY, and UCD. The latter 2 parent strains originally were isolated from calves and are known to be calf-virulent. The resultant aromatic-dependent (aro−) strains were used to vaccinate 27 calves (2 to 3 weeks old), usually giving 2 doses by the im route (109 bacteria) or orally (1.5 × 1011). Vaccination did not cause severe ill effects in any calf. Thus aro− defects cause loss of virulence for calves, as previously shown for mice.

Vaccinated and control calves were challenge exposed, usually at 5 weeks of age, by feeding 1.5 × 1011 cells of 1 of 2 calf-virulent S typhimurium strains, either UCD 108-11 or SL1323. Of the 16 challenge-exposed control calves, all became anorectic and depressed (cns), and 15 had diarrhea. Fourteen of the 16 died; all tested tissues were bacteriologically culture-positive for Salmonella at necropsy. Vaccination with the live UCD aro− vaccine strain, SL1479 by either of 2 schedules (im or orally) appeared effective. Six of the 7 calves vaccinated with 2 im doses of strain SL1479 survived challenge exposure (4 of the 7 not even developing diarrhea), and all of 3 calves which had been vaccinated with 2 oral doses of the live UCD vaccine also survived challenge exposure. In contrast, 3 calves which had been given 1 im dose and then the oral dose of strain SL1479 were not protected—2 of them dying after challenge exposure.

The other aro− strains (FIRN and WRAY) proved ineffective or relatively ineffective as live-organism vaccines, at least with the schedules tested. Failure of the FIRN aro− vaccine may reflect the organism's origin from a wild strain which, though mice-virulent, was of a bio type seldom isolated from cattle and perhaps not well adapted for persistence in bovine tissues. There is no reason that can be suggested for the vaccinal failure of 2 oral doses of the WRAY aro− strain.

Thus one aro− live bacterial vaccine, the S typhimurium UCD aro− strain SL1479, given im (2 doses) or orally (2 doses), did not cause significant side effects and prevented death or severe illness in challenge exposed calves.
Diabetes mellitus in dogs: Relationship of obesity to glucose tolerance and insulin response
Authors: Mattheeuws D. , Rottiers R. , Kaneko J. J. , Vermeulen A.
Published: February 2025

The iv glucose-tolerance test was performed in 71 diabetic dogs (fasting glycemia > 6.70 mmol/L) and in 20 healthy dogs. All diabetic dogs were characterized by various degrees of glucose intolerance as expressed by an abnormal glucose disappearance coefficient. On the basis of the fasting plasma insulin concentration (Io), insulin peak response (ipr), the insulinogenic index (ΔΙ/ΔG), and the total insulin secretion (tis), the diabetic dogs were classified, as follows: Type I dogs (n = 32) which had the severe clinical signs of diabetes and an absence of certain diagnostic responses: Io, ipr, ΔΙ/ΔG, and tis. Type II dogs (n = 15) which also had marked diabetic signs and an absence of ipr, ΔΙ/ΔG, and tis responses. The dogs were further subdivided into obese and nonobese groups; the Io was within acceptable limits in the nonobese group (n = 8), but was markedly increased in the obese group (n = 7). Type III dogs (n = 24) had no diabetic signs and a fasting plasma glucose < 12 mmol/L. They were also subdivided into obese and nonobese groups. The nonobese dogs (n = 13) had Io values within acceptable limits and decreased ipr, ΔΙ/ΔG, and Tis. In contrast, the obese dogs had increased Io, ipr, ΔI/ΔG, and tis.

Statistical analyses indicated that the tis and Io were highly significant linear functions of obesity. It was shown that obesity was the most important factor accounting for the variations in insulin responses among all types of diabetic dogs, as well as within each type.
Experimental infection of lambs with ovine adenovirus isolate RTS-151: Clinical, microbiological, and serologic responses
Authors: Lehmkuhl Howard D. , Cutlip Randall C.
Published: February 2025

Twelve 1-week-old colostrum-deprived lambs that were inoculated with ovine adenovirus isolate RTS-151 developed a mild febrile response between postinoculation days (pid) 4 and 10. They were inactive and some had serous nasal discharges; their respiratory rates and efforts were increased. Virus was isolated from nasal secretions from pid 2 to pid 8. Virus also was isolated from tracheal fluid and lung tissue of most lambs at necropsy (between pid 2 and 12), but not from liver, kidney, small intestine, and feces, indicating that the infection was confined to the respiratory tract. Four control lambs remained healthy and neither virus nor serum antibody was detected.
Cloning and comparison of heat-stable enterotoxin genes from Escherichia coli strains of bovine, porcine, and avian origins
Authors: Sekizaki Tsutomu , Terakado Nobuyuki , Hashimoto Kazunori
Published: February 2025

The Ent plasmid encoding Escherichia coli heat-stable enterotoxin (ST) isolated from bovine, porcine, and avian strains were used for the cloning of ST genes. The ST+ DNA regions were finally cloned into pBR322 as the 1.75 kilobases PstI fragment. The electron microscopic analysis of self-annealed molecules indicated that ST+ recombinant plasmid had a stem-loop structure of a size the same as that observed in their wild type Ent plasmids. The stem-loop structures and the restriction enzyme cleavage mappings indicated that 4 kinds of ST genes cloned in this experiment may be identical to Tn1681. The ST production levels of the recombinant plasmids were higher than those of the original plasmids.
Mammary blood flow measurements associated with the development of bovine udder edema
Authors: Al-Ani Falah K. , Vestweber Jerome G. E.
Published: February 2025

Mammary blood flow (mbf) and mammary plasma flow (mpf) were measured by an antipyrine absorption method in 8 cows affected with udder edema and 3 healthy (control) cows at least 2 weeks before parturition, at parturition, and 2 weeks after parturition.

Cows with udder edema had a significant decrease in mbf at calving compared with the control cows (P ≤ 0.05), whereas there was no significant difference (P > 0.05) in mbf between affected and control groups 2 weeks before or 2 weeks after parturition.

Cows with udder edema also had a decrease in mpf at parturition that was not statistically significant (P > 0.05) when compared with that in the control cows.
Effect of age on liver enzyme activities in serum of healthy Quarter Horses
Authors: Gossett Kent A. , French Dennis D.
Published: February 2025

Serum alkaline phosphatase (alp), γ-glutamyl transferase (ggt), 5′nucleotidase (5′NT), sorbitol dehydrogenase (sdh), and aspartate transaminase activities were measured in 10 clinically healthy foals, 10 yearlings, and 10 two-year-old Quarter Horses. Enzyme activities in foals at 0.5 to 3 days, 2 to 3 weeks, and 5 to 7 weeks of age were compared with enzyme activities from yearling and 2-year-old horses. Multivariate analyses of variance revealed significantly higher enzyme values in foals (P < 0.002). This increase was mainly a result of higher alp and ggt activities, with lesser effects due to higher sdh and 5′NT activities.

Standard deviations for alp and ggt were also larger in foals than in adult horses. The wide variation of alp and ggt activities may limit their usefulness in the diagnosis of hepatic disease in foals. Standard deviations for serum ast, sdh, and 5′NT activities were smaller. These enzymes may be indicators of hepatobiliary disease in foals.

The high serum enzyme activities in healthy foals may reflect a physiologic difference between foals and adult horses. Relative hepatic mass (as a percentage of body weight) and enzyme activity per gram of hepatic tissue are high in young animals, indicating that the high serum enzyme activities in foals are due partly to a high rate of enzyme production and release.
Bacillus stearothermophilus disk assay detection of penicillin in milk of dairy cows after postestrual intrauterine infusion
Authors: McClary David G.
Published: February 2025

Penicillin concentrations were quantitated in milk from cows after intrauterine infusions of various amounts of penicillin. Six healthy lactating Holsteins were assigned to 3 treatment groups in a complete randomized block design. Postestrual (12 to 48 hours) intrauterine infusions of potassium penicillin G in sterile diluent were given at 1 of 3 dosage levels: 2 × 106 IU (group I), 1.5 × 106 IU (group II), or 1 × 106 IU (group III). Milk samples were collected from 0 to 72 hours after infusion and were frozen until assayed for detectable antibiotic residues by the Bacillus stearothermophilus plate disk test.

Intrauterine infusion of 1, 1.5, or 2 million IU caused detectable penicillin residues (≥ 5 mIU/ml) within 12 hours after infusion in milk from 15 of 18 cows. After 12 hours, no samples were positive in groups II or III and only 3 of 30 samples representing 2 of 6 cows were positive in group I. Using the B stearothermophilus plate disk test, a cow given 1 to 2 million IU of potassium penicillin G intrauterine will have detectable amounts of antibiotics in the milk within 12 hours. It is unlikely that herd composite milk samples would contain detectable concentrations of antibiotics unless a large percentage of the herd was infused or unless massive doses were administered to individual cows.
Immune responses of calves antigenically stimulated and challenge exposed with Anaplasma marginale during tick infestation or treatment with dexamethasone
Authors: Eckblad W. P. , Stiller D. , Woodard L. F. , Kuttler K. L.
Published: February 2025

Similar anamnestic antibody responses to a 2nd injection of a Anaplasma marginale vaccinal antigen were observed in calves infested with the tick Dermacentor albipictus and in tick-free calves. When challenge exposure of these calves to virulent A marginale was done, infestation with the tick Boophilus microplus increased anemia (P < 0.01), but did not suppress antibody production to A marginale or increase parasitemia. None of the vaccinated calves, regardless of infestation, experienced clinical anaplasmosis. Mitogenic responses of lymphocytes from infested animals were unaltered by either infestation.

Tick infestations did not cause immune suppression in the calves, whereas use of dexamethasone resulted in a significantly lower antibody response (P < 0.05) after a 2nd injection of vaccinal antigen. After challenge with virulent A marginale, dexamethasone-treated calves showed more pronounced parasitemia (P < 0.01) and anemia (P < 0.01) than did control calves.

Anaplasmosis did not prevent the calves from developing resistance to reinfestation, which was accompanied by immediate, but not delayed, hypersensitivity reactions against homologous tick extracts. Dermacentor albipictus did not seem to share common antigenic determinants with B microplus, since extracts from the latter did not elicit immediate hypersensitivity responses in calves sensitive to D albipictus extracts. Calves were somewhat resistant to reinfestation as evidenced by reduced numbers of adult fed ticks, decreased weights of ticks after feeding, and smaller egg masses.
Response of anemic calves to exertion
Authors: Reece William O.
Published: February 2025

Twenty-one calves, 16 weeks of age, comprised 3 treatment groups. All calves in 2 of these groups were anemic. Several variables were measured before and immediately after an imposed exertion period. The anemic calves had significantly faster heart rates than did nonanemic calves, but there was no significant difference either in respiratory rates or acid-base variables. However, anemic calves became more acidic when made to work and also showed greater increase in respiratory rate than did nonanemic calves. The partial pressure of oxygen in venous blood was significantly lower in the anemic calves than in nonanemic calves both before and after exertion, but still represented adequate saturation of hemoglobin with oxygen.
Histochemical activity of alkaline phosphatase and acid phosphatase in the epididymis of mature intact and androgen-deprived bulls
Authors: Goyal H. O. , Vig M. M.
Published: February 2025

The histochemical localization of alkaline phosphatase (alp) and acid phosphatase (acp) was determined in regions I to VI of the epididymis in mature intact, orchidectomized, and orchidectomized testosterone-treated bulls. The intensity of alp activity was essentially the same in all regions; however, its localization varied depending upon the region. Although the stereocilia and luminal border of epithelial cells were strongly positive in regions I to III, these were negative in regions IV to VI. The basement membrane and circumtubular smooth muscle cells were strongly alp reactive in all regions. Epithelial alp activity was abolished completely by orchidectomy; however, it was restored to normal concentration by testosterone treatment implying its dependence on circulating testosterone. The acp activity was present in the epithelial cells of all regions with the strongest activity in the supranuclear region.

Similar to alp, acp activity was markedly reduced in the epithelial cells by orchidectomy. However, in contrast to alp activity, lost acp activity was only minimally increased by testosterone treatment in all regions, except in region VI where it was restored to a normal concentration. These observations imply that although the epithelial acp activity of region VI was mainly under the influence of circulatory testosterone, there may be other factors such as luminal androgens, testicular fluid, and sperm that may be important in regulating the acp activity of regions I to V of the epididymis. The importance of alp and acp in the epididymal epithelium was discussed.
Ovine caseous lymphadenitis: Disease prevalence, lesion distribution, and thoracic manifestations in a population of mature culled sheep from western United States
Authors: Stoops Steven G. , Renshaw Harland W. , Thilsted John P.
Published: February 2025

The prevalence, distribution, and severity of caseous lymphadenitis (cla) lesions in 4,089 mature culled sheep were determined from a sample obtained by random selection of animal lots from a total population of 37,383 animals presented at an abattoir. The animals originated from 5 geographic regions comprising 9 western states. The prevalence rate for all forms of cla was 42.41%. The prevalence of cla lesions was significantly different in animals originating from 2 regions than it was in animals from the other 3 regions. The results indicate that cla is a disease affecting a considerable number of mature culled sheep in different regions of western United States.

Lesion distribution was catalogued according to a 4-compartment system: thoracic lymph nodes, lung parenchyma, abdominal tissues, and skeletal tissues including peripheral lymphatic tissues. Prevalence rates were determined for lesions occurring in the thoracic viscera (24.97%), skeletal tissues (23.09%), and abdominal viscera (11.79%). The prevalences of thoracic cla lesions were significantly different for animals originating from 2 regions than for animals originating from the 3 other regions. Severe or advanced lesions were observed in the thoracic (3.74%) and abdominal viscera (1.27%). Involvements of cla in the thoracic cavity occurred as abscesses of lung parenchyma, thoracic lymph nodes, or both. The bronchial and mediastinal lymph nodes were the most frequently affected thoracic lymph nodes. The liver was the most frequently affected abdominal organ, with the kidney being the next most commonly affected. The gross and histopathologic characteristics of cla abscesses and tissues adjacent to the lesions were described.
Efficacy of a large magnesium alloy rumen bolus in the prevention of hypomagnesemic tetany in cows
Authors: Stuedemann J. A. , Wilkinson S. R. , Lowrey R. S.
Published: February 2025

Two cow-calf grazing studies and 2 rate-of-disappearance trials in steers surgically prepared with rumen fistula were conducted to evaluate the efficacy of a large Mg alloy rumen bolus in preventing hypomagnesemic tetany (grass tetany). The mineral composition of the forage and results of study of 2 cows in the cow-calf studies indicated that an environment conducive to the occurrence of grass tetany existed. Grass tetany occurred in a cow that was given a Mg bolus and in a control cow. Administration of 1 or 2 mg boluses did not affect blood serum Mg, Ca, Ρ, and Κ concentrations. Bolus treatment did not affect cow-calf performance or conception rate. The rate of weight loss of the boluses in the surgically prepared steers (rumen fistula) ranged from 0.71 to 1.43 g/day or 0.66 to 1.33 g of Mg/day. Steer differences affected the rates of disappearance patterns of the boluses. The rate of disappearance was relatively constant over a 175-day period and regurgitation or passage was not a problem. Although administration of the boluses could have prevented tetany in some animals (borderline), the rate of Mg release appears too slow to be highly effective in preventing grass tetany.
Anthelmintic activities of ivermectin against immature and adult Dictyocaulus viviparus
Authors: Benz G. W. , Ernst J. V. , Egerton J. R.
Published: February 2025

Eighteen calves about 3 months old were inoculated with 3,000 Dictyocaulus viviparus infective larvae. Three groups of 6 calves each were formed. Thirteen days after inoculations, 3 of the 6 group 1 control calves were given vehicle subcutaneously (sc) and the group 2 calves were given ivermectin at the dose rate of 200 μg/kg, sc. Thirty-five days after inoculation, the remaining 3 calves in group 1 were given vehicle sc and the group 3 calves were given ivermectin at the dose rate of 200 μg/kg, sc. Necropsies were performed 42 days after inoculations. A total of 474 D viviparus was recovered from the group 1 control calves, whereas none was recovered from the calves treated when the nematodes were in the 4th stage of development (group 2) or adult stage (group 3).
Isolation of bovine herpesvirus-1 from vesicular lesions of the bovine udder
Authors: Guy James S. , Potgieter Leon N. D. , McCracken Malcolm , Martin William
Published: February 2025

Bovine herpesvirus-1 was isolated from vesicular lesions on the udder and mammary papillae (teats) of a Charolais cow. Lesions on the animal consisted of papules and vesicles up to 10 mm in diameter. The virus was identified by fluorescent antibody and serum-neutralization tests.
Reproductive tract lesions in heifers after intrauterine inoculation with infectious bovine rhinotracheitis virus
Authors: Miller J. M. , Van Der Maaten M. J.
Published: February 2025

Cross-breed heifers given infectious bovine rhinotracheitis virus by intrauterine inoculation 1 day after natural mating with a noninfected bull were killed on postinoculation days 4 to 14. When reproductive organs were examined for gross and microscopic lesions and for virus infection, the most severe uterine lesions were found in the body and caudal portions of the uterine horns of heifers killed between postinoculation days 4 and 9. Primary pathologic features were necrosis, edema, hemorrhage, and a diffuse accumulation of mononuclear cells, mostly lymphocytes; numerous lymphocytes were in mitosis. In cranial parts of uterine horns, the only lesions observed were a few small lymphocytic foci in the endometrial lamina propria. Lesions were not seen in the oviducts.

In many heifers, the ovarian corpus luteum (cl) was cystic. In a few of these heifers, the cyst had a necrotic wall that was bordered by a zone of proliferating mononuclear cells. Focal necrosis and lymphoid proliferation were common in the parenchyma of cystic and noncystic cl. Similar necrotizing lesions were sometimes present in non-cl ovarian tissue.

Infectious bovine rhinotracheitis virus was most frequently isolated from the uterine body, the internal os of the cervix, and the cl. Isolations were not made from blood samples taken at the time of necropsy. Isolation of virus from the cl correlated with the detection of luteal inflammation by light microscopy, but did not correlate with the presence of cysts. There also was no correlation between cystic cl and the severity of uterine lesions.
Prevalence of bovine herpesvirus-1, bovine viral diarrhea, parainfluenza-3, goat respiratory syncytial, bovine leukemia, and bluetongue viral antibodies in sheep
Authors: Brako Emmanuel E. , Fulton Robert W. , Nicholson Steven S. , Amborski Grace F.
Published: February 2025

Sera from healthy sheep were collected in January and March 1982 from flocks of sheep located in southwestern and southeastern Louisiana. These sera were tested for bovine herpesvirus-1 (bhv-1), bovine viral diarrhea virus (bvdv), parainfluenza-3 (pi-3) virus, and goat respiratory syncytial virus (grsv) antibodies by microtitration virus-neutralization test. The sera were tested also for bovine leukemia virus (blv) and bluetongue virus (btv) antibodies by immunodiffusion tests. The number of flocks with seropositive sheep for each virus were: 2/8 (25%) for bvdv; 8/8 (100%) for pi-3 virus; 7/8 (87.5%) for grsv; and 6/8 (75%) for btv. Seropositive rates for each virus for the individual sheep tested were: 4/158 (2.5%) for bvdv; 117/158 (74.1%) for pi-3 virus; 77/158 (48.7%) for grsv; and 21/158 (13.3%) for btv. All sheep were seronegative for bhv-1 and blv.
Bovine coccidiosis: Protective effects of low-level infection and coccidiostat treatments in calves
Authors: Conlogue Gerald , Foreyt William J. , Wescott Richard B.
Published: February 2025

Twenty coccidia-free Holstein bull calves were allotted to groups to study effects of treatment with lasalocid and decoquinate on subsequent resistance to coccidiosis (Eimeria spp infections). Calves fed medicated rations of either drug at dosages of 50 mg/kg of feed (approx 1.2 mg/kg of body weight) had significantly fewer oocysts (P < 0.01) than did nontreated controls regardless of other procedures used. Treated calves premunized with 2,000 oocysts/day for 5 days and later challenge inoculated with 200,000 oocysts did not develop diarrhea, unless the drugs were withdrawn from feed. Animals premunized (2,000 oocysts/day for 5 days) in absence of drug were no more resistant to the challenge inoculation than nonpremunized animals. These results indicated that lasalocid and decoquinate were efficacious coccidiostats and protected calves as long as they were administered. Cessation of drug treatment usually resulted in appearance of oocysts in feces and diarrhea. Premunization alone cannot be expected to prevent coccidiosis when animals are exposed to large numbers of oocysts.
Functional and ultrastructural evaluation of neutrophils from foals and lactating and nonlactating mares
Authors: Coignoul F. L. , Bertram T. A. , Roth J. A. , Cheville N. F.
Published: February 2025

Neutrophils from 4 pony foals, 3 lactating pony mares, and 3 nonlactating mares were evaluated ultrastructurally and by in vitro function tests. Neutrophils from foals had significantly (P = 0.05) less random migration than neutrophils from mares; values in tests for iodination and Staphylococcus aureus ingestion were also lower with foal neutrophils. Neutrophils from lactating mares had lower responses to iodination, antibody-dependent cell-mediated cytotoxicity, and random migration tests than did neutrophils from nonlactating mares. Ultrastructurally, granule concentration did not differ significantly among groups. A slight decrease in primary granules and a corresponding increase in granules with a flocculent matrix indicates partial spontaneous neutrophil degranulation in foals and lactating mares.
Dyschondroplasias, including osteochondrosis, in boars between 25 and 169 days of age: Histologic changes
Authors: Hill Michael A. , Ruth George R. , Hilley Harvey D. , Hansgen Diane C.
Published: February 2025

Microscopic sections of physeal and articular-epiphyseal (a-e) cartilages from major limb bones of 60 boars between 25 and 169 days of age were examined. The objectives in this study were to determine the age of onset and pathogenesis of osteochondrosis, a defect of endochondral ossification.

Lesions regarded as typical of osteochondrosis were associated with physes of pigs from 25 days of age, indicating an earlier age of onset than has generally been documented. Two morphologically distinct lesions were observed, but both had areas with increased depth of the zone of hypertrophying chondrocytes. Some lesions were repairing. With increasing age of the pigs, the number of involved physes increased in each of 6 different age groups up to 169 days.

Lesions associated with physea were observed in boars younger than those with lesions associated with a-e complexes. A few pigs at, or older than, 53 days of age, had osteochondrosis-like lesions involving epiphyseal growth cartilages. However, a dyschondroplasia different from osteochondrosis and typified by chondrolysis was more frequently associated with a-e complexes of pigs at or > 79 days of age. The number of affected cartilages and sites with this type of lesion also increased with age. Although osteoarthrosis had not developed in any of the pigs, it is probable that chondrolytic areas were precursors of degenerative joint disease.

To date, osteochondrosis has been used to encompass lesions involving physes and a-e complexes. However, in view of the findings in the present study, dyschondroplasia is the preferred term to be used generically and then qualified by morphologic description, since causations may be different.
Dyschondroplasias, including osteochondrosis, in boars between 25 and 169 days of age: Radiologic changes
Authors: Hill Michael A. , Hilley Harvey D. , Feeney Daniel A. , Ruth George R. , Hansgen Diane C.
Published: February 2025

Boars in 6 different groups ((between 25 and 169 days of age) were examined radiographically to determine the age of onset of lesions associated with the sites of endochondral ossification in limb bones.

Although lesions were in histopathologic sections of physes from all groups of pigs, they were not found frequently in radiographs of live animals until boars were more than 100 days old. Microscopic lesions were infrequent in articular-epiphyseal (a-e) complexes of pigs < 80 days old, and radiographic examination of live animals had limited value until animals were > 100 days old. Radiographs of slabs of bone were useful in the detection of physes with lesions in all age groups and a-e complexes with lesions in boars 100 days of age or older.

So that the accuracy of radiographic examination of live animals for the diagnosis of dyschondroplasias could be evaluated, a comparison was made between the numbers of growth cartilages with lesions as determined by radiologic examination of live animals, radiographic examination of slabs of bone, and light microscopy (examination of tissue sections). Only 21% of the lesions associated with physes and 22% of the lesions associated with a-e complexes were detected in radiographs of bones of live pigs. The authors concluded that the latter method was inaccurate for the identification of dyschondroplastic foci. Identification of lesions by examination of radiographs of slabs of bone was only slightly more accurate, since 33% of physes and 23% of a-e complexes which had lesions were found. Potential errors in evaluation of radiographs were discussed.

Despite the limited diagnostic value that radiographs of live boars have for dyschondroplasias, these radiographs used in conjunction with those of slabs of bone enabled the authors to estimate the age of lesions. Lesions in histopathologic sections were associated with the physes of the youngest pigs and by using the depths of lesions in radiographs of slabs of bone to estimate ages of lesions, it was hypothesized that the age of onset was < 14 days. Lesions associated with physes and a-e complexes apparently developed continuously and regressed as the pigs grew.
Persistence of passively acquired antibodies to hemagglutinating encephalomyelitis virus in swine
Authors: Paul P. S. , Mengeling W. L.
Published: February 2025

The persistence of passively acquired antibodies to hemagglutinating encephalomyelitis virus (hev) was determined in 4 pigs in each of the litters of 10 sows. At time of delivery by the sows, the colostrum and serum samples (from the 10 sows) had hemagglutination-inhibiting antibodies to hev. All of the pigs also had hemagglutination-inhibiting antibodies to hev at 2 days of age. The level of circulating antibodies to hev decreased at a nonlinear rate and persisted for about 4 to 18 (mean 10.5) weeks in the circulation of pigs. All 40 pigs were seronegative at 20 weeks of age.
Extraction of viral DNA from erythrocytes of swine with acute African swine fever
Authors: Wesley Ronald D. , Quintero Julio C. , Mebus Charles A.
Published: February 2025

The preparation of wild-type African swine fever (asf) virus DNA from small amounts of viremic blood from acutely febrile pigs is outlined. The extracted DNA is viral and not host-cell DNA, because of specific homology with cell culture grown and purified asf virus and because no DNA bands are obtained with an equal amount of nonviremic pig blood. Thus, in the absence of suitable serologic methods for strain identification, it is now possible to catalogue wild-type isolates by characteristic DNA restriction patterns. The wild-type virus genome contains terminal single-stranded DNA cross-links and has the largest genome size (180 kilobase pairs) reported for the asf virus. Experimental passage of the virus in contact-infected pigs and buffy coat cultures appears to confirm the stable nature of the asf genome in the field.
Acute monensin toxicosis in sheep: Light and electron microscopic changes
Authors: Anderson T. D. , Van Alstine W. G. , Ficken M. D. , Miskimins D. W. , Carson T. L. , Osweiler G. D.
Published: February 2025

SUMMARY AND CONCLUSIONS

Monensin was administered orally to 3 sheep at dosages of 12 (the ld50), 16, and 24 mg/kg of body weight, respectively. Clinical signs of monensin toxicosis were observed in the sheep in 24 to 36 hours of administration. Clinical signs included cns depression, anorexia, diarrhea, and stiffness. Increased serum creatine phosphokinase and aspartate aminotransferase activities identified possible muscle damage. Sheep were euthanatized at 54 hours after dosing; at necropsy, there were skeletal muscle hemorrhages, pale myocardium, and pulmonary edema.

Ultrastructural lesions were in the liver, diaphragm, and myocardium; diaphragm and myocardium were most severely affected. Mitochondrial swelling and cristolysis, swollen sarcoplasmic reticulum, and disruption of myofibrillar architecture were prominent. These ultrastructural changes are consistent with the hypothesis that monensin causes muscle cell necrosis due to its ionophorous properties and disruption of cellular Na+:Ca2+ balance. It is proposed that this upset of normal ionic processes allows increased intracellular calcium, which directly leads to the functional and structural mitochondrial changes observed.
Critical test evaluations of oxfendazole and trichlorfon: Effectiveness of a paste formulation in the horse
Authors: Presson B. L. , Hamm D. , Yazwinski T. A. , Pote L. M.
Published: February 2025

Critical tests were performed on 6 horses to evaluate the antiparasitic effectiveness of oxfendazole given in combination with trichlorfon in a paste formulation. Treatments were given orally as a single dose. The rates of active ingredient administration were 2.5 and 40 mg/kg of body weight for oxfendazole and trichlorfon, respectively. The combined activities of the 2 antiparasitic compounds proved 100% efficacious in the removal of adult Strongylus vulgaris, S edentatus, Oxyuris equi, and Parascaris equorum. Fourth stage O equi, and 2nd and 3rd instars of Gasterophilus nasalis also were completely removed. Second and 3rd stage instars of G intestinalis were removed at the rates of 98.1% and 98.8%, respectively. Nematodes of the “small strongyle” category were removed at the combined rate of 97.0%.

Pronounced larvicidal effects of the test formulation were demonstrated via culturing fecal nematode eggs during the trial. Untoward effects of treatment were not seen in any of the trial animals.
Enhanced uptake of liposomes by bovine macrophages after opsonization with antibodies to Brucella abortus
Authors: Quelch V. , Reed K. R. , Erdos G. W. , Nicoletti P. L. , Hoffmann E. M.
Published: February 2025

Phosphatidylcholine:cholesterol liposomes containing 4(5) carboxyfluorescein were modified by incorporation of Brucella abortus lipopolysaccharide. These vesicles were opsonized with bovine anti-B abortus or anti-B abortus plus complement. The fluorescent marker entrapped in antibody-opsonized liposomes was taken up by cultured bovine macrophages more effectively than was the same compound which had been loaded into nonopsonized liposomes. The addition of bovine complement to antibody-opsonized liposomes did not increase the extent of 4(5) carboxyfluorescein uptake over that caused by antibodies alone.

The system, described in this report, could be used as a model for evaluation of the efficacy of selectively directing liposomes containing antibiotics to macrophages infected with intracellular B abortus, since macrophages possess Fc receptors capable of binding antibody-opsonized liposomes.
Immunoperoxidase localization of papillomaviruses in hyperplastic and neoplastic epithelial lesions of animals
Authors: Sundberg John P. , Junge Randall E. , Lancaster Wayne D.
Published: February 2025

In a retrospective study of selected hyperplastic and neoplastic epithelial lesions of wild, exotic, and domestic animals, paraffin sections from 438 biopsies and 15 necropsies were screened for the presence of papillomavirus structural antigens, using the peroxidase-antiperoxidase technique. Viral antigens were detected in tissues from 9 of 21 different mammalian, 1 of 5 avian, and 0 of 2 reptilian species. The latter tissues were histopathologically classified as papillomas, fibropapillomas, and fibromas and of canine origin (n = 6), squamous cell carcinoma. Virus could be readily detected by transmission electron microscopy in lesions that contained numerous nuclei which stained positively by the peroxidase-antiperoxidase technique.
Morbidity and mortality in neonatal kittens
Authors: Lawler Dennis F. , Monti Katherine L.
Published: February 2025

The mortality patterns of 294 Domestic Shorthair kittens indicated that birth weight was closely related to survivability.

Slightly over half of the nonsurviving kittens lost at 0 to 3 days of life were stillborn. Abnormal gross anatomy did not appear to be a major factor in neonatal kitten death. Mortality was lowest at the 5th parity and in litters of 5 kittens. Litters of 1 kitten experienced high mortality. Smaller queens tended to deliver fewer kittens per litter, but with improved kitten viability. Overweight queens experienced increased mortality of kittens. Further examination of mortality by litter size also revealed that low birth weight kittens tended to survive less often than normal birth weight kittens, even within the same litter.
Use of taste repellents and emetics to prevent accidental poisoning of dogs
Authors: Houpt Katherine , Zgoda James C. , Stahlbaum Cathi C.
Published: February 2025

Twelve taste repellents and 3 oral emetics were tested. The taste repellents were capsaicin, capsicum, oleoresin, sucrose octaacetate, quinine tonic, quassia wood extract, vanillamide, horseradish extract, caffeine, pepperoni enhancer, acorn extract, and commercially available bitter and hot flavors. The emetics tested were: antimony potassium tartrate, apomorphine, and copper sulfate. Intake of a 20% sucrose solution by Beagles was significantly depressed by addition of vanillamide at concentrations > 0.001%, by capsicum and capsaicin at concentrations > 0.01%, and by horseradish extract, pepperoni enhancer, and a commercially available hot flavor at concentrations > 0.1%. Antimony potassium tartrate, when added to the 20% sucrose solution at a concentration of 0.1%, produced emesis as did apomorphine at a concentration of 0.005% and copper sulfate at 1%. When the emetic antimony potassium tartrate was combined with vanillamide in a 20% sucrose solution, intake was reduced to < 20 ml, and vomiting occurred within 15 minutes. Capsaicin (0.02%) inhibited intake of ethylene glycol to less than the lethal dose in 5 dogs tested. Incorporation of such taste repellents and/or emetics into potentially poisonous substances would reduce accidental poisoning of animals and children.
Prevalence of enteric pathogens in the feces of healthy beef calves
Authors: Myers L. L. , Firehammer B. D. , Border Maryon M. , Shoop D. S.
Published: February 2025

Fecal specimens from 136 healthy beef calves (1 day to 12 weeks of age) were examined for the presence of infectious agents known to cause enteric disease in calves. The calves were selected from 22 herds in which all calves were free of clinically apparent enteric disease. Salmonella sp, enterotoxigenic Escherichia coli, Cryptosporidium, and coronavirus were not detected in any of the calves. Three calves were infected with rotavirus and 1 calf was infected with Yersinia enterocolitis. Campylobacter-like bacteria were isolated from 50 of 130 calves, with 36 of the calves positive for C jejuni. Seemingly, clinically normal calves may be infected more often with enterotoxigenic Ε coli, Cryptosporidium, coronavirus, or rotavirus in herds in which some calves have enteric disease than in herds free of major enteric disease. Campylobacter jejuni was well adapted to the bovine host and was of similar prevalence in diarrheal and nondiarrheal calves.

The K99 positive, nonenterotoxigenic Ε coli was isolated from the feces of 16 healthy calves. Information in addition to the presence of K99 antigen is useful when diagnosing enterotoxic colibacillosis in calves.
Neuromuscular and cardiovascular effects of pancuronium bromide in calves anesthetized with halothane
Authors: Hildebrand S. V. , Howitt G. A.
Published: February 2025

Pancuronium bromide was administered to calves to define the dosage level necessary to produce surgical relaxation (90% to 99% reduction of base-line evoked, hind-limb digital-extensor muscle twitch tension). Initial dosage level requirement was 43 ± 9 μg/kg of body weight. Calves with this degree of relaxation required 26 ± 14 minutes to achieve 50% recovery and 43 ± 19 minutes to achieve complete return of base-line muscle twitch. Calves given a repeat injection of pancuronium at base-line muscle twitch required 27 ± 9 μg/kg to achieve relaxation similar to that of the 1st dose. The 2nd dose did not last as long as the 1st, with complete recovery occurring in 37 ± 12 minutes. Maximum evoked tension occurred at 200-to 400-g resting tension on the hoof.

There was an absence of heart rate or blood pressure changes after injection of relaxant and a variable and inconsistent fade response to train-of-four and tetanic stimulus of the facial muscles. Acid-base values were alkalemic (pHa 7.5 ± 0.08) when ventilation was controlled at eucapnia (Paco2, 25 to 45 mm of Hg).
Inactivation of bovine leukemia virus-infected lymphocytes in milk
Authors: Rubino Michael J. , Donham Kelley J.
Published: February 2025

The survival of bovine leukemia virus (blv)-infected lymphocytes in milk was studied to determine whether treatments similar to those on a dairy farm would inactivate blv. Bovine leukemia virus was found in milk stored for 72 hours at 1.1 C (34 F); milk constituents, such as protein, total solids, minerals, fat, and somatic cell concentration did not affect the presence of blv. Infectivity also was found in the cream layer of milk. Pasteurization at 63 C for 30 minutes did inactivate blv-infected lymphocytes.
Experimental production of bovine respiratory tract disease with bovine viral diarrhea virus
Authors: Potgieter L. N. D. , McCracken M. D. , Hopkins F. M. , Walker R. D. , Guy J. S.
Published: February 2025

Five 6-month-old calves were inoculated with bovine viral diarrhea (bvd) virus (n = 3) or Pasteurella haemolytica (n = 2) endobronchially with a fiberoptic bronchoscope. Five additional calves were inoculated sequentially with bvd virus followed by Ρ haemolytica at a 5-day interval. Blood samples were collected daily from the calves for bacterial isolation. Clinical signs of respiratory tract disease in calves were recorded daily. If the calves survived, they were killed for necropsy 3 or 4 days after inoculation with Ρ haemolytica (or 8 days after inoculation with bvd virus). The extent and nature of pulmonary lesions in the calves were determined, and the lower portion of the respiratory tract (lungs and trachea) was examined for both these organisms.

The 3 calves, inoculated with bvd virus only, developed mild clinical signs mainly manifested as fever, nasal discharge, and occasional cough. Approximately 2% to 7% of the total lung capacity of these calves was pneumonic. Mild clinical signs and localized lesions involving about 15% of the lung volume developed in the 2 calves exposed to Ρ haemolytica only. However, severe fibrinopurulent bronchopneumonia and pleuritis involving 40% to 75% of lung volume developed in the 5 calves inoculated sequentially with bvd virus and Ρ haemolytica. The possible role bvd virus may have in bovine respiratory tract disease is discussed.
Topographic distribution of pulmonary ventilation and perfusion in the horse
Authors: Amis T. C. , Pascoe John R. , Hornof W.
Published: February 2025

The regional distribution of ventilation to perfusion ratios (V̇A/Q̇) in the lungs of 8 healthy standing Thoroughbred geldings (4.4 ± 1.5 years, 465.7 ± 46.6 kg) was studied, using steady-state inhalation and iv infusion of the radioactive gas krypton-81m. The V̇A/Q̇ was uniformly distributed within a vertical lung strip centered over the 9th rib on the right side. Ventilation per unit of alveolar volume (V̇/VA) assessed from the clearance of inhaled radioactive gas in 5 horses increased from 0.49 ± 0.13 (arbitrary units) in nondependent lung zones to 1.45 ± 0.16 in dependent lung zones. Seemingly, a vertical gradient of pulmonary ventilation exists in the horse that is matched by a similar gradient of perfusion.
Prevalence of Onchocerca cervicalis in equids in the Gulf Coast region
Authors: Klei Thomas R. , Torbert Betty , Chapman Melanie R. , Foil Lane
Published: February 2025

Microfilariae of Onchocerca cervicalis were detected in midventral skin biopsy samples in 64 of 84 (76%) mixed-breed ponies > 2 years old from the Gulf Coast area and in 42 of 51 (82.4%) horses from Louisiana breeding herds. The number of microfilariae per 8 mm of biopsied skin (ponies) ranged from 1 to 21,570. The number of microfilariae per 6 mm of biopsied skin (horses) ranged from 8 to 55,600.
Enzyme-linked immunosorbent assay for detection of transmissible gastroenteritis virus antibody in swine sera
Authors: Nelson L. D. , Kelling C. L.
Published: February 2025

An enzyme-linked immunosorbent assay (elisa) was developed for detection and quantification of serum antibodies to transmissible gastroenteritis virus (tgev) in swine. Sera from pigs inoculated with cell culture-origin tgev or gut-origin tgev were tested for anti-tgev antibody by elisa and by serum virus-neutralization test (nt). The elisa detected antibody 3 days (av) sooner than did the nt when sera from pigs inoculated with cell culture-origin tgev were tested and 1 day sooner than did the nt when sera from pigs inoculated with gut-origin tgev were tested. The elisa appeared to be more sensitive than the nt, since elisa was more responsive to low-level antibody and elisa titers exceeded nt titers.
Interaction of bovine respiratory syncytial virus and Pasteurella haemolytica in the ovine lung
Authors: Trigo F. J. , Breeze R. G. , Liggitt H. D. , Evermann J. F. , Trigo E.
Published: February 2025

The potential synergistic effect of bovine respiratory syncytial virus (rsv) and Pasteurella haemolytica in the production of pneumonia after aerosol/intranasal infection of conventionally reared lambs was evaluated.

A mild clinical response was observed in lambs given virus and/or bacteria. Gross pulmonary lesions were seen in 3 of 6 lambs given rsv and then P haemolytica 3 or 6 days later, respectively (groups D and E), and in 1 lamb of 5 given virus and bacteria simultaneously (group G). Gross lesions were not seen in control sheep (group A), in lambs given virus or bacteria alone (groups B and C), or in lambs exposed to bacteria and then virus 3 days later (group F).

Bovine rsv and P haemolytica were recovered from the lungs of 5 of 7 lambs with macroscopic lesions. Gross pulmonary lesions were cranioventral firm areas of red consolidation. Microscopically, the predominant lesion was a suppurative bronchopneumonia. Bovine rsv was recovered from the nasal cavity of 8 of 27 (30%) lambs given rsv during days 3 to 6 after viral inoculation, including 1 lamb in group B, 2 in groups D, E, and F, and 1 in group G. Pasteurella haemolytica was recovered from the nasal cavity of 9 of 28 (32%) inoculated lambs, including 2 lambs from groups C and E, 3 in group D, and 1 in groups F and G.

Viral antigen, as determined by immunofluorescence, was concentrated mainly in individual cells in alveolar walls, some alveolar macrophages, and a few bronchiolar epithelial cells. In vitro alveolar macrophage assays indicated decreased numbers of Fc receptors on those macrophages collected from lambs given rsv 6 days before P haemolytica infection, as compared with that in the other groups. These cellular defects disappeared after 24 hours of culture.

Seemingly, bovine rsv does facilitate P haemolytica pulmonary infection in conventional, immunocompetent lambs and provides evidence for decreased Fc receptors on alveolar macrophages.
Effects of furosemide on the plasma and urinary concentrations and the excretion of fentanyl: Model for the study of drug interaction in the horse
Authors: Soma Lawrence R. , Korber Kerry , Anderson Thaddeus , Hopkins Judy
Published: February 2025

The effects of furosemide (0.55 mg/kg iv) on the plasma and urinary fentanyl (PFE UFE) concentrations were studied during steady-state conditions. The PFE during the steady-state period was 0.31 ± 0.027 ng/mlFE, with no significant changes occurring, even though the rate of excretion of fentanyl (EX) increased during the 1st hour from 112.0 ± 21.6 to 534.5 ± 82.9 ng/minute. The EX returned to control levels within 3 hours, as did the UFE.

The injection of furosemide increased glomerular filtration rate from 1.97 ± 0.21 to 3.81 ± 0.75 ml/kg/min. The fractional reabsorption decreased from a control of 70.3 ± 6.2% to 25.2 ± 2.3% during the 1st hour, returning to control levels at 3 hours after furosemide was given. The total body clearance of fentanyl increased slightly during the peak period of diuresis. The return of EX, fractional reabsorption, UFE, and clearance of endogenous creatinine to control levels occurred before the return of urine specific gravity, indicating the ability of the kidney to concentrate fentanyl before its water concentrating capacity had returned.