Targeted drenching of Adult Ewes
| Project start date: | 20 January 2011 |
| Project end date: | 30 September 2013 |
| Project status: | Completed |
| Livestock species: | Lamb |
| Relevant regions: | Southern Australia |
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Summary
Internal parasite control remains a major problem for lamb producers in South-west Victoria and elsewhere in southern Australia. For many years recommended best practice has stressed the importance of drenching the entire flock at strategic times of the year (especially in summer) to underpin an integrated worm control program that includes grazing rotation, preparation of low worm risk paddocks and improved nutrition.
The South West Prime Lamb Group Incorporated (SWPLG), developed this Producer Demonstration Site (PDS) to refine the practical application of targeted drenching (TD) in the hands of producers, identify pitfalls and determine whether it was likely to be acceptable as a significant change to current management practice.
The project has demonstrated that if mean flock worm egg count (WEC) is kept below a maximum level, worm control can be maintained with little impediment to production, and drenching, particularly in summer, reduced substantially.
Objectives
The objective of this PDS was to demonstrate that monitoring of ewe WECs, in conjunction with body condition scores and evidence of scouring, can lead to programs of targeted drenching of only a portion of mature ewe flocks and that this will adequately control the effects of parasitism in the flock and reduce pasture contamination with worms to acceptable levels.
Progress
Average drench reductions of 58% and 48% were achieved in 2010-2011 and 2011-2012, respectively, without identified production penalties.
Summer drenching was reduced by 63% and 49%, respectively. The second summer drench averaged across both seasons was reduced by 66%.
Producers either had or rapidly developed the skills required to implement TD on their properties.
TD of mature ewe flocks is not a worm control program in its own right. It is imperative that there is an established worm control program using effective drenches.
Producers still need to formally quantify losses potentially incurred in a conservative TD program and weigh them against the benefits of savings in drench costs and postponement of drench resistance. This may help to offset some entrenched convictions that TD is unsuitable for south-eastern Australia.
