Screening tuber-bearingSolanum spp. for resistance to soft rot caused byErwinia carotovora ssp.atroseptica (van Hall) Dye

Summary Soft rot caused by Erwinia carotovora ssp. atroseptica is a major disease of stored potatoes. Since varietal resistance can contribute to control, the work reported was designed to find new sources of resistance among related tuber-bearing Solanum spp. True seeds were imported from two international collections and families were screened for resistance to tuber soft rot. Forty-eight resistant clones were found in 21 out of 100 accessions. These clones will be used in breeding programmes at the diploid or tetraploid level.     

The prevalence of <Emphasis Type="Italic">Mycobacterium bovis</Emphasis>-infection and atypical mycobacterioses in cattle in and around Morogoro,Tanzania

A study was conducted to determine the prevalence of Mycobacterium bovis-infection and atypical mycobacterioses in different cattle herd management systems in and around Morogoro, Tanzania. Between April and June 2005, a total of 728 bovines from 49 herds were tested for M. bovis-infection and atypical mycobacterioses. Milk samples were taken from tuberculin positive animals and analysed for the presence of mycobacteria. Total prevalences of 2.5% and 10.1% were found for M. bovis-infection and atypical mycobacterioses respectively, with more M. bovis-infection in cattle in the extensive management system and more atypical mycobacterioses in cattle in the intensive management system. From 8 out of 42 milk samples (19%) atypical mycobacteria were cultured. A higher prevalence of M. bovis-infection in the extensive sector could be due to several factors. In addition, such high prevalence puts herd owners and their families at risk for BTB. Therefore control of BTB, as well as education of cattle owners is important, especially in the extensive sector.     

Photoperiod manipulation for the reproductive management of captive wolffish populations: <Emphasis Type="Italic">Anarhichas minor</Emphasis> and <Emphasis Type="Italic">A. lupus</Emphasis>

This study provides new and practical information to implement the use of photoperiodic manipulation for the control of the sexual maturation of Canadian 6⁺ Atlantic wolffish (Anarhichas lupus) and 3⁺ first-time spawners spotted wolffish (Anarhichas minor) from Canadian and Norwegian populations. Wolffish reproductive cycle (gametogenesis and oocyte maturation and spermiation) was monitored for 23 consecutive months. Control groups were held under a 12-month simulated natural photoperiod and treatment groups under an 8-month compressed photoperiod. Plasma sex steroid concentrations (estradiol-17β and 11-ketotestosterone), oocyte diameter growth, and milt production were assessed monthly. For all groups under study, fish subjected to the compressed photoperiod spawned 2–6 months earlier than the controls. Complete out-of-shift cycle was not achieved based on the completion of two reproduction cycles, and this is briefly discussed. Photoperiod treatment induced temporal shifts in sex steroid profiles, which are the likely mediators of altered timing of ovulation/final maturation. Photoperiod has a strong influence on the timing of wolffish maturation and could be used as an efficient and inexpensive tool to secure wolffish reproduction operations (year-round supply of egg and milt and/or timing with optimal temperature regimes).     

Beating heart mitral valve replacement with a bovine pericardial bioprosthesis for treatment of mitral valve dysplasia in a Bull Terrier

OBJECTIVES: To describe an open, beating heart surgical technique and use of a bovine pericardial prosthetic valve for mitral valve replacement (MVR) in the dog. STUDY DESIGN: Clinical case report. ANIMALS: Male Bull Terrier (17-month-old, 26 kg) with mitral valve dysplasia and severe regurgitation. METHODS: A bovine pericardial bioprosthesis was used to replace the mitral valve using an open beating heart surgical technique and cardiopulmonary bypass. RESULTS: Successful MVR was achieved using a beating heart technique. Mitral regurgitation resolved and cardiac performances improved (left ventricular end-diastolic diameter decreased from 57.6 to 48.7 mm, and left atrium/aorta ratio returned to almost normal, from 1.62 to 1.19). Cardiopulmonary by-pass time and total surgical duration were decreased compared with standard cardioplegic techniques. Surgical recovery was uneventful and on echocardiography 6 months later valve function was excellent. CONCLUSION: Considering the technique advantages (no cardiac arrest, ischemic reperfusion injury, and hypothermia, or the need for aortic dissection and cannulation for administration of cardioplegic solution), short-term mortality and morbidity may be reduced compared with standard cardioplegic techniques. CLINICAL RELEVANCE: Based on experience in this dog, beating heart mitral valvular replacement is a seemingly safe and viable option for the dog and bovine pericardial prosthesis may provide better long-term survival than mechanical prostheses.