Protection of sheep by vaccination against experimental challenge with Leptospira borgpetersenii serovar Hardjo and L. interrogans serovar Pomona

AIMS: To evaluate a multivalent leptospiral and clostridial vaccine for prevention of renal colonisation and urinary shedding in sheep, following experimental challenge with New Zealand strains of Leptospira borgpetersenii serovar Hardjo type Hardjobovis and L. interrogans serovar Pomona.

METHODS: Two separate but similarly designed studies were conducted. In both studies, Romney-cross lambs, aged 9–11 weeks, were randomly allocated to a vaccinated group and a control group. Vaccinated lambs each received two 1.5-mL S/C doses of a multivalent leptospiral and clostridial vaccine, 4 weeks apart, and animals in the control groups received the same dose of saline. Groups of 12 vaccinated and 12 control lambs were randomly selected in each study for challenge with serovars Hardjo or Pomona. Challenge was initiated 16 weeks following the second vaccination with three daily doses of live leptospires by intranasal and conjunctival routes. Following challenge, urine samples were collected weekly for 6 weeks, for dark field microscopy and leptospiral culture; 6 weeks after challenge the lambs were slaughtered and kidneys collected for leptospiral culture.

RESULTS: In lambs challenged with serovar Hardjo, 8/12 unvaccinated lambs had ≥1 urine or kidney sample that was positive for leptospires following culture, compared with 0/12 lambs in the vaccinated group (p=0.001). In lambs challenged with serovar Pomona, 9/12 unvaccinated lambs had ≥1 urine or kidney sample that was positive following culture, compared with 0/12 lambs in the vaccinated group (p<0.001). Prevention of renal colonisation and urinary shedding, expressed as the prevented fraction, was 100 (95% CI=61.7–100)% and 100 (95% CI=68.3–100)% against challenge with serovars Hardjo and Pomona, respectively, at 4 months after vaccination.

CONCLUSIONS AND CLINICAL RELEVANCE: Use of a multivalent leptospiral and clostridial vaccine demonstrated protection against challenge from New Zealand strains of serovars of Hardjo and Pomona 4 months after vaccination in lambs first vaccinated at 9–11 weeks of age. Further studies are required to assess the duration of immunity against challenge in sheep.     

The detection of pigs carrying Streptococcus suis type 2

An indirect fluorescent antibody test (I.F.A.T.) was performed on tonsillar swabs collected at slaughter and on nasal swabs from electrically stunned pigs prior to exsanguination. The identification of carriers of Streptococcus suis type 2 using the I.F.A.T. was compared with bacteriological isolation. If it is assumed that 100% of pigs were carrying the bacterium, 76% of 89 carriers were detected when the I.F.A.T. was performed on the bacterial growth from blood agar cultures of tonsillar swabs, compared with only 15% detected using cultural techniques. Similarly, I.F.A.T. on nasal swabs increased the sensitivity of the detection of carriers. Nasal swabbing, although of lower sensitivity than tonsillar swabbing, allows for the detection of S. suis type 2 carriers in the live animal.     

Leptospirosis associated with serovars hardjo and pomona in red deer calves (Cervus elaphus)

Four red deer calves (Cervus elaphus) died with severe nephritis apparently associated with infection by Leptospira interrogans serovar pomona. The sera of 12 in-contact red deer calves were examined for leptospiral agglutinins and nine showed titres to pomona consistent with recent infection. Two also showed titres of 1:100 to serovar hardjo. The urine of five of these in-contact calves was examined periodically over a period of nine months. All were initially leptospiruric, four being infected with pomona and one with hardjo. In four animals leptospiruria could only be detected for up to six months, but one animal infected with pomona was leptospiruric for at least eight months. The apparent source of infection was from infected cattle, and it is suggested that deer are unlikely to act as maintenance hosts for serovar pomona.     

The effect of different slaughter methods on the post mortem glycolysis of muscle in lambs

Differences in muscular activity and rates of decline in the pH of the M. longissimus dorsi of lambs subjected to different methods of stunning and slaughter were observed. Lambs electrically stunned by a head-to-leg method had significantly lower initial pH values as compared to animals stunned by an electrical head-only method, or by captive bolt, or without any form of stunning prior to slaughter. When electrical stunning by a head-to-leg method was combined with low voltage (24 V) electrical stimulation during slaughter and bleeding, mean pH values declined at the highest rate and fell to approximately 6.0 within two hours of slaughter. This last procedure, therefore, has the potential to greatly reduce times between slaughter and freezing without increasing the risk of cold shortening and the associated toughness of meat.     

Spatial variation in yield and quality in a small apple orchard

We describe the yield and quality of apples from a 0.8 ha apple orchard located in northern Greece over two growing seasons and consider the potential for site-specific management. The orchard has two apple cultivars: Red Chief (main cultivar) and Fuji (pollinator). Yield was measured by weighing all fruit harvested from groups of five adjacent trees and the position of the central tree was recorded by GPS. Apple quality at harvest was evaluated from samples of the two cultivars in both years for which fruit mass, flesh firmness, soluble solids content, juice pH and acidity of the juice were determined. The variation in tree flowering was also measured in the spring of the second season using a stereological sampling procedure. The results showed considerable variability in the number of tree flowers, yield and quality across the orchard for both cultivars. The number of flowers was strongly correlated with the final yield. These data could potentially be used to plan precise thinning and for early prediction of yield; the latter is important for marketing the fruit. Several quality characteristics, including fruit juice soluble solids content and acid content were negatively correlated with yield. The general patterns of spatial variation in several variables suggested that changes in topography and aspect had important effects on apple yield and quality.     

Influence of Ovulation Status,Seasonality and Embryo Transfer Method on Development of Cloned Porcine Embryos

To improve pig cloning efficiency, the present study evaluated the effect of ovulation status, seasonality and embryo transfer (ET) method on in vivo development of cloned porcine embryos. Cloned embryos were transferred to surrogate mothers on the same day of somatic cell nuclear transfer. In pre‐ovulation stage (PO), pregnancy rate (PR) and delivery rate (DR) were 36.3% and 9.4%, respectively. In post‐ovulation stage, 22.7% PR and 2.1% DR were recorded (both PR and DR are significantly higher in PO). When ET was performed during winter (December–February), spring (March–May), summer (June–August) and autumn (September–November), the PRs were 13.4%, 37.3%, 24.6% and 51.0%, while DRs were 0%, 12.7%, 4.3% and 7.8%, respectively. The highest PRs were recorded in autumn groups. However, DRs were significantly lower in autumn (7.8%) group compared with spring (12.7%) group. The PR was the lowest and no piglets were born in winter group, which might be because of the effect of low temperature during ET. To overcome the low PR in winter group, 0.25 ml straws were used for ET to minimize exposure time of embryos to ambient temperature. The straw ET group showed significantly higher PR in the winter group (23. 9%) compared with the conventional catheter‐loading group (7.7%). We suggest that using PO recipient and ET in spring is the best condition for pig cloning. In addition, alternative method to reduce cold shock during ET in winter is necessary.     

Conceptual model of a future farm management information system

Future and even current European farmers are experiencing that the managerial tasks for arable farming are shifting to a new paradigm, requiring increased attention to economic viability and the interaction with the surroundings. To this end, an integration of information systems is needed to advise managers of formal instructions, recommended guidelines and documentation requirements for various decision making processes. In the EU funded project FutureFarm, a new model and prototype of a new Farm Information Management System (FMIS) which meets these changing requirements will be developed. The aim of the work presented in this paper is to define and analyse the system boundaries and relevant decision processes for such a novel FMIS as a prerequisite for a dedicated information modelling.The boundaries and scope of the system are described in terms of actors and functionalities, where actors are entities interfacing with the system (e.g. managers, software, databases). In order to analyse the complex and soft systems situations of how to develop an effective FMIS, which effectively meets farmers’ changing needs a conceptual model was developed based on soft systems methodology (SSM) and based on information derived from four pilot farms representing diverse conditions across the EU that are partners of the FutureFarm project. The system components were depicted as part of rich pictures and linked to the subsequent derived conceptual model of the overall system as an outline for the development of the specific FMIS requirements. This research has shown the benefit of using dedicated system analysis methodologies as a preliminary step to the actual design of a novel farm management information system compared with other more rigid and activity oriented system analysis methods.     

A systems analysis of information system requirements for an experimental farm

A systems analysis and design of information requirements for an experimental farm is presented. This study was carried out on the university farm (UF) at the University of Copenhagen in Denmark. The UF has several farm sites, many employees and clients, and collects data on the spatial variability of sites for site-specific management, and is responsible for running field trials. Soft and hard system analyses were performed to better understand the information needs and design an information system for the UF. Soft systems methodology was used to analyse the human activities and to identify user requirements, while a hard systems methodology was used to structure the data handling inside the farm office. The resulting information management system (IMS) includes modules for storage, processing and presentation of spatio-temporal data for research trials and site-specific management. A GIS-based farm IMS including the necessary interfaces was implemented and validated by the UF manager and staff. Limitations and constraints to the full implementation of the IMS in an experimental farm are also discussed.     

Evidence that moxidectin is a greater risk factor than ivermectin in the development of resistance to macrocyclic lactones by Ostertagia spp in sheep in south eastern Australia

AIM: To determine associations between resistance of Ostertagia (= Teladorsagia) spp to macrocyclic lactone (ML) anthelmintics and history of use of anthelmintics, by type, on commercial sheep farms in temperate regions of southern South Australia and Victoria, Australia.

METHODS: Faecal egg count reduction tests (FECRTs) were conducted during a 2.5-year period (from August 2001 to January 2004) and records of the type of anthelmintic used in the 5 years preceding the FECRTs were collected from commercial sheep farms (n=103) in southern South Australia and Victoria, and data analysed retrospectively. ML resistance was defined as <95% reduction of Ostertagia spp 10–14 days after treatment with ivermectin (IVM), orally, at half the manufacturer's recommended dose rate. Use of anthelmintics in the preceding 5 and 10 years on each property was classified according to the nett number of years each of the following classes of drug had been used: IVM oral liquid (IVO), IVM controlled-release capsules (CRCs), abamectin (ABA), moxidectin (MOX) or a non-ML an- thelmintic. The prevalence of ML resistance, by property, was analysed for associations with prior use of anthelmintics.

RESULTS: Resistance by Ostertagia spp to ML anthelmintics was evident on 51/103 (49.5%) properties. The prevalence of resistance was lowest (23%) on properties on which MOX had not been used, and was significantly higher (64–77%) on properties on which MOX had been used for ≥2 of the preceding 5 years (p<0.001). In contrast, the prevalence of resistance was highest (70–74%) on the properties on which IVM, or IVM and/ or ABA, had not been used in the previous 5 years (on which the use of MOX was predominant), and was markedly lower (20– 42%) on properties that had used IVM or IVM and/or ABA for at least one of the preceding 5 years. Prevalence of resistance was higher for properties on which the only ML anthelmintic used was MOX (19/29=66%) than for those on which the only ML used was IVO (2/19=11%; p<0.001). Properties on which the only ML used was MOX were 2.72 times more likely to have resistance than properties on which the only ML used was IVO (95% confidence interval (CI) = 1.01–5.08).

CONCLUSION: Use of MOX for ≥2 of the preceding 5 years was associated with a higher prevalence of resistance to ML by Ostertagia spp on sheep farms in south eastern Australia than the use of IVO.