Morphological diversity of ruminal bacteriophages from sheep and cattle

Large numbers of bacteriophages (2 x 10(7) to 1 x 10(8)/ml) were present in ruminal fluid from sheep and cattle. Twenty-six distinct types were identified and placed in three morphological groups; several phages possessed unusual structural features. The large numbers and diversity of phages observed indicates a possible role in bacterial lysis and hence in the population dynamics of the ruminal bacteria.

Effect of Increasing Low Dose Simplexin Exposure in Cattle consuming Pimelia trychostachya

Pimelea species (or desert riceflower) are small native plants endemic to the drier inland pastoral regions of Australia, which cause a unique syndrome in grazing cattle characterised by submandibular oedema and oedema in the brisket area as a result of right-sided heart failure attributed to the toxin simplexin. Field evidence suggests that poisoning can occur through minor, inadvertent consumption of Pimelea plant material, but the minimum simplexin intake required to induce Pimelea poisoning is not known. In this study, mild Pimelea poisoning was induced at a daily dose of 12.5 mg Pimelea/kg bodyweight per day, equivalent to 2.5 µg simplexin/kg bodyweight per day, demonstrating the high potential toxicity of these plant species. Effects in all animals diminished with prolonged low dose feeding and we postulate that these animals developed mechanisms for detoxifying simplexin, 1, possibly through rumen bacteria adaptation or activation of liver enzymes.

Cattle herd inspections and fly trapping for the detection of the Old World screw-worm fly (Chrysomya bezziana)

ObjectivesTo compare the sensitivity of inspections of cattle herds and adult fly trapping for detection of the Old World screw-worm fly (OWS). ProceduresThe incidence of myiases on animals and the number of OWS trapped with LuciTrap (R)/Bezzilure were measured concurrently on cattle farms on Sumba Island (Indonesia) and in peninsular Malaysia (two separate periods for the latter). The numbers of animal inspections and traps required to achieve OWS detection at the prevalent fly densities were calculated. ResultsOn Sumba Island, with low-density OWS populations, the sensitivity of herd inspections and of trapping for OWS detection was 0.30 and 0.85, respectively. For 95% confidence of detecting OWS, either 45 inspections of 74 animals or trapping with 5 sets of 4 LuciTraps for 14 days are required. In Malaysia, at higher OWS density, herd inspections of 600 animals (twice weekly, period 1) or 1600 animals (weekly, period 2) always detected myiases (sensitivity = 1), while trapping had sensitivities of 0.89 and 0.64 during periods 1 and 2, respectively. For OWS detection with 95% confidence, fewer than 600 and 1600 animals or 2 and 6 LuciTraps are required in periods 1 and 2, respectively. ConclusionsInspections of cattle herds and trapping with LuciTrap and Bezzilure can detect OWS populations. As a preliminary guide for OWS detection in Australia, the numbers of animals and traps derived from the Sumba Island trial should be used because the prevailing conditions better match those of northern Australia.

Using UHF proximity loggers to quantify male–female interactions: A scoping study of estrous activity in cattle

Reproductive efficiency is an important determinant of profitable cattle breeding systems and the success of assisted reproductive techniques (ART) in wildlife conservation programs. Methods of estrous detection used in intensive beef and dairy cattle systems lack accuracy and remain the single biggest issue for improvement of reproductive rates and such methods are not practical for either large-scale extensive beef cattle enterprises or free-living mammalian species. Recent developments in UHF (ultra high frequency) proximity logger telemetry devices have been used to provide a continuous pair-wise measure of associations between individual animals for both livestock and wildlife. The objective of this study was to explore the potential of using UHF telemetry to identify the reproductive cycle phenotype in terms of intensity and duration of estrus. The study was conducted using Belmont Red (interbred Africander Brahman Hereford–Shorthorn) cattle grazing irrigated pasture on Belmont Research Station, northeastern Australia. The cow-bull associations from three groups of cows each with one bull were recorded over a 7-week breeding season and the stage of estrus was identified using ultrasonography. Telemetry data from bull and cows, collected over 4 8-day logger deployments, were log transformed and analyzed by ANOVA. Both the number and duration of bull-cow affiliations were significantly (P < 0.001) greater in estrous cows compared to anestrus cows. These results support the development of the UHF technology as a hands-off and noninvasive means of gathering socio-sexual information on both wildlife and livestock for reproductive management.

Implications of retaining woody regrowth for carbon sequestration for an extensive grazing beef business: a bio-economic modelling case study

A bio-economic modelling framework (GRASP-ENTERPRISE) was used to assess the implications of retaining woody regrowth for carbon sequestration on a case study beef grazing property in northern Australia. Five carbon farming scenarios, ranging from 0% to 100% of the property regrowth retained for carbon sequestration, were simulated over a 20-year period (1993–2012). Dedicating regrowth on the property for carbon sequestration reduced pasture (up to 40%) and herd productivity (up to 20%), and resulted in financial losses (up to 24% reduction in total gross margin). A net carbon income (income after grazing management expenses are removed) of $2–4 per t CO2-e was required to offset economic losses of retaining regrowth on a moderately productive (~8 ha adult equivalent–1) property where income was from the sale of weaners. A higher opportunity cost ($ t–1 CO2-e) of retaining woody regrowth is likely for feeder steer or finishing operations, with improved cattle prices, and where the substantial transaction and reporting costs are included. Although uncertainty remains around the price received for carbon farming activities, this study demonstrated that a conservatively stocked breeding operation can achieve positive production, environmental and economic outcomes, including net carbon stock. This study was based on a beef enterprise in central Queensland’s grazing lands, however, the approach and learnings are expected to be applicable across northern Australia where regrowth is present.

Recent development and commercial adoption of legumes for heavy clay soils in Queensland

In previous chapters of this volume, various authors describe the development of herbaceous legumes for pastures on clay soils in Queensland until about the 1980s. Emphasis is on the collection and evaluation of the genus Desmanthus, given its relatively recent addition to agriculture and considerable potential for providing useful pasture legumes for clay soils, particularly in the seasonally dry areas of northern Australia. Other genera are also discussed, including early assessments of herbaceous legumes that were later developed for clay soils (Clitoria, Macroptilium and Stylosanthes). This chapter provides a summary of the development of herbaceous legumes for clay soils in Queensland from these earlier assessments until present. Beef cattle farming is the principal agricultural enterprise in seasonally dry areas of northern Australia, including large areas of clay soils in Queensland. Sown and naturally occurring grasses provide the key feed resource, and the inclusion of sown legumes can significantly improve live-weight gain and reproductive performance per unit area. Queensland has been the centre of development for legumes for clay soils in tropical and subtropical areas of Australia, mostly through assessing and developing plants held in the Australian Tropical Forages Genetic Resource Collection (ATFGRC) (now a component of the Australia Pastures Genebank (APG)). The systematic appraisal of genetic material for clay soils was a focus of well-resourced government research up to the early to mid-1990s, but declined thereafter as sown pasture research teams were dismantled and funding to maintain the ATFGRC declined. Cultivar development is now conducted by small government, private enterprise and university research teams that collaborate where possible. In recent studies the use of experienced researcher knowledge and old plant evaluation sites has been particularly valuable for identifying potentially useful material. Cultivars for long- and short-term pastures on clay soils have been developed to the level of commercial seed production for Desmanthus (five cultivars from four species with two cultivars (one composite) in current use), Clitoria ternatea (one cultivar), Macroptilium bracteatum (two) and Stylosanthes seabrana (two). Other potential cultivars of these species are currently in various stages of development. Each species has different production niches depending on climate, clay soil type and grazing strategy. Adoption of these cultivars is occurring but has variously been impeded by limited promotion, mismatch of seed supply and demand, and difficulty establishing legumes in pastures of some key grass species. Recent renewed investment by the Australian Beef Industry has seen revived government research into pasture legumes in Queensland and rejuvenation of the APG.

Distribution and abundance of white grubs (Coleoptera: Scarabaeidae) on groundnut in southern India

Scarab species associated with groundnuts were surveyed in Andhra Pradesh, Karnataka and Tamil Nadu, southern India, between 1995 and 2001. Scarab adults were collected from trees on which they were feeding and/or mating, and larvae (white grubs) from groundnut fields. Holotrichia species, especially H. reynaudi and H. serrata were the major species associated with groundnut. H. reynaudi predominated in the central Deccan area, while H. serrata was most abundant in areas to the south and west. A new, undescribed, Holotrichia species near H. consanguinea was collected south and south-west of Hyderabad in mixed populations with H. reynaudi. However, the full extent of this new species’ distribution remains uncertain. H. rufoflava was rarely associated with groundnut, but was common as an adult at some locations. Other genera encountered during surveys were Anomala, Adoretus, Schizonycha, Autoserica. In survey data, densities of Holotrichia larvae and ‘all other white grubs’ were both very highly correlated with % of damaged groundnut plants. These correlations in combination with concurrent observations of plant damage establish a causal link between white grubs and plant damage and death in southern Indian groundnut. Ranking of preferred host trees for adults were developed from field observations for four Holotrichia species and Schizonycha spp. and will assist grower-initiated surveys of pest occurrence. In combination with insecticide efficacy data published elsewhere, the survey provides the basis for an environmentally friendly and economically viable pest-management system for white grubs on groundnut in southern India.

Validation of a Competitive Enzyme-Linked Immunosorbent Assay for Detection of Babesia bigemina Antibodies in Cattle

A competitive enzyme-linked immunosorbent assay (cELISA) based on a broadly conserved, species-specific, B-cell epitope within the C terminus of Babesia bigemina rhoptry-associated protein 1a was validated for international use. Receiver operating characteristic analysis revealed 16% inhibition as the threshold for a negative result, with an associated specificity of 98.3% and sensitivity of 94.7%. Increasing the threshold to 21% increased the specificity to 100% but modestly decreased the sensitivity to 87.2%. By using 21% inhibition, the positive predictive values ranged from 90.7% (10% prevalence) to 100% (95% prevalence) and the negative predictive values ranged from 97.0% (10% prevalence) to 48.2% (95% prevalence). The assay was able to detect serum antibody as early as 7 days after intravenous inoculation. The cELISA was distributed to five different laboratories along with a reference set of 100 defined bovine serum samples, including known positive, known negative, and field samples. The pairwise concordance among the five laboratories ranged from 100% to 97%, and all kappa values were above 0.8, indicating a high degree of reliability. Overall, the cELISA appears to have the attributes necessary for international application.

Drivers for uptake of environmental management systems by pastoralists in western Queensland

Pastoralists from 37 beef cattle and sheep properties in western Queensland developed and implemented an environmental management system (EMS) over 18 months. The EMS implemented by them was customised for the pastoral industry as part of a national EMS pilot project, and staff from this project encouraged and assisted pastoralists during this trial. The 31 pastoralists surveyed at the end of the pilot project identified few benefits of EMS implementation, and these were largely associated with environmental management and sustainability. In terms of the reasons for uptake of an EMS, these pastoralists identified drivers similar to those reported in other primary industry sectors. These included improving property and environmental management, financial incentives, a range of market benefits, assistance with red tape issues, access to other training opportunities and assistance and support with the development of their EMS. However, these drivers are weak, and are not motivating pastoralists to adopt an EMS. In contrast, barriers to adoption such as the time involved in developing and implementing EMS are tangible and immediate. Given a lack of effective drivers and that pastoralists are under considerable pressure from ongoing rural adjustment processes, it is not surprising that an EMS is a low priority. It is concluded that widespread uptake and on-going use of an EMS in the pastoral industry will not occur unless pastoralists are required or rewarded for this by markets, governments, financiers, and regional natural resource management bodies.

Insecticide resistance and implications for future aphid management in Australian grains and pastures: A review

Aphids can cause substantial damage to cereals, oilseeds and legumes through direct feeding and through the transmission of plant pathogenic viruses. Aphid-resistant varieties are only available for a limited number of crops. In Australia, growers often use prophylactic sprays to control aphids, but this strategy can lead to non-target effects and the development of insecticide resistance. Insecticide resistance is a problem in one aphid pest of Australian grains in Australia, the green peach aphid (Myzus persicae). Molecular analyses of field-collected samples demonstrate that amplified E4 esterase resistance to organophosphate insecticides is widespread in Australian grains across Australia. Knockdown resistance to pyrethroids is less abundant, but has an increased frequency in areas with known frequent use of these insecticides. Modified acetylcholinesterase resistance to dimethyl carbamates, such as pirimicarb, has not been found in Australia, nor has resistance to imidacloprid. Australian grain growers should consider control options that are less likely to promote insecticide resistance, and have reduced impacts on natural enemies. Research is ongoing in Australia and overseas to provide new strategies for aphid management in the future.

Agonosoma trilineatum (Heteroptera: Scutelleridae) a biological control agent of the weed bellyache bush, Jatropha gossypiifolia (Euphorbiaceae)

Bellyache bush, Jatropha gossypiifolia L., is a serious weed of northern Australia. Agonosoma trilineatum (F.) is an insect from tropical America released in Australia in 2003 as a biological control agent against bellyache bush. It feeds on seeds and has the potential to reduce seed production, thereby potentially reducing the rate of spread and recruitment. To test the host specificity of A. trilineatum, four biological responses to host plant species were determined: development of nymphs, oviposition preferences, adult feeding and frequency of mating. Development of nymphs to adults and adult feeding only occurred on three Jatropha spp. These species also supported mating and oogenesis but only J. gossypiifolia was accepted for oviposition. Mating did not occur in the presence of other plant species. The evidence indicates that there is little risk associated with the release of this insect species in Australia and probably other countries where this weed is a problem. The probability of this insect expanding its host range is low because multiple aspects of the biology would need to change simultaneously. A. trilineatum was released in Australia between 2003 and 2007. A Climex model indicated that coastal areas of Queensland and the Northern Territory would be climatically most suitable for this insect.

Kangaroo bacteria to reduce methane emissions and increase productivity

Using kangaroo bacteria to reduce emissions of methane and increase productivity.

Swan’s Lagoon Celebrating 50 years

Swan’s Lagoon, which is 125 km south-south-west of Townsville, was purchased by the Queensland Government as a beef cattle research station in 1961. It is situated within the seasonally-dry tropical spear grass region of North Queensland. The station was expanded from 80 km2 to 340 km2 by purchase of the adjoining Expedition block in 1978. The first advisory committee formed and initiated research in 1961. The median annual rainfall of 708 mm (28 inches) is highly variable, with over 80% usually falling in December–April. Annual evaporation is 2.03 metres. The 60% of useable area is mostly flat with low fertility duplex soils, of which more than 50% is phosphorus deficient. Natural spear grass-based pastures predominate over the station. Swan’s Lagoon research has contributed to understanding the biology of many aspects of beef production for northern Australia. Research outcomes have provided options to deal with the region’s primary challenges of weaning rates averaging less than 60%, annual growth rates averaging as little as 100 kg, high mortality rates and high management costs. All these relate to the region’s variable and highly seasonal rainfall—challenges that add to insect-borne viruses, ticks, buffalo fly and internal parasites. As well as the vast amount of practical beef production science produced at Swan’s Lagoon, generations of staff have been trained there to support beef producers throughout Queensland and northern Australia to increase their business efficiency. The Queensland Government has provided most of the funds for staffing and operations. Strong beef industry support is reflected in project funding from meat industry levies, managed by Meat and Livestock Australia (MLA) and its predecessors. MLA has consistently provided the majority of operational research funding since the first grant for ‘Studies of management practices, adaption of different breeds and strains to tropical environments, and studies on tick survival and resistance’ in 1962–63. A large number of other agencies and commercial companies have also supported research.

Comparison of bioassay responses to the potential fungal biopesticide Metarhizium anisopliae in Rhipicephalus(Boophilus) microplus and Lucilia cuprina.

Quantal response bioassays were conducted with cattle ticks and sheep blowflies with three different isolates of Metarhizium anisopliae and different methods of inoculation. Ticks were either topically dosed with 2 mu l or immersed in the conidial preparations. Blowflies were either topically dosed with 2 mu l of the conidial preparation or fed on conidia mixed with sugar. Probit analyses were carried out on the mortality data to compare the virulence of these isolates to ticks and blowflies and look for indications of different virulence mechanisms employed by M. anisopliae isolates when invading these hosts. One isolate (ARIM16) showed high virulence to both hosts killing 95% of ticks after 2 days and 88 (+/- 2)% of blowflies after 4 days. Strikingly different mortality patterns indicated that virulence is dependent on different mechanisms in ticks and blowflies. The pattern of mortality seen with ticks suggested that the number of conidia adhering per unit area of the cuticle was more important for rapid tick death than the total number of conidia contacting the entire tick surface. Blowflies fed conidia mixed with food died rapidly after an initial lag phase regardless of dose.

Foraging behaviours of Diachasmimorpha kraussii (Fullaway) (Hymenoptera: Braconidae) and its host Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) in a nectarine (Prunus persica (L.) Batsch var. nectarina (Aiton) Maxim) orchard

Diachasmimorpha kraussii is a larval parasitoid of dacine fruit flies. Host utilisation behaviour, including field foraging behaviour, is poorly known in this species. The diurnal foraging behaviour of D. kraussii and one of its common hosts, Bactrocera tryoni, in a nectarine orchard was concurrently recorded. Observations of mating, resting, feeding and oviposition were taken two-hourly on 42 trees, commencing at 07:00 h and terminating at 17:30 h, for 17 days. Resting and oviposition were common events within the orchard for both species, while mating behaviours were not recorded in the orchard for either species. Feeding was not observed for D. kraussii and was rare for B. tryoni. At the level of the individual tree there was a very weak, but significant correlation between parasitoid and fly abundance over a day, but when broken down to the individual observation periods the correlations were absent, or were weakly significant in an inconsistent manner (i.e. sometimes positively correlated, sometimes negatively correlated). At the orchard level, abundance of the parasitoid was not correlated with adult fly abundance. Results suggest that D. kraussii forage independently to adult B. tryoni, a result consistent with a prediction that their foraging is largely driven by larval or plant damage cues.