Modeling co-occurrence of northern spotted and barred owls: Accounting for detection probability differences

Barred owls (Strix varia) have recently expanded their range and now encompass the entire range of the northern spotted owl (Strix occidentalis caurina). This expansion has led to two important issues of concern for management of northern spotted owls: (1) possible competitive interactions between the two species that could contribute to population declines of northern spotted owls, and (2) possible changes in vocalization behavior and detection probabilities of northern spotted owls induced by presence of barred owls. We used a two-species occupancy model to investigate whether there was evidence of competitive exclusion between the two species at study locations in Oregon, USA. We simultaneously estimated detection probabilities for both species and determined if the presence of one species influenced the detection of the other species. Model selection results and associated parameter estimates provided no evidence that barred owls excluded spotted owls from territories. We found strong evidence that detection probabilities differed for the two species, with higher probabilities for northern spotted owls that are the object of current surveys. Non-detection of barred owls is very common in surveys for northern spotted owls, and detection of both owl species was negatively influenced by the presence of the congeneric species. Our results suggest that analyses directed at hypotheses of barred owl effects on demographic or occupancy vital rates of northern spotted owls need to deal adequately with imperfect and variable detection probabilities for both species.     

Genetic characterization of porcine circovirus type 2 in captive wild boars in southern Brazil

Tropical Animal Health and Production - Porcine circovirus type 2 (PCV2) has been identified in pig population in Brazil since 2000, but scarce studies involving wild boars with PCV2 infection are...     

Decomposition of Bacillus thuringiensis (Bt) transgenic rice residues (straw and roots) in paddy fields

Background, aim, and scope  

Genetic modification of commercial crops may affect their decomposition and nutrient cycling processes in agricultural ecosystems. Intensive rice cultivation under partially submerged conditions (paddy rice) is an important and widespread cropping system, particularly in the tropics, yet there is little data on the decomposition of Bt rice residue under field conditions. We investigated straw and root decomposition of rice modified to express the Cry1Ab protein of Bacillus thuringiensis (Bt) to kill lepidopteran pests, compared with a parental non-Bt isoline. The objective of this study was to assess the possible impacts of cry gene transformation of rice on residue decomposition under intensive rice cultivation with long period of submergence.     

Seed germination of seven pepper cultivars at constant or alternating high temperatures

Summary

Seeds of seven pepper (Capsicum annuum L.) cultivars (Anaheim TMR 23, California Wonder 300, Coronado, Jalapeno M, Ma Belle, Mercury, and Yolo Wonder B) were germinated at constant day and night temperatures of 25,30,35 and 40°C or at alternating temperatures of 40/25,40/30 and 40/35°C for 14 days. Germination percentages and rates were similar at 25 and 30°C. Largest differences in cultivar responses occurred at 35°C where germination percentages ranged from 24 to 96%, and rates, calculated as summation of the number of seeds germinated on a given day divided by day number, varied from 3 to 26 (theoretical maximum value of 100). At 40°C, germination percentages were less than 5% and rates were less than one for all cultivars. Cultivars with the most heat tolerance were ‘Mercury’ and ‘Yolo Wonder B’. At alternating temperatures, germination percentages and rates were higher than those at constant 40°C. The increases were greatest when the temperature was lowered by 15°C (40/25°C) and least when temperatures were lowered by 5°C (40/35°C). Tetrazolium tests showed that a large percentage of the ungerminated seed was still viable from the highest temperature. At lower temperatures, fewer ungerminated seeds were viable with no viable ungerminated seeds from the lowest temperature.     

Experimental transmission of chronic wasting disease (CWD) from elk and white-tailed deer to fallow deer by intracerebral route: final report

Final observations on experimental transmission of chronic wasting disease (CWD) from elk (Cervus elaphus nelsoni) and white-tailed deer (Odocoileus virginianus) to fallow deer (Dama dama) are reported herein. During the 5-year study, 13 fawns were inoculated intracerebrally with CWD-infected brain material from white-tailed deer (n = 7; Group A) or elk (n = 6; Group B), and 3 other fawns were kept as uninoculated controls (Group C). As described previously, 3 CWD-inoculated deer were euthanized at 7.6 mo post-inoculation (MPI). None revealed presence of abnormal prion protein (PrP(d)) in their tissues. At 24 (Group A) and 26 (Group B) MPI, 2 deer were necropsied. Both animals had a small focal accumulation of PrP(d) in their midbrains. Between 29 and 37 MPI, 3 other deer (all from Group A) were euthanized. The 5 remaining deer became sick and were euthanized between 51 and 60 MPI (1 from Group A and 4 from Group B). Microscopic lesions of spongiform encephalopathy (SE) were observed in only these 5 animals; however, PrP(d) was detected in tissues of the central nervous system by immunohistochemistry, Western blot, and by commercial rapid test in all animals that survived beyond 24 MPI. This study demonstrates that intracerebrally inoculated fallow deer not only amplify CWD prions, but also develop lesions of spongiform encephalopathy.     

Caprine herpesvirus-2-associated malignant catarrhal fever in white-tailed deer (Odocoileus virginianus).

A subacute disease presenting primarily as alopecia and weight loss occurred in 2 white-tailed deer (Odocoileus virginianus) on farms in Minnesota and in Texas. A presumptive diagnosis of malignant catarrhal fever (MCF) was made on the basis of histological lesions. Antibody against an epitope conserved among the MCF group viruses was detected in the serum of both deer. DNA samples from the deer were subjected to a variety of PCR amplifications. Alignment of the amplified sequences from the diseased animals revealed that they were 100% identical to each other and to the same DNA fragment from the newly recognized member of the MCF virus group endemic in domestic goats (Capra hircus), provisionally named caprine herpesvirus 2 (CpHV-2). A seroprevalence survey from one of the deer farms showed a high rate of subclincal infection in the deer population. This study provides further confirmation that CpHV-2 is a pathogen, at least for deer, and emphasizes the risk of loss from MCF when mixing cervids with goats.     

Tidal Breathing Flow-Volume Loops in Healthy and Bronchitic Cats

Tidal breathing flow-volume loops (TBFVL) were obtained from 19 healthy cats and 7 cats with chronic bronchial disease. Peak inspiratory flow (PIF) occurred late in the inspiratory cycle and was preceded by a gradual but more linear increase in the flow rate. Peak expiratory flow (PEF) occurred early during expiration and was followed by a curvilinear decrease in flow to a point near the end of expiration where flow ceased. The loops obtained were generally reproducible. The mean coefficient of variation (CV) for TBFVL indices of healthy cats ranged from 5.6% to 21.9%. Loop indices from cats with chronic bronchial disease had a mean CV between 6.6% and 28.4%. Significant differences were noted in the bronchitic cats' TBFVLs, including an increased ratio of expiratory time to inspiratory time, lower expiratory flow rates, decreased area under total and peak expiratory flow curves, and decreased tidal breathing expiratory volumes (TBEV) at 0.1 and 0.5 seconds. Selected TBFVL indices were also significantly reduced. TBFVL evaluation in the cat is easy to perform, is reproducible, and has allowed for the detection of changes during tidal breathing in cats with histories and physical findings of chronic lower airway disease. (Journal of Veterinary Internal Medicine 1993; 7:388–393. Copyright © 1993 by the American College of Veterinary Internal Medicine.)