Characterization of protection against systemic infection and disease from experimental bovine viral diarrhea virus type 2 infection by use of a modified-live noncytopathic type 1 vaccine in calves

OBJECTIVE: To evaluate protection resulting from use of a modified-live noncytopathic bovine viral diarrhea virus (BVDV) type 1 vaccine against systemic infection and clinical disease in calves challenged with type 2 BVDV. ANIMALS: 10 calves, 5 to 7 months of age. PROCEDURES: Calves were allocated (n = 5/group) to be nonvaccinated or vaccinated SC on day 0 with BVDV 1 (WRL strain). Calves in both groups were challenged intranasally with BVDV type 2 isolate 890 on day 21. Rectal temperatures and clinical signs of disease were recorded daily, and total and differential WBC and platelet counts were performed. Histologic examinations and immunohistochemical analyses to detect lesions and distribution of viral antigens, respectively, were performed. RESULTS: After challenge exposure to BVDV type 2, nonvaccinated calves developed high rectal temperatures, increased respiratory rates, viremia, leukopenia, lymphopenia, and infection of the thymus. Vaccinated calves did not develop high rectal temperatures or clinical signs of respiratory tract disease. Vaccinated calves appeared to be protected against systemic replication of virus in that they did not develop leukopenia, lymphopenia, viremia, or infection of target organs, and infectious virus was not detected in peripheral blood mononuclear cells or the thymus. CONCLUSIONS AND CLINICAL RELEVANCE: The modified-live BVDV type 1 vaccine protected against systemic infection and disease after experimental challenge exposure with BVDV type 2. The vaccine protected calves against infection and viremia and prevented infection of target lymphoid cells.     

Tetramine cupruretic agents: a comparison in dogs

The cupruretic effects of 2 tetramine (N,N'-bis (2-aminoethyl) alkane diamine) chelators were examined in healthy dogs fed a commercial dog food containing 12.2 micrograms of copper/g of dry diet. Two groups of 3 dogs each were given either 300 mg of 2,2,2-tetramine tetrahydrochloride or 2,3,2-tetramine tetrahydrochloride for 23 consecutive days. Serum and 24-hour urine samples obtained before drug administration and during therapy were analyzed for copper, zinc, and iron concentrations. Both tetramines produced a significant cupruresis without significant changes in serum copper or in serum or urine zinc and iron concentrations. The 2,3,2-tetramine tetrahydrochloride produced a 4- to 9-fold greater cupruresis than did 2,2,2-tetramine tetrahydrochloride and resulted in a daily loss of more than 2 mg of copper in the urine. The dogs had no laboratory or clinical evidence of toxic side effects to either cupruretic agent during the treatment period. The results of the present study indicate that 2,3,2-tetramine should be an effective decoppering drug for use in dogs.     

Use of 2,3,2-tetramine as a hepatic copper chelating agent for treatment of copper hepatotoxicosis in Bedlington terriers

Five Bedlington Terriers with inherited copper (Cu) hepatotoxicosis and with hepatic Cu concentrations ranging from 3,000 to 11,000 micrograms/g of dry weight (normal, less than 350 micrograms/g of dry weight) were treated daily for up to 200 days with 2,3,2-tetramine tetrahydrochloride. During treatment, no change was made in the dietary Cu intake, which ranged from 12 to 16 micrograms/g of dry diet. Concentrations of hepatic and serum Cu, iron, and zinc were determined before and at the conclusion of the treatment period. In one dog, 24-hour urinary Cu concentration was measured before and during treatment. A liver biopsy specimen obtained after treatment had significantly (P less than 0.05) reduced hepatic Cu concentration (3,282 micrograms/g of dry weight; a 54.9% reduction), compared with the pretreatment value (7,281 micrograms/g of dry weight). After treatment, there was an overall general lessening of the extent of hepatic morphologic damage. Cytochemical examination for Cu in rhodanine-stained biopsy specimens revealed decreased numbers of Cu-laden hepatic lysosomes. The mean daily urinary Cu concentration increased as much as 25-fold during 2,3,2-tetramine treatment. Hepatic iron and zinc concentrations and serum Cu concentrations remained within normal ranges after treatment. Clinical or laboratory evidence of 2,3,2-tetramine toxicosis was not detected during treatment. These findings indicated that in affected Bedlington Terriers, 2,3,2-tetramine was a safe and rapid chelating agent of hepatic Cu.     

Sampling to characterize landscape pattern

Current reseach suggests that metrics of landscape pattern may reflect ecological processes operating at different scales and may provide an appropriate indicator for monitoring regional ecological changes. This paper examines the extent to which a 1/16 areal subset of the landscape using equally spaced 40-km² hexagons can characterize the spatial extent of land cover types and landscape pattern (number of types of edges, patch shape complexity, dominance, and contagion). For 200-m resolution data the hexagon subset gives a reasonable estimate of overall landscape cover but may not be adequate for monitoring uncommon land cover types such as wetlands. For agriculture and forest, their proportion of the full landscape units is only outside the 95% confidence interval of the hexagon estimate 4–8% of the time, whereas the proportions for wetland and barren areas are outside the confidence interval 11–34% of the time. The hexagon subset also does not appear to be adequate as the sole basis for monitoring landscape pattern. The values for contagion, dominance, and shape complexity calculated on the full landscape units are outside the 95% confidence interval of the hexagon estimate 27–76% of the time. Other statistical analyses include regressions between full landscape and hexagon subsets, mean differences and standard errors along with tests on number of positive and negative values, and percent relative error of hexagon estimates.Although the research described in this article has been funded in part by the U.S. Environmental Protection Agency, under Interagency Agreement DW89934921-01-0 with the U.S. Department of Energy under Contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc., it has not been subjected to Agency review. Therefore, it does not necessarily reflect the views of the Agency. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.Research supported by the Landscape Characterization Project, Environmental Monitoring and Assessment Program, U.S. Environmental Protection Agency, under Interagency Agreement DW89934921-01-0 with the U.S. Department of Energy under Contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc., Environmental Sciences Division Publication No. 4090.     

Evaluation of On-Arrival versus Prompted Metaphylaxis Regimes Using Ceftiofur Crystalline Free Acid for Feedlot Heifers at Risk of Developing Bovine Respiratory Disease

This study was designed to compare morbidity and mortality due to bovine respiratory disease (BRD) in 1,400 ranch-fresh, northern US calves that received either no metaphylaxis (MTX) (Group 1), MTX prompted by pen morbidity (Group 2), MTX prompted by a decline in feed intake (Group 3), or on-arrival MTX (Group 4). Ceftiofur crystalline free acid (6.6 mg/kg) was the MTX antimicrobial used. Decreased feed intake did not meet the study threshold, so Groups 1 and 3 were combined into a single control group. The percentage of calves not treated for BRD was 14% to 15% higher in Groups 4 and 2 (72.7% and 73.4%, respectively) compared with the controls (58.2%; P less than or equal to .02). Mortality was numerically higher in Group 2 (3.4%) compared with Groups 4 and 1 (0.9% and 1.6%, respectively). There were no differences in average daily gain or feed consumption. In northern, ranch-fresh calves, MTX as a health management practice reduces the incidence of BRD and has better utility when performed on-arrival versus relying on morbidity as a signal for timing antimicrobial administration.     

Characterization of protection from systemic infection and disease by use of a modified-live noncytopathic bovine viral diarrhea virus type 1 vaccine in experimentally infected calves

OBJECTIVE: To evaluate protection against systemic infection and clinical disease provided by use of a modified-live noncytopathic bovine viral diarrhea virus (BVDV) type 1 vaccine in calves challenged with NY-1 BVDV. ANIMALS: 10 calves, 5 to 7 months of age. PROCEDURES: Calves were allocated (n = 5/group) to be nonvaccinated or vaccinated SC on day 0 with BVDV type 1 (WRL strain). Calves in both groups were challenged intranasally with NY-1 BVDV on day 21. Calves' rectal temperatures and clinical signs of disease were recorded daily, total and differential WBC and platelet counts were performed, and serum neutralizing antibody titers against NY-1 BVDV were determined. Histologic examinations and immunohistochemical analyses to detect gross lesions and distribution of viral antigens, respectively, were performed. RESULTS: After challenge exposure to NY-1 BVDV, nonvaccinated calves developed high rectal temperatures, increased respiratory rates, viremia, leukopenia, lymphopenia, and infection of the thymus. Vaccinated calves did not develop high rectal temperatures or clinical signs of respiratory tract disease. Vaccinated calves appeared to be protected against systemic replication of virus in that they did not develop leukopenia, lymphopenia, viremia, or infection of target organs, and infectious virus was not detected in peripheral blood mononuclear cells or the thymus. CONCLUSIONS AND CLINICAL RELEVANCE: The modified-live BVDV vaccine protected calves against systemic infection and disease after experimental challenge exposure with NY-1 BVDV. The vaccine protected calves against infection and viremia and prevented infection of target lymphoid cells.     

Prevention of persistent infection in calves by vaccination of dams with noncytopathic type-1 modified-live bovine viral diarrhea virus prior to breeding

OBJECTIVE: To determine the ability of a modified-live virus (MLV) bovine viral diarrhea virus (BVDV) type 1 (BVDV1) vaccine administered to heifers prior to breeding to stimulate protective immunity that would block transmission of virulent heterologous BVDV during gestation, thus preventing persistent infection of a fetus. ANIMAL: 40 crossbred Angus heifers that were 15 to 18 months old and seronegative for BVDV and 36 calves born to those heifers. PROCEDURE: Heifers were randomly assigned to control (n = 13) or vaccinated (27) groups. The control group was administered a multivalent vaccine where-in the BVDV component had been omitted. The vaccinated heifers were administered a single dose of vaccine (IM or SC) containing MLV BVDV1 (WRL strain). All vaccinated and control heifers were maintained in pastures and exposed to BVDV-negative bulls 21 days later. Thirty-five heifers were confirmed pregnant and were challenge exposed at 55 to 100 days of gestation by IV administration of virulent BVDV1 (7443 strain). RESULTS: All control heifers were viremic following challenge exposure, and calves born to control heifers were persistently infected with BVDV. Viremia was not detected in the vaccinated heifers, and 92% of calves born to vaccinated heifers were not persistently infected with BVDV. CONCLUSIONS AND CLINICAL RELEVANCE: These results document that vaccination with BVDV1 strain WRL protects fetuses from infection with heterologous virulent BVDV1.     

A factor analysis of landscape pattern and structure metrics

Fifty-five metrics of landscape pattern and structure were calculated for 85 maps of land use and land cover. A multivariate factor analysis was used to identify the common axes (or dimensions) of pattern and structure which were measured by a reduced set of 26 metrics. The first six factors explained about 87% of the variation in the 26 landscape metrics. These factors were interpreted as composite measures of average patch compaction, overall image texture, average patch shape, patch perimeter-area scaling, number of attribute classes, and large-patch density-area scaling. We suggest that these factors can be represented in a simpler way by six univariate metrics - average perimeter-area ratio, contagion, standardized patch shape, patch perimeter-area scaling, number of attribute classes, and large-patch density-area scaling.     

Physiology of the growing and adult goose

The packed cell volume, haemoglobin concentration, erythrocyte sedimentation rate and specific gravity and percentage water of whole blood and plasma were determined at 4‐week intervals in male and female Pilgrim goslings from 1 to 20 weeks of age and in adult geese at 4‐ to 5‐week intervals from 34 to 59 weeks of age.

All parameters studied increased during the growing period except erythrocyte sedimentation rate which declined. There were no significant sex differences at any time during this period.

The packed cell volume of adult males remained relatively constant from 34 to 50 weeks while that of the females declined. After 50 weeks the female level began to rise in contrast to a decline in the males so that the values were about the same for both sexes at 59 weeks. Differences between sexes were highly significant between 43 and 50 weeks.

Changes in haemoglobin content and whole blood specific gravity were positively correlated with changes in packed cell volume while changes in erythrocyte sedimentation rate were negatively correlated.

Plasma specific gravity of adult males remained relatively constant whereas that of females decreased prior to commencement of egg production at 43 weeks, then increased significantly and remained significantly above the male level for the remainder of the adult period.