Summary
Tasmania started serioulsy promoting mulesing as a flystrike management tool in 1965. The small-scale hands-on learning field days resulted in the rapid development of a pool of skilled mulesing operators, many of whom were flock owners or managers. Within ten years half of the sheep in the state were being mulesed, and mulesing is now accepted as a management tool by most wool producers in Tasmania.
 
 

Summary
Although most members of the sheep industry currently defend surgical mulesing, there are strong indications that this position cannot be sustained in the medium to long term.

The industry must support a research and development program to enable an orderly retreat from surgical mulesing to non-surgical alternatives. In the short to medium term, non-genetic options can be used. Some of these will result in extra and on-going costs.

The long-term solutions should be based on an investment in permanent genetic solutions, as this will be cost effective to farmers in the long term. It is also likely to be the most advantageous option for public perception and consumer preferences.

This issue is very similar to integrated parasite management, where the short-term emphasis involves non-genetic solutions while there is a commitment to a longer-term genetic solution.
 
 

Summary
This paper reports a benefit-cost analysis of the value of mulesing to Australian sheep producers. It was estimated that the average Australian sheep producer receives a benefit of approximately $1.84 per sheep each year from mulesing their lambs. If flocks did not routinely mules their lambs, it was predicted that they would need a significant increase in on-farm labour. The high cost of this labour would necessitate the use of alternative preventative measures, mainly chemical treatments, to prevent flystrike. This would significantly increase the total chemical residue load in the Australian wool clip.
 
 

Summary
Forage plants which naturally contain condensed tannins have been under investigation for many years for their potential to ameliorate the impacts of intestinal parasites. Trials showed that lambs grazed on these forages developed fewer dags than lambs grazed on other herbages such as lucerne or pasture and in one case there was an associated reduction in flystrike prevalence. We review subsequent trials which confirmed that lambs grazed on birdsfoot trefoil, a condensed tannin-containing forage, developed fewer dags and suffered less from flystrike than lambs grazed on ryegrass / white clover. This occurred as long as the lambs grazed the birdsfoot trefoil for 7 or more days each fortnight. A series of extension / technology transfer trials on commercial sheep farms confirmed these findings with lambs grazed on pasture being 5 times more likely to be flystruck than lambs grazed on birdsfoot trefoil. Although these forages are expensive to grow and lack persistence farmer interest in them remains high. A number of options for integrating such forages into an integrated programme of flystrike management are proposed.
 
 

Summary
Fleece rot and body strike form a disease complex. The major components of resistance to body strike so far identified are wool and body conformation traits affecting susceptibility to fleece rot. The role of the host response in contributing to resistance to fleece rot and body strike is not clear, although the enhanced antibody responses to Pseudomonas aeruginosa seen in sheep selected for resistance to the disease complex may be important. The sporadic occurrence of body strike due to climatic variability necessitates indirect selection. Fleece rot has a high genetic correlation with body strike and is therefore a candidate for indirect selection; however, culling of sheep with fleece rot is already the industry norm. Thus indicator traits with higher prevalence or higher genetic correlation with body strike than is the case for fleece rot are needed to enhance rates of genetic improvement. Direct challenge with internal parasites has been a successful strategy for selecting sheep for resistance to internal parasites. It is unknown whether genetic variation occurs between sheep in survival and growth of larvae after eggs are deposited on the sheep. This question should be investigated to establish whether there is scope for selection for resistance to body strike independently of fleece rot. Applying contemporary molecular genetic techniques such as gene expression arrays to sheep with variability in resistance to fleece rot or larval survival and growth may lead to identification of gene markers for resistance.
 
 

Summary
The frequency of flystrike on specific sites (breech, body and poll) was investigated in 16-month hoggets from a selection experiment with South African Merinos. Lines that were involved were selected for an increased fleece weight, against reproduction failure and for a reduced fibre diameter. A Control line where no directed selection was done was maintained together with the selection lines. Data were obtained for 2 progeny groups, born in 1998 and 1999. Line differences in fleece and body traits were in correspondence with the selection objectives strived for. The clean fleece weight of progeny in the Fleece Weight line was 24% higher (P<0.05) than that of the Control line. Fibre diameter in the Fine wool line was approximately 9% finer (P<0.05) than in the other lines. The Wet and Dry line were plainer (P<0.05) with regard to fold development than the other lines, except the Fine wool line. No significant differences were found between lines for either breech, body or poll strike (the latter was assessed only in ram hoggets born during 1999). When data for the three selection lines were pooled, a lower proportion of selection line hoggets was affected by combined breech and/or body strike than control group contemporaries (0.125 vs. 0.189; P<0.05). Clean fleece weight and staple strength were compromised (P<0.05) in animals affected by body strike. Subjective scores for wool quality, regularity of crimp, wool colour and underlines were lower (P<0.05) in animals that suffered from body strike than in contemporaries that were not affected. In the case of breech strike, these relationships were not as clear, and differences (P<0.05) were only found for regularity of crimp and staple formation.
 
 

Summary
This review describes research projects conducted currently by NSW Agriculture targeted at the development of Merino breeding programs for commercial producers and ram breeders that incorporate flystrike resistance. Outcomes from these projects will include additional information on the mode of inheritance of flystrike resistance and the development of integrated breeding programs for resistance. Projects are planned to: estimate genetic differences in fleece rot resistance from industry sources; estimate genetic parameters involving resistance to body strike and fleece rot resistance; describe selection responses in body strike and fleece rot resistance; identify markers for major genes for resistance; evaluate different strategies to include resistance in Merino breeding programs; and evaluate the use of marker-assisted selection for resistance in Merino breeding programs. Existing technology transfer initiatives are also described.
 
 

Summary

• Breeding Objectives. Ram breeders need to be assisted to include body strike and fleece rot resistance in their breeding objectives. The ability of different methods (economic analysis, desired gains) of including these disease traits into breeding objectives needs study. Wider access is needed to advisers with the skills and software to assist ram breeders to set personalised breeding objectives that include body strike and fleece rot resistance.
• Genetic evaluation and prediction of selection responses. A more complete set of genetic parameters is needed (further information on the genetic correlation between the disease traits and the major production traits and indicator traits under natural conditions) to allow estimation of breeding values for body strike and fleece rot resistance and the prediction of response to selection.
• Monitoring of genetic progress and identification of superior sires. Ram breeders need to be encouraged and assisted to be involved in sire evaluation at a suitable level to enable genetic progress in body strike and fleece rot resistance to be monitored. Better reporting of fleece rot information recorded in Central Test Sire Evaluation is needed to allow the identification of superior sires in fleece rot and body strike resistance.

Summary

• Breeding objectives. Commercial producers need to be able to understand and set specific breeding objectives that include flystrike resistance. Wider access is needed to advisers with the skills to assist commercial producers in setting breeding objectives.
• Bloodline performance in fleece rot resistance. Information is needed on comparative bloodline performance in fleece rot resistance to allow commercial producers to meet their objectives. Wether comparisons should be encouraged and assisted to record routinely information on fleece rot. Statistical methods need to be developed that allow the inclusion of fleece rot information into the combined wether comparison analyses.

Evaluation of progress in ram sources. Improved availability and quality of information on breeding objectives and rates of progress in fleece rot and flystrike resistance from ram breeders; commercial producers need to be able to interpret and assess this information. Increased ability of advisory services to assist producers to identify suitable bloodline options for the selection of flock rams to breed for fleece rot and flystrike resistance.