Atlantic salmon in the North Pacific

The first catches of Atlantic salmon, Salmo salar L., in British Columbia (BC) waters occurred in 1987. The first reported escape of Atlantic salmon (2000 individuals) occurred in 1988. From 1988 to 1995, 97 799 Atlantic salmon were reported escaped from net pens in BC but the true number was higher as not all escapes are reported. Since 1987 a total of 9096 Atlantic salmon was caught in the coastal marine waters of BC, Washington and Alaska, and 188 were caught in fresh water. Most catches occurred in the Johnstone Strait area, where the abundance of salmon farms is highest. The most distant recovery occurred in 1994 when an Atlantic salmon was caught near the western end of the Alaska Peninsula. There have been no reports of successful reproduction of Atlantic salmon in the wild and no feral juveniles have been found. Atlantic salmon caught in the ocean in BC have substantial amounts of adipose tissue and they are heavier at length than fish caught in Alaska. The proportion of fish with prey items in their stomachs is generally low but higher in Alaska (13.1%) than in BC (5.8%). Most fish caught in fresh water are either maturing or mature.     

Farming practices in Sweden related to feeding milk and colostrum from cows treated with antimicrobials to dairy calves

Background

Milk produced by cows in receipt of antimicrobial therapy may contain antimicrobial residues. Such antimicrobial-containing waste milk must be withdrawn from human consumption and is therefore sometimes used as calf feed. Unfortunately, this approach might promote selection of antimicrobial resistant bacteria in the calves’ intestinal microbiota. The objectives of this study were therefore to obtain an overview of waste milk feeding practices on Swedish dairy farms and to investigate if these practices were associated with certain farm characteristics. A representative group of 457 Swedish dairy farmers participated in a web-based survey with questions about the use of colostrum and milk from cows treated with antimicrobials at dry off or during lactation, respectively, as calf feed.

Results

Colostrum (milk from the first milking after calving) and transition milk (milk from the second milking to the fourth day after calving) from cows treated with antimicrobials at dry off was fed to calves on 89% and 85% of the farms in the study, respectively. When antimicrobial therapy was given to cows during lactation, 56% of the farms fed milk that was produced during the course of treatment to calves, whereas milk that was produced during the subsequent withdrawal period was fed to calves on 79% of the farms. Surveyed farmers were less prone to feed such milk if the antimicrobial therapy was due to mastitis than other infections. In Sweden, a majority of antimicrobial treatments during lactation are systemic administration of benzylpenicillin and thus, the bulk of waste milk in Sweden is likely to contain residues of this drug. Feeding waste milk to calves was more common on non-organic farms, and on farms located in Southern Sweden, and was less common on farms with cows housed in cold free stalls barns.

Conclusions

Waste milk that may contain antimicrobial residues is, at least occasionally, used as feed for calves on a majority of surveyed Swedish dairy farms. Future work should focus on the effect of waste milk feeding on the occurrence of antimicrobial resistant bacteria in the calves’ intestinal microbiota.     

Chum salmon (Oncorhynchus keta) growth and temperature indices as indicators of the year–class strength of age‐1 walleye pollock (Gadus chalcogrammus) in the eastern Bering Sea

Ecosystem‐based fisheries management requires the development of physical and biological time series that index ocean productivity for stock assessment and recruitment forecasts for commercially important species. As recruitment in marine fish is related to ocean condition, we developed proxies for ocean conditions based on sea surface temperature (SST) and biometric measurements of chum salmon (Oncorhynchus keta) captured in the walleye pollock (Gadus chalcogrammus) fishery in the eastern Bering Sea in three periods (July 16–30, September 1–15 and September 16–30). The main purpose of this paper was to evaluate Pacific salmon (Oncorhynchus spp.) growth as a possible indicator of ocean conditions that, in turn, may affect age‐1 walleye pollock recruitment. Marine growth rates of Pacific salmon are the result of a complex interplay of physical, biological and population‐based factors that fish experience as they range through oceanic habitats. These growth rates can, therefore, be viewed as indicators of recent ocean productivity. Thus, our hypothesis was that estimated intra‐annual growth in body weight of immature and maturing age‐4 male and female chum salmon may be used as a biological indicator of variations in rearing conditions also experienced by age‐0 walleye pollock; consequently, they may be used to predict the recruitment to age‐1 in walleye pollock. Summer SSTs and chum salmon growth at the end of July and September explained the largest amount of variability in walleye pollock recruitment indicating that physical and biological indices of ocean productivity can index fish recruitment.     

Law Enforcement in Community Forestry: Consequences for the Poor

Decentralised forest management is believed to hold potential for increased economic and social equity. Implications of the associated local forest law enforcement on livelihoods, however, are not well understood. This paper explores the impacts of local forest law enforcement with a focus on the poorest forest users in community-managed forests. A case study including 14 community forest groups in western Nepal was conducted in 2008. Methods included review of archival data, a stakeholder survey (n?=?211), and recall of forest crimes by a random household sample (n?=?252). Local forest law enforcement was found to detect far more crimes than district-level enforcement. Crimes are primarily small-scale unauthorised appropriation of products for subsistence use by poorer households and rules are lightly enforced. It is argued that local law enforcement, while apparently not economically harmful to the poorer in the short term, may be used to perpetuate existing wealth and cast-based social inequities.     

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

Background

The anaerobic spirochetes Brachyspira hyodysenteriae and Brachyspira pilosicoli cause diarrheal diseases in pigs. Their fastidious nature has hampered standardization of methods for antimicrobial susceptibility testing. For monitoring of antimicrobial susceptibility wild type cutoff values are needed to define where the wild type distribution of MICs ends and no approved cutoffs are available for Brachyspira spp. In this study antimicrobial susceptibility data for both species (in total 906 isolates) were compiled and analyzed and wild type cut off values for B. hyodysenteriae proposed.

Methods

The MICs of tiamulin, valnemulin, tylosin, tylvalosin, doxycycline and lincomycin were determined by broth dilution in brain heart infusion broth supplemented with 10% fetal calf serum.

Results

The compiled MICs from the broth dilution tests of the B. hyodysenteriae type strain, B78^T (ATCC® 27164^T), showed that the method yields reproducible results. In an international perspective the frequencies of isolates with decreased antimicrobial susceptibility were low among both B. hyodysenteriae and B. pilosicoli. However, in B. pilosicoli a constant level of 10-15% isolates with tiamulin MICs >4 μg/ml was detected between 2002 and 2010 and in B. hyodysenteriae a gradual increase in tiamulin MICs was seen between 1990 and 2003 although this increase has ceased during the last years. The wild type cutoff values proposed for B. hyodysenteriae are: tiamulin >0.25 μg/ml, valnemulin >0.125 μg/ml, tylosin >16 μg/ml, tylvalosin >1 μg/ml, lincomycin >1 μg/ml and doxycycline >0.5 μg/ml.

Conclusions

The broth dilution method used in this study has over the years generated tightly grouped MIC populations for the field isolates and reproducible results for the control strain B78^T and is therefore a suitable antimicrobial susceptibility test method for monitoring of Brachyspira spp. Here we propose wild type cutoff values for six antimicrobial agents for B. hyodysenteriae tested by broth dilution based on MIC distributions and the current knowledge on mechanisms of resistance in this species. There are few studies on antimicrobial resistance mechanisms and MIC distributions in B. pilosicoli but to some extent the cutoff values proposed for B. hyodysenteriae may be applicable also for monitoring of antimicrobial susceptibility in B. pilosicoli.     

Climatic signal from <Emphasis Type="Italic">Pinus leucodermis</Emphasis> axial resin ducts: a tree-ring time series approach

Developing long-term chronologies of tree-ring anatomical features to evaluate climatic relationships within species might serve as an annual proxy to explore and elucidate the climatic drivers affecting xylem differentiation. Pinus leucodermis response to climate was examined by analyzing vertical xylem resin ducts in wood growing at high elevation in the Apennines of peninsular Southern Italy. Early- and latewood tree-ring resin duct chronologies, spanning the 1804–2010 time period, were constructed. We analyzed the relationships between resin duct chronologies and climate over the last century using correlation and response function analyses. Overall, results showed that ring width and resin duct relationships differed between early- and latewood, which indicated conditions affecting growth were not associated with resin duct production. Results also revealed differential responses to climate between early- and latewood resin duct chronologies. A notable observation was a positive and stable relationship between latewood resin duct number chronology and July maximum temperature throughout the twentieth century. This result suggested resin ducts might be a suitable proxy to evaluate P. leucodermis response to climate in the study area.     

The possible role of stress in the induction of pneumonic pasteurellosis.

Five groups of range bred calves (four calves per group) were used to investigate the effect of stress on susceptibility to aerosol exposures with bovine herpesvirus-1 or Pasteurella haemolytica. Twelve calves were weaned, transported, processed at a commercial feedlot and transported to isolation facilities three days later. An aerosol challenge of either 10 colony forming units of P. haemolytica or 10 plaque forming units of bovine herpesvirus-1 virus was given to two groups of calves and the third group was not challenged. The fourth group was transported directly to the isolation facilities after weaning and aerosol challenged with P. haemolytica. The fifth group remained at the farm after weaning and was not challenged. All transported animals had elevated plasma cortisol levels which remained above normal for at least three days postchallenge. The blastogenic response of all calves was depressed after leaving the farm and remained depressed throughout the experiment. The suppression correlated well with elevated serum cortisol levels. Calves processed through the feedlot encountered bovine herpesvirus-1 because eight out of 12 animals seroconverted to this antigen. Most calves seroconverted to P. haemolytica whether they were experimentally challenged or not. Where the unchallenged calves encountered P. haemolytica is unknown. Calves challenged with bovine herpesvirus-1 but not with P. haemolytica, had significant clinical signs of pneumonia and two animals died due to bovine herpesvirus-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Biological variation of canine serum thyrotropin (TSH) concentration

The aim of the present study was to estimate the between-dog, within-dog and analytical components of variance for serum thyrotropin (TSH) in healthy dogs, and to use these components of variance to 1) estimate the critical difference for significance between serial results; 2) assess the utility of the conventional population-based reference interval; 3) set a desirable performance standard for analytical imprecision; and 4) estimate the number of samples required for determination of the true mean value for an individual dog. Using the Immulite test system, TSH was measured in serum samples collected weekly for five weeks from eight clinically healthy dogs. Results were subjected to nested analysis of variance. Between-dog variation was 43.6%, within-dog variation was 13.6%, analytical variation was 8.8%, the one-sided critical difference was 37.8%, the index of individuality was 0.4, the maximum allowable analytical imprecision was 6.8%, and the number of samples required to determine the true mean value in a single dog was 40. In practical terms, the present study indicated that the analytical imprecision of canine serum TSH measurement should be < 7%, and that comparing a single serum TSH measurement from an individual dog to the conventional population-based reference range may be too insensitive to detect small but important changes in the serum TSH level of that particular dog. In addition, when treating a hypothyroid dog, serum TSH, measured on a weekly basis, should decrease by at least one-third before any effect of exogenous thyroxine supplementation can be said to have influenced the serum TSH level.