The relationship of training milestones with racing success in a population of Standardbred horses in New Zealand

AIM: To gather information on the repeatability of a faecal nematode egg count (FEC) reduction (FECR) test (FECRT), evaluating both different methods of calculating efficacy and variations within a method, in order to supply veterinarians and other advisors with sufficient information to apply some level of confidence around a diagnosis of anthelmintic resistance based on FECRT results.

METHODS: Two commercial sheep farms were selected on the basis of having previously recorded FECR <95% after treatment with ivermectin (Farm 1) or albendazole (Farm 2). On each farm at least 250 lambs, managed as a single mob, were individually ear-tagged and sampled for FEC. The resulting counts were used, 3—4 days later, to sort the lambs into 24 groups of 10. First, the animals were split into three groups of 80, having high, medium or low FEC. Second, within each of these groups the 80 animals were further divided into four replicate mobs of 20 (each with the same mean count). Third, each of these replicates was further split into two groups of 10: those that would be drenched and those that would remain as untreated controls. All animals were again faecal-sampled and those in the drenched groups were dosed, using a syringe, to their individual liveweight, with ivermectin (Farm 1) or albendazole (Farm 2). Ten days after treatment all animals were individually faecal- sampled again. FEC and larval cultures were undertaken for all 24 groups from both pre- and post-treatment samples. Ef- ficacy (FECR) of the undifferentiated FECRT was calculated using three different equations, and efficacy by genus was also calculated.

RESULTS: Calculated efficacies differed between equations, and the equation which did not utilise an untreated control yielded significantly lower efficacy estimates on both farms. Faecal cultures varied considerably in the proportions of parasite genera recovered. In general, this did not differ between FEC groups, except on Farm 1 where Haemonchus spp were more common and Cooperia spp less common in high-FEC samples. Estimated efficacies against individual genera varied considerably or very little, depending on the level of resistance. On both farms, differing proportions of tests against some genera passed or failed FECRTs based on a threshold pass mark of ≥95% FECR.

CONCLUSION: There was considerable variability in the outcomes of FECRTs and in larval culture results. Caution is warranted in interpreting the results of FECRTs when efficacy values fall into the 90—95% range. Further, the possibility of a test returning a false-negative result is raised, indicating that even an efficacy estimated ≥95% may not guarantee the absence of resistant parasites.     

BILATERAL ELBOW MALFORMATION IN A CAT CAUSED BY RADIO-ULNAR SYNOSTOSIS

A 9-month-old neutered male cat was referred because of left forelimb lameness. Physical examination, laboratory analysis, and radiographic examination of the entire skeleton were performed. The radiographic diagnosis was bilateral radio-ulnar synostosis with secondary elbow malformation. A comparison between clinical and radiographic findings of the cat and those described in children affected by radio-ulnar synostosis is reported. Correlations and differences are discussed.     

ULTRASONOGRAPHIC APPEARANCE OF OVARIAN TUMORS IN 10 DOGS

Signalment, clinical history, physical examination, clinicopathologic, readiographic and ultrasonographic findings of 10 female dogs with histologically confirmed ovarian neoplasms were reviewed. Ultrasonographic images and reports were reviewed for (1) location, size, outer margins, and echogenicity of the mass(es), (2) presence of free abdominal fluid, (3) evidence of uterine abnormalities, and (4) signs of metastatic disease. The masses were classified according to their ultrasonographic pattern in solid, solid with cystic component, and cystic. The masses were ultrasonographically reported as being of ovarian origin in eight dogs, and this origin was included in the list of differentials in the remaining two dogs. When present, abdominal effusions and uterine abnormalities were diagnosed by means of ultrasound.     

Solar wind outflow and the chromospheric magnetic network

Observations of outflow velocities in coronal holes (regions of open coronal magnetic field) have recently been obtained with the Solar and Heliospheric Observatory (SOHO) spacecraft. Velocity maps of Ne7+ from its bright resonance line at 770 angstroms, formed at the base of the corona, show a relationship between outflow velocity and chromospheric magnetic network structure, suggesting that the solar wind is rooted at its base to this structure, emanating from localized regions along boundaries and boundary intersections of magnetic network cells. This apparent relation to the chromospheric magnetic network and the relatively large outflow velocity signatures will improve understanding of the complex structure and dynamics at the base of the corona and the source region of the solar wind.     

Infestation in the dog by the paralysis tick, Ixodes holocyclus — 4. Cardiovascular effects

To determine the extent and significance of changes in heart rate and rhythm noticed previously in dogs paralysed with Ixodes holocyclus, two studies were undertaken. In one the electrocardiogram was recorded at stages throughout the disease and the traces analysed for changes, while in the second a detailed study of the effect of Ixodes holocyclus on the cardiovascular system was undertaken. The electrocardiographic changes were extremely variable between stages and between dogs. Generally, if a dysrhythmia occurred in stages 1, 2 or 3 it tended to be sinus tachycardia, ventricular tachycardia or sinus arrest. In stage 4 sinus arrest, sinus bradycardia, or sinus or ventricular tachycardia were the prominent dysrhythmias, whereas in stage 5 sinus bradycardia predominated. Cardiovascular measurements indicated an increase in peripheral vascular resistance leading to a significant elevation in mean arterial pressure at all stages of the disease. Cardiac output was decreased significantly only at stage 2, although it was below the control measurements at all stages. Pulmonary arterial pressure was significantly elevated at stages 2, 3 and 4 due most probably to an increase in pulmonary vascular resistance. Myocardial contractility was not significantly changed throughout the disease. The changes observed in the electrocardiogram and the cardiovascular system in stages 1, 2 and 3 are unlikely to be due to hypoxia and could represent dysfunction of the autonomic nervous system. During stages 4 and 5 oxygen levels were below normal and the bradycardia seen terminally is almost certainly due to hypoxaemia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of Gene Interactions in Hybrid Speciation: Evidence from Ancient and Experimental Hybrids

The origin of a new diploid species by means of hybridization requires the successful merger of differentiated parental species' genomes. To study this process, the genomic composition of three experimentally synthesized hybrid lineages was compared with that of an ancient hybrid species. The genomic composition of the synthesized and ancient hybrids was concordant (rs = 0.68, P < 0.0001), indicating that selection to a large extent governs hybrid species formation. Further, nonrandom rates of introgression and significant associations among unlinked markers in each of the three synthesized hybrid lineages imply that interactions between coadapted parental species' genes constrain the genomic composition of hybrid species.     

Presence and diversity of mixed avian Plasmodium spp. infections in introduced birds whose distribution overlapped with threatened New Zealand endemic birds

ABSTRACT

Aims: To determine the presence of infection and co-infection of Plasmodium lineages in introduced birds at translocation sites for the North Island saddleback (Philesturnus rufusater), to investigate their role as Plasmodium spp. reservoirs.

Methods: Blood samples were collected from introduced bird species, with a special focus on blackbirds (Turdus merula) and song thrushes (Turdus philomelos), at six locations in the North Island of New Zealand that were the origin, or translocation sites, for North Island saddleback. Where available, blood smears were examined, and blood samples were tested using nested PCR with subsequent sequence analysis, for the presence of Plasmodium spp.

Results: Of the 55 samples tested using PCR analysis, 39 (71%) were positive for Plasmodium spp., and 28/40 (62%) blood smears were positive for Plasmodium spp. Overall, 31 blood samples were from blackbirds with 28/31 (90%) samples positive for Plasmodium spp. Six distinct avian Plasmodium lineages were identified, including three cosmopolitan lineages; Plasmodium vaughani SYAT05 was detected in 16 samples, Plasmodium matutinum Linn1 in 10 samples and Plasmodium elongatum GRW6 in eight samples. Mixed infections with more than one lineage were detected in 12 samples. Samples from two Australian magpies (Gymnorhina tibicen) were positive for Plasmodium. sp. lineage MYNA02, previously not identified in New Zealand.

Conclusions and clinical relevance: This is the first report from New Zealand in which specific Plasmodium spp. mixed infections have been found in introduced birds. Co-infections with several cosmopolitan Plasmodium lineages were identified, as well as the first report in New Zealand of an exotic avian Plasmodium sp. lineage, in Australian magpies. Whilst the role of introduced birds in maintaining and spreading pathogenic avian malaria in New Zealand is unclear, there is a potential infection risk to native birds, especially where distributions overlap.