bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of early lactation milk yield on reproductive disorders in dairy cows
Authors: Gröhn Yrjö T. , Hertl Julia A. , Harman Jane L.
Published: January 2024

Association between individual cumulative milk yield and various reproductive disorders in 56,772 Finnish Ayrshire cows belonging to 5,912 herds in 80 communities was studied. All cows delivered calves between September 1985 and September 1986.

Five logistic regression models were fitted, 1 for each outcome disorder of interest: early metritis, late metritis, silent heat, ovarian cyst, and other infertility. Cumulative individual 37-day milk yield was used in the early metritis model, and cumulative individual 60-day milk yield was used in the other models, on the basis of median days in milk when these disorders developed. Cumulative 305 - day herd milk yield, parity, calving season, presence or absence of other disorders, and community were also included in the models. Point estimates from the models represented odds ratios for the likelihood of having the outcome disorder.

Lactational incidence risks for the 5 reproductive disorders studied were: early metritis (2.4%), late metritis (1.1 %), silent heat (5.4%), ovarian cyst (6.6 %), and other infertility (2.1 %). The risk of early metritis decreased with increasing 37-day milk yield. The risk of silent heat, ovarian cyst, and other infertility increased with increasing 60-day milk yield; 60-day milk yield had no effect on late metritis. The 305-day herd milk yield increased the risk of early metritis, ovarian cyst, and other infertility; it had no effect on late metritis or silent heat.

Parity had an effect on all disorders, except late metritis. Cows that delivered calves during the colder, darker seasons of the year had a higher risk of reproductive disorders than did those that delivered calves at other times of the year. A number of other disorders, reproductive and otherwise, were significant predictors of development of the outcome disorders.
Comparison of body surface area-based and weight-based dosage protocols for doxorubicin administration in dogs
Authors: Arrington Kathryn A. , Legendre Alfred M. , Tabeling Gretchen Simpson , Frazier Donita L.
Published: January 2024

Pharmacokinetics and toxicity of a single dose of doxorubicin, at dosages of 30 mg/m2 of body surface area and 1 mg/kg of body weight, were compared in 17 dogs. Effects of doxorubicin on complete blood cell count, platelet count, and the dogs' clinical condition were evaluated for 14 days. Cluster analysis, on the basis of clinical signs of doxorubicin toxicosis at the 30- mg/m2 dosage, revealed that 6 of 7 small dogs (≤ 10 kg) became ill, whereas 7 of 10 large dogs (> 10 kg) remained clinically normal. Small dogs that received doxorubicin at a dosage of 30 mg/m2 had higher peak plasma concentrations, greater area under the curve for plasma drug concentration vs time, longer drug elimination half - lives, greater volumes of distribution, and more clinical signs of toxicosis than had large dogs (P ≤ 0.05). Five of 9 small dogs that received doxorubicin at a dosage of 30 mg/m2 developed severe myelosuppression (<1 × 103 granulocytes/μl). In contrast to the toxicoses with body surface area - based dosing, myelosuppression was not induced in small dogs that received doxorubicin at a dosage of 1 mg/kg. In small and large dogs given doxorubicin at a dosage of 1 mg/kg, pharmacokinetic characteristics and clinical signs of toxicosis were similar. Mean wbc counts and granulocyte counts for all dogs were lower on day 7 with 30 mg of doxorubicin/m2 (n = 17), compared with that for 1 mg of doxorubicin/kg (n = 14; P ≤ 0.01).This study indicated that a body weight - based (milligram per kilogram) dosing regimen may result in more uniform therapeutic and toxic responses in dogs. Limited toxicosis was observed in dogs weighing > 10 kg treated with doxorubicin with either dosing scheme; however, differences in pharmacokinetic profiles suggested that 1 mg/kg may be an inappropriately low dosage.
Evaluation of the single-injection plasma disappearance of technetium-99m mercaptoacetyltriglycine method for determination of effective renal plasma flow in dogs with normal or abnormal renal function
Authors: Itkin Randall J. , Krawiec Donald R. , Twardock A. Robert , Gelberg Howard B. , Koritz Gary D.
Published: January 2024

Effective renal plasma flow (erpf) was evaluated, using continuous-infusion p-aminohippurate clearance (clpah) and single-injection plasma clearance of technetium-99m mercaptoacetyltriglycine (99mTc-MAG3; clmag3) methods. Simultaneous clearance determinations were made in 6 dogs: 2 determinations for each dog before, and 1 determination after renal failure was induced by administration of amphotericin B. Linear regression analysis was used to derive an equation to estimate erpf from clmag3 after the single iv injection. A Student’s t-test was used to compare pharmacokinetics between the dogs when they were healthy and when they were in renal failure. An F-test was used to determine the appropriate Student’s t-test. Results indicated that clmag3 correlated reasonably well (r = 0.83, P < 0.0001) with erpf obtained from the clpah value. The volume of distribution and elimination of 99mTc-MAG3 decreased during renal failure. Although there was minimal binding of 99mTc-MAG3 to erythrocytes, it was significantly (P = 0.0008) lower during renal failure. Protein binding was not significantly different during renal failure. All dogs had signs of nausea and emesis at variable times after injection of 99mTc-MAG3. Determination of clmag3 after a single injection provides an adequate means to rapidly assess erpf in dogs. The technique could easily be performed in dogs with renal disease, thus providing valuable information regarding progression of naturally acquired renal failure.
Effects of subject stance time and velocity on ground reaction forces in clinically normal Greyhounds at the trot
Authors: McLaughlin Ronald M. , Roush James K.
Published: January 2024

Force plate gait analysis was used to study the effects of subject stance time and velocity on ground reaction forces in 6 adult Greyhounds at the trot. Data for 210 valid trials were obtained. Stance time negatively correlated with velocity (r = −0.85 for the forelimbs, r = −0.61 for the hind limbs), decreasing as velocity increased. Stance time in the forelimbs and hind limbs correlated more closely with changes in vertical peak force and impulse than did velocity. The trials were divided into 3 distinct velocity ranges (V1 = 1.5 to 1.8 m/s, V2 = 2.1 to 2.4 m/s, and V3 = 2.7 to 3.0 m/s), 3 distinct forelimb stance time ranges (fst1 = 0.144 to 0.176 second, fst2 = 0.185 to 0.217 second, and fst3 = 0.225 to 0.258 second), and 3 distinct hind limb stance time ranges (hst1 = 0.105 to 0.132 second, hst2 = 0.139 to 0.165 second, and hst3 = 0.172 to 0.198 second). Peak forces increased as velocity increased and decreased as stance time increased. Vertical impulse decreased as velocity increased and increased as stance time increased. The relation between stance time, subject velocity, and ground reaction forces was documented for clinically normal Greyhounds at the trot. Changes in stance time accurately reflected changes in subject velocity and ground reaction forces in clinically normal dogs and could be used to normalize trial data within a sampling period.
Prevalence of aerobic bacteria in bronchoalveolar lavage fluids from healthy pigs
Authors: Hensel Andreas , Ganter Martin , Kipper Sabine , Krehon Silvester , Wittenbrink Max M. , Petzoldt Klaus
Published: January 2024

Fiberoptic bronchoscopy was performed in pigs to assess bacterial contamination of bronchoalveolar lavage fluids (balf) obtained by use of the method and to determine the aerobic bacterial species in bronchoalveolar airways of healthy pigs. Bacterial contamination of balf caused by insertion of the bronchoscope was evaluated, using a chromogenic bacterial tracer strain, and was found to be 0.22% of total colony-forming units (cfu), with range between 0 and 1.6%. A total of 164 pulmonary-healthy pigs from 6 closed herds were selected. The balf obtained from these pigs were examined bacteriologically. Bacteria could not be isolated from 10.4% of all balf; 5.5% of the balf samples yielded pure cultures; and 84.1% yielded mixed aerobic bacterial growth. In balf from 29.2% of the pigs, ≤ 5 × 102 cfu of bacteria/ml were isolated. The total number of bacteria in balf from 50% of the pigs varied between 5 × 102 and 103 cfu/ml; 10.4% of balf samples contained between 103 cfu/ml and 5 × 103 cfu/ml. More than 1 bacterial species were isolated from a single lung lavage of 84.1% of the pigs. Up to 6 species were isolated from a single balf sample. A total of 443 bacterial isolates were differentiated into 25 bacterial genera and species. Samples of balf yielded staphylococci (67.6%: Staphylococcus hyicus from 13.4% of the samples and S aureus from 2.4%), α-hemolytic streptococci (49.4%), Escherichia coli (42.1%), non-hemolytic streptococci (26.2%), Klebsiella spp (18.3%), micrococci (12.8%), and Coryneformes (11.0%). Other bacterial species were found, but less frequently. In our study, balf from all pigs yielded < 5 × 103 cfu/ml. Thus, low numbers of bacteria known to be facultative pathogens were isolated from balf without causing detectable pneumonia.
Effects of vincristine and prednisone on platelet numbers and function in clinically normal dogs
Authors: Mackin Andrew J. , Allen Dana G. , Johnstone Ian B.
Published: January 2024

Effects of a single iv administered therapeutic dose of vincristine sulfate on platelet numbers and function were evaluated in 16 clinically normal dogs over the 2 weeks after drug administration. Results were statistically compared with those of a previous control study in which the same 16 dogs were administered saline solution (iv), instead of vincristine. Of the 16 dogs, 8 were orally administered daily immunosuppressive doses of prednisone concurrently throughout the saline-control and vincristine study periods. Platelet numbers and mean platelet volume were measured, using an automated hematology analyzer. Platelet function was evaluated by turbidimetric measurement of platelet aggregation in response to collagen, platelet-activating factor, and adenosine diphosphate (adp), and by clot retraction (diluted whole-blood method) and buccal mucosa bleeding time.

Vincristine had a significant (P < 0.05) effect on circulating platelet numbers. Vincristine induced a transient mild decrease in platelet numbers, followed by a moderate increase in numbers, with peak platelet count observed 8 days after drug administration. Mean platelet volume was not significantly affected by administration of vincristine.

Vincristine had no significant effects on platelet aggregation in response to collagen, low or high doses of platelet-activating factor, and a high dose of adp. The maximal degree of platelet aggregation attained in response to a low dose of adp was not significantly affected by prior administration of vincristine. The maximal rate of platelet aggregation induced by a low dose of adp after vincristine administration, however, was significantly (P < 0.05) lower than the rate of aggregation induced by a similar dose of adp in the previous control study. Vincristine had no significant effects on clot retraction and bleeding time. Prednisone did not significantly affect platelet numbers and function, and did not modify vincristine's effects on the same variables.
Effect of venipuncture sites on hematologic and clinical biochemical values in desert tortoises (Gopherus agassizii)
Authors: Gottender Nicole L. , Jacobson Elliott R.
Published: January 2024

Paired blood samples were collected from the postoccipital venous plexus and jugular vein of desert tortoises (Gopherus agassizii) for hematologic and plasma biochemical analyses. Comparison of hematologic values revealed significantly (P ≤ 0.05) lower pcv, rbc count, wbc count, and hemoglobin values for samples obtained from the occipital site. When comparisons were made between plasma biochemical values for the 2 sites, significant (P ≤ 0.05) differences were measured for: glucose, potassium, chloride, uric acid, calcium, phosphorous, total protein, albumin, globulin, alkaline phosphatase, aspartate transaminase, alanine transaminase, and total cholesterol. Significant differences between hematologic and plasma biochemical values from the occipital region samples vs jugular vein samples were attributed to hemodilution of the occipital region samples with extravascular fluid or lymph or both.
Aggregate risk study of exposure to endophyte-infected (Acremonium coenophialum) tall fescue as a risk factor for laminitis in horses
Authors: Rohrbach Barton W. , Green Eleanor M. , Oliver Jack W. , Schneider John F.
Published: January 2024

Loline and ergot alkaloids found in endophyte-infected (Acremonium coenophialum) tall fescue (eitf) cause vasoconstriction of equine vessels in vitro. An aggregate risk study was used to evaluate the association between horses exposed to eitf and development of laminitis. Veterinary teaching hospitals participating in the Veterinary Medical Data Base were grouped by whether equine accessions were likely to have been at high, moderate, or low risk for exposure to eitf. From 1980-1990, there were 185,781 accessions, of which 5,536 had diagnosis of laminitis. Proportion of equine accessions with laminitis reported by veterinary teaching hospitals for high, moderate, and low risks, were 3.41, 3.04, and 2.00 cases/100 accessions, respectively (P < 0.0001). Comparison of the proportion of accessions with laminitis in the high- and moderate-risk groups with that in the low-risk group revealed significant differences between risk groups over all months (P = 0.063) and differences from month to month within risk groups (P = 0.0001). If the difference among risk groups is attributed entirely to exposure to eitf, the population-attributable risk is 7 cases/1,000 admissions, or 15% of all admissions for laminitis at veterinary teaching hospitals in our data base. Preliminary data support an association between horses exposed to eitf and increased risk of laminitis; however, studies at the individual animal level are indicated to confirm this hypothesis.
Investigation of pseudorabies virus DNA and RNA in trigeminal ganglia and tonsil tissues of latently infected swine
Authors: Cheung Andrew K.
Published: January 2024

Pseudorabies virus (prv) nucleic acids in the trigeminal ganglia and tonsils of swine latently infected with the virus were analyzed. By use of dna-polymerase chain reaction (pcr), 14 of 14 trigeminal ganglia and 12 of 14 tonsils were positive for prv genomes. By use of rna-pcr, rna containing the large latency transcript splice junction were detected in 4 of 4 trigeminal ganglia and 4 of 5 tonsils. In general, results of both pcr procedures indicated that the amounts of prv dna and rna per microgram of cellular nucleic acids were higher in trigeminal ganglia than in tonsils.

Identification of peripheral tissues that harbor latent prv is an important asset for prv research. The presence of large latency transcript in tonsil tissues, in the absence of virus replication, is a critical characteristic, which indicates that the tonsil is a site of prv latency. For diagnostic purposes, animals need not be euthanatized to obtain their nervous tissue to determine latency; instead, tonsil biopsy specimens could be obtained from live animals for analysis. For pathogenesis studies, multiple specimens obtained sequentially from the same animal would be available for examination for the duration of the experiment.
Ultrasonographic morphology of the bicipital tendon and bursa in clinically normal Quarter Horses
Authors: Crabill Mark R. , Chaffin M. Keith , Schmitz David G.
Published: January 2024

The bicipital tendons and bursae of 25 healthy adult Quarter Horses were ultrasonographically examined. Cross-sectional images of the right and left bicipital tendons were obtained from each horse, using a 7.5-MHz transducer held in the frontal plane at the point of the shoulder. The bicipital tendon at the point of the shoulder appeared as a bilobate structure overlying the echogenic surface of the humerus. Median distance from the skin surface to the cranial surface of the tendon on the medial sagittal plane of the tendon was 23 mm (range, 16.5 to 30 mm); median distance on the lateral sagittal plane was 14 mm (range, 8.5 to 19 mm). Median distance from the skin surface to the tendon on the midsagittal plane of the tendon was 17 mm (range, 10.5 to 22 mm). Median cranial-to-caudal widths of the lateral and medial lobes of the tendon at their greatest dimensions were 20.5 mm (range, 18 to 27.5 mm) and 16 mm (range, 13 to 20.5 mm), respectively. The median cranial-to-caudal width of the central (midsagittal) portion of the tendon was 10 mm (range, 7 to 13.5 mm). The bicipital bursa was ≤ 3 mm wide at all locations at which it was measured. Ultrasonographic imaging was easily performed and allowed evaluation of the bicipital tendon, bursa, and surface of the underlying humerus.
Effect of auriculopalpebral nerve block and intravenous administration of xylazine on intraocular pressure and corneal thickness in horses
Authors: van der Woerdt A. , Gilger B. C. , Wilkie D. A. , Strauch S. M.
Published: January 2024

Intraocular pressure (iop) was measured, using applanation tonometry, in both eyes of 20 horses after topical application of 0.5% proparacaine to the cornea. Ultrasonic pachymetry was used to measure central, mid-peripheral, and peripheral corneal thickness (ct) in all 4 quadrants of both eyes of 25 horses. All measurements were repeated after auriculopalpebral nerve block, sedation by iv administration of xylazine, or combination of nerve block and sedation. Mean iop after topical anesthesia of the cornea was 20.6 ± 4.7 mm of Hg for the left eye and 20.35 ± 3.7 mm of Hg for the right eye. Mean central ct was 793.2 ± 42.3 μm. The peripheral part of the cornea was significantly (P < 0.05) thicker, on average, than the central part of the cornea. Auriculopalpebral nerve block had no significant effect on iop or ct. Intravenous administration of xylazine resulted in a significant (P < 0.05) decrease in iop, but had no effect on ct.
Antiphagocytic properties of uterine isolates of Streptococcus zooepidemicus and mechanisms of killing in freshly obtained blood of horses
Authors: Causey Robert C. , Paccamonti Dale L. , Todd William J.
Published: January 2024

A total of 22 clinical streptococcal isolates, pre-dominantly Streptococcus zooepidemicus, associated with endometritis in horses were tested for their ability to withstand the natural bactericidal properties of freshly obtained blood. During a 3-hour incubation in blood from a single horse, 8 of these isolates survived and grew; the remainder were killed. To determine whether this ability to grow extended to blood of other horses, 5 of these growing isolates were tested for their ability to grow in the blood of 5 additional horses. The same 5 horses were used for each isolate. The isolates grew in blood of some of the horses, but were killed in blood of the others. However, the horse’s blood that mediated killing was different for each isolate. Killing required leukocytes, but the specificity for killing appeared to reside in plasma, although plasma by itself was not bactericidal. Heatstable and heat-labile components in plasma, interpreted as antibody and complement, respectively, appeared necessary for killing. Isolates that could grow in fresh blood lost this ability after 10 passages in artificial media. Results of these experiments of phagocytosis in fresh blood may provide helpful insights into the phagocytosis of S zooepidemicus in equine uterine fluid.
Tissue and serum enzyme activities in the yellow rat snake (Elaphe obsoleta quadrivitatta)
Authors: Ramsay Edward C. , Dotson Thomas K.
Published: January 2024

Activities of diagnostically important enzymes were measured in serum and lysates of liver, kidney, skeletal muscle, heart, intestine, lung, and pancreatic tissues from wild-caught yellow rat snakes, Elaphe obsoleta quadrivitatta. All samples were analyzed for alkaline phosphatase, lactate dehydrogenase (ld), aspartate transaminase (ast), alanine transaminase, γ-glutamyltransferase, and creatine kinase (ck) activities. The major enzyme activities found in the liver were ld and ast. The kidney had moderate activities of ld, ast, alanine transaminase, and ck. Skeletal muscle and heart contained high ck activity. Intestine, lung, and pancreas had low activities for most enzymes analyzed. Little to no γ-glutamyltransferase activity was found in serum or tissues analyzed. Serum enzyme activities in yellow rat snakes were similar to those described for other reptile species, except for serum ck activity, which was increased in rat snakes.
Microvascular permeability and endothelial cell morphology associated with low-flow ischemia/reperfusion injury in the equine jejunum
Authors: Dabareiner Robin M. , Snyder Jack R. , White Nathaniel A. , Pascoe John R. , Harmon Faye A. , Gardner Ian , Woliner Michael J. , Pinney Diane , Sullins K. E.
Published: January 2024

Microvascular permeability of the jejunum of clinically normal equids and microvascular permeability associated with 60 minutes of ischemia (25% baseline blood flow) and subsequent reperfusion were investigated. Eight adult horses were randomly allotted to 2 equal groups: normal and ischemic/reperfusion injury. Lymphatic flow rates, mesenteric blood flow, and lymph and plasma protein concentrations were determined at 15-minute intervals throughout the study. Microvascular permeability was determined by estimates of the osmotic reflection coefficient, which was determined when the ratio of lymphatic protein to plasma protein concentration reached a constant minimal value as lymph flow rate increased (filtration-independent lymph flow rate), which occurred at venous pressure of 30 mm of Hg. Full-thickness jejunal biopsy specimens were obtained at the beginning and end of each experiment, and were prepared for light microscopy to estimate tissue volume (edema) and for transmission electron microscopy to evaluate capillary endothelial cell morphology.

The osmotic reflection coefficient for normal equine jejunum was 0.19 ± 0.06, and increased significantly (P < 0.0001) to 0.48 ± 0.05 after the ische- mia/reperfusion period. Microscopic evaluation revealed a significant increase (P < 0.0001) in submucosal and serosal volume and capillary endothelial cell damage in horses that underwent ischemia/reperfusion injury. Results indicate that ischemia/re-perfusion of the equine jejunum caused a significant increase in microvascular permeability.
Ultrastructural study of unidentified inclusions in the cornea and iridocorneal angle of dogs with pannus
Authors: Rapp Eva , Kölbl Sylvia
Published: January 2024

The corneas and/or the iridocorneal angles of 13 dogs were examined morphologically by use of transmission electron microscopy. Virologic identification techniques also were used for tissue from 2 dogs. Four dogs had clinical signs of chronic superficial keratitis or pannus, 9 dogs had normal eyes.

In the tissue from 7 dogs (4 German Shepherd Dogs with chronic superficial keratitis; 2 German Shepherd Dogs and 1 mixed-breed dog with normal eyes) we found unusual cytoplasmic inclusions. Inclusions were not found in dogs of other breeds with normal eyes. The inclusions were observed in comeal fibroblasts, vascular endothelial cells, and macrophages, as well as in trabecular cells and fibroblasts of the iridocorneal angle. They were often grouped within the rough endoplasmic reticulum or found free in the cytoplasm. The cylindrical particles had a helical substructure, measuring 20 nm in diameter and up to 400 nm long, with a distance of 10 nm for the repeating turns.

Results of virologic culturing on canine and seal kidney cells were negative, as was staining with fluorescein isothiocyanate-labeled antibodies against canine distemper virus, canine herpesvirus, canine parvovirus, and canine adenovirus.

Relevance of the inclusion bodies described is discussed. Because our results seem to hint at a correlation between presence of the rod shaped particles and German Shepherd Dogs with pannus, we suggest that an etiologic or pathogenic connection exists that merits further examination.
Comparison of a radioimmunoassay (Charm II) test with high-performance liquid chromatography for detection of oxytetracycline residues in milk samples from lactating cattle
Authors: Moats William A. , Anderson Kevin L. , Rushing John E. , Wesen Donald P.
Published: January 2024

A radioimmunoassay test for tetracyclines (Charm II) was compared with high-pressure liquid chromatography (hplc) for detection of oxytetracycline (otc) residues in milk samples from individual lactating cows. Oxytetracycline was administered by 1 of 3 routes (IV, IM, or intrauterine) to 21 lactating dairy cows. A total of 292 duplicate milk samples were collected from milkings before and through 156 hours after otc administration. Concentration of otc in these samples was determined by use of the Charm II test and an hplc method with a lower limit of quantitation, approximately 2 ng of otc/ml. Samples were also classified with respect to presence of otc residues relative to the fda safe concentration (< 30 ng/ml), using the Charm II (by control point determination) and hplc methods.

There was a significant (P < 0.05) difference between test methods in classification of milk samples with respect to presence or absence of otc at the fda safe concentration. A total of 48 of the 292 test results (16.4%) did not agree. Using the hplc test results as the standard with which Charm II test results were compared, 47 false presumptive-violative test results and 1 false presumptive-nonviolative Charm fi test result (a sample containing 31 ng of otc/ml, as evaluated by hplc) were obtained. The samples with false presumptive-violative Charm fi results contained < 30 ng of otc/ml, as evaluated by hplc.

In some respects, the Charm H test performed appropriately as a screening test to detect otc residues in milk samples from individual cows. However, the tendency for the test to yield presumptive-violative test results at otc concentrations lower than the fda safe concentration (as evaluated by hplc), suggests that caution should be exercised in using the test as the sole basis on which a decision is made to reject milk. As indicated by the manufacturer, presumptive-violative Charm II test results should be confirmed by additional testing. Although not specifically evaluated, the tendency for misclassification of milk samples as presumptive-violative by the Charm II test may or may not occur in commingled milk, compared with milk samples from individual cows.
Evaluation of in vitro cytotoxicity of nonsteroidal anti-inflammatory drugs against canine tumor cells
Authors: Knapp Deborah W. , Chan Thomas C. K. , Kuczek Thomas , Reagan William J. , Park Beth
Published: January 2024

Piroxicam and other nonsteroidal anti-inflammatory drugs (nsaid) have antitumor activity against naturally acquired cancer in dogs and human beings, and against experimentally induced tumors in rodents. We are investigating potential mechanisms of nsaid antitumor activity. The direct cytotoxicity of piroxicam, indomethacin, and aspirin against 4 canine tumor cell lines (transitional cell carcinoma, squamous cell carcinoma, melanoma, and soft tissue sarcoma) was determined in short-term growth rate assays and in clonogenic assays. Piroxicam was evaluated alone and in combination with the lipoxygenase inhibitor zileuton, and in combination with the chemotherapeutic agents cisplatin and carboplatin. The 50% inhibitory concentrations (lC50) against melanoma cells in short-term growth rate assays were: 530 μM piroxicam, 180 μM indomethacin, and greater than 1 mM aspirin. These IC50 values were over 10 times greater than serum concentrations of these drugs that could safely be achieved in vivo. The IC50 of zileuton combined with piroxicam (280 μM) was not different from the IC50 of zileuton alone (230 μM; anova P = 0.47) in melanoma cells. Similarly, addition of piroxicam did not alter the IC50 of either cisplatin (1.6 μM) or carboplatin (6.1 μM). These results suggest that nsaid, at serum concentrations achievable in vivo, do not have direct cytotoxicity against canine tumor cells tested. It is unlikely that the in vivo antitumor activity of nsaid is attributable to a direct cytotoxic effect.
Comparison of the stride kinematics of the collected, medium, and extended walks in horses
Authors: Clayton Hilary Mary
Published: January 2024

Six horses, highly trained for dressage competition, were used to study the stride kinematics of the walk, and to compare the kinematics of the collected, medium, and extended walks. Horses were filmed in a sagittal plane at a rate of 150 frames/s; temporal, linear, and angular data were extracted from the films. Results of anova and Duncan's multiple range test indicated that the speed of the collected walk (1.37 m/s) was significantly (P < 0.01) slower than that of the medium (1.73 m/s) and extended (1.82 m/s) walks, values for which were not significantly different from each other. The increase in speed was associated with a significant increase in stride length, from 157 cm in the collected walk to 193 cm in the extended walk. This was a result of an increase in the over-tracking distance, whereas there was no significant difference in the distance between lateral placements of the limbs. Stride duration decreased (P < 0.01) from the collected walk (1,159 ms) to the extended walk (1,064 ms). Angles of the metacarpal and metatarsal segments, measured on the palmar/plantar aspect, were higher at impact and lower at lift off in the collected than in the extended walk (P < 0.01). This indicated greater range of angular motion of this segment during the stance phase in the extended walk. Only 1 of the 6 horses had a regular 4-beat rhythm of the footfalls, with equal time elapsing between the lateral and diagonal footfalls.
Colonization of the tonsils and nasopharynx of calves by a rifampicin-resistant Pasteurella haemolytica and its inhibition by vaccination
Authors: Frank Glynn H. , Briggs Robert E. , Zehr Emilie S.
Published: January 2024

A rifampicin-resistant Pasteurella haemolytica serotype 1 with 2 added plasmids was used as a colonization-challenge strain in calves to test the resistance to colonization elicited by vaccination. Nine calves were vaccinated with a tissue culture-derived P haemolytica serotype-1 vaccine which, in a prior study, had elicited a serotype-specific inhibition of nasal and tonsillar colonization by the homologous serotype under field conditions. The vaccinates and 9 nonvaccinated control calves were exposed by tonsillar instillation with the challenge strain. The P haemolytica were enumerated in nasal secretion and tonsil wash specimens collected biweekly for 3 weeks. Rifampicin-supplemented agar medium inhibited growth of other bacterial species in the specimens and, thus, increased the sensitivity of detection of the challenge P haemolytica by 100-fold. The challenge strain retained its plasmids during the period of colonization. Inhibition of colonization was evidenced by lower frequency of isolations and fewer isolations of the challenge strain from nasal secretion and tonsil wash specimens of the vaccinates than from those of the nonvaccinates.
Evaluation of health and ruminal variables during adaptation to grain-based diets in beef cattle
Authors: Leedle Jane A. Z. , Coe Michael L. , Frey Russell A.
Published: January 2024

Health and ruminal variables were intensively measured during adaptation to grain-based diets in 6 beef cattle with fistulated rumens. The cows had been maintained on prairie grass hay-supplemented diets, and were converted to a grain-based finishing ration by feeding each successive diet (diets 1-4, respectively) for a period of 7 days. Each cow was evaluated and samples were obtained 3 times each day for the first 5 days that each diet was fed. Health variables monitored were rectal temperature, pulse, respiratory and rumen motility rates, fecal consistency, demeanor, blood pH, and blood glucose and l(+) lactate concentrations. Ruminal variables monitored were pH and glucose, dl-lactate, and volatile fatty acid concentrations of rumen contents. Data were analyzed by use of a multivariate anova. We determined that most of the health variables were within reference range limits throughout the adaptation period; however, analysis of pulse and respiratory rates indicated that diets 2 and 4 were stressful. Although blood pH continually decreased during feeding of the 4 diets (7.38 to 7.30), blood l(+) lactate and glucose concentrations had large increases only within diet 4. The pH of ruminal contents decreased progressively from 6.8 to 5.3. Rumen glucose concentration was low (< 1 μmol/ml), except with diet 4 in which values were 8 times higher than for other diets. By the end of the study, the ruminal contents of all animals were acidic (pH < 5.5), and, on the basis of higher than background amounts of ruminal glucose and dl-lactate, it was determined that rumen microbial equilibrium had not yet been achieved. Analysis of results of this study suggested that ruminal imbalance could be evaluated by monitoring pulse and respiratory rates, blood pH, and blood glucose concentrations.Assessment of the rumen alone could be accomplished by monitoring the variables of rumen pH, rumen glucose, and dl-lactate concentrations. Respiratory rate, blood and rumen content pH, and blood l(+) lactate concentrations were significantly (P < 0.001) affected by time after feeding.
Subcellular biochemical changes during the development of the small intestine of pony foals
Authors: Batt R. M. , Burgess D. , Edwards G. B. , van de Waal S. , Sørensen S. H. , Hart C. A.
Published: January 2024

To examine the postnatal development of equine small intestine, biopsy specimens of jejunal mucosa from 8 ponies, between 6 and 28 weeks old, were subjected to analytical subcellular fractionation and assay organelle marker enzymes. Fractionation revealed a reduction in the particulate brush border component of β-galactosidase (lactase) activity between 6 and 28 weeks, and a corresponding increase in soluble activity, although the reduction in mean specific activity was not significant. There also was a decrease in the proportion of brush border to soluble aminopeptidase N activity, a relative loss of brush border γ-glutamyltransferase and a considerable decrease the specific activity of alkaline phosphatase throughout the gradient fractions. In contrast, there were marked increases in activities α-glucosidase (maltase) and sucrase in the older ponies, accompanied by considerable changes in the intracellular distribution of particulate α-glucosidase activity, which was predominantly associated with endoplasmic reticulum at 6 weeks, whereas the large increase in activity observed by 28 weeks was clearly associated with the brush border. The modal density brush borders also increased with age, suggestive of an increase in the glycoprotein-to-lipid ratio of the microvillar membrane. In contrast to these brush border changes, there was relatively little alteration in the activities or density distributions of marker enzymes for endoplasmic reticulum, basolateral membranes, mitochondria, or lysosomes. These findings indicate that maturation of equine intestinal epithelium during the first few months of life results in major changes in the properties and enzyme composition of enterocyte brush borders.
Evaluation of pulmonary function and analgesia in dogs after intercostal thoracotomy and use of morphine administered intramuscularly or intrapleurally and bupivacaine administered intrapleurally
Authors: Stobie Daniel , Caywood Dennis D. , Rozanski Elizabeth A. , Bing Dennis R. , Dhokarikar Pradnya , Raffe Marc R. , Kannan Mathur S. , King Vickie L. , Hegstad Rebecca L. , Randall Debbie A.
Published: January 2024

Eighteen dogs undergoing lateral thoracotomy at the left fifth intercostal space were randomly assigned to 1 of 3 postoperative analgesic treatment groups of 6 dogs each as follows: group A, morphine, 1.0 mg/kg of body weight, im; group B, 0.5% bupivacaine, 1.5 mg/kg given interpleurally; and group C, morphine, 1.0 mg/kg given interpleurally. Heart rate, respiratory rate, arterial blood pressure, arterial blood gas tensions, alveolar-arterial oxygen differences, rectal temperature, pain score, and pulmonary mechanics were recorded hourly for the first 8 hours after surgery, and at postoperative hours 12, 24, and 48. These values were compared with preoperative (control) values for each dog. Serum morphine and cortisol concentrations were measured at 10, 20, and 30 minutes, hours 1 to 8, and 12 hours after treatment administration.

All dogs had significant decreases in pHa, PaO2, and oxygen saturation of hemoglobin, and significant increases in PaCO2 and alveolar-arterial oxygen differences in the postoperative period, but these changes were less severe in group-B dogs. Decreases of 50% in lung compliance, and increases of 100 to 200% in work of breathing and of 185 to 383% in pulmonary resistance were observed in all dogs after surgery. Increases in work of breathing were lower, and returned to preoperative values earlier in group-B dogs. The inspiratory time-to-total respiratory time ratio was significantly higher in group-B dogs during post-operative hours 5 to 8, suggesting improved analgesia. Blood pressure was significantly lower in group-A dogs for the first postoperative hour. Significant decreases in rectal temperature were observed in all dogs after surgery, and hypothermia was prolonged in dogs of groups A and C. Significant differences in pain score were not observed between treatment groups. Cortisol concentration was high in all dogs after anesthesia and surgery, and was significantly increased in group-B dogs at hours 4 and 8. Significant differences in serum morphine concentration between groups A and C were only observed 10 minutes after treatment administration. In general, significant differences in physiologic variables between groups A and C were not observed.

Results of the study indicate that anesthesia and thoracotomy are associated with significant alterations in pulmonary function and lung mechanics. Interpleurally administered bupivacaine appears to be associated with fewer blood gas alterations and earlier return to normal of certain pulmonary function values. Interpleural administration of morphine does not appear to provide any advantages, in terms of analgesia or pulmonary function, compared with its im administration.
Prothrombotic events in the prodromal stages of acute laminitis in horse
Authors: Weiss Douglas J. , Trent Ava M. , Johnston Gary
Published: January 2024

Prothrombotic changes occurring in the prodromal stages of carbohydrate-induced laminitis were investigated. Hemostatic alterations were evaluated by determining platelet counts, platelet survival, activated partial thromboplastin time, one-stage prothrombin time, and monocyte procoagulant activity. Thrombosis of vessels in the hoof wall was evaluated by contrast arteriography and histologic examination. Of 5 horses, 4 became lame between 28 and 52 hours after carbohydrate administration. Mean platelet count in laminitis-affected horses was lower throughout the prodromal stages of laminitis, compared with that in control horses, but differences were not statistically significant. However, survival of indium-111-labeled platelets was less than the value in control horses by 6 hours after carbohydrate administration. Arteriography of disarticulated feet revealed marked reduction in blood supply to hooves in laminitis-affected horses. Histologic examination of the laminar dermis disclosed microthrombi in venules of the laminar dermis in 2 of 4 affected horses. Statistically significant changes in prothrombin time were not observed, and changes in activated partial thromboplastin time were slight and occurred only at the onset of lameness. Statistically significant changes in monocyte procoagulant activity were not observed. Plasma endotoxin-like activity was not detected in laminitis-affected horses. These data indicate that platelet survival was decreased within the first 6 hours after induction of carbohydrate-induced laminitis, but systemic activation of the coagulation system was not detected.
Histologic evaluation of tissue reactivity and absorption in response to a new synthetic fluorescent pigmented polypropylene suture material in rats
Authors: Beardsley Stephanie L. , Smeak Daniel D. , Weisbrode Steven E.
Published: January 2024

The degree and type of tissue reactivity and the absorption of a new suture material was determined by implantation within rat gluteal muscles. Amount and type of tissue inflammatory reaction was compared among the new suture material, polypropylene, and coated polyamide.

Histologic evaluation of the tissues in which sutures were implanted indicated that the new suture material, polypropylene, and coated polyamide had similar amounts and types of reaction at 30 days or less after implantation, but differed after 30 days. The new suture material and polypropylene had an inflammatory reaction zone measuring less than 25% of the high-power field after 60 days, but the coated polyamide still induced reaction greater than 45% of the field at 90 days. At 60 and 90 days after implantation, the new suture material and polypropylene induced a mature fibrous reaction; the reaction to coated polyamide was either immature fibrous or granulomatous, depending on whether there was rupture of the suture coat. There was no observable absorption of the new suture material at 90 days.

This study indicated that the new suture material is nonabsorbable and is minimally reactive in rat muscle. The tissue reactions induced by this suture material are similar to those of polypropylene and significantly less than those induced by coated polyamide after 30 days following implantation.
Sonographic-anatomic correlation and imaging protocol for the kidneys of horses
Authors: Hoffmann K. L. , Wood A. K. W. , McCarthy P. H.
Published: January 2024

Sonographic and anatomic observations were made of the kidneys of 23 Thoroughbreds or Standardbreds. In an in vitro study of 16 horses, precise correlations were established between the gross anatomic features of the kidneys and their sonographic appearance in images obtained in dorsal, sagittal, transverse, and transverse oblique anatomic planes. The renal cortex had a uniformly mottled echogenicity, and the renal medulla was relatively hypoechogenic, compared with the cortex. Acoustic anisotropy was observed in the cortex and medulla of the cranial and caudal extremities of each kidney. The distinctive renal pelvis was seen in the transverse plane as an echogenic pair of diverging lines that lead to the crescent shaped renal crest in the lateral half of the kidney. In images made in the sagittal plane, the renal pelvis was seen as a pair of parallel echogenic lines separated by the moderately echogenic line of the renal crest. The terminal recesses were best seen in the transverse oblique views of each extremity, where they appeared as moderately echogenic lines in the medulla of the cranial and caudal extremities. The interlobar vessels were represented as irregular echogenic lines in the medulla, and the arcuate vessels were seen as echogenic points at the corticomedullary junction. At the hilus, the renal artery or its branches was located cranial to the renal vein, which in turn was cranial to the position of the proximal portion of the ureter.

In an in vivo study of 7 horses, sonographic images of the right kidney were obtained in the sagittal, transverse, and transverse oblique anatomic planes in all horses, with the transducer positioned at the 15th, 16th, or 17th intercostal space; images in the dorsal plane were obtained, however, in only 3 of the horses. For the left kidney, sonographic images were obtained in each of the anatomic planes when the transducer was positioned at the 16th or 17th intercostal space or the paralumbar fossa; rectal location of the transducer gave images in the dorsal and sagittal planes.

In this study, a routine sonographic imaging protocol, using standard anatomic planes, enabled each kidney to be examined in its entirety. The protocol provided definition of normal renal sonographic anatomic features and may permit a more informed and accurate recognition of renal pathologic change.
Enzyme-linked immunosorbent assay for serum apolipoprotein B-100, a major triglyceride-transport protein in dairy cows
Authors: Yamamoto Osamu , Oikawa Shin , Katoh Norio
Published: January 2024

An elisa was developed to determine serum concentration of apolipoprotein B-100, a major triglyceride-binding protein in very low-density lipoproteins and a putative maker for hepatic lipidosis of dairy cows. Serum apolipoprotein B-100 was prepared electrophoretically, and antibodies to this protein were raised in rabbits. The antiserum prepared was further purified by affinity chromatography, using bovine serum albumin-Sepharose 4B, to remove antibodies to albumin. For the elisa, addition of 2-mercaptoethanol to the coating buffer (50 mM sodium carbonate, pH 9.6) was required to evaluate apolipoprotein B-100 concentration in serum. The elisa developed was sensitive (detection limit was 300 to 400 ng/ml of serum) and reliable (coefficients of variance were in the range of 3.3 to 7.6%). By use of the established elisa, the serum apolipoprotein B-100 concentration was found to be significantly (P < 0.01) lower during the early lactating stage than during other stages of lactation. Reduced hepatic synthesis or secretion of apolipoprotein B-100 during the early lactating stage, together with the excess uptake by the liver of serum nonesterified fatty acids, is suggested to be relevant in the accelerated accumulation of triglycerides in the liver of dairy cows during the periparturient period.
Epidemiologic evidence for clustering of equine motor neuron disease in the United States
Authors: de la Rúa-Domènech Ricardo , Mohammed Hussni O. , Atwill Edward R. , Cummings John F. , Divers Thomas J. , Summers Brian A. , deLahunta Alexander , Jackson Cindy
Published: January 2024

Objective

To examine the regional variations in the distribution of equine motor neuron disease (emnd) in the United States and the factors that might explain those variations.

Design

Cluster investigation and case-control study.

Sample population

The study population consisted of 97 horses with histopathologically confirmed emnd and 698 controls with diagnosis of other spinal cord disorders at 21 US veterinary teaching hospitals participating in the Veterinary Medical Data Base.

Procedure

The total horse population of the United States was divided into 21 regions, and the regional incidence rates of emnd from January 1985 through January 1995 were estimated. Moran's index of spatial autocorrelation was calculated to test for spatial clustering of the disease. The 21 regions were then joined in broader areas according to the similarity of their emnd rates by means of the cluster analysis statistical technique. Finally, the role of potential confounding factors (age at diagnosis, month of diagnosis, breed, and sex) in the present distribution of emnd was assessed, using logistic regression analysis.

Results

Differences in estimated rates across the 21 regions resulted in a strong pattern of spatial clustering of emnd in the United States. The geographic units were grouped into 5 risk regions, with the gradient of emnd incidence rates increasing from the western states (almost 0 cases/1,000,000 horse-years) toward New England (20.78 cases/1,000,000 horse-years). Reported risk factors of emnd (age, breed) and other extraneous factors (sex, month of diagnosis) could not explain the observed geographic variations of disease rates. Nevertheless, there is evidence of some confounding attributable to age and breed.

Conclusions

Although the mechanism responsible for the clustering of emnd in northeastern states is still unexplained, it is not an epiphenomenon caused by regional differences in the distribution of the factors investigated.