Spatial model of site index based on Y-ray spectrometry and a digital elevation model for two Pinus species in Tuan Toolara State Forest, Queensland, Australia

Site index prediction models are an important aid for forest management and planning activities. This paper introduces a multiple regression model for spatially mapping and comparing site indices for two Pinus species (Pinus elliottii Engelm. and Queensland hybrid, a P. elliottii x Pinus caribaea Morelet hybrid) based on independent variables derived from two major sources: g-ray spectrometry (potassium (K), thorium (Th), and uranium (U)) and a digital elevation model (elevation, slope, curvature, hillshade, flow accumulation, and distance to streams). In addition, interpolated rainfall was tested. Species were coded as a dichotomous dummy variable; interaction effects between species and the g-ray spectrometric and geomorphologic variables were considered. The model explained up to 60% of the variance of site index and the standard error of estimate was 1.9 m. Uranium, elevation, distance to streams, thorium, and flow accumulation significantly correlate to the spatial variation of the site index of both species, and hillshade, curvature, elevation and slope accounted for the extra variability of one species over the other. The predicted site indices varied between 20.0 and 27.3 m for P. elliottii, and between 23.1 and 33.1 m for Queensland hybrid; the advantage of Queensland hybrid over P. elliottii ranged from 1.8 to 6.8 m, with the mean at 4.0 m. This compartment-based prediction and comparison study provides not only an overview of forest productivity of the whole plantation area studied but also a management tool at compartment scale.

Use of part records in Merino breeding programs - The inheritance of wool growth and fibre traits during different times of the year to determine their value in Merino breeding programs

Fibre diameter can vary dramatically along a wool staple, especially in the Mediterranean environment of southern Australia with its dry summers and abundance of green feed in spring. Other research results have shown a very low phenotypic correlation between fibre diameter grown between seasons. Many breeders use short staples to measure fibre diameter for breeding purposes and also to promote animals for sale. The effectiveness of this practice is determined by the relative response to selection by measuring fibre traits on a full 12 months wool staple as compared to measuring them only on part of a staple. If a high genetic correlation exists between the part record and the full record, then using part records may be acceptable to identify genetically superior animals. No information is available on the effectiveness of part records. This paper investigated whether wool growth and fibre diameter traits of Merino wool grown at different times of the year in a Mediterranean environment, are genetically the same trait, respectively. The work was carried out on about 7 dyebanded wool sections/animal.year, on ewes from weaning to hogget age, in the Katanning Merino resource flocks over 6 years. Relative clean wool growth of the different sections had very low heritability estimates of less than 0.10, and they were phenotypically and genetically poorly correlated with 6 or 12 months wool growth. This indicates that part record measurement of clean wool growth of these sections will be ineffective as indirect selection criteria to improve wool growth genetically. Staple length growth as measured by the length between dyebands, would be more effective with heritability estimates of between 0.20 and 0.30. However, these measurements were shown to have a low genetic correlation with wool grown for 12 months which implies that these staple length measurements would only be half as efficient as the wool weight for 6 or 12 months to improve total clean wool weight. Heritability estimates of fibre diameter, coefficient of variation of fibre diameter and fibre curvature were relatively high and were genetically and phenotypically highly correlated across sections. High positive phenotypic and genetic correlations were also found between fibre diameter, coefficient of variation of fibre diameter and fibre curvature of the different sections and similar measurements for wool grown over 6 or 12 months. Coefficient of variation of fibre diameter of the sections also had a moderate negative phenotypic and genetic correlation with staple strength of wool staples grown over 6 months indicating that coefficient of variation of fibre diameter of any section would be as good an indirect selection criterion to improve stable strength as coefficient of variation of fibre diameter for wool grown over 6 or 12 months. The results indicate that fibre diameter, coefficient of variation of fibre diameter and fibre curvature of wool grown over short periods of time have virtually the same heritability as that of wool grown over 12 months, and that the genetic correlation between fibre diameter, coefficient of variation of fibre diameter and fibre curvature on part and on full records is very high (rg > 0.85). This indicates that fibre diameter, coefficient of variation of fibre diameter and fibre curvature on part records can be used as selection criteria to improve these traits. However, part records of greasy and clean wool growth would be much less efficient than fleece weight for wool grown over 6 or 12 months because of the low heritability of part records and the low genetic correlation between these traits on part records and on wool grown for 12 months.

Australian Bat Lyssavirus

In Chapter 1, the literature relating to rabies virus and the rabies like lyssaviruses is reviewed. In Chapter 2, data are presented from 1170 diagnostic submissions for ABLV testing by fluorescent antibody test (Centocor FAT). All 27 non-bat submissions were ABLV-negative. Of 1143 bat accessions 74 (16%) were ABLV-positive, including 69 of 974 (7.1%) flying foxes (Pteropus spp.), 5 of 7 (71.4%) Saccolaimus flaviventris (Yellow-bellied sheathtail bats), none of 151 other microchiropteran bats, and none of 11 unidentified bats. Statistical analysis of data from 868 wild Black, Grey-headed, Little Red and Spectacled flying foxes (Pteropus alecto, P. poliocephalus, P. scapulatus, and P. conspicillatus) indicated that three factors; species, health status and age were associated with significant (p< 0.001) differences in the proportion of ABLV-positive bats. Other factors including sex, whether the bat bit a person or animal, region, year, and season submitted, were not associated with ABLV. Case data for 74 ABLV-positive bats, including the circumstances in which they were found and clinical signs, is presented. In Chapter 3, the aetiological diagnosis was investigated for 100 consecutive flying fox submissions with neurological signs. ABLV (32%), spinal and head injuries (29%), and neuro-angiostrongylosis (18%) accounted for most neurological syndromes in flying foxes. No evidence of lead poisoning was found in unwell (n=16) or healthy flying foxes (n=50). No diagnosis was reached for 16 cases, all of which were negative for ABLV by TaqMan PCR. The molecular diversity of ABLV was examined in Chapter 4 by sequencing 36 bases of the leader sequence, the entire N gene, and start of the P gene of 28 isolates from pteropid bats and 3 isolates from Yellow-bellied sheathtail (YBST) bats. Phylogenetic analysis indicated all ABLV isolates clustered together as a discrete group within the Lyssavirus genera closely related to rabies virus and European bat lyssavirus-2 isolates. The ABLV lineage consisted of two variants; one (ybst-ABLV) consisted of isolates only from YBST bats, the other (pteropid-ABLV) was common to Black, Grey-headed and Little Red flying foxes. No associations were found between the sequences and either the geographical location or year found, or individual flying fox species. In Chapter 5, 15 inocula prepared from the brains or salivary glands of naturally-infected bats were evaluated by intracerebral (IC) and footpad (FP) inoculation of Quackenbush mice in order to select and characterize a highly virulent inoculum for further use in bats (Inoculum 5). In Chapter 6, nine Grey-headed flying foxes were inoculated with 105.2 to 105.5 MICED50 of Inoculum 5 divided into four sites, left footpad, pectoral muscle, temporal muscle and muzzle. Another bat was inoculated with half this dose divided into the footpad and pectoral muscle only. Seven of 10 bats developed clinical disease of 1 to 4 days duration between PI-days 10 and 19 and were shown to be ABL-positive by FAT, HAM immunoperoxidase staining, virus isolation in mice, and TaqMan PCR. Five of the seven bats displayed overt aggression, one died during a seizure, and one showed intractable agitation, pacing, tremors, and ataxia. Viral antigen was demonstrated throughout the central and peripheral nervous systems and in the epithelial cells of the submandibular salivary glands (n=4). All affected bats had mild to moderate non-suppurative meningoencephalitis and severe ganglioneuritis. No ABLV was detected in three bats that remained well until the end of the experiment on day 82. One survivor developed a strong but transient antibody response. In Chapter 7, the relative virulence of inocula prepared from the brains and salivary glands of experimentally infected flying foxes was evaluated in mice by IC and FP inoculation and TaqMan assay. The effects in mice were correlated to the TaqMan CT value and indicated a crude association between virulence and CT value that has potential application in the selection of inocula. In Chapter 8, 36 Black and Grey-headed flying foxes were vaccinated with one (day 0) or two (+ day 28) doses of Nobivac rabies vaccine and co-vaccinated with keyhole limpet haemocyanin (KLH). All bats responded to the Nobivac vaccine with a rabies-RFFIT titer > 0.5 IU/mL that is nominally indicative of protective immunity. Plasma from bats with rabies titres >2 IU/mL had cross-neutralising ABLV titres >1:154. A specifically developed ELISA detected a strong but transient response to KLH.

Myelodysplasia as a cause of hindlimb ataxia in two beef calves.

Myelodysplasia is a general term referring to abnormal development of the spinal cord. Unless associated with vertebral malformations, it can be difficult to distinguish clinically from other causes of spinal cord disease. These case reports describe the clinical and pathological findings in two calves with a distinctive non-progressive pelvic limb ataxia. The syndrome was observed in two calves on a large, extensively managed beef cattle property near Richmond, north Queensland. Both calves had similar clinical signs, including hindlimb ataxia with swaying of the pelvis and a well-coordinated bilateral hopping-like action. The differential diagnoses are discussed. A focal or diffuse myelodysplasia should be suspected in calves that have exhibited a non-progressive hindlimb ataxia from birth.