Reproducing for parasite resistance in sheep - a spotless green methodology now being received by Australian sheep raise.


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Foundation on sheep generation and the issue of inside parasites ... It has been conceivable to breed sheep for imperviousness to a metazoan parasite ...
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Breeding for parasite resistance in sheep - a perfect green system now being embraced by Australian sheep raisers Laurie Piper CSIRO Livestock Industries Armidale NSW Australia

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Outline of Seminar Background on sheep generation and the issue of interior parasites Breeding for imperviousness to inside parasites: Research discoveries Technology exchange The future: "Practical control of inward parasites in sheep"

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Australian Livestock Production measurements Industry Production esteem 2000/01 Sheep $ 4055 m (30%)* Cattle $ 4555 m (34%) Pig meat $ 850 m (6%) Poultry meat $ 1339 m (10%) Milk $ 2681 m (20%) * Percentage of aggregate estimation of animals creation

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Australian Sheep Production insights

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Agricultural creation zones

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The expense of inner parasites to the fleece business ($million)

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Current parasite control techniques No viable antibodies Reliance on key dousing programs: Wormbuster (south-east QLD) Wormkill (northern NSW) Wormplan (VIC and TAS) Drenchplan (southern NSW) Crack and Wormwise (WA) Rotational munching with cows Limited utilization of rearing advances

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Prevalence of resistance (viability < 95%)

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Breeding for imperviousness to metazoan parasites Would it be conceivable ? interfacing genomes, hereditary variety in resistance of sheep and parasite, relative era interims Would it be ideal to breed for flexibility ? less test to the parasite yet would it be as successful as far as host efficiency ?

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Breeding for resistance in Merinos Beginning in 1973 - utilize direct larval test and fecal egg checks (eggs/gm) to appraise hereditary variety in resistance inside groups (Hc) By 1977 have sensible appraisals of heritability and hereditary connections with different qualities of financial significance In 1978 start choice trials went for showing reaction to choice (Hc and Tc) and making lines for immunology thinks about

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Breeding for resistance in Merinos Research discoveries: Differences amongst strains and runs (studs) Long term determination lines Including resistance in reproducing programs Benefits of safe sheep Resilience? Innovation exchange: The Nemesis program

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Strain Flock Within Flock Non-Genetic Sources of hereditary variety GFW MFD BW Worm resistance Compared to creation attributes, the contrasts amongst strains and studs are little for resistance. The hereditary contrasts for resistance are most prominent between creatures. Heritability around 0.25.

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1.0 0.8 0.6 0.4 0.2 FEC EBV 0.0 - 0.2 - 0.4 - 0.6 - 0.8 - 1.0 Sire Differences between sires in CPT There are expansive contrasts between sires in resistance Sires which are very safe may likewise have high generation

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Long term determination lines CSIRO choice lines built up in 1978: H. contortus T. colubriformis UNE "Brilliant Ram" group Hamilton determination lines (Victoria) Rylington Park line (West Australia) Estimated heritabilities range from 0.2 to 0.3

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Susceptible herd 40000 30000 Unselected group FEC (eggs/gram) 20000 Resistant herd 10000 0 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 Year of Birth Response in CSIRO H.c. choice lines With serious choice, it might be conceivable to decrease FEC in weaners by up to half in around 10 years

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Can the parasites react to the hereditary change in the host ? Parasites passaged through sheep from the defenseless and safe lines for 30 eras Relative infectivity of the two populaces of passaged parasites contrasted and control parasites in sheep from the helpless and safe lines No distinctions saw in infectivity between the three parasite populaces

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Including resistance in rearing projects Incorporating resistance in a formal reproducing target is troublesome: Hard to foresee the investment funds because of decreased treatment Production misfortunes hard to quantify Desired additions approach: Economic qualities for creation characteristics Specify accentuation to put on resistance (%)

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Genetic associations with generation Correlations in Australian Merinos: Clean wool weight 0.08 Fiber diameter - 0.05 Body weight - 0.21 Reproductive rate - 0.14 New Zealand comes about (Morris et al , 2000): Fleece weight Unfavorable Body weight Unfavorable Reproduction Favorable

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Index WORM50 WORM70 Selection by and by Selection on a generation list (INDEX) and on worm resistance (FEC EBV) can be made autonomously Alternatively, a file including worm resistance can be figured with moderate (WORM50) or high (WORM70) accentuation on resistance

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2000 1600 Large Bowel Worm 1200 Black Scour Worm FEC (eggs/gram) Small Brown Stomach Worm 800 400 0 Unselected weaners Resistant weaners Susceptible weaners Benefits of selecting for resistance Genetic imperviousness to worms can be distinguished by weaning age Resistance reaches out to various worm species

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6000 5000 Resistant group 4000 Unselected herd Lambing Fecal egg tally (epg) 3000 Susceptible group 2000 1000 0 Dry - 5 - 4 - 3 - 2 - 1 0 +1 +2 +3 +4 +5 Weeks Benefits of selecting for resistance Reduced field tainting amid lambing

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120 100 80 60 % of infective hatchlings on fields 40 20 0 Random Resistant Undrenched Drenched Pasture sullying is lessened extraordinarily by eating worm safe sheep instead of soaked creatures

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Year Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 Rep 6 Rep 7 Rep 8 Rep 9 Rep 10 1 3 2 3 3 4 3 5 3 6 3 7 3 8 3 9 3 2 10 2 3 2 3 2 11 2 3 1 3 2 3 2 12 1 2 1 3 1 3 2 13 1 2 0 1 0 3 1 2 0 1 14 1 0 1 0 2 1 0 1 15 0 1 0 2 1 0 1 16 0 2 0 17 0 1 0 18 0 1 0 19 0 20 0 Benefits of selecting for resistance: diminished recurrence of splashing

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Breeding for flexibility? Favorable circumstances: Simplicity No choice weight on the parasite Disadvantages: Very low heritability Unable to recognize generation and ailment alleles Possible bargains to creature wellbeing No epidemiological advantages

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Technology exchange: the Nemesis program Initiated in 1994 A system of raisers, fleece cultivators, counselors, and researchers Established to exchange research results to industry

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Nemesis structure 11 center ram reproducers who, by means of Woolmark subsidizing, get: FEC estimations on individual creatures EBV\'s for FEC, and sometimes, for creation qualities Advice on joining resistance into their rearing projects Over 600 raisers, fleece producers, guides, and researchers who get data by means of bulletins

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Traits recorded by Merino studs (overview comes about, n=200) Fleece weight 80.4% Fiber diameter 93.5% CV of fiber diameter 91.1% Body weight 39.8% Pedigree 69.1% Selection index 23.6% Estimated rearing values 23.6% Fecal egg counts 9.8%

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The future: Integrated Parasite Management "SCIPS" (Sustainable Control of Internal Parasites of Sheep): More insightful and incredibly decreased utilization of anthelmintics Breeding parasite safe sheep Improved touching administration Better sustenance and upgraded invulnerability of sheep Innovative herd administration

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SCIPS R,D & TT segments Improved symptomatic methods Improved learning and appropriation of maintainable control rehearses Computer based models: Decision bolster bundle to help woolgrowers and consultants National site Accelerated reception of Nemesis Education

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Conclusions It has been conceivable to breed sheep for imperviousness to a metazoan parasite The model of measuring reaction to direct test with the ordinary infective type of the parasite uncovered generous added substance hereditary variety We are going to utilize this model in another endeavor to breed sheep for imperviousness to the sheep blowfly

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