BOOK REVIEW

ECG Interpretation in Dogs and Cats, Video produced by Provet for the Unit of Veterinary Continuing Education of the Royal Veterinary College     

Tracking the long-term decline and recovery of an isolated population

Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.     

Hunting behavior of a marine mammal beneath the antarctic fast Ice

The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.     

Prevalence of gastrointestinal helminths in domestic bison herds in northwestern Alberta

A fecal survey was conducted to determine the prevalence of gastrointestinal helminth eggs found in 431 domestic bison from 22 herds. Eggs detected (percent of herds affected in parentheses) were: strongyle-type (100%), Capillaria sp. (63.6%), Moniezia sp. (54.6%), Nematodirus sp. (50%), Trichuris sp. (40.9%), and Strongyloides sp. (9.1%).     

Confirmation of spatial patterns and temperature effects in Bluetongue virus serotype-8 transmission in NW-Europe from the 2007 reported case data

Two separate analyses were carried out to understand the epidemiology of Bluetongue virus serotype 8 (BTV-8) in 2007 in North West Europe: First, the temporal change in transmission rates was compared to the evolution of temperature during that season. Second, we evaluated the spatio-temporal dynamics of newly reported outbreaks, to estimate a spatial transmission kernel. For both analyses, the approach as used before in analysing the 2006 BTV-8 epidemic had to be adapted in order to take into account the fact that the 2007 epidemic was not a newly arising epidemic, but one advancing from whereto it had already spread in 2006. We found that within the area already affected by the 2006 outbreak, the pattern of newly infected farms in 2007 cannot be explained by between-farm transmission, but rather by local re-emergence of the virus throughout that region. This indicates that persistence through winter was ubiquitous for BTV-8. Just like in 2006, we also found that the temperature at which the infection starts to spread lies close to 15 °C. Finally, we found that the shape of the transmission kernel is in line with the one from the 2006 epidemic. In conclusion, despite the substantial differences between 2006 and 2007 in temperature patterns (2006 featured a heat wave in July, whereas 2007 was more regular) and spatial epidemic extent, both the minimum temperature required for transmission and the transmission kernel were similar to those estimated for the 2006 outbreak, indicating that they are robust properties, suitable for extrapolation to other years and similar regions.     

Effects of droplet crystallization and melting on the aroma release properties of a model oil-in-water emulsion

Aroma compounds partition between the dispersed and the continuous phases in emulsions, and phase transitions in the lipid droplets profoundly affect the position of the equilibrium. In the present study, the release of ethyl butyrate, ethyl pentanoate, ethyl heptanoate, and ethyl octanoate from a series of sodium caseinate-stabilized, n-eicosane emulsions was investigated as a function of solid and liquid lipid droplet concentration. For all compounds, headspace volatile concentrations above the solid droplet emulsions were higher than those above the liquid droplet emulsions. The interaction with liquid droplets could be modeled in terms of volume-weighted bulk partition coefficients while the more nonpolar volatiles bound to the surface of solid lipid droplets. The amount of volatiles bound to solid surfaces increased with aqueous concentration up to a critical point and then rapidly increased. The critical point corresponds to the dissolution of the solid lipid in a phase of adsorbed volatile. The binding of volatiles to both solid and liquid eicosane droplets is reversible.     

Influence of fat crystallization on the stability of flocculated emulsions

Various degrees of flocculation were induced in a 20 wt % n-hexadecane and confectionery-coating fat emulsion by adding xanthan gum (0-0.3 wt %). The emulsions were temperature cycled (40 to -10 to 40 to -10 degrees C) in a differential scanning calorimeter. The emulsified and de-emulsified fat crystallized at different temperatures, and the ratio of the two enthalpies was used to calculate the proportion of de-emulsified fat and hence the extent of breakdown of the emulsion. The n-hexadecane droplets were stable to temperature cycling, whereas the confectionery-coating fat destabilized to a greater or lesser extent. The maximum destabilization of the confectionery-coating fat occurred at those concentrations of xanthan required to induce creaming.     

Current distribution of sarcoptic mange in wombats

Objective To determine the distribution and prevalence of sarcoptic mange in wombats, particularly the common wombat ( Vombatus ursinus ).
Design Questionnaire survey in two parts.
Procedure Questionnaires were distributed to biologists, rangers, animal carers and naturalists. Part 1 of the questionnaire aimed to determine the present distribution of sarcoptic mange in wombats (103 responses). Part 2 invited respondents to assess the prevalence of sarcoptic mange in wombats over a 3 month period (four responses). Information on wombats from 66 localities was received. Each locality represented an area of about 2500 km².
Results Mange was observed at 93% of localities surveyed and Sarcoptes scabiei was present in common wombats at 52% of localities. Sarcoptic mange was highly prevalent (22%) in two common wombat populations in Victoria. Anecdotal evidence suggested that mange epizootics are sporadic, cause significant morbidity and mortality and have a substantial effect on local abundance. The respondents did not report sarcoptic mange in either northern hairy-nosed wombats ( Lasiorhinus krefftii ) or southern hairy-nosed wombats ( Lasiorhinus latifrons ).
Conclusions Sarcoptic mange occurs in common wombat populations throughout the range of the common wombat including Tasmania and Flinders Island. While mange epizootics are sporadic, they have the potential to threaten the long-term survival of small, remnant populations.