Ben J. Gonzales

Mining activity and habitat use by mountain sheep (Ovis canadensis)

We studied mountain sheep in the vicinity of three high-wall limestone mines in San Bernardino County, CA, USA to evaluate factors that influenced habitat use and, specifically, to investigate the influence of mining activity on distribution of those specialized ungulates. We used aerial telemetry data to estimate a resource selection function by fitting a logistic regression model and then comparing environmental characteristics at observed sheep locations to those at random locations. Distribution of mountain sheep was most influenced by a fire in 1999 that resulted in an area they avoided. Mountain sheep used steeper slopes, areas of lower terrain roughness, higher elevations, and areas closer to escape terrain than were random points. In contrast, sheep avoided areas near roads (federal and state highways, local roads, and off-road vehicle trails) but used areas near hiking trails and a railway. Water sources had the smallest effect of the factors considered, with sheep being associated with areas further from water points than were random locations. The disturbed area associated with the mines had a moderate influence on distribution, with sheep being associated with areas closer to the mine than were random points. Mining activities can alter terrain features and vegetation structure or composition in a way that promotes occupancy by sheep if they create steep slopes and rugged terrain (escape terrain) or reduce vegetation density or height (i.e., improve visibility). Whether increased occupancy reflects a benefit depends on the demographic responses of those sheep to the resources and conditions available on mine sites; information about those responses remains lacking.

Reference intervals for mineral concentrations in whole blood and serum of bighorn sheep (Ovis canadensis) in California

Whole blood and serum mineral concentrations were measured in diverse bighorn sheep (Ovis canadensis) metapopulations in California, and 90% reference intervals were determined. While there were some statistical differences between median concentrations among the different metapopulations, detected values were generally in good agreement with concentrations reported for other bighorn sheep populations and with reference ranges widely accepted for domestic sheep (Ovis aries). Although median whole blood selenium and serum copper concentrations were within adequate ranges reported for domestic sheep, some metapopulations had substantial numbers of individuals whose concentrations would be considered suboptimal for domestic sheep. There are a number of factors that can influence mineral concentrations in wildlife species such as bighorn sheep and that make the establishment of reference ranges challenging. However, the establishment of mineral reference ranges is important for such species, as their health and productivity are increasingly scrutinized and actively managed.

PRESUMPTIVE COPPER DEFICIENCY IN HAND-REARED CAPTIVE PRONGHORN (ANTILOCAPRA AMERICANA) FAWNS

Abstract Presumptive copper deficiency was diagnosed in hand-reared captive pronghorn (Antilocapra americana) at the Los Angeles Zoo. Clinical signs, which were manifested in growing fawns, included anemia, anorexia, diarrhea, progressive paresis/recumbency, and aortic rupture. The range of serum copper concentrations in fawns born during the 1989 season (0.08–0.67 ppm) was below levels considered normal for domestic sheep and goats (0.7–2.0 ppm) and below concentrations measured in adult pronghorn (0.4–1.43 ppm). Copper sulfate supplementation of the hand-rearing formula, which was initiated in 1989, resulted in a significant increase in mean (±SD) serum copper levels from 0.45 ± 0.18 ppm before supplementation to 0.68 ± 0.05 ppm after supplementation (P < 0.05). Fawns born in subsequent seasons (April 1990–August 1993) continued to be supplemented with copper in the hand-rearing formula. Mean serum copper concentration from these fawns (0.68 ± 0.22 ppm) was similar to the mean values from supplemented 1989 fawns and adult pronghorn in this herd (0.85 ± 0.34 ppm; P > 0.05). No clinical signs of copper deficiency were detected in any fawns after supplementation was started. Analyses of the herds diet revealed marginal dietary copper levels. Suspected dietary deficiency was confirmed by marginal tissue and serum copper concentrations in some of the herds adult animals. Dietary copper levels were corrected to prevent future cases of clinical copper deficiency.

EVALUATION OF THE WESTERN IMMUNOBLOT AS A DETECTION METHOD FOR BRUCELLA ABORTUS EXPOSURE IN ELK

Brucella abortus has been an important wildlife disease issue for most of the last century, especially because wildlife species are considered to be important disease reservoirs for cattle. Diagnostic uncertainty, caused in part by cross-reactions of antibodies to environmental pathogens such as Yersinia enterocolitica O:9 on standard Brucella serology, has exacerbated the challenges of managing the disease and has highlighted the need for test validation in wildlife species. The western immunoblot was evaluated for use in detecting B. abortus exposure in elk (Cervus elaphus) and for ruling out exposure to cross-reacting bacteria. Samples collected from 2003 to 2006, including 54 female and immature elk from four different elk herds, were tested using standard Brucella serologic methods (card, rapid automated presumptive [RAP], and rivanol tests), as well as the western immunoblot. Samples (n=28) from animals known to be naturally infected with B. abortus biovar 1 served as positive controls. For presumed negative samples, sera (n=26) were collected from two elk herds in which negative serologic tests, and the absence of clinical signs of disease such as abortions, supported Brucella-negative classification. In addition to these study samples, serologic data from 12 tule elk (Cervus elaphus nannodes) were provided from the California Department of Fish and Game in order to illustrate a field application of the western blot. The western immunoblot had the highest sensitivity (1.0;% 0.899–1.0) and specificity (1.0; 0.891–1.0) among all tests used in the study. The Kappa statistic for agreement between the western blot and the card, rivanol, and RAP tests were 0.701, 0.808, and 0.921, respectively, showing good to excellent agreement with the standard diagnostic tests currently in use. Although the western immunoblot is more expensive and time intensive than other tests, in this limited study, it was shown to be reliable for establishing and confirming B. abortus disease status in elk. In addition to this study, subsequent applications of the western blot assay have been successful in detecting Yersinia sp. exposure in elk after their antibodies cross-reacted on standard Brucella serology.

Psoroptes Mites and Mule Deer (Odocoileus hemionus): Additional Notes from the San Bernardino Mountains, California

Vernon C. Bleich, Jeffrey T. Villepique, James H. Davis, Steven G. Torres, and Ben J. Gonzales California Department of Fish and Wildlife, Sierra Nevada Bighorn Sheep Recovery Program, 407 W. Line St., Bishop, CA 93514 USA California Department of Fish and Wildlife, P.O. Box 3222, Big Bear City, CA 92314 USA California Department of Fish and Wildlife, Wildlife Investigations Laboratory, 1701 Nimbus Rd., Rancho Cordova, CA 95670 USA

PSOROPTES INFESTATION AND TREATMENT IN AN ISOLATED POPULATION OF BIGHORN SHEEP (OVIS CANADENSIS)

Abstract:  The authors captured bighorn sheep (Ovis canadensis) comprising a small population in the San Bernardino Mountains of California and evaluated the degree of infestation by mites of the genus Psoroptes for each individual. The animals were treated with two novel methods: amitraz-impregnated collars and cyfluthrin-impregnated ear tags and recaptured the following year to evaluate the effect of treatment. The authors compared data on degree of infestation for animals recaptured in the posttreatment year, detected no significant interyear differences in infestation severity scores among animals treated with amitraz or cyfluthrin, and could not detect any differences between treatment types. However, a significant (P < 0.10) decreased pattern in severity scores from the beginning to the end of treatments was detected, suggesting a cumulative therapeutic value in repeated annual treatments across the 3-yr period. Additionally, the authors detected a lower median mite severity score between 2000 and a later capture in 2006. These positive outcomes may be the result of previous treatments during 2000–2002, but environmental covariates not accounted for could have been contributing factors. Avermectin drugs with longer release profiles may be a more effective treatment option in this and other small bighorn sheep populations that are compromised with mite infestations.