scholarly journals Dieldrin and Diazinon Resistance in Populations of the Australian Sheep Blowfly, Lucilia cuprina, from Sheep-grazing Areas and Rubbish Tips

1984 ◽  
Vol 37 (6) ◽  
pp. 367 ◽  
Author(s):  
JA McKenzie

Populations of L. cuprina collected from adjacent sheep-grazing areas and rubbish tips in Victoria (Mansfield and Warrnambool) and New South Wales (Lismore) were tested for resistance to the insecticides diazinon and dieldrin. Populations from sheep-grazing areas had a significantly higher diazinon Rop-l allele frequency than those from adjacent tips with the Victorian populations being more resistant than those from Lismore. Victorian sheep and tip populations had similar gene frequencies at the dieldrin resistance locus, but the Rdl allele frequency was significantly greater in the population at the tip than in the population from the sheep-grazing area at Lismore. The Rdl allele is at a higher frequency in flies from the Lismore area than in Victorian populations. The results at both loci are explained by a balance of selection and gene flow between sheep and tip populations and by selective differences between geographical areas.

2015 ◽  
Vol 191 ◽  
pp. 504-511 ◽  
Author(s):  
Katie O'Connor ◽  
Michael Powell ◽  
Catherine Nock ◽  
Alison Shapcott

1974 ◽  
Vol 25 (2) ◽  
pp. 339 ◽  
Author(s):  
AD Wilson

The water consumption and water turnover of Merino sheep grazing on three natural pastures of south-western New South Wales were recorded throughout 1 year, and supplementary data on the water consumption of sheep on some pastures were collected for a further 2–4 years. On Danthonia caespitosa grassland, water was consumed for up to 7 months each year over the summer months. Maximum intakes were 3–3.5 litres per sheep per day, but this was reduced for 1–2 weeks after falls of rain of less than 25 mm and for longer periods after heavier falls. The provision of shade reduced water turnover by a maximum of 0.3–0.5 litre per day on some occasions only, which indicates that shade is of little importance to woolled sheep. On the saltbush (Atriplex vesicaria) and belah-rosewood (Casuarina cristata-Heterodendrum oleifolium) communities, water intakes were up to 6–7 litres per day in summer. In the particularly dry summer of 1972–73, water intakes of the sheep on saltbush rose to 12 litres per day for several months. The higher water intakes of these sheep were attributed mainly to the high mineral content of the Atriplex and Bassia spp. eaten by them, although the sheep on the belah-rosewood community were also in a hotter environment. In contrast to the sheep on Danthonia, those on the bush communities consumed significant amounts of water throughout the winter in years of low rainfall.


2002 ◽  
Vol 42 (5) ◽  
pp. 571 ◽  
Author(s):  
W. M. Kelman ◽  
G. M. Lodge ◽  
R. A. Culvenor

Successful seedling recruitment events in sparse stands of the grass Phalaris aquatica (phalaris) are rare. A major contributing factor to this situation is the seed-harvesting activity of ants. In recently developed cultivars of phalaris, the seed is retained within the glumes of the floret and is shed in a seed-retaining panicle fragment. We tested the hypothesis that seed contained in panicle fragments was less likely to be harvested by ants than naked seed and that this would be reflected in increased seedling recruitment. Observations of ant seed-harvesting activity and records of seedling recruitment following dispersal of seed and panicle fragments onto field plots were made at Canberra, Australian Capital Territory, and Tamworth, New South Wales, over 2 years. In the second year, the effects of 2 pasture renovation treatments (sheep-grazing and shallow-discing) on seedling recruitment from seed and panicle fragments were examined. Averaged over the 2 localities, 4% of large-sized (>10�florets), 13% of medium-sized (5-10 florets) and 27% of the small-sized (2 or 3 florets) panicle fragments were harvested in a 24 h period by ants (mainly Pheidole spp.), compared with 83% of the naked phalaris seed. The effects of panicle fragment size on recruitment were variable depending on site in the first year and the interaction of site and renovation treatments in the second year, but contrary to expectation, recruitment often was not higher in panicle fragment treatments than in seeded treatments. Seedling recruitment at Canberra (a hardsetting sandy loam) was lower (22 plants/m2 from naked seed and 15 plants/m2 from seed in panicle fragments) because of the competition from existing vegetation and germination of subterranean clover from the seedbank, than at Tamworth (a self-mulching red chromosol; 179 plants/m2 from naked seed and 118 plants/m2 from seed in panicle fragments), where seedling recruitment was also significantly increased by the sheep-grazing renovation treatment. At Tamworth, a larger seedbank was recovered from plots of oversown panicle fragments compared with plots oversown with naked phalaris seed. This suggested that protection of seeds in panicle fragments over the summer months on the Tablelands of New South Wales would increase the time over which phalaris seeds are available for recruitment. Further work is needed to test seedling recruitment in panicle shattering v. non-shattering phalaris populations and to define the conditions under which the seedbank contained in the panicle fragments can be exploited to improve stand persistence.


2016 ◽  
Vol 64 (6) ◽  
pp. 402 ◽  
Author(s):  
S. Dennison ◽  
G. J. Frankham ◽  
L. E. Neaves ◽  
C. Flanagan ◽  
S. FitzGibbon ◽  
...  

Habitat loss and fragmentation are key threats to local koala (Phascolarctos cinereus) populations. Broad-scale management is suboptimal for koalas because distribution models are not easily generalised across regions. Therefore, it is imperative that data relevant to local management bodies are available. Genetic data provides important information on gene flow and potential habitat barriers, including anthropogenic disturbances. Little genetic data are available for nationally significant koala populations in north-eastern New South Wales, despite reported declines due to urbanisation and habitat loss. In this study, we develop 14 novel microsatellite loci to investigate koala populations in north-eastern New South Wales (Port Macquarie, Coffs Harbour, Tyagarah, Ballina) and south-eastern Queensland (Coomera). All locations were significantly differentiated (FST = 0.096–0.213; FʹST = 0.282–0.582), and this pattern was not consistent with isolation by distance (R2 = 0.228, P = 0.058). Population assignment clustered the more northern populations (Ballina, Tyagarah and Coomera), suggesting contemporary gene flow among these sites. For all locations, low molecular variation among (16%) rather than within (84%) sites suggests historical connectivity. These results suggest that koala populations in north-eastern New South Wales and south-eastern Queensland are experiencing contemporary impediments to gene flow, and highlight the importance of maintaining habitat connectivity across this region.


2014 ◽  
Vol 54 (6) ◽  
pp. 783 ◽  
Author(s):  
Angus J. D. Campbell ◽  
Annefleur Broekhuizen ◽  
Kimbal Curtis ◽  
Keith P. Croker ◽  
Ralph Behrendt ◽  
...  

A cross-sectional telephone survey of post-weaning sheep management and mortality was conducted involving 1410 farmers from across Australia. The average reported post-weaning mortality was 4.6%. Mortality was greatest in Queensland and Western Australia, and least in New South Wales, Victoria, and South Australia. Weaner mortality was also greater in the pastoral zone than in the sheep–cereals or high-rainfall zones. Overall, 44% of farms had mortality identified as ‘high’, exceeding the suggested benchmark of ≤4% per annum. High mortality was reported on 50% and 32% of farms with predominantly Merino and crossbred weaners, respectively. There was no statistically significant association between high mortality and the main month of lambing for a flock. Larger sheep flocks, flocks with a smaller proportion of weaners, and farms of smaller area were associated with a greater likelihood of high weaner mortality. The odds of high mortality in weaner flocks that were routinely separated according to bodyweight or condition score was half that of flocks that were managed as one group. Overall, 84% of farmers regularly provided supplementary feed to weaner sheep, but the kind of supplement offered and the proportions of farms routinely supplementing differed between states and sheep production zones. Only high-protein supplementary feeding was associated with lower odds of high mortality. This survey confirms that poor post-weaning survival remains a widespread issue for the Australian sheep industry but identifies farm and management factors associated with reduced weaner mortality.


2016 ◽  
Vol 362 ◽  
pp. 205-217 ◽  
Author(s):  
Mervyn Shepherd ◽  
David J. Lee

1981 ◽  
Vol 21 (111) ◽  
pp. 382 ◽  
Author(s):  
GM Lodge ◽  
BA Hamilton

A group of six-month-old Merino wether weaners was grazed from January to July 1977 on a natural pasture containing seeds of wiregrass (Aristida ramosa), corkscrew grass (Stipa variabilis), barley grass (Hordeum leporinum) and burrs of Medicago minima. The sheep were then removed from the natural pasture, shorn and grazed for a further 23 months on lucerne and oats pastures that were free of grass seed. The number and species of grass seeds and burrs in the wool, hide and carcases were measured to determine the levels of seed and burr contamination and the long-term fate of seeds entering the carcase. The highest number of seeds in the wool, hide and carcase of sheep grazing natural pasture were those of wiregrass. Numbers of seeds of this species per 100 cm2 ranged from 85 to 651 in the wool, 43 to 159 in the hide, and 1 to 8 in the carcase. Most of the grass seeds in the wool were located on the stomach and shoulders, while most of the burrs were on the hind legs and stomach. Percentages of grass seed were highest about the stomach area and shoulders for the hide and carcase, respectively. After the sheep were removed from the natural pasture, and grazed on lucerne and oats pastures for 23 months, the mean grass seed contents decreased by 81% in the hide and 83% in the carcase. Wiregrass seeds were the only seeds that penetrated the hide and remained in the carcase. Numbers of contaminating seeds decreased most rapidly within 6 months of the sheep being removed from the natural pasture. Over the experimental period no seed-free hides or carcases were observed.


2005 ◽  
Vol 45 (10) ◽  
pp. 1255 ◽  
Author(s):  
W. H. Johnston ◽  
P. S. Cornish ◽  
T. B. Koen ◽  
V. F. Shoemark

The productivity, carrying capacity and liveweight performance of wether sheep grazing pastures of Eragrostis curvula cv. Consol and Medicago sativa cv. Nova, which were also sown with annual grasses and Trifolium subterraneum, were compared under an intensive 4-paddock rotational grazing regime in a ‘put-and-take’ grazing experiment at Wagga Wagga, New South Wales from November 1993 to August 1996. The productivity of the pastures was broadly similar, with production peaks of >1000 kg/ha in winter and >3000 kg/ha in spring and summer in paddocks that had been spelled for 6 weeks. Although annual species contributed a high proportion of the total herbage mass in spring, over the remainder of the year, both pastures were dominated by their respective perennials. E. curvula maintained an average plant density of approximately 20 plants/m2. The density of M. sativa declined noticeably during the 3 years, and at the end of the experiment M. sativa plants in 1 replicate of the experiment were killed by rising groundwater and dryland salinity. The long-term average stocking rate of E. curvula and M. sativa pastures were similar (12.1 v. 12.5 sheep/ha) and both pastures were capable of sustaining high stocking rates for lengthy periods in spring and summer. Sheep grazing M. sativa tended to be heavier than animals grazing E. curvula, and they produced, on average, 1.1 kg (or 21%) more wool. However, M. sativa was more difficult to establish and its costs for weed and insect control were higher. Therefore, although it was more productive, it might not have been the most economically viable of the 2 pastures. The implications of the findings were discussed within a whole-farm context and it was concluded that E. curvula has a complimentary role to M. sativa for sowing on landscapes and in situations to which M. sativa is poorly adapted.


Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1586
Author(s):  
Kayla Kopp ◽  
Marta Hernandez-Jover ◽  
Susan Robertson ◽  
Angel Abuelo ◽  
Michael Friend

High lamb mortality rates reduce profitability and reduce the perceived animal welfare standards of the industry. This study aimed to understand producer knowledge of lamb mortality rates and causes of lamb mortality, and to investigate various practices and perceptions of producers that may contribute to lamb deaths. Postal and online surveys gathered data on Australian sheep producer’s knowledge and practices around lambing and management practices. Based on results, approximately 50% of producers estimated less than 10% mortality of lambs between birth and marking, compared to published data estimates of 20–25% mortality. Pre-lambing vaccination of ewes was not undertaken by 10–20% of producers. Ninety-six percent of producers vaccinated lambs; however, 17% of Merino and 23% of crossbred lamb producers only gave a single vaccination instead of the recommended initial vaccine and booster. The lower estimated mortality impacts producer’s perceived benefits of management strategies being undertaken. Research undertaken needs to be more effectively distributed to producers via extension services to ensure producers understand the causes of mortality. Important messages to convey to producers include the limited impact of predation in most cases and the total costs of lamb mortality on-farm.


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