Grazier perceptions and management practices for liver fluke control in north eastern NSW, Australia.

A survey of livestock producers (graziers) located in north eastern NSW Australia, collected information on perceptions and management practices for liver fluke control in livestock. The total area farmed by the 161 respondents was 195,600 ha (ranging in size from 4 to 10,522 ha) with cattle and sheep being the dominant livestock enterprises. Overall, 80% of graziers relied exclusively on anthelmintics for liver fluke control and few of these graziers (9%) integrated parasite management (IPM) strategies to reduce disease prevalence.

Ecology of the free-living stages of Trichostrongylid parasites of sheep.

The prevalence of gastrointestinal nematodes (GINs) is dictated by environmental conditions which influence the survival, development, and migration rates of the free-living stages. While the faecal pellet is the most important micro-environment for GINs, limited data on the impact of temperature and faecal water content (FWC) on their survival, development, and migration limits accurate prediction of nematode pasture infectivity. This study investigated the impact of temperature and FWC on the dynamics of the free-living stages of T.

Prevalence and gross pathology of liver fluke in macropods cohabiting livestock farms in north eastern NSW, Australia, and diagnosis using cELISA.

Liver fluke () is a parasite of herbivores including wildlife. Macropods such as Eastern grey kangaroo () and Common wallaroo (), are frequently observed sharing grazing sites with domestic livestock. The impact of Macropods, as reservoirs of infection, on livestock production and risks to cross-species transmission are largely unknown.

Kangaroos and liver fluke: The role played in cross-species transmission and drug resistance.

Australian livestock are challenged by liver fluke (Fasciola hepatica) in grazing regions endemic to the intermediate snail host. Liver fluke infests a wide range of herbivores including free-roaming wildlife such as kangaroos (Macropods). The role played by Macropods in cross-species transmission and as vectors for anthelmintic resistance is largely unknown.

Australian surveys on parasite control in sheep between 2003 and 2019 reveal marked regional variation and increasing utilisation of online resources and on-farm biosecurity practices.

Australian Wool Innovation Limited (AWI) commissioned three cross-sectional surveys of sheep producers' sheep parasite control practices over a 15-year period from 2003 to 2018. The aims were to document current sheep parasite incidence and control practices, to measure change in sheep parasite control practices over time and to inform extension messages for sheep industry advisors and sheep farmers. The surveys were conducted in 2004, 2012 and 2019 measuring sheep parasite control practices in the years 2003, 2011 and 2018.

Prevalence and pathology of liver fluke (Fasciola hepatica) in fallow deer (Dama dama).

A survey conducted on fallow deer (n = 79) in northern New South Wales Australia, aimed to ascertain the prevalence and gross pathology of liver fluke. In total, three deer populations were assessed (1 farmed and 2 wild) across 2 sites (site A and B) by conducting total fluke counts in the liver and fluke egg counts in faecal samples. At site A, 16 of 19 farmed deer (84.

Diarrhoea associated with gastrointestinal parasites in grazing sheep.

Diarrhoea is a common, widespread and frustrating reality for sheep enterprises in most sheep producing regions globally and of particular concern in Australia as the major risk factor for breech flystrike. Parasitic disease has long been recognised as an important factor in diarrhoea in sheep, particularly the gastrointestinal nematodes (Trichostrongylus and Teladorsagia species). This review focuses on the role of parasitic infections in causing diarrhoea in sheep, with emphasis on the epidemiology of diarrhoea outbreaks related to worms and opportunities to manage the risk of diarrhoea outbreaks in sheep related to parasitic infections.

Which is the best phenotypic trait for use in a targeted selective treatment strategy for growing lambs in temperate climates?

Targeted selective treatment (TST) requires the ability to identify the animals for which anthelmintic treatment will result in the greatest benefit to the entire flock. Various phenotypic traits have previously been suggested as determinant criteria for TST; however, the weight gain benefit and impact on anthelmintic efficacy for each determinant criterion is expected to be dependent upon the level of nematode challenge and the timing of anthelmintic treatment. A mathematical model was used to simulate a population of 10,000 parasitologically naïve Scottish Blackface lambs (with heritable variation in host-parasite interactions) grazing on medium-quality pasture (grazing density=30 lambs/ha, crude protein=140g/kg DM, metabolisable energy=10MJ/kg DM) with an initial larval contamination of 1000, 3000 or 5000 Teladorsagia circumcincta L3/kg DM.

The specific diagnosis of gastrointestinal nematode infections in livestock: larval culture technique, its limitations and alternative DNA-based approaches.

The specific diagnosis of gastrointestinal nematode infections in ruminants is routinely based on larval culture technique and on the morphological identification of developed third-stage larvae. However, research on the ecology and developmental requirements of different species suggests that environmental conditions (e.g.

Measurement of phenotypic resilience to gastro-intestinal nematodes in Merino sheep and association with resistance and production variables.

A cross-over experiment was conducted to compare six different phenotypic measures of resilience to gastro-intestinal nematodes (predominantly Haemonchus contortus) in Merino sheep and their association with resistance and production levels. On each of six farms, 120 ewes born in 2006 and 120 older mixed age ewes were selected at shearing in 2007. Of these, 60 in each mob were serially treated with long-acting anthelmintics to suppress worm populations.

Interaction between the effects of evaporation rate and amount of simulated rainfall on development of the free-living stages of Haemonchus contortus.

A factorial experiment (3 x 4 x 2 x 3) was conducted in programmable incubators to investigate interaction between the effects of rainfall amount, rainfall distribution and evaporation rate on development of Haemonchus contortus to L3. Sheep faeces containing H. contortus eggs were incubated on sterilised soil under variable temperatures typical of summer in the Northern Tablelands of NSW, Australia.

Moisture requirements for the free-living development of Haemonchus contortus: quantitative and temporal effects under conditions of low evaporation.

The key influence of moisture availability on development of the free-living stages of Haemonchus contortus is well-documented, although quantitative relationships between moisture variables and development are poorly defined. A factorial experiment (3x2x2) was conducted in programmable incubators to determine the effects of amount and distribution of simulated rainfall on H. contortus development at low evaporation rates (approximately 2 mm/day) under temperatures typical of summers on the Northern Tablelands of NSW, Australia.

The effects of amount, timing and distribution of simulated rainfall on the development of Haemonchus contortus to the infective larval stage.

Three studies were undertaken to determine the effects of amount, timing and distribution of simulated rainfall on the developmental success of Haemonchus contortus. Faeces containing H. contortus eggs were deposited onto pasture plots under a rainfall-activated retractable roof which eliminated incident rainfall.

Ecology of the free-living stages of major trichostrongylid parasites of sheep.

Significant developments over recent decades make it timely to review the ecology of the major gastrointestinal nematode (GIN) species of sheep. These include the relentless development and spread of anthelmintic resistance in all of the major sheep production regions of the world, and the consequent drive towards integrated parasite management (IPM) systems incorporating non-chemotherapeutic strategies such as grazing management. The success of such programs is dependent on a detailed understanding of the environmental influences on the free-living stages of the nematode lifecycle.