Activation of Zona‐Free Buffalo (Bubalus bubalis) Oocytes by Chemical or Electrical stimulation,and Subsequent Parthenogenetic Embryo Development

Parthenogenetic activation using zona‐free oocytes offers an alternative model that could be applied to develop protocols for the activation of reconstructed embryos for cloning. The aim of this study was to compare the efficacy of different methods for the activation of zona‐free buffalo oocytes in terms of their effects on the developmental competence of parthenogenetic embryos. The effects of zona removal on parthenogenetic activation and in vitro developmental competence of metaphase II oocytes were also examined. All activation methods were followed by incubation of 2 mm 6‐dimethylaminopurine (6‐DMAP) for 4 h. Out of three different pulse strengths (1.2, 2.1 or 3.3 kV/cm) used, 2.1 kV/cm resulted in the highest blastocyst rate (25.3%). On comparing different chemical agents and electric pulse, highest blastocyst rate was observed for calcium ionophore (CaI) (28.6%) followed by ethanol (25.0%), electric pulse (22.5%) and combined CaI and ethanol treatment (16.7%) although differences among them were not significant. Furthermore, a significantly reduced developmental potential was observed in zona‐free oocytes when compared to zona‐intact ones up to the blastocyst stage (44.3% vs 27.1%). In conclusion, zona‐free buffalo oocytes can be successfully activated for parthenogenetic development using chemical or electrical stimulation. Out of different agents examined, CaI followed by 6‐DMAP resulted in the highest blastocyst rate.     

Oocyte viability and cortical activation under different salt solutions in Prochilodus lineatus (Teleostei: Prochilodontidae)

This study aimed to evaluate the effect of five salt solutions in the maintenance of morphological features of cortical alveolus, hydration and fertilization capacity of Prochilodus lineatus oocytes. For this purpose, five saline solutions were tested: Ringer's solution, Ringer's lactate solution, Hank's balanced salt solution (HBSS), Hank's balanced salt solution without calcium (HBSS without calcium) and solution for salmonid eggs. Oocytes were maintained for 2 hr in saline solution with controlled temperature subsequently evaluated for hydration, cortical activation and fertilization ability. In the evaluation of the fertilization ability, two controls were used: C1—fertilized oocytes after extrusion—and C2—oocytes kept in ovarian fluid and fertilized after 2 hr. There was a significant reduction in the viability of oocytes C2 (28.8% ± 12.9%) compared to C1 (65.3% ± 26.7%), and no significant differences were found between treatments HBSS and HBSS without calcium and C2. Only HBSS and HBSS without calcium maintained the non‐activated state of the gametes, with a fertilization rate of 16.4% ± 6.7% and 5.6% ± 2.3%, respectively; however, they did not extend the viability of oocytes, such that they continued to undergo degradation during the storage period, similar to oocytes retained only in ovarian fluid.     

Comparison of intradermal testing and serum testing for allergen-specific IgE using monoclonal IgE antibodies in 84 atopic dogs

OBJECTIVE: To compare an ELISA measuring serum allergen-specific IgE with intradermal skin testing in canine atopic dermatitis. PROCEDURE: Eighty-four dogs with the clinical diagnosis of atopic dermatitis underwent intradermal skin testing and serum testing for allergen-specific IgE. Tests were performed in a blinded fashion. Positive reactions were compared and the sensitivity and specificity of the serum test (using intradermal skin test as the standard) were determined overall and for individual allergen groups (grass pollens, weed pollens, tree pollens, house dust mites and fleas). RESULTS: The sensitivity of the ELISA overall was 90.4%. Evaluating the individual allergen groups, the sensitivity for dust mite hypersensitivity was 95.1%, for fleas 85.4%, for tree pollens 84.3%, for grass pollens 95.1% and for weed pollens 96.4%. The specificity was 91.6% overall, for dust mites 96.3%, for fleas 92.7%, for tree pollens 95.2%, for grass pollens 94% and for weed pollens 80.7%. CONCLUSION: The evaluated ELISA seemed reliable for the diagnosis of atopy in practice and can be recommended as a screening test prior to intradermal skin testing or for use in dogs when immunotherapy is not a therapeutic option.     

Risk factors for musculoskeletal injuries of the lower limbs in Thoroughbred racehorses in New Zealand

AIM: To investigate risk factors for injury to musculoskeletal structures of the lower fore- and hind-limbs of Thoroughbred horses training and racing in New Zealand.

METHODS: A case-control study analysed by logistic regression was used to compare explanatory variables for musculoskeletal injuries (MSI) in racehorses. The first dataset, termed the Training dataset, involved 459 first-occurrence cases of lower-limb MSI in horses in training, and the second, the Starting dataset, comprised a subset of those horses that had started in at least one trial or race in the training preparation that ended with MSI (n=294). All training preparations for horses that did not suffer from MSI for which complete data were available were used in the analyses as controls, and provided 2,181 and 1,639 preparations for the Training and Starting datasets, respectively. Multivariate logistic regression was used to evaluate risk factors, and results were reported as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS: Horses aged ≥5 years were at higher risk of injury than 2-year-olds. Elevated odds of MSI occurred in horses in the Starting dataset that were training in the 1997–1998 year compared with the 1999–2000 year, and in those horses where trials comprised >20% of all starts in a preparation. Training preparations that ended in winter, and horses in their third or later training preparation, had lower odds of MSI compared with those ending in other seasons or the first preparation, respectively. Reduced odds of MSI were observed in preparations in which starts occurred compared with those that had no starts, and in the Starting dataset, preparations that included more than one start had a reduced likelihood of MSI compared with preparations that had only one start. In the Training dataset, preparations longer than 20 weeks were associated with reduced odds of MSI compared with those shorter than 20 weeks.

Cumulative racing distance in the last 30 days of a training preparation was best modelled with linear and quadratic terms. Results indicated that increasing cumulative racing distances were associated with an initial reduction in the odds of MSI that then levelled out and finally appeared to increase again as the explanatory variable continued to increase. The risk of MSI varied significantly between trainers.

CONCLUSION: This study identified intrinsic (age) and extrinsic risk factors for MSI in training and racing Thoroughbreds in New Zealand. The risk of MSI initially decreased, then increased, as cumulative racing distance increased. Significant variation between trainers indicated management and training methods influence the risk of MSI.     

Decision support systems for monitoring and maintaining health in food animal populations

To mitigate the effects of risks to food safety and infectious disease outbreaks in farmed animals, animal health authorities need to have systems in place to identify and trace the source of identified problems in a timely manner. In the event of emergencies, these systems will allow infected or contaminated premises (and/or animals) to be identified and contained, and will allow the extent of problems to be communicated to consumers and trading partners in a clear and unambiguous manner. The key to achieving these goals is the presence of an effective animal health decision support system that will provide the facilities to record and store detailed information about cases and the population at risk, allowing information to be reported back to decision makers when it is required. Described here are the components of an animal health decision support system, and the ways these components can be used to enhance food safety, responses to infectious disease incursions, and animal health and productivity. Examples are provided to illustrate the benefit these systems can return, using data derived from countries that have such systems (or parts of systems) in place. Emphasis is placed on the features that make particular system components effective, and strategies to ensure that these are kept up to date.