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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. The surveys focused on incidence and control of the three major sheep parasite groups; gastrointestinal nematodes, blowflies and lice. The 2003 and 2011 surveys were paper-based and the 2018 survey was accessed via a link to an online survey. This article is the first in a series of four presenting the results of the three surveys and will cover methods, demographics, production systems and general parasite management. Response rates to the surveys declined each year from the peak response rate in 2003 (n = 1365 in 2003; n = 575 in 2011 and n = 354 in 2018). Mean reported rainfall was significantly lower in 2018 (407 mm) than in 2003 (611 mm) and 2011 (650 mm). The demographics of the respondents and their production systems were largely similar between the three surveys for respondent age, median property size, income from wool and sheep meat, proportion of the property area cropped, median sheep dry sheep equivalent (DSEs), ewes as a proportion of the total flock and median cattle DSEs. Month of weaning was more likely to be in summer months for summer dominant rainfall areas and spring for intermediate and winter dominant rainfall areas. There was a marked increase in the proportion of respondents asking for an animal health history when introducing sheep to their flock from 2011 (9%) to 2018 (65%). Similarly, a greater proportion of respondents isolated introduced sheep for at least 2 weeks in 2018 (82%) compared with 2011 (19%). However, there was a decrease in the use of a quarantine lice treatment for introduced sheep from 2011 (50%) to 2018 (21%). Farmers rated themselves, other farmers or member of their staff as most important sources of information on parasite control in both 2011 and 2018. There was a significant increase in the proportion of respondents visiting the ParaBoss suite of websites from 2011 to 2018 confirming their growing importance for information delivery and decision support.

The sheep body louse (Bovicola ovis) is a parasite of major economic concern in Australia. This article reports lice incidence and control practices on Australian sheep farms as determined by three cross-sectional surveys of the years 2003, 2011 and 2018. The incidence of live lice detected within a flock was similar across the survey years with a slight decline in 2018 (2003: 20%, 2011: 18.6% and 2018: 13.9%). In an average year, most farmers did not see any direct or indirect evidence of lice infestation (2011: 59.3% and 2018: 69.5%), however, over a five-year period 38.9% (2003), 66.3% (in 2011) and 55.8% (in 2018) reported seeing evidence of lice infestation at least once with significant variation between sheep producing regions in 2011. In an average year, nearly three quarters of respondents treated for lice (2011:73.5% and 2018: 73.3%) with the majority treating immediately following shearing and very few treating sheep with long wool. Even higher percentages treated for lice at least once in the preceding five-year period (2011: 86.2% and 2018: 87.5%). Backliner was the most popular method of chemical application for lice control in sheep off-shears or with short wool (2003: 77%, 2011: 73% and 2018: 74.3%). For long wool treatments, hand jetting declined in popularity from 2003 (64%) to 2011 (54%) and 2018 (8.6%) as backliners became more popular (2003: 36%, 2011: 51% and 2018: 60%). The use of benzoylphenyl urea insect growth regulators (IGR) for off-shears/short wool treatment declined from 2003 (92.8%) to 2011 (51%) and 2018 (2.9%) and were largely replaced by neonicotinoids and spinosad for backliner/spray-on products. The use of organophosphates declined for plunge dipping (2003: 83.8%, 2011: 83% and 2018: 7.7%). Spinosad use for plunge dipping off-shears/short wool increased over the survey years (2003, 0%, 2011: 9% and 2018:46.2%). The use of IGRs declined for backliner application on long wool and were mainly replaced by spinosad in 2011 and 2018. Fewer respondents reported suspected resistance to lice control products in 2018 (8%) compared with 2003 (26%) and 2011 (13%) with most reporting suspected resistance to IGR and synthetic pyrethroids and emerging suspicions of resistance to neonicotinoids in 2018. Resistance to lice control products also reduced in importance as a reason for recurring lice infestations between 2011 (ranked 2nd) and 2018 (ranked 6th). Biosecurity was important to sheep producers with the highest ranked reason for recurring lice infestations being from stray or purchased sheep.

Cross-sectional surveys of sheep parasite control practices in Australia were conducted in 2004, 2012 and 2019 to document parasite problems, control practices and measure change over time. This article reports the results pertaining to gastrointestinal nematode infection; comparisons between years are mostly descriptive and not based on statistical inference. There was a general increase in the use of grazing management to prepare clean pastures for sheep to control gastrointestinal nematode infections with the largest increases in the use of: cropping, long acting anthelmintics to prepare clean pastures, feeding strategies, selecting rams for resistance to nematodes, and leaving some sheep untreated. The proportion of respondents using faecal worm egg count monitoring (WEC) and the number of WEC monitors per year were similar in 2003 (weaners: 3.0 WEC/year, adult ewes: 2.6 WEC/year) and 2018 (lambs and weaners and adult ewes both 3.1 WEC/year) but lower in 2011(lambs and weaners: 2.0 WEC/year, adult ewes: 2.9 WEC/year), whilst there was a higher number of anthelmintic treatments given in 2011 than 2003 and 2018 which were similar. There was an increase in the proportion of respondents carrying out WEC monitors themselves from 2011 (21%) to 2018 (30%) and a corresponding reduction in the use of private laboratories, government laboratories and veterinarians with regional differences in who carried out WECs. The top three anthelmintic groups used did not differ between the three survey years with macrocyclic lactones the most used followed by benzimidazoles (BZ) and levamisole (LEV) although the percentage of MLs used in 2011 and 2018 was lower than in 2003 with higher proportions of respondents using BZ and LEV groups in the latter two survey years. Moxidectin was in the most commonly used active in all survey years. There was an increase in the use of combination of anthelmintics from different groups, especially for a combination of three anthelmintics (2003: 4.4%, 2011: 19.1%, 2018: 21.5%), with lower use of single anthelmintics in 2011 (57.0%) and 2018 (55.4%) compared with 2003 (74.5%). The use of testing for anthelmintic resistance was generally low across the survey years with a lower proportion of respondents using tests in 2011 and 2018 than in 2003 (2003:48%, 2011: 29%, 2018: 37%). Time of year, results from WEC and seasonal weather condition were the most important factors when deciding when to apply anthelmintic treatment.

Context The third Australian national survey on control practices for internal and external parasites of sheep, following similar surveys in 2003 and 2011. Aims To document current parasite control practices and attitudes, measure change and to provide a benchmark against which to assess future practices and attitudes. Methods An online survey emailed to 6460 sheep producers, with a paper version supplied on request. A follow up short survey was conducted to assess non-response bias. Analysis by region and key sheep enterprise. Key results There were 354 and 250 useable responses to the main and short surveys respectively. Mean reported rainfall of 407 mm in 2018 was 27% lower than the average for respondents and >200 mm lower than mean reported rainfall in the previous surveys. The top three methods for worm control over the past 5 years were preventative treatments (74%), preparing clean pastures by spelling paddocks (62%) and treatment on the basis of faecal worm egg count (WEC, 54%). The proportion of respondents using WEC monitoring in 2018 was 40.4%, with a mean frequency of 3.1/year, and this was unaffected by sheep class. The frequency of anthelmintic treatment for ewes and lambs and weaners was 2.1/year. Of the respondents, 36.7% had performed an anthelmintic resistance test in the previous 5 years. The most popular flystrike control methods were timing of crutching (76.4%), preventative chemical treatment (75.9%), timing of shearing (63.1%), mulesing (46.8%) and genetic selection (46.4%). Pain relief was widely used for mulesing ewes (86.6%) and wethers (90.9%). Only 17.3% used Australian Sheep Breeding Values for traits in rams. Most respondents reported ‘evidence of lice’ in the past 5 years (55.8%) and had treated for lice off shears (50.1%), short wool (16.6%) or long wool (6.6%), with only 26.7% having not treated at all in the period. Web-based sources of information on parasite control have become increasingly important. Conclusions Notable changes since the earlier surveys were high rates of pain relief when mulesing, an increase in the use of Australian Sheep Breeding Values for parasite-related traits, an increase in WEC monitoring since 2011 and an increased use of web-based resources. Implications Parasite control remains important for sheep producers and continues to evolve with new drugs and approaches. The surveys highlight the effectiveness of extension networks and identify where more attention is required.

We have previously reported marked reductions in faecal worm egg counts (WECs) and drenching frequency in sheep on an intensive rotational grazing system (IRG) in a cool temperate environment with summer-dominant rainfall. These experiments were designed to determine the role of the host and environmental factors in mediating this. The role of host factors was investigated by administering a fixed larval challenge in each of the 4 seasons of the year to groups of 20 young sheep on three different management systems, including IRG. This comprised a mixed larval challenge containing infective larvae of Haemonchus contortus and Trichostrongylus colubriformis 7 days after short-acting anthelmintic treatment. A range of measurements was then made up to day 35 post-challenge. The role of environmental factors was determined by assessing pasture infectivity in four seasons using faecal worm egg counts (WECs) and pooled faecal culture of worm-free tracer sheep. The management systems were high input (HI) with high fertiliser inputs high stocking rate and relatively long grazing periods; typical New England management system (TYP) with moderate fertiliser inputs and stocking rate and relatively long grazing periods and; Intensive rotational grazing (IRG) with moderate fertiliser inputs and stocking rate but very short (mean 5 days) grazing periods and long (mean 103 days) rest periods. IRG sheep had higher mean WEC at 28 and 35 days after fixed larval challenge than HI and TYP sheep in spring (IRG: 9500 ± 1000; HI: 4000 ± 1000; TYP: 7200 ± 1000 eggs/g, P0.01) and summer (IRG: 8400 ± 750; HI: 5300 ± 800; TYP: 4400 ± 700 eggs/g; P0.001) and also had lower live weights during these seasons. There was no difference in WEC after the autumn challenge (IRG: 5100 ± 450 HI: 4500 ± 450; TYP: 4200 ± 450 eggs/g; P ≈ 0.36) but IRG had lower WEC than TYP following the winter challenge (IRG: 2900 ± 400; HI: 2300 ± 400; TYP: 4300 ± 400 eggs/g, P0.01). The tracer sheep (used to determine pasture infectivity) on IRG had significantly lower WECs during winter, spring and summer than those under the other management systems. Faecal culture and larval differentiation revealed that faeces from tracers on IRG contained significantly lower proportions of H. contortus and significantly higher proportions of Trichostrongylus spp. and Teladorsagia circumcincta than faeces from tracers on the HI and TYP treatments. Thus, when IRG was most efficacious for worm control, during spring and summer when short graze and long rest periods were maintained, sheep on this system exhibited greater susceptibility to larval challenge while tracer sheep indicated lower pasture infectivity. This demonstrates that the effects of IRG on WEC are mediated by reduced larval challenge rather than increased host resistance to infection.

While rotational grazing methods have an accepted role in the management of gastrointestinal nematodosis (GIN) of small ruminants in humid tropical regions, their efficacy and application in cool temperate regions is more controversial. This study evaluated GIN over 2 years in three classes of fine wool Merino sheep (lambs, hoggets and ewes) under three different sheep management systems in a cool tableland environment near Armidale NSW Australia (950m altitude, 30 degrees 31'S, 151 degrees 39'E). The management systems were High input (HI) with high fertiliser inputs, a target of 100% sown pasture, high stocking rate (13.4 dry sheep equivalents/ha) and relatively long grazing periods; Typical (TYP) New England management system with moderate fertiliser inputs and stocking rate (9.3DSE/ha) and relatively long grazing periods; and Intensive rotational grazing (IRG) with moderate fertiliser inputs and stocking rate (8.8DSE/ha) but very short (mean 5 days) grazing periods and long (mean 103 days) rest periods. Twenty sheep of each class in each management treatment were sampled monthly for faecal worm egg counts (WEC, followed by larval differentiation), and body weights with a blood sample taken for haematology every second month. The proportion of sheep with WEC above zero did not differ between management systems but the magnitude of WEC did, with sheep under IRG displaying lower mean WEC than those on the other treatments (IRG: 326, HI: 594, TYP: 536, eggs/g P0.0001). This was despite a significantly longer mean interval between anthelmintic treatments (IRG: 144 days, HI: 77 days, TYP: 78 days, P0.0001). The IRG management system also influenced the composition of the infections with sheep on this treatment having a significantly lower proportion of Haemonchus contortus in their faecal cultures (IRG: 59.7%, HI: 79.4%, TYP: 80.9%, P0.05) and a significantly higher proportion of Trichostrongylus spp. Sheep on the IRG treatment also had a significantly higher haematocrit (HCT) than those on the other management systems. Despite the lower WEC and higher HCT, sheep under IRG also had significantly lower bodyweights and fleece weights overall, although this was only evident in sheep raised to adulthood prior to the experiment, not those raised during the 2-year experimental period. The results demonstrate that IRG systems with short grazing periods and long rest periods between grazing events can assist with control of GIN in cool temperate climates where H. contortus is the dominant parasite.

This paper reports changes in livestock weights recorded in a whole-farmlet experiment, which aimed to examine the profitability and sustainability of three different pasture and grazing management strategies. The assessment of liveweights was considered a key component of measuring the integrated effects of the farmlet-scale treatments. The three farmlets comprised a typical management regime, which employed flexible rotational grazing over eight paddocks with moderate soil fertility (farmlet B), a system based on the same grazing management and paddock number but with higher levels of sown pasture and soil fertility (farmlet A) and a farmlet with moderate soil fertility and intensive rotational grazing over 37 paddocks (farmlet C). Early in the experimental period, there were no significant differences between farmlets in the liveweight of any class of livestock. However, from the second year onwards, as the pasture renovation, soil fertility and grazing management treatments took effect, differences in liveweight between farmlets became more apparent and significant. The stocking rate, which was treated as an emergent property of each farmlet, reached a maximum annual average value after 5 years of 12.6, 8.5 and 7.7 dry sheep equivalents (dse)/ha on farmlets A, B and C representing 84, 113 and 51% of their respective target stocking rates which were 15, 7.5 and 15 dse/ha. The liveweights of ewes, both before joining and during pregnancy, varied with year and farmlet with those on farmlets A and B tending to be significantly heavier than those on farmlet C. From 2003 to 2006, liveweights were significantly (P < 0.001) affected by a wide array of factors and their interactions including: date, ewe age, green digestible herbage, legume herbage mass, proportion of farmlet grazed, stocking rate and level of supplementary feeding. The weights of lambs/weaners/hoggets, both pre- and post-weaning, were at times also higher on farmlets A and B compared with those on farmlet C and were affected by a similar range of factors to those which affected ewe weights. Similar relative differences also applied to the liveweights of the other livestock run on the farmlets, namely wethers and non-reproductive cattle. The results suggest that stocking rate was able to be increased towards the higher target of farmlet A due to the higher level of pasture renovation and soil fertility on that farmlet, which led to high liveweights per head as well as the higher stocking rate. However, as the stocking rate increased on farmlet A, the differences between farmlets in liveweight per head diminished and the need for supplementary feeding increased. In contrast, the intensive rotational grazing practised on farmlet C did not allow the farmlet to increase its stocking rate towards its higher target. It appears that the higher proportion of each of farmlets A and B grazed at any one time allowed all classes of livestock to reach higher liveweights per head than on farmlet C, due presumably to the greater proportion of those two farmlets grazed at any one time.

Managing infections of sheep with gastrointestinal nematode parasites (worms) and problems of resistance to anthelmintic treatments continue to be major challenges for graziers on the Northern Tablelands of New South Wales, Australia. The whole-farmlet study of grazing enterprises undertaken by the Cicerone Project tested the broad hypotheses that compared with typical management (farmlet B), internal parasites can be more effectively managed with improved nutrition (farmlet A) or by intensive rotational grazing (farmlet C). Further aims were to identify the major sources of variation in faecal worm egg count (WEC) over the 6-year period and to examine the efficacy of the various anthelmintic treatments used during the experiment. This paper describes the management of sheep worms at the whole-farmlet level during the experiment, and analyses data from the routine WEC monitoring (5644 records) and larval differentiation tests (322 records) carried out on behalf of the Cicerone Management Board and by a doctoral candidate. It complements more detailed investigations published elsewhere. Over the period from July 2000 to December 2006, worm infections in ewes, lambs, hoggets and wethers were, with some exceptions, successfully controlled on the farmlets through a combination of regular monitoring of WEC, treatment with a wide array of anthelmintics and grazing management. Farmlet C had lower mean WEC (444 epg) and annual anthelmintic treatment frequency (3.1 treatments/year) over the whole experimental period than farmlets B (1122 epg, 4.3 treatments/year) or A (1374 epg, 4.7 treatments/year). The main factors influencing WEC were the time since the last anthelmintic treatment, and the anthelmintic used at that treatment. The magnitude of these effects dwarfed those of climatic and management factors that might be expected to influence the epidemiology of gastrointestinal nematode infections via environmental or host-mediated mechanisms. Nevertheless management factors associated with stocking rate and grazed proportion (proportion of each farmlet grazed at any one time), and climatic indicators of both temperature and moisture availability had significant effects on WEC. The results show that, in a region with Haemonchus contortus as the major sheep nematode, improved host nutrition in a higher input system (farmlet A) did not provide more effective control of gastrointestinal nematodes than typical management (farmlet B); however, it was observed that gastrointestinal nematode control was no worse on farmlet A than on farmlet B in spite of farmlet A supporting a 48% higher stocking rate by later in the trial period (2005). The study provided strong support for the proposition that intensive rotational grazing (farmlet C) provides more effective control of gastrointestinal nematodes than typical management (farmlet B) as evidenced by significantly lower WEC counts and anthelmintic treatment frequency. Tactical worm control based on routine monitoring of WEC provided adequate control of worms on all three farmlets for much of the experimental period but failed to prevent significant spikes in WEC to values associated with significant production loss on multiple occasions, and significant ewe mortality on farmlets A and B on one occasion.

The Cicerone Project conducted a grazed farmlet experiment on the Northern Tablelands of New South Wales, Australia, from July 2000 to December 2006, to address questions raised by local graziers concerning how they might improve the profitability and sustainability of their grazing enterprises. This unreplicated experiment examined three management systems at a whole-farmlet scale. The control farmlet (farmlet B) represented typical management for the region, with flexible rotational grazing and moderate inputs. A second farmlet (farmlet A) also used flexible rotational grazing but had a higher level of pasture renovation and soil fertility, while the third farmlet (farmlet C) had the same moderate inputs as farmlet B but employed intensive rotational grazing. The present paper provides an integrated overview of the results collated from component papers and discusses the inferences that can be drawn from what was a complex, agroecosystem experiment. The measurements recorded both early and late in the experiment were tabulated for each of the farmlets and compared with each other as relative proportions, allowing visual presentation on a common, indexed scale. Because of equivalent starting conditions, there was little difference between farmlets early in the experimental period (2000–01) across a wide array of measured parameters, including herbage mass, potential pasture growth rate, liveweight, wool production per head, stocking rate, gross margin and equity. Although the experiment experienced drier-than-average conditions, marked differences emerged among farmlets over time, due to the effects of treatments. During the latter half of the experimental period (2003–06), farmlet A showed numerous positive and a few negative consequences of the higher rate of pasture renovation and increased soil fertility compared with the other two farmlets. While intensive rotational grazing resulted in superior control of gastrointestinal nematodes and slightly finer wool, this system had few effects on pastures and no positive effects on sheep liveweights, wool production or stocking rate. Whereas farmlet A showed higher gross margins, it had a negative and lower short-term cash position than did farmlets B and C, due largely to the artificially high rate of pasture renovation undertaken on this farmlet during the experiment. Although farmlet B had the highest cash position at the end of the experiment, this came at a cost of the declining quality of its pastures. Modelling of the farmlet systems allowed the results to be considered over the longer timeframes needed to assess sustainability. Thus, returns on investment were compared over realistic amortisation periods and produced outcomes based on long-term climatic expectations which were compared with those that arose under the drier-than-average conditions experienced during the experimental period. The main factors responsible for lifting the productivity of farmlet A were the sowing of temperate species and increased soil fertility, which enhanced the amount of legume and increased pasture quality and potential pasture growth. The factor that affected farmlet C most was the low proportion of the farmlet grazed at any one time, with high stock density imposed during grazing, which decreased feed intake quality. The paper concludes that more profitable and sustainable outcomes are most likely to arise from grazing enterprises that are proactively managed towards optimal outcomes by maintaining sufficient desirable perennial grasses with adequate legume content, enhancing soil fertility and employing flexible rotational grazing.