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in Journal of the American Veterinary Medical Association

Summary

One hundred and fifty lactating Holstein cows from 2 genetic lines selected for high and average milk production were used in the study. Sera from 6 annual herd tests were analyzed by agar-gel immunodiffusion test for antibodies to bovine leukemia virus. Odds of being seropositive were analyzed by use of stepwise and backward logistic regression procedures. Analysis within birth year revealed that estimated ln odds increased by 0.19/year of age among cows of the high genetic line and by 0.43 among cows of the average genetic line. This was accompanied by a more important cohort effect among high producers than among average producers.

Free access
in American Journal of Veterinary Research

Objective

To determine the prognosis in horses with cecocolic or cecocecal intussusception.

Design

Retrospective study.

Animals

30 horses with cecocolic intussusception or cecocecal intussusception.

Procedure

Information on history, physical examination findings, and laboratory values was summarized from the medical records. Laboratory data included results of hematologic examination, serum biochemical analysis, and peritoneal fluid color, total nucleated cell count, and total protein concentration. A one-year follow-up via the telephone was used to determine long-term survival.

Results

Horses ranged from 7 months to 30 years old, but 63% were ≤ 3 years. Standardbred horses were significantly overrepresented. Twenty-six horses had acute-to-subacute disease, and 4 had a chronic wasting disease. Cecal intussusceptions were suspected on the basis of finding a mass on abdominal palpation per rectum (14 of 24 horses) and positive ultrasonographic findings (2 of 3 horses). Thirteen horses with colic for > 1 day had scant, soft feces.

Six horses died or were euthanatized without undergoing surgery, and 24 were treated surgically. Six of the latter horses were euthanatized during surgery because of peritonitis, rupture of the cecum, and irreducible intussusception. All 4 horses with a chronic disease were euthanatized because of irreversible changes in the cecum. Of the 18 horses allowed to recover from surgery, 15 survived long-term. Surgical treatments were reduction, with or without partial typhlectomy (6 horses), partial typhlectomy through a colotomy and reduction (6), reduction through a colotomy and partial typhlectomy (3), partial typhlectomy for a cecocecal intussusception (1) and an ileocolostomy (2).

Clinical Implications

Cecal intussusception has a good prognosis with surgical correction without delay. Reduction through colotomy has a high success rate. Bypass by ileocolostomy should be used as a last resort. (J Am Vet Med Assoc 1999;214:80–84)

Free access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate nonselective computed tomographic (CT) venography for evaluating the cervical internal vertebral venous plexus (IVVP), define the diameter and area dimensions of the IVVP, and determine the relationship between dimensions of the cervical IVVP and other vertebral components in medium-sized dogs.

Animals—6 healthy dogs that weighed 18 to 27 kg.

Procedure—Helical CT scans were performed from C1 to C7 before and after IV injection of contrast medium (480 mg of iodine/kg) and a continuous infusion (240 mg of iodine/kg). Image data were transferred to a CT workstation, and measurements were performed on displayed transverse images. Diameter and area measurements of the vertebral canal, dural sac, IVVP, and vertebral body were obtained at C3 to C7.

Results—Opacification of vertebral venous structures was achieved in all dogs with no adverse reactions. Sagittal diameters of the IVVP for C3 to C7 ranged from 0.6 to 3.2 mm. Transverse diameters ranged from 2.32 to 5.74 mm. The IVVP area represented 12.4% of the mean vertebral canal transverse area and 30.61% of the mean vertebral epidural space area. Area measurements of the IVVP were significantly correlated with vertebral canal area and dural sac area.

Conclusions and Clinical Relevance—Results indicated that nonselective CT venography is a safe, sensitive method for performing morphometric assessments of the cervical IVVP in dogs. Findings support the theory that there may be a physiologic or developmental relationship between cervical vertebral canal components. (Am J Vet Res 2005;66:2039–2045)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To study the effects of phenylbutazone, indomethacin, prostaglandin E2 (PGE2), glutamine, and butyrate on restitution of oxidant-injured right dorsal colon of horses in vitro.

Sample Population—Right dorsal colon from 9 adult horses euthanatized for reasons other than gastrointestinal tract disease.

Procedure—Mucosal segments from the right dorsal colon were injured via exposure to HOCl and incubated in Ussing chambers in solutions containing phenylbutazone, indomethacin, indomethacin and PGE2, glutamine, and butyrate. Transepithelial resistance and mucosal permeability to mannitol were measured, and all mucosal segments were examined histologically.

Results—The HOCl-injured mucosa had lower resistance and higher permeability to mannitol, compared with control tissue. Histologic changes were also evident. Resistance of HOCl-injured mucosa recovered partially during the incubation period, and glutamine improved recovery. Phenylbutazone and indomethacin increased resistance, but these increases were not significant. Butyrate and PGE2 had no effects, compared with nontreated HOCl-injured tissues. Mucosal permeability to mannitol was lower in glutamine-treated tissue, compared with nontreated tissue. Histologic changes reflected the resistance and permeability changes.

Conclusions and Clinical Relevance—According to our findings, phenylbutazone and indomethacin do not seem to interfere with restitution of oxidant-injured mucosa of equine colon in vitro, and glutamine could facilitate mucosal restitution. (Am J Vet Res 2004;65:1589–1595)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine effects of sodium hyaluronate (HA) on corticosteroid-induced cartilage matrix catabolism in equine articular cartilage explants.

Sample Population—30 articular cartilage explants from fetlock joints of 5 adult horses without joint disease.

Procedure—Articular cartilage explants were treated with control medium or medium containing methylprednisolone acetate (MPA; 0.05, 0.5, or 5.0 mg/mL), HA (0.1, 1.0, or 1.5 mg/mL), or both. Proteoglycan (PG) synthesis was measured by incorporation of sulfur 35-labeled sodium sulphate into PGs, and PG degradation was measured by release of radiolabeled PGs into the medium. Total glycosaminoglycan (GAG) content in media and explants and total explant DNA were determined.

Results—Methylprednisolone acetate caused a decrease in PG synthesis, whereas HA had no effect. Only the combination of MPA at a concentration of 0.05 mg/mL and HA at a concentration of 1.0 mg/mL increased PG synthesis, compared with control explants. Methylprednisolone acetate increased degradation of newly synthesized PGs into the medium, compared with control explants, and HA alone had no effect. Hyaluronate had no effect on MPAinduced PG degradation and release into media. Neither MPA alone nor HA alone had an effect on total cartilage GAG content. Methylprednisolone acetate caused an increase in release of GAG into the medium at 48 and 72 hours after treatment. In combination, HA had no protective effect on MPA-induced GAG release into the medium. Total cartilage DNA content was not affected by treatments.

Conclusions and Clinical Relevance—Our results indicate that HA addition has little effect on corticosteroid- induced cartilage matrix PG catabolism in articular cartilage explants. (Am J Vet Res 2005;66:48–53)

Full access
in American Journal of Veterinary Research

Abstract

Objectives—To establish reference values for the range of the number of eosinophils found in equine gastrointestinal mucosa and to describe the distribution of this cell within the equine gastrointestinal mucosa.

Sample Population—Gastrointestinal mucosal specimens from 14 adult horses euthanatized for reasons other than gastrointestinal disease.

Procedures—Gastrointestinal mucosal specimens were collected and grouped according to their anatomic regions. For histologic examination slides were stained with Luna's eosinophil stain to determine eosinophil accumulation and distribution. The mucosa was divided into 5 sections for each anatomic location, and the percentage of eosinophils in each of the 5 sections relative to the total eosinophil count in all sections was determined. Additionally, the number of eosinophils per square millimeter of mucosa was calculated as a measure of the degree of eosinophil accumulation.

Results—Lowest numbers of eosinophils were found in the stomach, and numbers increased from there to the cecum, then decreased from the ascending colon (right ventral colon, left ventral colon, pelvic flexure, left dorsal colon, and right dorsal colon) to small colon. In all gastrointestinal sections, most eosinophils were located near the muscularis mucosae and were rarely found near or on the luminal surface of the mucosa.

Conclusions and Clinical Relevance—The distribution of eosinophils in the gastrointestinal tract of horses followed a pattern within the mucosa and between different sections of the gastrointestinal tract. The derived reference values and distribution data could be used to detect changes in eosinophil response in the equine gastrointestinal mucosa caused by diseases states.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate the eosinophilic response in intestinal mucosa of horses with intestinal ischemia and reperfusion or with strangulation of the jejunum or colon.

SAMPLE Mucosal samples from horses with naturally occurring strangulation (n = 24 horses) or distention (n = 6) of the jejunum or colon (11), with experimentally induced ischemia and reperfusion of the jejunum (6) or colon (15), or that were euthanized for reasons other than gastrointestinal tract disease (13).

PROCEDURES Mucosal samples were collected and grouped by type of intestinal injury. Slides were stained with Luna eosinophil stain and histologically examined to determine eosinophil accumulation and distribution. Number of eosinophils per mm2 of mucosa was calculated as a measure of eosinophil accumulation. Additionally, mucosa was categorized into 5 regions; the percentage of eosinophils in each of the 5 regions, relative to the total eosinophil count in all regions, was determined.

RESULTS Eosinophil migration toward and onto the luminal surface was evident in tissues after ischemia and reperfusion and after naturally occurring strangulating disease of the jejunum and colon, as indicated by a decrease in the number of eosinophils near the muscularis mucosa and an increase in the number of eosinophils on or near the luminal surface. Ischemia alone did not change eosinophil distribution in the jejunum or colon.

CONCLUSIONS AND CLINICAL RELEVANCE Eosinophils responded to mucosal damage evoked by ischemia and reperfusion by migration toward and onto the luminal surface. This migration could represent an important component of the inflammatory response to injury in equine gastrointestinal mucosa.

Full access
in American Journal of Veterinary Research