Managing the Growth of Weaner Cattle The impact of internal parasites and nutritional management on enterprise profitability
| Project start date: | 14 August 2009 |
| Project end date: | 30 January 2012 |
| Project status: | Completed |
| Livestock species: | Grass-fed Cattle |
| Relevant regions: | Southern Australia |
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Summary
Despite beef production expanding over the last decade into the most important grazing enterprise on the NSW tablelands and worms being identified as a major health issue for beef production, at the beginning of this PDS project we had little quantitative information on whether current worm control as practiced in the region was effective in eliminating production loss in well managed herds. Previous estimates were done during the 1970s prior to the release of the effective mectin drenches.
To update this situation, 6 group member herds were monitored in Year 1, by comparing the growth of worm-free heifers, produced by repeated treatment with long acting macrocyclic lactone (mectin) drenches, with heifers treated with the latest drenches and worm control practices. As a result of this, in Year 2, a modified strategic drenching program, applied at weaning, was evaluated.
The results of this PDS will be of immediate benefit to the group as well as the local and wider southern beef industry. Similar production losses are likely to be occurring across the industry and the project results highlights the need for producers to control the impact of worms in the immediate post weaning period without compromising the effectiveness of the mectin drench family. Because of this, further demonstrations of the use of other drench classes in combination with worm safe pastures would be worthwhile.
Objectives
The objectives of this project were to have:
• 2 drops of heifers across 6 herds monitored to confirm the increased growth from better control of internal parasites, and have a total of 12 district herds assessed for the presence of drench resistance
• 10 group members complete cost of production and production benchmarking workshops with the aim of providing the skills to group members to determine the benefit of these strategies to the profitability of their beef production businesses.
Progress
Undrenched weaner heifers were 60 kg lighter than the suppressed weaners 12 months after weaning, while the heifers drenched using normal commercial practice with short acting drenches were 30 kg lighter than the suppressed weaners at the same time.
This difference had developed by 6 months pw suggesting that the developing immune system can effectively control worms after about 12 months of age.
Improving worm control in the 6 months after weaning by a single treatment with a long acting mectin drench recouped these losses.
While WECs and plasma pepsinogen levels were elevated in worm affected heifers these indicators were low and would be difficult to use as predictors of the need to drench. Hence generic strategic drenching recommendations would be more useful for tablelands beef producers than tactical drenching following monitoring.
