SELENIUM CONCENTRAnONS IN BLOOD OF FREE-RANGING MULE DEER IN CAUFORNIA

Abstract: Whole blood samples from 1,695 mule deer (Odocoileus hemionus) were collected from 15 geographical herd groups from 1980 to 1988, and analyzed for whole blood selenium (Se). Mean Se concentrations for each group were compared to accepted values for livestock species. Eleven groups bad mean blood Se concentrations <0.10 mg/L (deficient by livestock standards for groups of animals). Two-thirds of the groups bad fint quartile Se concentrations (Ql) that were considered seriously deficient (<0.05 mg/L). Significant (P <0.05) difference in blood Se concentrations were found for geographical location, season (reproductive phase), sex, and resident venus migratory behavior. No significant differences were detected for sub-species or age. 1be likelihood and manifestations of Se deficiency in deer, especially decreased fawn survivability, are discussed with possible explanations for predisposing influences

Effectiveness of Grass Filters in Reducing Phosphorus and Sediment Runoff

Surface water contamination can often be reduced by passing runoff water through perennial grass filters. Research was conducted in 2006 to 2008 to evaluate the size of cool season grass filters consisting primarily of tall fescue (Festuca arundinacea Schreb) with some orchard grass (Dactylis glomerata L.) relative to drainage area size in reducing runoff sediment and phosphorus (P). The soil was Pohocco silt loam Typic Eutrochrepts with a median slope of 5.5%. The grass filters occupying 1.1 and 4.3% of the plot area were compared with no filter with four replications. The filters were planted in the V-shaped plot outlets which were 3.7 × 11.0 m in size. The filter effect on sediment and P concentration was determined from four natural runoff events when nearly all plots had runoff. Filter effect on runoff volume and contaminant load was determined using total runoff and composites of samples collected from 12 runoff events. Sediment concentration was reduced by 25% with filters compared with no filter (from 1.10 to 1.47 g L−1), but P concentration was not affected. The 1.1 and 4.3% filters, respectively, compared with having no grass filter, reduced: runoff volume by 54 and 79%; sediment load by 67 and 84% (357 to 58 kg ha−1); total P load by 68 and 76% (0.58 to 0.14 kg ha−1); particulate P (PP) load by 66 and 82% (0.39 to 0.07 kg ha−1); and dissolved reactive P (DRP) load by 73 and 66% (0.2 to 0.07 kg ha−1), respectfully. A snowmelt runoff event had 56 % greater DRP concentration compared with rainfall-induced runoff events. Grass filters reduced sediment and P load largely by reducing runoff volume rather than reducing concentration. Well-designed and well-placed grass filters that occupy 1.0 to 1.5% of the drainage area and intercept a uniform flow of runoff from a drainage area can reduce sediment and nutrient loss in runoff by greater than 50%

SEROLOGICAL SCREENING FOR INFECTIOUS CATTLE DISEASES: I. INFLUENCE OF REPRODUCTIVE STATUS

A cohort of 125 cows (Zebu-Holstein crosses) were screened every two months during a period of two years for IgG antibodies to 20 viral, bacterial, rickettsial and parasitic agents. The screening was performed on sera using the ELISA procedure. The IgG levels fluctuated during pregnancy in a regular and similar way for all the antigens tested. IgG reached its lowest levels in the fourth and seventh month of pregnancy, a significant increase ocurred during the last month of pregnancy and this was followed by a precipitous decline during the first month post partum. The IgG fluctuations associated with the different phases of reproductive status may interact with seasonal changes in IgG levels. The changes in IgG levels during pregnancy may have the result that an individual animal oscillates between being seropositive and seronegative. This can have an important impact on serological studies of abortion epidemiology

A STUDY OF ASSOCIATION BETWEEN ELISA RESPONSE TO INFECTIOUS DISEASE AGENTS AND CALVING INTERVAL IN CATTLE IN THE TROPICS OF MÉXICO

Forty eight cows of Holstein-Zebu crosses with at least one completed pregnancy were tested for antibodies to 20 disease agents. The testing was performed within one month (average two weeks) after calving when the IgG level constantly reaches its lowest value during the cows reproductive cycle. The results indicate that increasing levels of IgG against Leptospira interrogans serovar hardjo and Mycobacterium paratuberculosis may be associated with an increased calving interval. Increase in calving intervals could not be explained by age of cows or their genotypic characteristics

SEROLOGICAL SCREENING FOR INFECTIOUS CATTLE DISEASES: II. ASSOCIATION BETWEEN PREVALENCE AND LEVEL OF ELISA RESPONSE

A herd of cattle (Holstein-Zebu crosses) was screened every two months by ELISA during a period of two years for IgG antibodies against 19 infectious disease agents. Two hundred and ninety five sera were collected from 157 young animals (0-4 months of age), 1037 sera from 292 developing animals (4-36 months of age) and 1468 sera from 259 producing animals (> 36 months of age). The results indicate that the difference in ELISA between positive and negative tests is associated with the overall prevalence of positive tests. When the prevalence of positive tests is low the difference between positive and negative tests is greater than when the prevalence is intermediate or high. This means that ELISA, presumably other serological tests for IgG antibodies, is more reliable at low disease (antibody) prevalence. This will tend to offset the declining predictive value of positive tests at low prevalence and may contribute to the successful use of serological tests in disease eradication

Targeting of watershed management : practices for water quality protection (2008)

"Heartland Regional Water Coordination Initiative.""EPA Region VII : University of Nebraska-Lincoln, Iowa State University, Kansas State University, University of Missouri-Columbia, USDA-ARS, USDA-NRCS.""This material is based upon work supported by the Cooperative State Research, Education, and Extension Services, U.S. Department of Agriculture, under Agreement No. 2004-51130-02249.